Home » Public Forums » GMCnet » Re: [GMCnet] Cylinder Head Torque Value
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| Re: [GMCnet] Cylinder Head Torque Value [message #359470 is a reply to message #359469] |
Wed, 14 October 2020 23:38   |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
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Senior Member |
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I figure the engineers that designed the engines, in conjunction with the
gasket manufacturers know more about this than I do. So, I usually use
factory specifications if I am using factory style gaskets. But after
market gaskets sometimes have different specifications. I use them instead.
I always use a 3 step torquing procedure. 50% first round, 75% second
round, 100% on the third. I really prefer to use "permatorque" gaskets.
After inital warmup of a fresh engine, I leave the head torque alone. Just
what I was taught, and what I do. Others may have techniques that differ
from mine. O.K. by me.
Jim Hupy
Salem, Oregon
On Wed, Oct 14, 2020, 9:26 PM THOMAS R WHITTON via Gmclist <
gmclist@list.gmcnet.org> wrote:
> I want to torque the head bolts on my 455 engine. The book says to first
> torque in sequence to 60 foot pounds. Then, re-torque to 85 foot pounds.
> 85 foot pounds seems light to me. What torque do you engine rebuilders
> suggest?
> Thanks,Tom Whitton26 foot upgraded GMCPaducah, KY 42001
>
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| Re: [GMCnet] Cylinder Head Torque Value [message #359473 is a reply to message #359470] |
Thu, 15 October 2020 09:20 |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
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James Hupy wrote on Thu, 15 October 2020 00:38I figure the engineers that designed the engines, in conjunction with the gasket manufacturers know more about this than I do. So, I usually use factory specifications if I am using factory style gaskets. But after market gaskets sometimes have different specifications. I use them instead.
I always use a 3 step torquing procedure. 50% first round, 75% second round, 100% on the third. I really prefer to use "permatorque" gaskets.
After inital warmup of a fresh engine, I leave the head torque alone. Just what I was taught, and what I do. Others may have techniques that differ from mine. O.K. by me.
Jim Hupy
Salem, Oregon
James, please no offense intended, but as I was an engineer with McCord (RIP) for a few years as both the heavy duty and aftermarket guy, I can assure you that retorquing is always good.
What Permatorque (a registered trade mark of Fel-Pro (RIP)(was family owned and now a small part of Fegeral-Mogul), really was just a bet that the relaxation encountered in the assembly would not go critical. Every assembled joint will show some relaxation with time and temperature cycles (both just makes more). While it is a noble goal, gaskets need to have some compliance to perform as required. That compliance means that the material must crush to some extent. That crush is where the relaxation is actually in the favor of getting the joint to seal. Yes, even the multi-layer gaskets have some relaxation. (Actually, hard joins like main journals and connecting rods have some as well, but it is much less than a join with any sealing element included.
As the cylinder head covers of an assembled 455 are substantially not removable, I will advise that while sticking with the 85 top number, you try to let the engine sit a day and then come back and do another pull at that load. I will bet you that you do rotate at least some of the fasteners a few degrees. Those few degrees are FREE CLAMPING LOAD. This really good if you can do it after a (or several) thermal cycle(s).
What a fun experiment??
Get a bending beam torque wrench.
Put it on any fastener of a bolted joint and pull it about half load and picture where in space the end of the pointer is....
Pull it at load and watch how much the pointer moves.
It didn't move??
Now, crack it loose some. Did you feel the break-away?
Now pull it back to design load....
I bet you can see that the pointer has moved. Again, that is the free clamping load.
Technically, this is called a "Torque to Align" and it is a standard test used in the industry. We had the $5000 torque wrench to do this without guessing.
Matt - getting back to enjoying his replacement computer
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
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| Re: [GMCnet] Cylinder Head Torque Value [message #359474 is a reply to message #359473] |
Thu, 15 October 2020 09:45 |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
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Senior Member |
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Many engines today, "Particularly foreign made ones" use torque to yield
values. They intentionally stretch head bolts/studs to somewhere in the
middle of their maximum point of elasticity. That is the point where if you
exceed it, the length of the fastener will not return to somewhere close
to where it started out before you applied the tightening torque. Those
fasteners, once used, are supposed to be discarded and new fasteners used
in their place. In actual use, that hardly ever happens. And many head
gasket failures can be traced back to that.
I hate any gasket failure. We used to encounter the greatest number of
failures with steel gaskets, iron blocks, and aluminum heads. If everything
is not absolutely flat with the correct finish, steel gaskets eventually
fail. Then the builder gets a phone call from an irate customer. I have had
my share of those calls. I quit using steel gaskets because of them.
Ah yes, the great old line companies that got bought out by
mega-corporations that were more interested in the bottom line than
function. Too many sad stories to relate. Gaskets, rings, bearings, you
name it. Makes an engine rebuilder dream of palm trees, sandy beaches, beer
in the hand, toes in the water, ass in the sand.
Jim Hupy
Salem, Oregon
On Thu, Oct 15, 2020, 7:21 AM Matt Colie via Gmclist <
gmclist@list.gmcnet.org> wrote:
> James Hupy wrote on Thu, 15 October 2020 00:38
>> I figure the engineers that designed the engines, in conjunction with
> the gasket manufacturers know more about this than I do. So, I usually use
>> factory specifications if I am using factory style gaskets. But after
> market gaskets sometimes have different specifications. I use them instead.
>> I always use a 3 step torquing procedure. 50% first round, 75% second
> round, 100% on the third. I really prefer to use "permatorque" gaskets.
>> After inital warmup of a fresh engine, I leave the head torque alone.
> Just what I was taught, and what I do. Others may have techniques that
>> differ from mine. O.K. by me.
