Home » Public Forums » GMCnet » [GMCnet] Not AGAIN!!!
| [GMCnet] Not AGAIN!!! [message #224272] |
Tue, 01 October 2013 20:59  |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
|
Senior Member |
|
|
Yep, I pulled the right rocker cover off of the Cad500 this afternoon.
Guess what? The rocker pedestal I swiped from one of JimK's engines in
June failed in Mississippi! :-(
Same sequence of events, apparently: The exhaust valve (maybe it's bent or
otherwise binding?) broke its "arm" off of the T-pedestal, followed by the
intake doing the same thing, perhaps because of the excess load of trying
to open against trapped combustion/exhaust gases.
The first pedestal that broke had a dark shadow all around the edges of the
broken area; I couldn't decide whether that was from heat treatment or was
evidence of fatigue cracking. This pedestal, on the exhaust side, is dark
all the way across the broken area, as if it had a fatigue crack for a long
time. The other, intake, side also has more darkened area than the first
pedestal, but does have some shiny, recently broken, material, so it was
not fatigued nearly as badly as the exhaust side.
Now I'm dubious about what I should do: New pedestals are available, but
at $20 each, they, if mated with new rockers, cost about as much as a
shaft-based system with new rockers and push rods. That SHOULD, IMHO, be a
more reliable system -- but the T-pedestals seem to have served most
Cadillacs well since the early 60's.
Any applicable experience to share?
Ken H.
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
|
|
|
|
| Re: [GMCnet] Not AGAIN!!! [message #224273 is a reply to message #224272] |
Tue, 01 October 2013 21:07  |
Jeff Marten
Messages: 199
Registered: August 2013
Karma: 1
|
Senior Member |
|
|
Guide tolerance too tight causing the valve to stick?
> From: hend4800@bellsouth.net
> Date: Tue, 1 Oct 2013 21:59:15 -0400
> To: gmclist@temp.gmcnet.org
> Subject: [GMCnet] Not AGAIN!!!
>
> Yep, I pulled the right rocker cover off of the Cad500 this afternoon.
> Guess what? The rocker pedestal I swiped from one of JimK's engines in
> June failed in Mississippi! :-(
>
> Same sequence of events, apparently: The exhaust valve (maybe it's bent or
> otherwise binding?) broke its "arm" off of the T-pedestal, followed by the
> intake doing the same thing, perhaps because of the excess load of trying
> to open against trapped combustion/exhaust gases.
>
> The first pedestal that broke had a dark shadow all around the edges of the
> broken area; I couldn't decide whether that was from heat treatment or was
> evidence of fatigue cracking. This pedestal, on the exhaust side, is dark
> all the way across the broken area, as if it had a fatigue crack for a long
> time. The other, intake, side also has more darkened area than the first
> pedestal, but does have some shiny, recently broken, material, so it was
> not fatigued nearly as badly as the exhaust side.
>
> Now I'm dubious about what I should do: New pedestals are available, but
> at $20 each, they, if mated with new rockers, cost about as much as a
> shaft-based system with new rockers and push rods. That SHOULD, IMHO, be a
> more reliable system -- but the T-pedestals seem to have served most
> Cadillacs well since the early 60's.
>
> Any applicable experience to share?
>
> Ken H.
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
1985 Gulf Stream 34' Sun Stream
1964 Falcon 'Vert
1980 Bradley GTE
1999 Chevy Tahoe
2005 Saab 93 Aero
1987 Suzuki Intruder 1400
1978 Glastron/Carlson CV23
|
|
|
|
| Re: [GMCnet] Not AGAIN!!! [message #224274 is a reply to message #224272] |
Tue, 01 October 2013 21:19 |
kerry pinkerton
Messages: 2565
Registered: July 2012
Location: Harvest, Al
Karma: 15
|
Senior Member |
|
|
Well, that is good news. At least it is the best kind of bad news anyway.
I'm sure Larry W. will post but he has STRONGLY encouraged me to go with a shaft system on the Cad 500 that John Beaver machined for me. Given his recommendation and your experiences, I'm no doubt going to go that route.
