[GMCnet] 502 post mortem
Steven Ferguson
something two years ago and he swapped in a new one. I finally got
around to doing a post-mortem on the motor. He left it for me at the
Dyno Shop in San Diego where the swap was accomplished. Kerry uses
Swepco Oil exclusively and is a dealer. He is religious about oil
changes and I have to say, that this is most likely the best looking
180,000 mile engine I have ever taken apart The crank mikes out
perfect and will require a polish only. The cyl bores are still
within spec and the rod bearings have the most even wear on them I've
ever seen. #1 piston got the hell beat out of it when someone dropped
something down the intake, (left impressions on the piston that
indicate it was round like a 1/4"ball bearing and that would account
for the broken compression ring. The inside of
I guess it goes to show that these things need to be driven and
nothing beats a comprehensive maintenance schedule.
--
Steve Ferguson
'76 EII
Sierra Vista, AZ
Urethane bushing source
www.bdub.net/ferguson/
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Shan Rose
s the 502 a bored out 455, or a chevy/caddy based motor?
Gary Casey
________________________________
From: Shan Rose <defc...@gmail.com>
To: gmc...@temp.gmcnet.org
Sent: Thu, December 10, 2009 9:12:01 AM
Subject: Re: [GMCnet] 502 post mortem
__________________________________________________
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John Wright
are several different versions available with different compression
ratio's and output ratings. Some of the models are 338hp HT502, 450hp
502 HO, 502hp Ram Jet End and the 502 hp ZZ502. There may be more
options available:
J.R. Wright
Rob Mueller
I thought that the 8.1 moniker went with the Vortec engine?
http://www.workhorse.com/Default.aspx?tabid=160
This is the engine that Dave Lenzi installed in his GMC.
I have heard via the grapevine that he's doing another one now; anybody know
it that's correct and whose GMC it is?
Regards,
Rob Mueller
Sydney, Australia
AUS '75 Avion-The Blue Streak TZE365V100428
USA '75 Avion-Double Trouble TZE365V100426
-----Original Message-----
From: gmclist...@temp.gmcnet.org
[mailto:gmclist...@temp.gmcnet.org] On Behalf Of Gary Casey
Sent: Friday, 11 December 2009 3:34 AM
To: gmc...@temp.gmcnet.org
Subject: Re: [GMCnet] 502 post mortem
What is normally referred to as the "502" is indeed a bored-out 455 Chevy,
otherwise known as the 8.1.
_______________________________________________
Hal Kading
The 502 Cid is a Gen VI GM big block that is also known as the 8.2 Lt. It is a bored out 454, same stroke. The 8.1 Lt is a quite different design engine and is also called a Gen VII BB or 8100 VORTEC. It is a longer stroke crank than the 454/502, and is 496 Cid. The 8.1 is the engine Dave Lenzi put in his coach.
Hal Kading 78 Buskirk Stretch, formerly turbo/EFI 454 and soon to be NA/EFI 502.
John Wright
month he said he was doing 2. One is for J.R. Slaten and I am unsure
who the second one is for. I had hoped to talk to him today as we
meet on the second Thursday of the month, but the roads were so bad
that we didn't get to go.
J.R. Wright
Gary Casey
At least I got the bored-out part - same stroke as the 454 with a bigger bore - siamezed cylinders, as I recall.
Gary
________________________________
Gary,
I thought that the 8.1 moniker went with the Vortec engine?
http://www.workhorse.com/Default.aspx?tabid=160
This is the engine that Dave Lenzi installed in his GMC.
I have heard via the grapevine that he's doing another one now; anybody know
it that's correct and whose GMC it is?
Regards,
Rob Mueller
Sydney, Australia
AUS '75 Avion-The Blue Streak TZE365V100428
USA '75 Avion-Double Trouble TZE365V100426
Steven Ferguson
It is one of 900 HO 502 Chevy engines hand assembled for marine use.
Circa late 80's, iron heads, metric pistons. 502cu in/502hp.
I will be boring it to 4.5" and installing KB hypereutectic pistons.
The HO 502 are referred to as Gen VII blocks and share little with the
earlier generation Chevy BBs. All of the current production 502 BBC
have aluminum heads.