>> Jim Hupy
>> Salem, Oregon
>
> James, please no offense intended, but as I was an engineer with McCord
> (RIP) for a few years as both the heavy duty and aftermarket guy, I can
> assure
> you that retorquing is always good.
>
> What Permatorque (a registered trade mark of Fel-Pro (RIP)(was family
> owned and now a small part of Fegeral-Mogul), really was just a bet that the
> relaxation encountered in the assembly would not go critical. Every
> assembled joint will show some relaxation with time and temperature cycles
> (both
> just makes more). While it is a noble goal, gaskets need to have some
> compliance to perform as required. That compliance means that the material
> must crush to some extent. That crush is where the relaxation is actually
> in the favor of getting the joint to seal. Yes, even the multi-layer
> gaskets have some relaxation. (Actually, hard joins like main journals
> and connecting rods have some as well, but it is much less than a join with
> any sealing element included.
>
> As the cylinder head covers of an assembled 455 are substantially not
> removable, I will advise that while sticking with the 85 top number, you
> try to
> let the engine sit a day and then come back and do another pull at that
> load. I will bet you that you do rotate at least some of the fasteners a
> few
> degrees. Those few degrees are FREE CLAMPING LOAD. This really good if
> you can do it after a (or several) thermal cycle(s).
>
> What a fun experiment??
> Get a bending beam torque wrench.
> Put it on any fastener of a bolted joint and pull it about half load and
> picture where in space the end of the pointer is....
> Pull it at load and watch how much the pointer moves.
> It didn't move??
> Now, crack it loose some. Did you feel the break-away?
> Now pull it back to design load....
> I bet you can see that the pointer has moved. Again, that is the free
> clamping load.
>
> Technically, this is called a "Torque to Align" and it is a standard test
> used in the industry. We had the $5000 torque wrench to do this without
> guessing.
>
> Matt - getting back to enjoying his replacement computer
>
> --
> Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL,
> GMCES
> Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum
> Brakes with Applied Control Arms
> SE Michigan - Near DTW - Twixt A2 and Detroit
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
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| Re: [GMCnet] Cylinder Head Torque Value [message #359475 is a reply to message #359474] |
Thu, 15 October 2020 10:35 |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
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Senior Member |
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Never hurts to go back over and retorque as you will find that
sometimes one can encounter . Also there is a difference when the bolt
threads are slightly lubricated.
My feeling is that it does not hurt to check torque at least couple times.
Also the surfaces of the block and head need to be clean and surfaced
properly.
On Thu, Oct 15, 2020 at 7:46 AM James Hupy via Gmclist <
gmclist@list.gmcnet.org> wrote:
> Many engines today, "Particularly foreign made ones" use torque to yield
> values. They intentionally stretch head bolts/studs to somewhere in the
> middle of their maximum point of elasticity. That is the point where if you
> exceed it, the length of the fastener will not return to somewhere close
> to where it started out before you applied the tightening torque. Those
> fasteners, once used, are supposed to be discarded and new fasteners used
> in their place. In actual use, that hardly ever happens. And many head
> gasket failures can be traced back to that.
> I hate any gasket failure. We used to encounter the greatest number of
> failures with steel gaskets, iron blocks, and aluminum heads. If everything
> is not absolutely flat with the correct finish, steel gaskets eventually
> fail. Then the builder gets a phone call from an irate customer. I have had
> my share of those calls. I quit using steel gaskets because of them.
> Ah yes, the great old line companies that got bought out by
> mega-corporations that were more interested in the bottom line than
> function. Too many sad stories to relate. Gaskets, rings, bearings, you
> name it. Makes an engine rebuilder dream of palm trees, sandy beaches, beer
> in the hand, toes in the water, ass in the sand.
> Jim Hupy
> Salem, Oregon
>
> On Thu, Oct 15, 2020, 7:21 AM Matt Colie via Gmclist gmclist@list.gmcnet.org> wrote:
>
>> James Hupy wrote on Thu, 15 October 2020 00:38
>>> I figure the engineers that designed the engines, in conjunction with
>> the gasket manufacturers know more about this than I do. So, I usually
> use
>>> factory specifications if I am using factory style gaskets. But after
>> market gaskets sometimes have different specifications. I use them
> instead.
>>> I always use a 3 step torquing procedure. 50% first round, 75% second
>> round, 100% on the third. I really prefer to use "permatorque" gaskets.
>>> After inital warmup of a fresh engine, I leave the head torque alone.
>> Just what I was taught, and what I do. Others may have techniques that
>>> differ from mine. O.K. by me.
>>> Jim Hupy
>>> Salem, Oregon
>>
>> James, please no offense intended, but as I was an engineer with McCord
>> (RIP) for a few years as both the heavy duty and aftermarket guy, I can
>> assure
>> you that retorquing is always good.
>>
>> What Permatorque (a registered trade mark of Fel-Pro (RIP)(was family
>> owned and now a small part of Fegeral-Mogul), really was just a bet that
> the
>> relaxation encountered in the assembly would not go critical. Every
>> assembled joint will show some relaxation with time and temperature
> cycles
>> (both
>> just makes more). While it is a noble goal, gaskets need to have some
>> compliance to perform as required. That compliance means that the
> material
>> must crush to some extent. That crush is where the relaxation is
> actually
>> in the favor of getting the joint to seal. Yes, even the multi-layer
>> gaskets have some relaxation. (Actually, hard joins like main journals
>> and connecting rods have some as well, but it is much less than a join
> with
>> any sealing element included.
>>
>> As the cylinder head covers of an assembled 455 are substantially not
>> removable, I will advise that while sticking with the 85 top number, you
>> try to
>> let the engine sit a day and then come back and do another pull at that
>> load. I will bet you that you do rotate at least some of the fasteners a
>> few
>> degrees. Those few degrees are FREE CLAMPING LOAD. This really good if
>> you can do it after a (or several) thermal cycle(s).