Although the OEM setup has lasted for years, it's has aged and fatigued and while they may look perfect, they may not be perfect at the molecular level.
If you decide to go back OEM, I'd certainly carry a spare rocker pedestal.
Not really knowing much about the Caddy engine, I'll suggest something to help you determine if the exhaust valve has a problem.
Get the piston as close to TDC as you can so that if the valve drops, the stem will still be 'grabable'. Using an adapter, pressurize the cylinder with shop air to hold both valves closed. Remove the valve spring keepers and valve springs. Grab the valve stem and release the shop air. You should be able to turn the valve easily and feel if it is bent.
I've done this with a couple engines over the years but never with a Caddy. I've got a spark plug to male air hose adapter I can mail to you or you can make one out by brazing an old spark plug bottom to a male air hose fitting.
Kerry Pinkerton - North Alabama
Had 5 over the years. Currently have a '06 Fleetwood Discovery 39L
|
|
|
|
| Re: [GMCnet] Not AGAIN!!! [message #224276 is a reply to message #224272] |
Tue, 01 October 2013 21:24 |
kerry pinkerton
Messages: 2565
Registered: July 2012
Location: Harvest, Al
Karma: 15
|
Senior Member |
|
|
Larry mentioned to me that he had purchased a shaft rocker system off Ebay. I don't know if it is this one or not:
Kerry Pinkerton - North Alabama
Had 5 over the years. Currently have a '06 Fleetwood Discovery 39L
|
|
|
|
| Re: [GMCnet] Not AGAIN!!! [message #224281 is a reply to message #224272] |
Tue, 01 October 2013 21:37 |
cadelec
Messages: 303
Registered: September 2011
Location: Brisbane Australia
Karma: 1
|
Senior Member |
|
|
hi ken from what i have read the pedestall system on the 500 caddy engine is their downfall . if i recall a shaft system off of a 429 may fit using ford fe arms but dont quote me this may be for a 1967 429 caddy engine
| Ken Henderson wrote on Tue, 01 October 2013 20:59 |
Yep, I pulled the right rocker cover off of the Cad500 this afternoon.
Guess what? The rocker pedestal I swiped from one of JimK's engines in
June failed in Mississippi! 
Same sequence of events, apparently: The exhaust valve (maybe it's bent or
otherwise binding?) broke its "arm" off of the T-pedestal, followed by the
intake doing the same thing, perhaps because of the excess load of trying
to open against trapped combustion/exhaust gases.
The first pedestal that broke had a dark shadow all around the edges of the
broken area; I couldn't decide whether that was from heat treatment or was
evidence of fatigue cracking. This pedestal, on the exhaust side, is dark
all the way across the broken area, as if it had a fatigue crack for a long
time. The other, intake, side also has more darkened area than the first
pedestal, but does have some shiny, recently broken, material, so it was
not fatigued nearly as badly as the exhaust side.
Now I'm dubious about what I should do: New pedestals are available, but
at $20 each, they, if mated with new rockers, cost about as much as a
shaft-based system with new rockers and push rods. That SHOULD, IMHO, be a
more reliable system -- but the T-pedestals seem to have served most
Cadillacs well since the early 60's.
Any applicable experience to share?
Ken H.
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
|
Trevor
Brisbane Australia
Siesta Koala 76 Edgemont (old Bobby Moores)
71 Cadillac Eldo Convert
58 Cadillac Eldorado Brougham Project
|
|
|
|
| Re: [GMCnet] Not AGAIN!!! [message #224305 is a reply to message #224272] |
Wed, 02 October 2013 00:31 |
George Beckman
Messages: 1085
Registered: October 2008
Location: Colfax, CA
Karma: 11
|
Senior Member |
|
|
| Ken Henderson wrote on Tue, 01 October 2013 18:59 |
Yep, I pulled the right rocker cover off of the Cad500 this afternoon.
Guess what? The rocker pedestal I swiped from one of JimK's engines in
June failed in Mississippi!