--
Steve Ferguson
'76 EII
Sierra Vista, AZ
Urethane bushing source
www.bdub.net/ferguson/
Steven Ferguson
http://www.gmperformanceparts.com/EngineShowcase/index.jsp?engId=502HO&engine=502+HO&sku=12568778&engCat=bb
The first ones, that were hand assembled, came with flat tappet
camshafts. As you can see from the GM performance sites, all later
ones came with roller camshafts and the very hi hp ones have aluminum
heads. Hard to find parts for this engine without going through GM
and paying exorbitant prices. The aftermarket is starting to catch up
and this is what I've been waiting for. The new BBC manuals finally
include the HO 502 in the BB family.
On Thu, Dec 10, 2009 at 8:12 AM, Shan Rose <defc...@gmail.com> wrote:
>
>
--
Steve Ferguson
'76 EII
Sierra Vista, AZ
Urethane bushing source
www.bdub.net/ferguson/
Shan Rose
how hard is it to drop in a chevy based engine? is it bolt up or does stuff have to be modified?
also one could go with a merlin based engine from World Product$, if you have the desposible income you could have up to 632 CID or 10.3 liters! 8o
Steven Ferguson wrote on Fri, 11 December 2009 08:36
John Wright
It takes an adapter plate to mate the eng. to transmission and of
course you have to modify the oil pan to accept the axle shaft thru
the pan (very close clearance with the crank). Modify the block for
the RH axle bearing support. There were a number of coaches that had
this combination installed and I know of at least 2 that are Great
Laker members. Not as straight forward and easy as putting a Cad in
but it has been done.
J.R. Wright
On Dec 11, 2009, at 11:57 AM, Shan Rose wrote:
>
>
> how hard is it to drop in a chevy based engine? is it bolt up or
> does stuff have to be modified?
>
> also one could go with a merlin based engine from World Product$, if
> you have the desposible income you could have up to 632 CID or 10.3
> liters! 8o
>
>
Ray Erspamer
Ray
Ray & Lisa Erspamer
78 Royale Center Kitchen
The Malosco Cruiser (TZE368V101144)
Wauwatosa, Wisconsin 53226
Email: 78GMC-...@att.net
414-745-3188
Web Site: http://ray-lisa.page.tl/
________________________________
From: Shan Rose <defc...@gmail.com>
To: gmc...@temp.gmcnet.org
Sent: Fri, December 11, 2009 10:57:48 AM
Subject: Re: [GMCnet] 502 post mortem
how hard is it to drop in a chevy based engine? is it bolt up or does stuff have to be modified?
also one could go with a merlin based engine from World Product$, if you have the desposible income you could have up to 632 CID or 10.3 liters! 8o
Steven Ferguson wrote on Fri, 11 December 2009 08:36
Steven Ferguson
Shop in San Deigo purchased a new HO 502 for Kerry, Mark took one look
at the huge ports on the alum heads and did not like them. With
Kerry's permission, he returned them to GM and swapped in a set of
peanut port heads. Much more suited for our needs. NOW, if Kerry had
the 4.11 ratio final drive installed, the heads might have been more
suitable......but then mileage would have gone out the window. I
don't think Kerry tracks his mileage. He just fills up and drives and
drives and drives. He has quite a few miles on that one year old
engine now.
For a mileage report on a big block Chevy in a GMC, we're going to
have to wait for a report from Dave L. But then, his engine is not
the same displacement or specs.
The oil pan is a real hum dinger to build. I took a new Gen VII pan
to Hal Kading's in Las Cruces to Xfer dimensions from his pan, to mine
for a future project. There is no area of the pan that doesn't need
modification to work with the GMC front wheel drive. Ken Rose's
modifications took away so much volume that he had to add an
additional area to the rear sump to make up for it. After looking at
it I had to wonder if it would have been easier to cut up the Toro pan
and graft it onto the Chevy pan. A ton of work went into that and I
bet the rest of the installation was easy by comparison. Ken also
modified the TH425 bellhousing in order to eliminate the need for an
adapter from the Chevy bolt pattern to the BOP. Smarter and easier
IMHO. However, it means that there are no direct bolt in rebuilt
transmissions available in the event of a failure.
Every time I talk to Kerry he seems quite pleased with the coach
performance but I get the impression that he seldom, if ever,
stretches it's legs. He pretty much prefers secondary routes and
shuns interstates.
