Home » Public Forums » GMCnet » onan head torque
| onan head torque [message #182465] |
Thu, 30 August 2012 19:24  |
sgltrac
Messages: 2797
Registered: April 2011
Karma: 1
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Senior Member |
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Put new motor mounts on the Onan tonight and when I pulled the cooling tins on the heads I noticed the two center head bolts were oily. It appears all of the head bolts have worked loose. Does anyone of the collective brain trust recall off hand the head torque spec for the onan 6kw??
Thanks
Sully
77 Royale basket case.
Future motorhome land speed record holder(bucket list)
Seattle, Wa.
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| Re: [GMCnet] onan head torque [message #182486 is a reply to message #182480] |
Thu, 30 August 2012 20:25  |
k2gkk
Messages: 4452
Registered: November 2009
Karma: -8
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And the tightening sequence is on page 20.
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
~~ ~ D C "Mac" Macdonald ~ ~~
~ ~ Amateur Radio - K2GKK ~ ~
~ ~ USAF and FAA, Retired ~ ~
~ ~ ~ Temp nr Omaha, NE ~ ~ ~
~~ ~ ~ "The Money Pit" ~ ~ ~~
~ ~ ~ ex-Palm Beach, 76 ~ ~ ~
~ www.gmcmhphotos.com/okclb ~
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
> From: sgltrac@gmail.com
> Date: Thu, 30 Aug 2012 18:03:43 -0700
> To: gmclist@temp.gmcnet.org
> Subject: Re: [GMCnet] onan head torque
>
> Thanks for the link John
>
> Sully
> 77 royale
>
> Sent from my iPhone
>
> On Aug 30, 2012, at 5:39 PM, John Wright <powerjon@chartermi.net> wrote:
>
> > Go to the manual and read page 7.
> >
> > http://www.bdub.net/manuals/Onan/Onan6kwNH_Major-Service.pdf
> >
> > JR Wright
> > On Aug 30, 2012, at 8:24 PM, sgltrac wrote:
> >
> >>
> >>
> >> Put new motor mounts on the Onan tonight and when I pulled the
> >> cooling tins on the heads I noticed the two center head bolts were
> >> oily. It appears all of the head bolts have worked loose. Does
> >> anyone of the collective brain trust recall off hand the head torque
> >> spec for the onan 6kw??
> >>
> >> Thanks
> >> --
> >> Sully
> >> 77 Royale basket case.
> >> Future motorhome land speed record holder(bucket list)
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| Re: [GMCnet] onan head torque [message #182502 is a reply to message #182486] |
Thu, 30 August 2012 21:35 |
sgltrac
Messages: 2797
Registered: April 2011
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Thanks Mac!
Sully
77 royale
Sent from my iPhone
On Aug 30, 2012, at 6:25 PM, D C *Mac* Macdonald <k2gkk@hotmail.com> wrote:
>
> And the tightening sequence is on page 20.
>
> ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
> ~~ ~ D C "Mac" Macdonald ~ ~~
> ~ ~ Amateur Radio - K2GKK ~ ~
> ~ ~ USAF and FAA, Retired ~ ~
> ~ ~ ~ Temp nr Omaha, NE ~ ~ ~
> ~~ ~ ~ "The Money Pit" ~ ~ ~~
> ~ ~ ~ ex-Palm Beach, 76 ~ ~ ~
> ~ www.gmcmhphotos.com/okclb ~
> ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
>
>
>
>
>
>> From: sgltrac@gmail.com
>> Date: Thu, 30 Aug 2012 18:03:43 -0700
>> To: gmclist@temp.gmcnet.org
>> Subject: Re: [GMCnet] onan head torque
>>
>> Thanks for the link John
>>
>> Sully
>> 77 royale
>>
>> Sent from my iPhone
>>
>> On Aug 30, 2012, at 5:39 PM, John Wright <powerjon@chartermi.net> wrote:
>>
>>> Go to the manual and read page 7.
>>>
>>> http://www.bdub.net/manuals/Onan/Onan6kwNH_Major-Service.pdf
>>>
>>> JR Wright
>>> On Aug 30, 2012, at 8:24 PM, sgltrac wrote:
>>>
>>>>
>>>>
>>>> Put new motor mounts on the Onan tonight and when I pulled the
>>>> cooling tins on the heads I noticed the two center head bolts were
>>>> oily. It appears all of the head bolts have worked loose. Does
>>>> anyone of the collective brain trust recall off hand the head torque
>>>> spec for the onan 6kw??
>>>>
>>>> Thanks
>>>> --
>>>> Sully
>>>> 77 Royale basket case.
>>>> Future motorhome land speed record holder(bucket list)
>
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Sully
77 Royale basket case.
Future motorhome land speed record holder(bucket list)
Seattle, Wa.