>>
>> What a fun experiment??
>> Get a bending beam torque wrench.
>> Put it on any fastener of a bolted joint and pull it about half load and
>> picture where in space the end of the pointer is....
>> Pull it at load and watch how much the pointer moves.
>> It didn't move??
>> Now, crack it loose some. Did you feel the break-away?
>> Now pull it back to design load....
>> I bet you can see that the pointer has moved. Again, that is the free
>> clamping load.
>>
>> Technically, this is called a "Torque to Align" and it is a standard test
>> used in the industry. We had the $5000 torque wrench to do this without
>> guessing.
>>
>> Matt - getting back to enjoying his replacement computer
>>
>> --
>> Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL,
>> GMCES
>> Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum
>> Brakes with Applied Control Arms
>> SE Michigan - Near DTW - Twixt A2 and Detroit
>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
--
Jim Kanomata
Applied/GMC, Newark,CA
jimk@appliedairfilters.com
http://www.gmcrvparts.com
1-800-752-7502
_______________________________________________
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Jim Kanomata
Applied/GMC
jimk@appliedairfilters.com
www.appliedgmc.com
1-800-752-7502
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| Re: [GMCnet] Cylinder Head Torque Value [message #359482 is a reply to message #359475] |
Thu, 15 October 2020 14:22 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Senior Member |
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Strange to me that JimK's brief mention is the first discussion in this
thread of bolt thread lubrication vs torque...I, for one, would like to see
more on that subject from our experts.
Ken H.
On Thu, Oct 15, 2020 at 11:36 AM Jim Kanomata via Gmclist <
gmclist@list.gmcnet.org> wrote:
> Never hurts to go back over and retorque as you will find that
> sometimes one can encounter . Also there is a difference when the bolt
> threads are slightly lubricated.
> My feeling is that it does not hurt to check torque at least couple times.
> Also the surfaces of the block and head need to be clean and surfaced
> properly.
>
>
> On Thu, Oct 15, 2020 at 7:46 AM James Hupy via Gmclist gmclist@list.gmcnet.org> wrote:
>
>> Many engines today, "Particularly foreign made ones" use torque to yield
>> values. They intentionally stretch head bolts/studs to somewhere in the
>> middle of their maximum point of elasticity. That is the point where if
> you
>> exceed it, the length of the fastener will not return to somewhere close
>> to where it started out before you applied the tightening torque. Those
>> fasteners, once used, are supposed to be discarded and new fasteners used
>> in their place. In actual use, that hardly ever happens. And many head
>> gasket failures can be traced back to that.
>> I hate any gasket failure. We used to encounter the greatest number
> of
>> failures with steel gaskets, iron blocks, and aluminum heads. If
> everything
>> is not absolutely flat with the correct finish, steel gaskets eventually
>> fail. Then the builder gets a phone call from an irate customer. I have
> had
>> my share of those calls. I quit using steel gaskets because of them.
>> Ah yes, the great old line companies that got bought out by
>> mega-corporations that were more interested in the bottom line than
>> function. Too many sad stories to relate. Gaskets, rings, bearings, you
>> name it. Makes an engine rebuilder dream of palm trees, sandy beaches,
> beer
>> in the hand, toes in the water, ass in the sand.
>> Jim Hupy
>> Salem, Oregon
>>
>> On Thu, Oct 15, 2020, 7:21 AM Matt Colie via Gmclist > gmclist@list.gmcnet.org> wrote:
>>
>>> James Hupy wrote on Thu, 15 October 2020 00:38
>>>> I figure the engineers that designed the engines, in conjunction with
>>> the gasket manufacturers know more about this than I do. So, I usually
>> use
>>>> factory specifications if I am using factory style gaskets. But after
>>> market gaskets sometimes have different specifications. I use them
>> instead.
>>>> I always use a 3 step torquing procedure. 50% first round, 75%
> second
>>> round, 100% on the third. I really prefer to use "permatorque" gaskets.
>>>> After inital warmup of a fresh engine, I leave the head torque alone.
>>> Just what I was taught, and what I do. Others may have techniques that
>>>> differ from mine. O.K. by me.
>>>> Jim Hupy
>>>> Salem, Oregon
>>>
>>> James, please no offense intended, but as I was an engineer with McCord
>>> (RIP) for a few years as both the heavy duty and aftermarket guy, I can
>>> assure
>>> you that retorquing is always good.
>>>
>>> What Permatorque (a registered trade mark of Fel-Pro (RIP)(was family
>>> owned and now a small part of Fegeral-Mogul), really was just a bet
> that
>> the
>>> relaxation encountered in the assembly would not go critical. Every
>>> assembled joint will show some relaxation with time and temperature
>> cycles
>>> (both
>>> just makes more). While it is a noble goal, gaskets need to have some
>>> compliance to perform as required. That compliance means that the
>> material
>>> must crush to some extent. That crush is where the relaxation is
>> actually
>>> in the favor of getting the joint to seal. Yes, even the multi-layer
>>> gaskets have some relaxation. (Actually, hard joins like main journals
>>> and connecting rods have some as well, but it is much less than a join
>> with
>>> any sealing element included.
>>>
>>> As the cylinder head covers of an assembled 455 are substantially not
>>> removable, I will advise that while sticking with the 85 top number,
> you
>>> try to
>>> let the engine sit a day and then come back and do another pull at that
>>> load. I will bet you that you do rotate at least some of the
> fasteners a
>>> few
>>> degrees. Those few degrees are FREE CLAMPING LOAD. This really good
> if
>>> you can do it after a (or several) thermal cycle(s).
>>>
>>> What a fun experiment??