Shan Rose
it seems the easiest way to get more cubes in our coaches is still the big old caddy motors. could build one of them and stroke it, then just drop it in and forget it. I remember seeing a 541 build which made 611 ft lbs of torque at 2700 RPM!
scott cowden
>>
> it seems the easiest way to get more cubes in our coaches is still the big old caddy motors. could build one of them and stroke it, then just drop it in and forget it. I remember seeing a 541 build which made 611 ft lbs of torque at 2700 RPM!
Don't know if everyone get's a british car tv program called 'top gear' these guys are crazy, but it's a hilarious show to watch.
yesterday, they reviewed a new Bently called the 'brooklands' i think.
6.75 litre engine- 525 hp, 1000 ft lbs torque!
don't suppose we'll be seeing one of these available at the local 'mens mall' anytime soon!!
Scott '74 Glacier Orillia, ON, Canada
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Mr.erf ERFisher
>
>
> it seems the easiest way to get more cubes in our coaches is still the big
> old caddy motors. could build one of them and stroke it, then just drop it
> in and forget it. I remember seeing a 541 build which made 611 ft lbs of
> torque at 2700 RPM!
>
>
did not seem to be the case for torque, old post from GaryC
gene
-----------------------------
was digging through some old GM test data and thought I would share the
following:
Olds 455 test data with an uncertain pedigree (Toro or not? Test
conditions?) and it showed a torque at 2800 and below of about 398. No data
below 2000, but other tests implied a peak torque at 1200 to 1600 rpm. Peak
hp was 234 at 3600.
Cadillac 500 EFI - peak torque 395 at 1200 and 1600 rpm. Peak hp 225 at
3600. The engine was knock limited and spark was retarded about 10 degrees
from MBT at most rpms. Both of these are consistent with other big GM
engines built at the time(except for the knock-limited part). Max torque
was always below 2000 rpm and peak hp was never above 4000. That's not
counting performance engines like the Chevy 427 or the Chrysler Hemi, of
course.
Olds 350 EFI (Cadillac Seville) - peak torque 290 at 1200, peak power 190 at
4400 and still rising. Not knock limited.
If the Cad 500 were tested on today's fuels would it be knock-limited?
Don't know.
Here is some examples using a typical fixed-pitch torque converter with a
2.05 stall torque ratio:
Stall speed, assuming 400 ft-lb input - 2253 rpm.
The efficiency rises with increasing speed, so I picked a couple of
operating conditions to look at - one was for a "high-load" cruise with 150
ft-lb input. I think actual loads might a little less for a coach without a
trailer. The efficiency rises, and the torque ratio drops and reaches a
peak of about 92% efficiency. Then there is a dip at the coupling point
where the torque ratio becomes 1.0 and from then on the efficiency continues
to rise. I haven't made a chart of this to post, so I hope you get the
idea. In the cruise assumption the efficiency reaches 88% at an engine
speed of 1491 and finally climbs over 92% at 1890. At 2500 it is over 96%,
so at a normal cruise speed the efficiency loss is probably 4% or less. Not
too bad, but not good.
At full load as might be used climbing a hill I assumed an input torque of
360, not quite full throttle, but close, and on a hot day at any normal
elevation that might be all there is. The converter reached 88% efficiency
at 2310 engine rpm and finally climbed over 92% at 2930. What that says is
that if you are running with your foot in it you want to have the rpm over
2930 or you can expect to be putting about 10% of the engine hp into the
transmission oil. Really not good, unless you have a direct pipeline to a
refinery and have a really big oil cooler. Better to downshift.
Hopefully this data will be useful to somebody.
Gary
--
Gene Fisher -- 74-23,77PB/ore/ca
“Give a man a fish; you have fed him for today --- give him a URL and
-------
http://gmcmotorhome.info/
Alternator Protection Cable
http://gmcmotorhome.info/APC.html
Rob Mueller
I reckon you're correct; the book "The Big Inch Caddy" outlines how to build
the 540 cu inch monster; that's what Jim K's GMC has in it.
It is relatively easy to stroke as you reduce the rod journals from 2.5
inches to 2.25 inches and use different rods. I left my copy in the USA so I
may be a bit off with this info.
I was going to do that but when I looked at the additional cost I decided
that 500 cubic inches was enough!