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| Re: onan head torque [message #182536 is a reply to message #182465] |
Fri, 31 August 2012 06:22 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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It isn't much. 17 comes to mind but I would look it up rather than trust Ken B.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: [GMCnet] onan head torque [message #182576 is a reply to message #182561] |
Fri, 31 August 2012 10:02 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Senior Member |
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| Matt Colie wrote on Fri, 31 August 2012 08:56 |
| Steven Ferguson wrote on Fri, 31 August 2012 08:43 |
Now is a great time to remove those heads, and bead blast the carbon off.
Paint both sides of the head gaskets with half a dozen coats of cheap silver spray paint, let dry, and reinstall them according to the book.
Your Onan will be happy.
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Steve is right about the decarbon. Any means at all will be a good thing. If the gaskets are copper with a filler (may still be asbestos) and they show no signs of leakage, don't bother with the paint. The paint may cause them to stick and be damaged on a subsequent service.
Just be very careful to NOT OVER TIGHTEN the cylinder head bolts.
Matt (The aftermarket guy from what used to be McCord).
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A trick I learned from the local Steel Mill millwrights is to coat them with anti-seize as a gasket sealer. It works great and make future removal a snap.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: [GMCnet] onan head torque [message #182578 is a reply to message #182561] |
Fri, 31 August 2012 10:00 |
sgltrac
Messages: 2797
Registered: April 2011
Karma: 1
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Senior Member |
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Thanks to all the replies. I will pull the heads and remove carbon even if it is against my new GMC mantra of if it ain't broke.......
Sully
77 royale
Sent from my iPhone
On Aug 31, 2012, at 6:56 AM, Matt Colie <matt7323tze@gmail.com> wrote:
>
>
> Steven Ferguson wrote on Fri, 31 August 2012 08:43
>> Now is a great time to remove those heads, and bead blast the carbon off.
>> Paint both sides of the head gaskets with half a dozen coats of cheap silver spray paint, let dry, and reinstall them according to the book.
>> Your Onan will be happy.
>
> Steve is right about the decarbon. Any means at all will be a good thing. If the gaskets are copper with a filler (may still be asbestos) and they show no signs of leakage, don't bother with the paint. The paint may cause them to stick and be damaged on a subsequent service.
>
> Just be very careful to NOT OVER TIGHTEN the cylinder head bolts.
>
> Matt (The aftermarket guy from what used to be McCord).
> --
> Matt & Mary Colie
> '73 Glacier 23 Chaumière (say show-me-air) Just about as stock as you will find
> SE Michigan - Twixt A2 and Detroit
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Sully
77 Royale basket case.
Future motorhome land speed record holder(bucket list)
Seattle, Wa.
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| Re: [GMCnet] onan head torque [message #182582 is a reply to message #182576] |
Fri, 31 August 2012 10:31 |
sgltrac
Messages: 2797
Registered: April 2011
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I like that one Ken. I happen to have a jug ;)
Sully
77 royale
Sent from my iPhone
On Aug 31, 2012, at 8:02 AM, Ken Burton <n9cv@comcast.net> wrote:
>
>
> Matt Colie wrote on Fri, 31 August 2012 08:56
>> Steven Ferguson wrote on Fri, 31 August 2012 08:43
>>> Now is a great time to remove those heads, and bead blast the carbon off.
>>> Paint both sides of the head gaskets with half a dozen coats of cheap silver spray paint, let dry, and reinstall them according to the book.
>>> Your Onan will be happy.
>>
>> Steve is right about the decarbon. Any means at all will be a good thing. If the gaskets are copper with a filler (may still be asbestos) and they show no signs of leakage, don't bother with the paint. The paint may cause them to stick and be damaged on a subsequent service.
>>
>> Just be very careful to NOT OVER TIGHTEN the cylinder head bolts.
>>
>> Matt (The aftermarket guy from what used to be McCord).
>
>
> A trick I learned from the local Steel Mill millwrights is to coat them with anti-seize as a gasket sealer. It works great and make future removal a snap.
>
>
> --
> Ken Burton - N9KB
> 76 Palm Beach
> Hebron, Indiana
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
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Sully
77 Royale basket case.
Future motorhome land speed record holder(bucket list)
Seattle, Wa.
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| Re: onan head torque [message #182622 is a reply to message #182465] |
Fri, 31 August 2012 15:39 |
sgltrac
Messages: 2797
Registered: April 2011
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Senior Member |
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So I cleaned the heads and pistons which were coated with crud as well as the gaskets which i also put a layer of anti sieze on and re assembled to the correct torque. When the heads came off there was evidence of large leaks on both. I fired the barbarian up and it started readily then settled into idle. I was feeling around the exhaust pipe for a leak that I saw evidence of when suddenly the barbarian stopped firing just like the kill button had been pressed then KAPOOOW!! Holy s#$t good thing I had ear muffs on. I looked everything over half expecting to see engine parts and oil on the floor. Went to restart and it turned longer than usual then KAPOWWW! once again. God d&^n it. WTF? Did this thing just skip time or what? Crap I knew I should have followed my new GMC mantra of "If it aint broke........."