>>> Get a bending beam torque wrench.
>>> Put it on any fastener of a bolted joint and pull it about half load
> and
>>> picture where in space the end of the pointer is....
>>> Pull it at load and watch how much the pointer moves.
>>> It didn't move??
>>> Now, crack it loose some. Did you feel the break-away?
>>> Now pull it back to design load....
>>> I bet you can see that the pointer has moved. Again, that is the free
>>> clamping load.
>>>
>>> Technically, this is called a "Torque to Align" and it is a standard
> test
>>> used in the industry. We had the $5000 torque wrench to do this
> without
>>> guessing.
>>>
>>> Matt - getting back to enjoying his replacement computer
>>>
>>> --
>>> Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL,
>>> GMCES
>>> Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum
>>> Brakes with Applied Control Arms
>>> SE Michigan - Near DTW - Twixt A2 and Detroit
>>>
>>> _______________________________________________
>>> GMCnet mailing list
>>> Unsubscribe or Change List Options:
>>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>
>
>
> --
> Jim Kanomata
> Applied/GMC, Newark,CA
> jimk@appliedairfilters.com
> http://www.gmcrvparts.com
> 1-800-752-7502
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
_______________________________________________
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Unsubscribe or Change List Options:
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Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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| Re: [GMCnet] Cylinder Head Torque Value [message #359483 is a reply to message #359469] |
Thu, 15 October 2020 14:33 |
TR 1
Messages: 348
Registered: August 2015
Location: DFW
Karma: -7
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Senior Member |
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So I've always followed this rule of thumb when it comes to re-torqueing headbolts, etc.... However, I welcome any critique or suggestions regarding any of the following:
On Torque to Yield (TTY) bolts, torque them once and don't touch them again
On standard bolts, -OR- in instances where you've replaced TTY bolts with standard (For example, replacing the TTY head bolts on an LS engine with an ARP head stud kit) you should consider retorquing. For myself, I try to generally run an engine gently after any major repair to "run things in", then retorque the headbolts and anything else I can easily reach after a couple hundred miles or so. Once this is done, I feel better about running the engine harder.
I will also retorque standard head bolts any time I have a valve cover off, but generally, after that initial retorque, I will not open a valve cover for the express purpose of retorqueing...
If I'm reading what Matt and Jim are explaining above correctly, I believe that is essentially what they are explaining as well....
Now, I guess as a follow on, exactly how do you "retorque" a head properly? I've always started in the middle and backed out the fastener a quarter turn, then run it back up to spec... Working my way back out to the outside fasteners... Would this be the best way to do this?
Mark S. '73 Painted Desert,
Manny 1 Ton Front End,
Howell Injection,
Leigh Harrison 4bag and Rear Brakes,
Fort Worth, TX
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| Re: [GMCnet] Cylinder Head Torque Value [message #359485 is a reply to message #359482] |
Thu, 15 October 2020 14:53 |
TR 1
Messages: 348
Registered: August 2015
Location: DFW
Karma: -7
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Senior Member |
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Ken Henderson wrote on Thu, 15 October 2020 14:22Strange to me that JimK's brief mention is the first discussion in this
thread of bolt thread lubrication vs torque...I, for one, would like to see
more on that subject from our experts.
Ken H.
I do not consider myself an expert, but ARP supplies a "Torque Lube" with any of their bolt kits... Idea being the torque specs they provide in their instructions go with the coefficient of friction in their lube... Which makes sense if you think about it.... Lots of variability in how slippery various lubes, greases, etc. are....
https://www.amazon.com/ARP-100-9910-Torque-Assembly-Lubricant/dp/B004XJRFCK
Mark S. '73 Painted Desert,
Manny 1 Ton Front End,
Howell Injection,
Leigh Harrison 4bag and Rear Brakes,
Fort Worth, TX
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| Re: [GMCnet] Cylinder Head Torque Value [message #359486 is a reply to message #359485] |
Thu, 15 October 2020 15:20 |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
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Senior Member |
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Whenever there are more than 3/8" of thread, it does not matter the load at
each ridge, there is friction.
It is small, but cause the torque to be effected.
On Thu, Oct 15, 2020 at 12:54 PM Mark Sawyer via Gmclist <
gmclist@list.gmcnet.org> wrote:
> Ken Henderson wrote on Thu, 15 October 2020 14:22
>> Strange to me that JimK's brief mention is the first discussion in this
>> thread of bolt thread lubrication vs torque...I, for one, would like to
> see
>> more on that subject from our experts.
>>
>> Ken H.
>
> I do not consider myself an expert, but ARP supplies a "Torque Lube" with
> any of their bolt kits... Idea being the torque specs they provide in their
> instructions go with the coefficient of friction in their lube... Which
> makes sense if you think about it.... Lots of variability in how slippery
> various lubes, greases, etc. are....
>
> https://www.amazon.com/ARP-100-9910-Torque-Assembly-Lubricant/dp/B004XJRFCK
>
> --
> Mark S. '73 Painted Desert,
> Manny 1 Ton Front End,
> Howell Injection,
> Leigh Harrison 4bag and Rear Brakes,
> Fort Worth, TX
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
--
Jim Kanomata
Applied/GMC, Newark,CA
jimk@appliedairfilters.com
http://www.gmcrvparts.com
1-800-752-7502
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
Jim Kanomata
Applied/GMC
jimk@appliedairfilters.com
www.appliedgmc.com
1-800-752-7502
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| Re: [GMCnet] Cylinder Head Torque Value [message #359487 is a reply to message #359483] |
Thu, 15 October 2020 15:54 |
|
Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
|
Senior Member |
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TR 1 wrote on Thu, 15 October 2020 15:33<Snip>
If I'm reading what Matt and Jim are explaining above correctly, I believe that is essentially what they are explaining as well....