Regards,
Rob Mueller
Sydney, Australia
AUS '75 Avion-The Blue Streak TZE365V100428
USA '75 Avion-Double Trouble TZE365V100426
-----Original Message-----
From: gmclist...@temp.gmcnet.org
[mailto:gmclist...@temp.gmcnet.org] On Behalf Of Shan Rose
Sent: Sunday, 13 December 2009 9:28 AM
To: gmc...@temp.gmcnet.org
Subject: Re: [GMCnet] 502 post mortem
dennis...@aol.com
Scott,
I think most of the Bentleys and RR of that era also have a GM hydramatic transmission.
Dennis Sexton
73 GMC
Germantown, TN
USA
-----Original Message-----
From: scott cowden <scotty...@hotmail.com>
To: GMC <gmc...@temp.gmcnet.org>
Sent: Sat, Dec 12, 2009 4:46 pm
Subject: Re: [GMCnet] 502 post mortem
>
it seems the easiest way to get more cubes in our coaches is still the big old
addy motors. could build one of them and stroke it, then just drop it in and
orget it. I remember seeing a 541 build which made 611 ft lbs of torque at 2700
PM!
on't know if everyone get's a british car tv program called 'top gear' these
uys are crazy, but it's a hilarious show to watch.
yesterday, they reviewed a new Bently called the 'brooklands' i think.
6.75 litre engine- 525 hp, 1000 ft lbs torque!
don't suppose we'll be seeing one of these available at the local 'mens mall'
nytime soon!!
Scott '74 Glacier Orillia, ON, Canada
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MCnet mailing list
ist Information and Subscription Options:
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Larry Davick
when it ran?
Ljdavick at comcast.net
Steven Ferguson
hp & torque.
--
Steve Ferguson
'76 EII
Sierra Vista, AZ
Urethane bushing source
www.bdub.net/ferguson/
Steven Ferguson
the trend: I have a small block Chevy engine that i built 10 or so
years ago that is 352 cu in, runs on regular, and puts out 440 ft lbs
of torque at 3,600 rpm and 420 hp at 5,600 rpm. One of these days I'm
going to put it in a car.
On Sat, Dec 12, 2009 at 2:28 PM, Shan Rose <defc...@gmail.com> wrote:
>
>
--
Steve Ferguson
'76 EII
Sierra Vista, AZ
Urethane bushing source
www.bdub.net/ferguson/
Mr.erf ERFisher
It made it to Palm Desert----- you were there
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29091
Not home,but who's counting
gene
--
Gene Fisher -- 74-23,77PB/ore/ca
“Give a man a fish; you have fed him for today --- give him a URL and
-------
http://gmcmotorhome.info/
Alternator Protection Cable
http://gmcmotorhome.info/APC.html
Shan Rose
Rob, heres the article I was talking about...
http://www.hotrod.com/techarticles/engine/hrdp_0804_541_big_block_cadillac_v8/index.html
the motor peeked at 649 ft lbs of tq and 526 hp. one of these motors would be a nice drop in for our rigs. and if thats not enough HP you could probably add a small centerflugal blower with 5 or 6 psi to help on those grades....
BTW what ever did happen to Jim K's coach, did they figure out what killed the engine?
Robert Mueller wrote on Sat, 12 December 2009 18:32
Kosier
Unfortunately, that article was a very large crock of
self-serving crock of BS.
That clown knows very little about Cadillacs and the article
served to
eliminate any sign of credibility that Hot Rod Magazine ever had.
Gary Kosier who has a Cadillac-powered motorhome and seven
spares.
----- Original Message -----
From: "Shan Rose" <defc...@gmail.com>
To: <gmc...@temp.gmcnet.org>
Rob Mueller
When I decided to build the Caddy 500 I bought a copy of "Big Inch Cadillac,
"MTS Cadillac Tech Guide," 1972 Cadillac Workshop Manual, and a few other
bits and pieces.
I found there were three "players" in the Caddy arena: Jerry Potter of
Potter Automotive in Soddy-Daisy, TN: Marty & Paul Lane of Maximum Torque
Specialties in Green Valley CA; and Chris of The Cad Company, in
Albuquerque, NM.
I communicated with Jerry, Marty, and Chris and found out that Jerry Potter
had been building Caddy 500's way longer than the others. In fact Jerry
built a Caddy 500 engine for Marty and Paul and that's why they got into
Caddy 500's!