Help
Sully
77 Royale basket case.
Future motorhome land speed record holder(bucket list)
Seattle, Wa.
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| Re: onan head torque [message #182626 is a reply to message #182465] |
Fri, 31 August 2012 16:28 |
sgltrac
Messages: 2797
Registered: April 2011
Karma: 1
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Senior Member |
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I never believe in coincidences but here we are. I checked compression (with my thumb) in each hole and felt ok, checked spark and one side seemed a little less frequent. Checked the point and it was opening and closing. Then I started looking at wires and pulled the point feed out of its holder and noticed that it had been forced against the side of the condenser by the point cover and the raised rib in the condenser body had left a deep indentation in the wire casing but did not look like it went through to the wire. pulled the wire away from the condenser and she fired and ran like normal. Wow, speechless.
Thanks to all for the usual prompt replies.
Sully
77 Royale basket case.
Future motorhome land speed record holder(bucket list)
Seattle, Wa.
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| Re: [GMCnet] onan head torque [message #182722 is a reply to message #182719] |
Sat, 01 September 2012 07:30 |
midlf
Messages: 2212
Registered: July 2007
Location: SE Wisc. (Palmyra)
Karma: 1
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| Steven Ferguson wrote on Sat, 01 September 2012 07:10 |
It's always something simple when it comes to these things running. As
long as I have been on this net, I have never heard of an Onan tossing a
rod or breaking a crank or any other engine mechanical failure.
Steve Ferguson
Sierra Vista, AZ
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Well simple is relative. If you are not up on electrical stuff they can drive you nuts. However you are correct that a mechanical problem with the basic prime mover just never happens, if we don't count oil leaks. (But hey, I own an old Harley so oil leaks are a fact of life around here. <GRIN>)
Based on comments on the GMCnet/forum and my experience the problems will most likely be in this order:
control board
ignition (coil or points/timing)
oil pressure switch
broken starter bracket
bridge rectifier
Failure to remote start/stop is almost always corrosion on the "hidden" plug behind the slide out.
The major mechanical "problems" are the leaks, cleaning the carbon off the cylinder head, replacing the motor mounts, and the exhaust system.
Steve Southworth
1974 Glacier TZE064V100150 (for workin on)
1975 Transmode TZE365V100394 (parts & spares)
Palmyra WI
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| Re: [GMCnet] onan head torque [message #182746 is a reply to message #182722] |
Sat, 01 September 2012 10:22 |
Steven Ferguson
Messages: 3447
Registered: May 2006
Karma: 0
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Senior Member |
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For most Harley owners, an oil leak is comforting. It's the only way they
know it has oil in it.
On Sat, Sep 1, 2012 at 5:30 AM, Steve Southworth <midlf@centurytel.net>wrote:
>
>
> Steven Ferguson wrote on Sat, 01 September 2012 07:10
> > It's always something simple when it comes to these things running. As
> > long as I have been on this net, I have never heard of an Onan tossing a
> > rod or breaking a crank or any other engine mechanical failure.
> >
> > Steve Ferguson
> > Sierra Vista, AZ
>
>
> Well simple is relative. If you are not up on electrical stuff they can
> drive you nuts. However you are correct that a mechanical problem with the
> basic prime mover just never happens, if we don't count oil leaks. (But
> hey, I own an old Harley so oil leaks are a fact of life around here.
> <GRIN>)
>
> Based on comments on the GMCnet/forum and my experience the problems will
> most likely be in this order:
>
> control board
> ignition (coil or points/timing)
> oil pressure switch
> broken starter bracket
> bridge rectifier
>
> Failure to remote start/stop is almost always corrosion on the "hidden"
> plug behind the slide out.
>
> The major mechanical "problems" are the leaks, cleaning the carbon off the
> cylinder head, replacing the motor mounts, and the exhaust system.
> --
> Steve Southworth
> 1974 Glacier TZE064V100150 (for workin on)
> 1975 Transmode TZE365V100394 (parts & spares)
> Palmyra WI
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
--
Fathom the hypocrisy of a nation where every citizen must prove they have
health insurance......but not everyone has to prove they're a citizen.
Steve Ferguson
Sierra Vista, AZ
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| Re: [GMCnet] onan head torque [message #182799 is a reply to message #182746] |
Sat, 01 September 2012 17:28 |
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USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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Steve's,
C'mon - EVERYBODY knows that Harley's don't leak oil; they're just marking their spot! ;-)
Regards,
Rob M.
-----Original Message-----
From: Steven Ferguson
For most Harley owners, an oil leak is comforting. It's the only way they
know it has oil in it.
Steve Ferguson
(But hey, I own an old Harley so oil leaks are a fact of life around here. GRIN>)
Steve Southworth
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Regards,
Rob M. (USAussie)
The Pedantic Mechanic
Sydney, Australia
'75 Avion - AUS - The Blue Streak TZE365V100428
'75 Avion - USA - Double Trouble TZE365V100426
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