Now, I guess as a follow on, exactly how do you "retorque" a head properly? I've always started in the middle and backed out the fastener a quarter turn, then run it back up to spec... Working my way back out to the outside fasteners... Would this be the best way to do this?
Mark,
The fact that you are doing it matters far more than specficialy how you do it.
Rarely is back off required, but it is not a bad practice as it will redisrtibute the lubrication. Center out is good, but as it is often said that it is so the gasket came even itself out. If that were the case in an assembled joint with a hard gasket, you have way many more problems than the tensioning pattern can correct.
And yes, fastener lubrication and thread cleanliness are absolutely critical. There was a warranty case where a technician used a moly loaded lube on some critical fasteners. These were not Torque To Yield, but many of the fasteners failed before reaching design torque.
I really should go back and find the printed copy of the "Bolts and Gaskets" torque that I gave at an international some time back. Just to reassure those that think this may be an involved subject, it took me a long time to prepare and I was finally able to condense it to just an hour and a half and as I recall, I had to cut the end of that short.
If someone remembers when that got printed in Vintage, please come back and tell us.
Matt
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
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| Re: [GMCnet] Cylinder Head Torque Value [message #359488 is a reply to message #359487] |
Thu, 15 October 2020 17:53 |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
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What Matt is saying is accurate. As always. USUALLY manufacturers technical
manuals are the straight skinny. And if I have the OEM stuff, that is what
I use. Second best is Clymer's, etc. Motor's Manuals and aftermarket
information comes in about third. Internet, in my opinion is the last place
you should rely upon, EXCEPT FOR GMC NET.
But, 40 years in the trades counts for something, also. Always, always
have everything hospital operating room clean. NO JOKE! Threads must be
clean to start with. Don't forget the female threads. There are taps called
thread chasers, and their only purpose is to chase all the crud out of
threaded holes. If the male threads have a special coating, go easy with
the wire wheels. If in doubt about a fastener, throw it away and find
another fastener that is identical in all respects to what you threw away.
On an Oldsmobile 455, there are some short bolts near the exhaust ports.
Really look these over carefully. Exhaust heat damages them. If there is
any corrosion on the unthreaded portions that go through water jackets,
look them over carefully as well. Again, If in doubt, throw it out. But as
a general rule, never assemble fasteners without some lubrication. Many
manufacturers recommend plain old engine oil. Have a clean can of it deep
enough to immerse the entire fastener, pull it out, shake the excess off,
and screw it into the hole. In blind holes, make sure there is not a puddle
of oil in the bottom of the hole. If you screw a bolt down into that and
continue to tighten it, you risk breaking the casting or the very least
screwing up your torque readings. Hope this helps clarify, instead of
confuses any who read it.
Jim Hupy
Salem, Oregon
On Thu, Oct 15, 2020 at 1:55 PM Matt Colie via Gmclist <
gmclist@list.gmcnet.org> wrote:
> TR 1 wrote on Thu, 15 October 2020 15:33
>>
>>
>> If I'm reading what Matt and Jim are explaining above correctly, I
> believe that is essentially what they are explaining as well....
>>
>> Now, I guess as a follow on, exactly how do you "retorque" a head
> properly? I've always started in the middle and backed out the fastener a
>> quarter turn, then run it back up to spec... Working my way back out to
> the outside fasteners... Would this be the best way to do this?
>
> Mark,
>
> The fact that you are doing it matters far more than specficialy how you
> do it.
>
> Rarely is back off required, but it is not a bad practice as it will
> redisrtibute the lubrication. Center out is good, but as it is often said
> that
> it is so the gasket came even itself out. If that were the case in an
> assembled joint with a hard gasket, you have way many more problems than the
> tensioning pattern can correct.
>
> And yes, fastener lubrication and thread cleanliness are absolutely
> critical. There was a warranty case where a technician used a moly loaded
> lube on
> some critical fasteners. These were not Torque To Yield, but many of the
> fasteners failed before reaching design torque.
>
> I really should go back and find the printed copy of the "Bolts and
> Gaskets" torque that I gave at an international some time back. Just to
> reassure
> those that think this may be an involved subject, it took me a long time
> to prepare and I was finally able to condense it to just an hour and a half
> and as I recall, I had to cut the end of that short.
>
> If someone remembers when that got printed in Vintage, please come back
> and tell us.
>
> Matt
> --
> Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL,
> GMCES
> Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum
> Brakes with Applied Control Arms
> SE Michigan - Near DTW - Twixt A2 and Detroit
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
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| Re: [GMCnet] Cylinder Head Torque Value [message #359510 is a reply to message #359504] |
Fri, 16 October 2020 14:43 |
|
Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
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THOMAS R WHITTON wrote on Fri, 16 October 2020 11:13Appreciate the expert insight. Follow up... I suspect my builder, now retired, tightened at a torque value higher than 85 foot pounds but I don't know for sure. Then someone else, not me, loosened and tightened two or three bolts on the left hand front, near number one cylinder. To make sure all the head bolts are set at the same value, I want to reset the all on the left head. I'm looking for how to best do it. Do I loosen all the bolts and retorque to 85 foot pound in sequence? Does it matter that the builder may have torqued higher than 85? Need your suggestions.
Tom Whitton
26 foot upgraded GMCPaducah, KY
Oh Boy Tom.......
This is a question that is much easier to answer than it is to explain.
If you are concerned, in the sequence from the manual, crack each off and re-pull it to design load.
Now what is an interesting thing about cylinder head bolts is that you are fighting two battles....
The first is the clamp load that is needed to hold in the fire pressure. Most everybody understands that issue.
The second is that head bolt tension can affect cylinder bore distortion. If you get this wrong, you can make what was a clean engine into an oil burner.