I'm not going to bad mouth anybody as it's only my opinion but at the end of
the day Jerry said some things that impressed me the most as being 100% up
front and no BS. So I went with his recommendations. I visited him last year
when Helen and I toured the east coast and it's just him and Matt that build
the engines. I met him at the shop that does his machine work and it was
without a doubt the cleanest and most organized automotive machine shop I
had ever seen!
By the way IMHO the engine that Hot Rod and Big Inch Caddy describe is not
really suited to the GMC, I'll bet both of them have a torque band is WAY
too high for us. We want the max grunt down as low as possible. However,
both have some good tips that we can use when building an engine for a GMC.
Regards,
Rob Mueller
Sydney, Australia
AUS '75 Avion-The Blue Streak TZE365V100428
USA '75 Avion-Double Trouble TZE365V100426
Shan Rose
Granted the torque curve is more suted fro a Rod then a MH from that build but more then likely that is due to the cam, a cam a little more suted fro a motorhome would probably be better, youd loose some of the top end HP but then again we never see that end of the RPM band anyway. Im sure though by 2k rpm the tq is already well above 500 ft lbs, even with that engine. so its easy to see how you can make a real stump puller with one of those motors.
Robert Mueller wrote on Sun, 13 December 2009 21:45
Shan Rose
Gary care to get into why you say that just a little?
Kosier wrote on Sun, 13 December 2009 18:58
> Shan,
>
> Unfortunately, that article was a very large crock of
> self-serving crock of BS.
> That clown knows very little about Cadillacs and the article
> served to
> eliminate any sign of credibility that Hot Rod Magazine ever had.
>
> Gary Kosier who has a Cadillac-powered motorhome and seven
> spares.
>
> ----- Original Message -----
> From: "Shan Rose" <defc...@gmail.com>
> To: <gmc...@temp.gmcnet.org>
> Sent: Sunday, December 13, 2009 2:28 PM
> Subject: Re: [GMCnet] 502 post mortem
>
>
> >
> >
> > Rob, heres the article I was talking about...
> >
> > http://www.hotrod.com/techarticles/engine/hrdp_0804_541_big_block_cadillac_v8/index.html
> >
> > the motor peeked at 649 ft lbs of tq and 526 hp. one of these
> > motors would be a nice drop in for our rigs. and if thats not
> > enough HP you could probably add a small centerflugal blower
> > with 5 or 6 psi to help on those grades....
> >
> >
> >
> > BTW what ever did happen to Jim K's coach, did they figure out
> > what killed the engine?
> >
> >
> > Robert Mueller wrote on Sat, 12 December 2009 18:32
Rick Denney
> Shan,
> Unfortunately, that article was a very large crock of
> self-serving crock of BS.
> That clown knows very little about Cadillacs and the article
> served to
> eliminate any sign of credibility that Hot Rod Magazine ever had.
Gary, I worry about you, bottling up these emotions like you do. You
really need to learn how to let it out, and tell us how you really
feel.
When it comes to GMC motors, there are three things that are
important:
1. Torque at low RPMs
2. Torque at low RPMs
3. Torque at low RPMs
And the way to get that is with smooth-flowing, narrow passages that
keep velocity high and create a dense charge. All that is lousy for
hot rods that want to live at high RPMs for competition--they'll run
out of air with engines designed for our use.
Another thing that is important for GMC engines are well-oiled and
large bearing surfaces and heavy construction. When an engine is
routinely asked to make maximum power at lower RPMs, the internal
forces on the block, crank, rods, and pistons are high. There are lots
of lightweight engines with high horsepower and torque specs on a
dyno, but let's see how long they last pushing a 12,000 motorhome
around. Hot-rod engines, on the other hand, want throttle response,
and favor lightweight rotating parts. They also rebuild those suckers
every 15 minutes, too.
There is a reason that big truck engines rate horsepower at 1200-1500
RPMs and weigh as much as a battleship.
Rick "whose working redline is 4000 RPMs" Denney
'73 230 Ex-Glacier "Jaws"
Northern Virginia
Rob Mueller
Absolutely!
The cam I have for the Caddy is one that produces max torque at lower rpm.
Also as Rick has noted the Bulldog heads have ports that not optimized for
low end torque. They also cost $2600 a pair!