Same sequence of events, apparently: The exhaust valve (maybe it's bent or
otherwise binding?) broke its "arm" off of the T-pedestal, followed by the
intake doing the same thing, perhaps because of the excess load of trying
to open against trapped combustion/exhaust gases.
|
if the same one broke I also wonder about a valve stem that is grabby. Just seems odd that the replacement pedestal would fail in the same way. Or maybe a hefty valve spring got in there.
'74 Eleganza, SE, Howell + EBL
Best Wishes,
George
|
|
|
|
| Re: [GMCnet] Not AGAIN!!! [message #224312 is a reply to message #224272] |
Wed, 02 October 2013 07:36 |
Steven Ferguson
Messages: 3447
Registered: May 2006
Karma: 0
|
Senior Member |
|
|
Shaft system.
Steve F.
On Tue, Oct 1, 2013 at 6:59 PM, Ken Henderson <hend4800@bellsouth.net>wrote:
> Yep, I pulled the right rocker cover off of the Cad500 this afternoon.
> Guess what? The rocker pedestal I swiped from one of JimK's engines in
> June failed in Mississippi! :-(
>
> Same sequence of events, apparently: The exhaust valve (maybe it's bent or
> otherwise binding?) broke its "arm" off of the T-pedestal, followed by the
> intake doing the same thing, perhaps because of the excess load of trying
> to open against trapped combustion/exhaust gases.
>
> The first pedestal that broke had a dark shadow all around the edges of the
> broken area; I couldn't decide whether that was from heat treatment or was
> evidence of fatigue cracking. This pedestal, on the exhaust side, is dark
> all the way across the broken area, as if it had a fatigue crack for a long
> time. The other, intake, side also has more darkened area than the first
> pedestal, but does have some shiny, recently broken, material, so it was
> not fatigued nearly as badly as the exhaust side.
>
> Now I'm dubious about what I should do: New pedestals are available, but
> at $20 each, they, if mated with new rockers, cost about as much as a
> shaft-based system with new rockers and push rods. That SHOULD, IMHO, be a
> more reliable system -- but the T-pedestals seem to have served most
> Cadillacs well since the early 60's.
>
> Any applicable experience to share?
>
> Ken H.
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
--
Take care,
Steve
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
|
|
|
|
|
|
| Re: [GMCnet] Not AGAIN!!! [message #224351 is a reply to message #224315] |
Wed, 02 October 2013 12:36 |
djeffers
Messages: 219
Registered: June 2004
Karma: 2
|
Senior Member |
|
|
Hello Ken,
The shaft rocker system you have noted uses Buick rockers on custom shafts, stands and pushrods. The seller is a speed shop, not the manufacturer.
If you need replacement pushrods, they can be made on order. Various companies can make pushrods for you.
The rocker arm ratio of the Buick rocker is 1.6 vs 1.65 for the stock Cad 500.
My computer models indicate the full throttle torque loss at 2500 rpm with 1.6 rockers is negligible. The full throttle HP loss at 2500 is a little less than 2%. Below full throttle, the loss can be compensated for with a little more throttle.
Other aftermarket rocker systems for the Cad 500 utilize a rocker arm ratio of 1.7 or a little more, and cost at least a couple of hundred dollars more. Those systems use stock Cad 500 pushrods.
We would be interested in seeing your broken parts. Any photos?
Don & Susan Jeffers
78 Eleganza II Cad 500 MPFI
[Updated on: Wed, 02 October 2013 12:39] Report message to a moderator |
|
|
|
|
|
| Re: [GMCnet] Not AGAIN!!! [message #224359 is a reply to message #224357] |
Wed, 02 October 2013 13:51 |
A Hamilto
Messages: 4508
Registered: April 2011
Karma: 39
|
Senior Member |
|
|
| A Hamilto wrote on Wed, 02 October 2013 13:47 |
| Ken Henderson wrote on Tue, 01 October 2013 20:59 |
Yep, I pulled the right rocker cover off of the Cad500 this afternoon. Guess what? The rocker pedestal I swiped from one of JimK's engines in June failed in Mississippi!
Same sequence of events, apparently: The exhaust valve (maybe it's bent or otherwise binding?) broke its "arm" off of the T-pedestal, followed by the intake doing the same thing, perhaps because of the excess load of trying to open against trapped combustion/exhaust gases.