Now, in your case, the gasket has been fully compressed, so not much of the clamping load can change, but over tension fasteners can distort the bore and make what was a nice round hole - not so nice. On a 403, this is real critical. The bore distortion is a static load issue, so letting the tension back to where is should be will probably allow it to clear.
Matt
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
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| Re: [GMCnet] Cylinder Head Torque Value [message #359511 is a reply to message #359510] |
Fri, 16 October 2020 15:08 |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
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Senior Member |
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When cylinders are bored, often times, particularly with non-robust engine
blocks, cylinder bore stabilization plates are used. They are purpose
built, very thick, very dimensionally stable, plates that simulate a
cylinder head. The bores in the engine match bores in the plate that allow
boring machinery, (cutters or hones) access to the engine cylinder bores
for re-machining. The bore plates are torqued down on the cylinder blocks,
and cylinders are re-machined. Then after re-machining, the bore plates are
removed, and the rest of the machining is completed to the blocks. Then,
when the engine is re-assembled, the cylinder head torque matches what the
torque plate torque was, and the bore shape supposedly is round.
Engines like the small block 5 litre Ford, and yes, the Olds 403,
benefit from this extra step. Like Matt says, overtorquing from
retightening the head bolts, can distort the thin wall engine blocks.
So, It's a crap shoot. In my opinion based upon personal experience
in machine shops, it is probably best to not molest it if possible.
Jim Hupy
Salem, Oregon
On Fri, Oct 16, 2020, 12:45 PM Matt Colie via Gmclist <
gmclist@list.gmcnet.org> wrote:
> THOMAS R WHITTON wrote on Fri, 16 October 2020 11:13
>> Appreciate the expert insight. Follow up... I suspect my builder, now
> retired, tightened at a torque value higher than 85 foot pounds but I
>> don't know for sure. Then someone else, not me, loosened and tightened
> two or three bolts on the left hand front, near number one cylinder. To
>> make sure all the head bolts are set at the same value, I want to reset
> the all on the left head. I'm looking for how to best do it. Do I loosen
>> all the bolts and retorque to 85 foot pound in sequence? Does it matter
> that the builder may have torqued higher than 85? Need your
>> suggestions.
>> Tom Whitton
>> 26 foot upgraded GMCPaducah, KY
>
> Oh Boy Tom.......
>
> This is a question that is much easier to answer than it is to explain.
> If you are concerned, in the sequence from the manual, crack each off and
> re-pull it to design load.
>
> Now what is an interesting thing about cylinder head bolts is that you are
> fighting two battles....
> The first is the clamp load that is needed to hold in the fire pressure.
> Most everybody understands that issue.
> The second is that head bolt tension can affect cylinder bore distortion.
> If you get this wrong, you can make what was a clean engine into an oil
> burner.
>
> Now, in your case, the gasket has been fully compressed, so not much of
> the clamping load can change, but over tension fasteners can distort the
> bore
> and make what was a nice round hole - not so nice. On a 403, this is real
> critical. The bore distortion is a static load issue, so letting the
> tension back to where is should be will probably allow it to clear.
>
> Matt
> --
> Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL,
> GMCES
> Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum
> Brakes with Applied Control Arms
> SE Michigan - Near DTW - Twixt A2 and Detroit
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
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| Re: [GMCnet] Cylinder Head Torque Value [message #359512 is a reply to message #359511] |
Fri, 16 October 2020 17:29 |
Hal StClair
Messages: 971
Registered: March 2013
Location: Rio Rancho NM
Karma: -12
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Senior Member |
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Some of the 'really' good builders are even heating the block to about 150 degrees with the torque plates to simulate running conditions. You can imagine that a block will expand different amounts depending on the wall thickness. Looking for the last little bit of advantage. Fun to watch the advances.
Hal
"I enjoy talking to you. Your mind appeals to me. It resembles my own mind, except you happen to be insane."
1977 Royale 101348,
1977 Royale 101586, Diesel powered,
1974 Eagle Bus 45',w/slideout,
Rio Rancho, NM
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| Re: [GMCnet] Cylinder Head Torque Value [message #359513 is a reply to message #359512] |
Fri, 16 October 2020 18:35 |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
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Senior Member |
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When I was building racing go kart engines, standard practice was: Rebuild
the engine, assemble it and run it in. Disassemble it and measure the bore
with precision bore gages, inspect the piston for any sign of scuffing. If
any was found, they were buffed off and the engine re-assembled, back on
the test stand, and test run again. Understand that some of these engines
turned 20,000 rpm. They didn't live long, but my oh my would they run. 100
cc engines making 40 horsepower, on a 215 pound go kart with a 125 pound
rider. Easily exceeded 100 mph. They lasted a couple of heat races, and a
main event. Then, it was back on the bench for a very close inspection.
Always rings before they went back together. Couple, three races, and it
was cylinder time again. Expensive hobby.
Jim Hupy
Salem, Oregon
On Fri, Oct 16, 2020, 3:30 PM Hal StClair via Gmclist <
gmclist@list.gmcnet.org> wrote:
> Some of the 'really' good builders are even heating the block to about 150
> degrees with the torque plates to simulate running conditions. You can
> imagine that a block will expand different amounts depending on the wall
> thickness. Looking for the last little bit of advantage. Fun to watch the
> advances.
> Hal
> --
> "I enjoy talking to you. Your mind appeals to me. It resembles my own
> mind, except you happen to be insane."