Regards,
Rob Mueller
Sydney, Australia
AUS '75 Avion-The Blue Streak TZE365V100428
USA '75 Avion-Double Trouble TZE365V100426
-----Original Message-----
From: gmclist...@temp.gmcnet.org
[mailto:gmclist...@temp.gmcnet.org] On Behalf Of Shan Rose
Sent: Tuesday, 15 December 2009 4:26 AM
To: gmc...@temp.gmcnet.org
Subject: Re: [GMCnet] 502 post mortem
Granted the torque curve is more suted fro a Rod then a MH from that build
but more then likely that is due to the cam, a cam a little more suted fro a
motorhome would probably be better, youd loose some of the top end HP but
then again we never see that end of the RPM band anyway. Im sure though by
2k rpm the tq is already well above 500 ft lbs, even with that engine. so
its easy to see how you can make a real stump puller with one of those
motors.
Mike Miller
Rick Denney wrote on Mon, 14 December 2009 09:49
> ...
> When it comes to GMC motors, there are three things that are important:
>
> 1. Torque at low RPMs
> 2. Torque at low RPMs
> 3. Torque at low RPMs
>
> And the way to get that is with smooth-flowing, narrow passages that keep velocity high and create a dense charge. All that is lousy for hot rods ...
I can understand this on the intake side. It is also why most long stroke engines have good low end torque.
Does anyone know the best set-up, for torque, on the exhaust side? i.e. Muffler near the front or in the back, how big pipes? Manifolds or headers?
I am more interested if anyone really has the numbers, not just feelings or "That is how we have always done it."
Two points:
- I seem to remember same dyno pulls done on Arch's motor that showed manifolds had better low end torque... but the dyno being used was a bit unreliable at that low of RPM.
- Most cars with high rev'ing motor have the mufflers in the rear. Is this for horsepower or just where the muffler "fits?"
--
Mike Miller
`73 26' X Painted D.
`78 23' Birchaven
Hillsboro, OR
Rob Mueller
This question has come up in the past and invariably the responses have been
along the lines of; "I put headers on my GMC and it performed way better."
However, I have yet to see any before and after dyno run data.
Regards,
Rob Mueller
Sydney, Australia
AUS '75 Avion-The Blue Streak TZE365V100428
USA '75 Avion-Double Trouble TZE365V100426
-----Original Message-----
From: gmclist...@temp.gmcnet.org
[mailto:gmclist...@temp.gmcnet.org] On Behalf Of Mike Miller
Sent: Tuesday, 15 December 2009 11:36 AM
To: gmc...@temp.gmcnet.org
Subject: Re: [GMCnet] 502 post mortem
Rick Denney
> - I seem to remember same dyno pulls done on Arch's motor that
> showed manifolds had better low end torque... but the dyno being
> used was a bit unreliable at that low of RPM.
We need to remind ourselves that the headers they used in that test
were Hooker performance headers, not Thorley Tri-Y headers. The
Thorleys have smaller passages and the Tri-Y design and are not
designed for high-rev performance.
Even so, I don't imagine the headers make that much of a difference. A
resonant header will help evacuate the cylinder when the exhaust
valve, but headers are tuned to a particular engine and RPM range.
As far as mufflers go, the advantage of the single rear muffler is
removing a lot of heat from under the floor in the middle of the
coach. For most people, that reason is about 432,586 times as
important as 1% one way or the other in engine performance. The modern
3" exhausts with mandrel-bent tubes will be good enough to keep the
exhaust system from holding the engine back in any measureable way, it
seems to me.
Rick "agreeing with Gene: It won't change your life" Denney
'73 230 Ex-Glacier "Jaws"
Northern Virginia
_______________________________________________
Shan Rose
thats not as bad as the same price for an Esslinger head for my SVO motor. and thats just one head!
I'd like to see some of the numbers on the bulldog heads, I know that smaller runners with more cubes generally means more torque, are there any good aluminum aftermarket heads for the caddy?
Robert Mueller wrote on Mon, 14 December 2009 13:20
Rob Mueller
Here's the website for:
The Cad Company:
Maximum Torque Specialties:
http://www.mtscadparts.com/MTSHome.htm
Potter Automotive:
http://www.cadillacperformanceparts.com/
GO FOR IT!
Regards,
Rob Mueller
Sydney, Australia
AUS '75 Avion-The Blue Streak TZE365V100428
USA '75 Avion-Double Trouble TZE365V100426
-----Original Message-----
From: gmclist...@temp.gmcnet.org
[mailto:gmclist...@temp.gmcnet.org] On Behalf Of Shan Rose
Sent: Tuesday, 15 December 2009 4:43 PM
To: gmc...@temp.gmcnet.org
Subject: Re: [GMCnet] 502 post mortem
thats not as bad as the same price for an Esslinger head for my SVO motor.
and thats just one head!