...
|
So now I am confused. If you don't have it rigged to shut down on low/no oil pressure, why did the engine quit? Why didn't it just continue to run on 7 cylinders? Glad it did quit, just curious about how/why.
|
Never mind. I went back and read your post where you explained "The EFI, as designed, controls the high pressure pump which is fed from the surge tank. That control consists of a 2-3 second run when ignition is turned on..."
|
|
|
|
| Re: [GMCnet] Not AGAIN!!! [message #224363 is a reply to message #224351] |
Wed, 02 October 2013 14:48 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
|
Senior Member |
|
|
Don,
Thanks for the information and analysis. The system on eBay looks very
much like that from
http://www.cad500parts.com/catalog/page20.htm
and both do specify 1.6:1 ratio. I'll try to find out if they're the same
system before deciding whether to save a few bucks.
Have you installed a shaft system on your engine? Closer examination shows
that the tip of the exhaust valve is considerably abraded, convincing me
that the stem is bend (possibly during the first episode) or otherwise
binding. That would explain the miss I reported also. I'm obviously going
to have to remove at least that head. With my pit set up here, it's almost
as easy to pull the engine+transmission+final drive as to pull the right
cylinder head. I'm debating those options right now.
Thanks,
Ken
On Wed, Oct 2, 2013 at 1:36 PM, Don Jeffers <don.jeffers@frontier.com>wrote:
>
>
> Hello Ken,
>
> The shaft rocker system you have noted uses Buick rockers on custom
> shafts, stands and pushrods. The seller is a speed shop, not the
> manufacturer.
>
> If you need replacement pushrods, they can be made on order. Various
> companies can make pushrods for you.
>
> The rocker arm ratio of the Buick rocker is 1.6 vs 1.65 for the stock Cad
> 500.
>
> My computer models indicate the full throttle torque loss at 2500 rpm with
> 1.6 rockers is negligible. The full throttle HP loss at 2500 is a little
> less than 2%. Below full throttle, the loss can be compensated for with a
> little more throttle.
>
> Other aftermarket rocker systems for the Cad 500 utilize a rocker arm
> ratio of 1.7 or a little more, and cost at least a couple of hundred
> dollars more. Those systems use stock Cad 500 pushrods.
>
> Don & Susan Jeffers
> 78 Eleganza II Cad 500 MPFI
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
|
|
|
|
| Re: [GMCnet] Not AGAIN!!! [message #224393 is a reply to message #224272] |
Wed, 02 October 2013 20:48 |
cbryan
Messages: 451
Registered: May 2012
Location: Ennis, Texas
Karma: 3
|
Senior Member |
|
|
Ken,
I don't have that "Big Inch Cadillac" book with me,
but I definitely remember that the rocker shaft they
used in their stroked 500 looked like the setup
pictured on eBay. I saw new pushrods are provided.
I read somewhere that one problem with a new aftermarket
cam is that the pushrods length will have to be changed.
remember I think that you have a bone stock cam
in this engine with the broken rocker tower.
My offer of sending you my extra copy still
stands. It has some rebuilding tips reminiscent
of Joe Mondello's advice for the 455/403.
Glad it wasn't worse. I think if it was something
other than the valve train you would have wanted
to go with the rocker shaft setup for peace of
mind anyway, so in a way you were fortunate.
Best,
Carey
Carey from Ennis, Texas
78 Royale, 500 Cadillac, Rance Baxter EFI.
|
|
|
|
| Re: [GMCnet] Not AGAIN!!! [message #224400 is a reply to message #224393] |
Wed, 02 October 2013 22:29 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
|
Senior Member |
|
|
Carey,
Thanks for the offer. I found my copy of "Big Inch..." today. It's pretty
well smudged & highlighted from the first 500 I built. :-)
Today I put a spring compressor on the exhaust valve which apparently
initiated the failures. To my surprise, it moved easily; I really expected
it to be binding in the guide. Quite the contrary, it has excessive
clearance. MUCH more than it did when we assembled it about 12,000 miles
ago! My engine expert and I are agreed that I should pull the engine so we
can do a complete valve train replacement and have easy access for such
things as setting lifter pre-load. There are some other things I need to
attend to also, so it's not all bad. For example, I've somehow got a leak
at the front of the oil pan, where the front plate meets it. I thought I
was very careful when assembling that, but there's a pretty good leak there
which pretty well rustproofed everything from there back. I'll get another
shot at that. Wonder if it would help to invest in CadCo's $95 SS plate...