>
> 1977 Royale 101348,
>
> 1977 Royale 101586, Diesel powered,
>
>
>
> 1974 Eagle Bus 45',w/slideout,
>
> Rio Rancho, NM
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
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| Re: [GMCnet] Cylinder Head Torque Value [message #359514 is a reply to message #359511] |
Fri, 16 October 2020 19:55 |
|
Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
|
Senior Member |
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James Hupy wrote on Fri, 16 October 2020 16:08When cylinders are bored, often times, particularly with non-robust engine blocks, cylinder bore stabilization plates are used. They are purpose built, very thick, very dimensionally stable, plates that simulate a cylinder head. The bores in the engine match bores in the plate that allow boring machinery, (cutters or hones) access to the engine cylinder bores for re-machining. The bore plates are torqued down on the cylinder blocks, and cylinders are re-machined. Then after re-machining, the bore plates are removed, and the rest of the machining is completed to the blocks. Then, when the engine is re-assembled, the cylinder head torque matches what the torque plate torque was, and the bore shape supposedly is round.
Engines like the small block 5 litre Ford, and yes, the Olds 403, benefit from this extra step. Like Matt says, overtorquing from retightening the head bolts, can distort the thin wall engine blocks.
So, It's a crap shoot. In my opinion based upon personal experience in machine shops, it is probably best to not molest it if possible.
Jim Hupy
Salem, Oregon
Jim, when we did this, we found three essentials:
The plate had to be more than just a solid plate, it had to be machined so as to duplicate the flexibility of the cylinder head casting.
It (of course) had to be put down at the design fastener tension. We used gages that measured the bolt tension.
You had to use it with the headgasket that was planned for the final assembly.
The Ford 302 was way better than the 2.3l particularly in the SVO version, but one of the worse was the Chevy SB 400 and you can guess why.
It was a siamese bore (like the 403) but there was no metal left.
Great days - those were? We made it all work. A 455 is easy.
Matt
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
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| Re: [GMCnet] Cylinder Head Torque Value [message #359515 is a reply to message #359514] |
Fri, 16 October 2020 20:10 |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
|
Senior Member |
|
|
A technical instructor at the GM Training Center near Portland, where I got
much of my Oldsmobile training, demonstrated on a 400 SB Chev block on the
flimsy bore stability. He took a telescoping gage, set it so it would stay
in the bore by itself, then, using only his hands, squeezing the bore
sides. This caused the telescoping gage to fall right out of the bottom. I
had no idea they were that flimsy. Wouldn't happen on a 455 Olds, I am
sure. He didn't have much love for the V-6's either. Nor did I.
Jim Hupy
Salem, Oregon
On Fri, Oct 16, 2020, 5:56 PM Matt Colie via Gmclist <
gmclist@list.gmcnet.org> wrote:
> James Hupy wrote on Fri, 16 October 2020 16:08
>> When cylinders are bored, often times, particularly with non-robust
> engine blocks, cylinder bore stabilization plates are used. They are purpose
>> built, very thick, very dimensionally stable, plates that simulate a
> cylinder head. The bores in the engine match bores in the plate that allow
>> boring machinery, (cutters or hones) access to the engine cylinder bores
> for re-machining. The bore plates are torqued down on the cylinder blocks,
>> and cylinders are re-machined. Then after re-machining, the bore plates
> are removed, and the rest of the machining is completed to the blocks. Then,
>> when the engine is re-assembled, the cylinder head torque matches what
> the torque plate torque was, and the bore shape supposedly is round.
>> Engines like the small block 5 litre Ford, and yes, the Olds 403,
> benefit from this extra step. Like Matt says, overtorquing from
>> retightening the head bolts, can distort the thin wall engine blocks.
>> So, It's a crap shoot. In my opinion based upon personal
> experience in machine shops, it is probably best to not molest it if
> possible.
>> Jim Hupy
>> Salem, Oregon
>
> Jim, when we did this, we found three essentials:
> The plate had to be more than just a solid plate, it had to be machined so
> as to duplicate the flexibility of the cylinder head casting.
> It (of course) had to be put down at the design fastener tension. We used
> gages that measured the bolt tension.
> You had to use it with the headgasket that was planned for the final
> assembly.
>
> The Ford 302 was way better than the 2.3l particularly in the SVO version,
> but one of the worse was the Chevy SB 400 and you can guess why.
> It was a siamese bore (like the 403) but there was no metal left.
>
> Great days - those were? We made it all work. A 455 is easy.
>
> Matt
> --
> Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL,
> GMCES
> Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum
> Brakes with Applied Control Arms
> SE Michigan - Near DTW - Twixt A2 and Detroit
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
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| Re: [GMCnet] Cylinder Head Torque Value [message #359517 is a reply to message #359515] |
Sat, 17 October 2020 00:08 |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
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Senior Member |
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When I rebuilt my 540CAD I used a torque plate to bore and hone the
cylinder.
It is amassing how the bolts when torqued will show up on the walls.
I'm now too old to waste time and money on those luxuries.
Still have the Torque plate I will let go for cheap.
On Fri, Oct 16, 2020 at 6:11 PM James Hupy via Gmclist <
gmclist@list.gmcnet.org> wrote:
> A technical instructor at the GM Training Center near Portland, where I got
> much of my Oldsmobile training, demonstrated on a 400 SB Chev block on the
> flimsy bore stability. He took a telescoping gage, set it so it would stay
> in the bore by itself, then, using only his hands, squeezing the bore
> sides. This caused the telescoping gage to fall right out of the bottom. I
> had no idea they were that flimsy. Wouldn't happen on a 455 Olds, I am
> sure. He didn't have much love for the V-6's either. Nor did I.