I'd like to see some of the numbers on the bulldog heads, I know that
smaller runners with more cubes generally means more torque, are there any
good aluminum aftermarket heads for the caddy?
_______________________________________________
John Wright
If you look again at the article on the Cadillac in the April 2000
issue of Hot Rod the Flow of the Bulldog Heads both unported and
ported is presented at the bottom of the cylinder head section and
these are aluminum heads.
Cadillac did offer 5 different factory casting for the the 425/472/500
cu/in motors. 68 thru 73 they offered the 250/902/950 castings which
featured a 76 cc combustion chamber. The 950 casting being the rarest
with 250/902 being fairly common and these were compression ratio
varied 10.01 to 10.5 with these heads. These heads are also better
for 3000 to 6000 rpm applications. The heads that make the most sense
for building a motor for the coach are the 493 (smog) and 552 (non
smog) casting. They are both 120 cc heads with typical compression
ratio of 8.5 to 1 and have larger coolant passages. These heads are
good for lower rpm high torque applications, idle to 4000 rpm. You
can raise the CR to 8.7 to 1 by taking a .020 cut off the heads. What
is also interesting is that Cadillac used 5 different pistons
depending on the head and compression ratio over the years. It can
get confusing.
There were several articles on building a Cadillac motor in earlier
car magazines. Car Craft Magazine in the August and September 1999
had two very good articles by John Kiewicz who was the original owner
of CMD. Hot Rod July 2000 also had an article on the Cadillac motor
called "Torque Pig".
I have to agree with Rob that the Hot Rod motor has no practical use
in our coaches as it was built. There are alot of techniques that were
used that could be useful in assembly a motor for our coaches. I too
am consider building a Cadillac motor for the 75 coach. I would
consider the using a Jim Bounds "Kryptonite" cam design grind on a Cad
blank. As for compression ratio the 8.5 to 1 is the way to go but if
your going to us MPFI and Spark control the 8.7 to 1 might work
better. I understand with the LPG that you can run over 10 to 1. I
don't know if I would go much over a 513 motor (.030 overbore) because
of the cost of going bigger, but a 541 could be done using less
expensive parts and machine work. After all I would not be building a
5500 rpm+ motor. As for fuel and control I would at a minimum I would
use at least a TBI and spark control, but if I get dumb and build the
541 I would use the multi-port system from: <http://www.massfloefi.com/mass-flo-systems-cadillac-c-1_14/cadillac-472-500-efi-system-p-1
> I have a friend here in the GMC Great Lakers who has this system
installed on his 455 and he is really impressed with the performance
and fuel economy. See: <http://www.massfloefi.com/mass-flo-systems-oldsmobile-c-1_9
>
So much for rambling on, but there are a number of good parts to build
a really good Cadillac motor for the coach that will make a ton of
torque and that's where the name of the game is.
J.R. Wright
On Dec 15, 2009, at 12:42 AM, Shan Rose wrote:
>
>
> thats not as bad as the same price for an Esslinger head for my SVO
> motor. and thats just one head!
>
> I'd like to see some of the numbers on the bulldog heads, I know
> that smaller runners with more cubes generally means more torque,
> are there any good aluminum aftermarket heads for the caddy?
>
>
> Robert Mueller wrote on Mon, 14 December 2009 13:20
>> Shan,
>>
>> Absolutely!
>>
>> The cam I have for the Caddy is one that produces max torque at
>> lower rpm.
>>
>> Also as Rick has noted the Bulldog heads have ports that not
>> optimized for
>> low end torque. They also cost $2600 a pair!
>>
>> Regards,
>> Rob Mueller
>> Sydney, Australia
>> AUS '75 Avion-The Blue Streak TZE365V100428
>> USA '75 Avion-Double Trouble TZE365V100426
>>
_______________________________________________
John Wright
J.R. Wright
On Dec 15, 2009, at 1:16 PM, John Wright wrote:
> Shan,
>
> If you look again at the article on the Cadillac in the April 2000
> issue of Hot Rod the Flow of the Bulldog Heads both unported and
> ported is presented at the bottom of the cylinder head section and
> these are aluminum heads.