I see differences between the Stage 1 shaft at CadCo and the one in "Big
Inch...". The CadCo has springs on the shaft to keep the rockers in place.
That in "Big..." has Teflon retainer buttons between the "ears" of the
rockers. The one on eBay has springs, but different looking pedestals than
CadCo's. I did keep the OEM cam in this engine but on this iteration, I
may replace it. But this time I'll make sure the base diameter is the same
as stock so the stock push rod lengths should be correct -- even if I have
to buy the NOS cam on eBay.
More fun than I know what to do with!
Ken H.
On Wed, Oct 2, 2013 at 9:48 PM, Carey Bryan <chbryan@bigfoot.com> wrote:
>
>
> Ken,
>
> I don't have that "Big Inch Cadillac" book with me,
> but I definitely remember that the rocker shaft they
> used in their stroked 500 looked like the setup
> pictured on eBay. I saw new pushrods are provided.
> I read somewhere that one problem with a new aftermarket
> cam is that the pushrods length will have to be changed.
> remember I think that you have a bone stock cam
> in this engine with the broken rocker tower.
>
> My offer of sending you my extra copy still
> stands. It has some rebuilding tips reminiscent
> of Joe Mondello's advice for the 455/403.
>
> Glad it wasn't worse. I think if it was something
> other than the valve train you would have wanted
> to go with the rocker shaft setup for peace of
> mind anyway, so in a way you were fortunate.
>
> Best,
>
> Carey
> --
> Carey from Ennis, Texas
> 78 Royale, 500 Cadillac, Rance Baxter EFI.
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
|
|
|
|
| Re: [GMCnet] Not AGAIN!!! [message #224403 is a reply to message #224363] |
Thu, 03 October 2013 00:43 |
djeffers
Messages: 219
Registered: June 2004
Karma: 2
|
Senior Member |
|
|
| Ken Henderson wrote on Wed, 02 October 2013 15:48 |
Don,
Thanks for the information and analysis. The system on eBay looks very
much like that from
http://www.cad500parts.com/catalog/page20.htm
and both do specify 1.6:1 ratio. I'll try to find out if they're the same
system before deciding whether to save a few bucks.
Have you installed a shaft system on your engine? Closer examination shows
that the tip of the exhaust valve is considerably abraded, convincing me
that the stem is bend (possibly during the first episode) or otherwise
binding. That would explain the miss I reported also. I'm obviously going
to have to remove at least that head. With my pit set up here, it's almost
as easy to pull the engine+transmission+final drive as to pull the right
cylinder head. I'm debating those options right now.
Thanks,
Ken
|
We have not installed a shaft system, yet, although we plan to do so. After your T pedestal failure in CA, I took a good look into what's available.
That also prompted me to do the computer simulations with the 1.6 rockers, the least expensive set out there. I have several 507 Cad engines modeled, so simply changing rocker arm ratios on a stock engine and running the simulation was very easy.
I will choose a rocker set once I finish the several projects I have going now. Some of those rocker arm sets won't clear the stock valve covers.
I would strongly urge you to replace the exhaust manifold bolts with studs. Broken bolts are a common problem with Cad 500s in cars and the motorhome is a more severe duty.
I had frozen and broken exhaust manifold bolts, 6 on the right head and 2 on the left head. 4 were broken off flush with the head. Couldn't get them out with drill, easy-out, welded-on-nuts, torch, vise grips or BFH. I had to take the heads off just to get the broken bolts out.
Took the heads to a first class machine shop that got the broken bolts out without damaging the threads, not a trivial task. I would not put inserts in the heads as all the automotive machine shops wanted to do.