> Jim Hupy
> Salem, Oregon
>
> On Fri, Oct 16, 2020, 5:56 PM Matt Colie via Gmclist gmclist@list.gmcnet.org> wrote:
>
>> James Hupy wrote on Fri, 16 October 2020 16:08
>>> When cylinders are bored, often times, particularly with non-robust
>> engine blocks, cylinder bore stabilization plates are used. They are
> purpose
>>> built, very thick, very dimensionally stable, plates that simulate a
>> cylinder head. The bores in the engine match bores in the plate that
> allow
>>> boring machinery, (cutters or hones) access to the engine cylinder
> bores
>> for re-machining. The bore plates are torqued down on the cylinder
> blocks,
>>> and cylinders are re-machined. Then after re-machining, the bore plates
>> are removed, and the rest of the machining is completed to the blocks.
> Then,
>>> when the engine is re-assembled, the cylinder head torque matches what
>> the torque plate torque was, and the bore shape supposedly is round.
>>> Engines like the small block 5 litre Ford, and yes, the Olds 403,
>> benefit from this extra step. Like Matt says, overtorquing from
>>> retightening the head bolts, can distort the thin wall engine blocks.
>>> So, It's a crap shoot. In my opinion based upon personal
>> experience in machine shops, it is probably best to not molest it if
>> possible.
>>> Jim Hupy
>>> Salem, Oregon
>>
>> Jim, when we did this, we found three essentials:
>> The plate had to be more than just a solid plate, it had to be machined
> so
>> as to duplicate the flexibility of the cylinder head casting.
>> It (of course) had to be put down at the design fastener tension. We
> used
>> gages that measured the bolt tension.
>> You had to use it with the headgasket that was planned for the final
>> assembly.
>>
>> The Ford 302 was way better than the 2.3l particularly in the SVO
> version,
>> but one of the worse was the Chevy SB 400 and you can guess why.
>> It was a siamese bore (like the 403) but there was no metal left.
>>
>> Great days - those were? We made it all work. A 455 is easy.
>>
>> Matt
>> --
>> Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL,
>> GMCES
>> Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum
>> Brakes with Applied Control Arms
>> SE Michigan - Near DTW - Twixt A2 and Detroit
>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
--
Jim Kanomata
Applied/GMC, Newark,CA
jimk@appliedairfilters.com
http://www.gmcrvparts.com
1-800-752-7502
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www.appliedgmc.com
1-800-752-7502
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| Re: [GMCnet] Cylinder Head Torque Value [message #359518 is a reply to message #359517] |
Sat, 17 October 2020 07:35 |
Larry
Messages: 2875
Registered: January 2004
Location: Menomonie, WI
Karma: 10
|
Senior Member |
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jimk wrote on Sat, 17 October 2020 00:08When I rebuilt my 540CAD I used a torque plate to bore and hone the
cylinder.
It is amassing how the bolts when torqued will show up on the walls.
I'm now too old to waste time and money on those luxuries.
Still have the Torque plate I will let go for cheap.
On Fri, Oct 16, 2020 at 6:11 PM James Hupy via Gmclist <
gmclist@list.gmcnet.org> wrote:
> A technical instructor at the GM Training Center near Portland, where I got
> much of my Oldsmobile training, demonstrated on a 400 SB Chev block on the
> flimsy bore stability. He took a telescoping gage, set it so it would stay
> in the bore by itself, then, using only his hands, squeezing the bore
> sides. This caused the telescoping gage to fall right out of the bottom. I
> had no idea they were that flimsy. Wouldn't happen on a 455 Olds, I am
> sure. He didn't have much love for the V-6's either. Nor did I.
> Jim Hupy
> Salem, Oregon
>
> On Fri, Oct 16, 2020, 5:56 PM Matt Colie via Gmclist gmclist@list.gmcnet.org> wrote:
>
>> James Hupy wrote on Fri, 16 October 2020 16:08
>>> When cylinders are bored, often times, particularly with non-robust
>> engine blocks, cylinder bore stabilization plates are used. They are
> purpose
>>> built, very thick, very dimensionally stable, plates that simulate a
>> cylinder head. The bores in the engine match bores in the plate that
> allow
>>> boring machinery, (cutters or hones) access to the engine cylinder
> bores
>> for re-machining. The bore plates are torqued down on the cylinder
> blocks,
>>> and cylinders are re-machined. Then after re-machining, the bore plates
>> are removed, and the rest of the machining is completed to the blocks.
> Then,
>>> when the engine is re-assembled, the cylinder head torque matches what
>> the torque plate torque was, and the bore shape supposedly is round.
>>> Engines like the small block 5 litre Ford, and yes, the Olds 403,
>> benefit from this extra step. Like Matt says, overtorquing from
>>> retightening the head bolts, can distort the thin wall engine blocks.
>>> So, It's a crap shoot. In my opinion based upon personal
>> experience in machine shops, it is probably best to not molest it if
>> possible.
>>> Jim Hupy
>>> Salem, Oregon
>>
>> Jim, when we did this, we found three essentials:
>> The plate had to be more than just a solid plate, it had to be machined
> so
>> as to duplicate the flexibility of the cylinder head casting.
>> It (of course) had to be put down at the design fastener tension. We
> used
>> gages that measured the bolt tension.
>> You had to use it with the headgasket that was planned for the final
>> assembly.
>>
>> The Ford 302 was way better than the 2.3l particularly in the SVO
> version,
>> but one of the worse was the Chevy SB 400 and you can guess why.
>> It was a siamese bore (like the 403) but there was no metal left.
>>
>> Great days - those were? We made it all work. A 455 is easy.
>>
>> Matt
>> --
>> Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL,
>> GMCES
>> Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum
>> Brakes with Applied Control Arms
>> SE Michigan - Near DTW - Twixt A2 and Detroit
>>
>> _______________________________________________
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> _______________________________________________
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--
Jim Kanomata
Applied/GMC, Newark,CA
jimk@appliedairfilters.com
http://www.gmcrvparts.com
1-800-752-7502
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Larry 
78 Royale w/500 Caddy
Menomonie, WI.
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