Rob Mueller
Is it possible to see the articles on the Caddy 500 online?
I tried a Goggle search and also a search in Hot Rod but nothing came up.
I did a search in Car Craft and this came up:
http://www.carcraft.com/featuredvehicles/ccrp_0505_542_ci_cadillac_horsepowe
r/index.html
This is the engine that Jerry and Richard (his son) Potter built. Jerry was
reassembling this engine after checking it out completely before he shipped
it to the guy that bought it.
The thing was AWESOME! Over the top for a GMC but it was AWESOME!
Regards,
Rob Mueller
Sydney, Australia
AUS '75 Avion-The Blue Streak TZE365V100428
USA '75 Avion-Double Trouble TZE365V100426
-----Original Message-----
From: gmclist...@temp.gmcnet.org
[mailto:gmclist...@temp.gmcnet.org] On Behalf Of John Wright
Sent: Wednesday, 16 December 2009 5:17 AM
To: gmc...@temp.gmcnet.org
Subject: Re: [GMCnet] 502 post mortem
John Wright
I will have to scan them in and send them that way. I just have the
articles cut out of magazines. You do have the 2008 article out of
hotrod copied??
I have been looking at building a Cadillac for a long time and I
believe that it is a very good options for the coach.
Give me a little time and I will see what I can do.
John
On Dec 15, 2009, at 4:57 PM, Rob Mueller wrote:
> John,
>
> Is it possible to see the articles on the Caddy 500 online?
>
> I tried a Goggle search and also a search in Hot Rod but nothing
> came up.
>
> I did a search in Car Craft and this came up:
>
> http://tinyurl.com/yd75y5z
>
> http://www.carcraft.com/featuredvehicles/ccrp_0505_542_ci_cadillac_horsepowe
> r/index.html
>
> This is the engine that Jerry and Richard (his son) Potter built.
> Jerry was
> reassembling this engine after checking it out completely before he
> shipped
> it to the guy that bought it.
>
> The thing was AWESOME! Over the top for a GMC but it was AWESOME!
>
> Regards,
> Rob Mueller
> Sydney, Australia
> AUS '75 Avion-The Blue Streak TZE365V100428
> USA '75 Avion-Double Trouble TZE365V100426
>
>
>
Steven Ferguson
no matter what they called it in the performance book, it is a GEN VI
block. That's what the P/N translates to. With the .510 lift cam,
8.75:1 CR, and iron, big valve heads, I would also say it is 450jHP.
To continue the post mortem, this thing had a lot of life left in it.
It did need a timing chain swap though as I can see where it had
started rubbing against the inside of the timing chain cover. Hasn't
been going on for too long as the grooved area is quite small. The
teeth on the sprockets were getting pretty sharp also. Some foreign
matter, could've been alum shavings from the inside of the Tchain
cover, did make it to the bearings. Again, minimal damage and I have
seen a whole lot worse on lower mileage engines. Some slight damage
to the gears in the oil pump too but again, minimal. It could
probably be reused but for $50 or less, why? The cam and lifters were
what I call gorgeous. I may end up regrinding that bumpstick if I
don't go with a roller setup.
Lastly, end play was right at .007 so it looks like the BBC took it's
licking better than most Olds 455s.
I congratulate Kerry on whatever maintenance program he has for his
GMC. It is obviously working well.
On Thu, Dec 10, 2009 at 8:36 AM, John Wright <powe...@chartermi.net> wrote:
> For the most part this is the 502 that is being talked about, there
> are several different versions available with different compression
> ratio's and output ratings. Some of the models are 338hp HT502, 450hp
> 502 HO, 502hp Ram Jet End and the 502 hp ZZ502. There may be more
> options available:
>
> <http://www.gmperformanceparts.com/EngineShowcase/index.jspengId=ZZ502502HO&engine=ZZ%20502/502&sku=12496963&engCat=bb&seo=goo_%7C_2009_Performance_Parts_Upfront_%7C_Big-Block_502_%7C_Chevy_Engine_%7C_502_chevy
> >
>
> http://tinyurl.com/yet8wpl
>
> J.R. Wright
>
>
>
>>
>>
>> s the 502 a bored out 455, or a chevy/caddy based motor?
> _______________________________________________
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>
--
Steve Ferguson
'76 EII
Sierra Vista, AZ
Urethane bushing source
www.bdub.net/ferguson/