I checked many sources and the only black oxide studs I could get locally came from, strangely enough, Ace Hardware. They had to order a set of 16 as they only stocked 3 normally. I don't remember the size offhand but they were the largest in stock and the correct size. Maybe I can find the size for you. I used brass nuts and stainless washers on the studs.
Taking the engine out is not too much extra work with your set up and gives you lots of internal access and options.
Have you considered a torque/RV cam in the engine? An aftermarket cam might have a little higer lift at the cam and offset the lower rocker arm ratio. I've liked all the torque cams I've installed.
Regards,
Don & Susan Jeffers
78 Eleganza II 507 Cad (30 over)
|
|
|
|
| Re: [GMCnet] Not AGAIN!!! [message #224404 is a reply to message #224400] |
Thu, 03 October 2013 00:48 |
jim kanomata
Messages: 257
Registered: March 2007
Location: fremont,ca
Karma: 12
|
Senior Member |
|
|
Ken,
My Rocker tube system was installed backin 1994.
I purchased it from the original Cad Motorsport..
There might be a problem with that cylinder, as I find it hard to see repeated failer
Jim Kanomata
Applied/GMC, Fremont,CA
jimk@appliedairfilters.com
http://www.appliedgmc.com
1-800-752-7502
|
|
|
|
| Re: [GMCnet] Not AGAIN!!! [message #224414 is a reply to message #224403] |
Thu, 03 October 2013 06:58 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
|
Senior Member |
|
|
Don,
Thanks for reminding me about the exhaust manifold studs. When I assembled
this engine, I used Permatex Nickle anti-seize compound on all the bolts.
During this trip I blew out a stock-style exhaust gasket and replaced it
with the Remflex I'd taken along. I thought I was going to break several
of the bolts getting them out. I'll check Fastenal & McMaster-Carr for
studs (we no longer have any hardware except Lowes), but if you have the
sizes handy, it save me figuring it out.
If I do consider an RV cam, I'll be sure to check whether it's ground on a
new billet. I made the mistake on the first Cad of buying a CompCams grind
that everyone recommended. Turned out to be a reground OEM cam so the base
diameter was smaller, forcing me to install longer pushrods -- which I
didn't discover until I'd installed the engine and remembered, late, to
check lifter pre-loads. :-( There are NOS GM cams available on eBay right
now; that's tempting.
Ken
On Thu, Oct 3, 2013 at 1:43 AM, Don Jeffers <don.jeffers@frontier.com>wrote:
>
>
> Ken Henderson wrote on Wed, 02 October 2013 15:48
> > Don,
> >
> > Thanks for the information and analysis. The system on eBay looks very
> > much like that from
> > http://www.cad500parts.com/catalog/page20.htm
> > and both do specify 1.6:1 ratio. I'll try to find out if they're the
> same
> > system before deciding whether to save a few bucks.
> >
> > Have you installed a shaft system on your engine? Closer examination
> shows
> > that the tip of the exhaust valve is considerably abraded, convincing me
> > that the stem is bend (possibly during the first episode) or otherwise
> > binding. That would explain the miss I reported also. I'm obviously
> going
> > to have to remove at least that head. With my pit set up here, it's
> almost
> > as easy to pull the engine+transmission+final drive as to pull the right
> > cylinder head. I'm debating those options right now.
> >
> > Thanks,
> >
> > Ken
>
> We have not installed a shaft system, yet, although we plan to do so.
> After your T pedestal failure in CA, I took a good look into what's
> available.
>
> That also prompted me to do the computer simulations with the 1.6 rockers,
> the least expensive set out there. I have several 507 Cad engines modeled,
> so simply changing rocker arm ratios on a stock engine and running the
> simulation was very easy.
>
> I will choose a rocker set once I finish the several projects I have going
> now. Some of those rocker arm sets won't clear the stock valve covers.
>
>
> I would strongly urge you to replace the exhaust manifold bolts with
> studs. Broken bolts are a common problem with Cad 500s in cars and the
> motorhome is a more severe duty.
>
> I had frozen and broken exhaust manifold bolts, 6 on the right head and 2
> on the left head. 4 were broken off flush with the head. Couldn't get them
> out with drill, easy-out, welded-on-nuts, torch, vise grips or BFH. I had
> to take the heads off just to get the broken bolts out.
>
> Took the heads to a first class machine shop that got the broken bolts out
> without damaging the threads, not a trivial task. I would not put inserts
> in the heads as all the automotive machine shops wanted to do.
>
> I checked many sources and the only black oxide studs I could get locally
> came from, strangely enough, Ace Hardware. They had to order a set of 16
> as they only stocked 3 normally. I don't remember the size offhand but they
> were the largest in stock and the correct size. Maybe I can find the size
> for you. I used brass nuts and stainless washers on the studs.
>
>
> Taking the engine out is not too much extra work with your set up and
> gives you lots of internal access and options.
>
> Have you considered a torque/RV cam in the engine? An aftermarket cam
> might have a little higer lift at the cam and offset the lower rocker arm
> ratio. I've liked all the torque cams I've installed.
>
> Regards,
>
> Don & Susan Jeffers
> 78 Eleganza II 507 Cad (30 over)
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
|
|
|
|
| Re: [GMCnet] Not AGAIN!!! [message #224418 is a reply to message #224315] |
Thu, 03 October 2013 07:55 |
Steven Ferguson
Messages: 3447
Registered: May 2006
Karma: 0
|
Senior Member |
|
|
Ken,
All of the ones I've seen come from CAD CO. I would bet though, that
there's really only one mfr and everyone repackages under their own name.
Any shaft system is better than the OEM system IMHO.
Steve
On Wed, Oct 2, 2013 at 5:44 AM, Ken Henderson <hend4800@bellsouth.net>wrote:
> But which one?
>
> Know anything about this one?:
>
>
> http://www.ebay.com/itm/Cadillac-472-500-Rocker-Arm-assembly-1968-69-70-71-72-73-74-75-76-arms-shafts-/190881612814?pt=Vintage_Car_Truck_Parts_Accesso ries&hash=item2c716e440e&vxp=mtr
>
> Ken H.
>
>
> On Wed, Oct 2, 2013 at 8:36 AM, Steven Ferguson <botiemad11@gmail.com
> >wrote:
>
> > Shaft system.
> > Steve F.
> >
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
--
Take care,
Steve
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
|
|
|
|
| Re: [GMCnet] Not AGAIN!!! [message #224420 is a reply to message #224418] |
Thu, 03 October 2013 08:00 |
Steven Ferguson
Messages: 3447
Registered: May 2006
Karma: 0
|
Senior Member |
|
|
I should have mentioned also that you need to find out if the shaft system
requires special length pushrods.
Steve
On Thu, Oct 3, 2013 at 5:55 AM, Steven Ferguson <botiemad11@gmail.com>wrote:
> Ken,
> All of the ones I've seen come from CAD CO. I would bet though, that
> there's really only one mfr and everyone repackages under their own name.
> Any shaft system is better than the OEM system IMHO.
> Steve
>
>
> On Wed, Oct 2, 2013 at 5:44 AM, Ken Henderson <hend4800@bellsouth.net>wrote:
>
>> But which one?
>>
>> Know anything about this one?:
>>
>>
>> http://www.ebay.com/itm/Cadillac-472-500-Rocker-Arm-assembly-1968-69-70-71-72-73-74-75-76-arms-shafts-/190881612814?pt=Vintage_Car_Truck_Parts_Accesso ries&hash=item2c716e440e&vxp=mtr
>>
>> Ken H.
>>
>>
>> On Wed, Oct 2, 2013 at 8:36 AM, Steven Ferguson <botiemad11@gmail.com
>> >wrote:
>>
>> > Shaft system.
>> > Steve F.
>> >
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>>
>
>
>
> --
> Take care,
> Steve
>
>
--
Take care,
Steve
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
|
|
|
|
|
|
Goto Forum:
Current Time: Wed Aug 28 11:15:34 CDT 2024
Total time taken to generate the page: 0.01247 seconds
|
GMCforum
Search
Help
Register
Login
Home
