Home » Public Forums » GMCnet » [GMCnet] 502 post mortem
| [GMCnet] 502 post mortem [message #67024] |
Wed, 09 December 2009 09:54  |
Steven Ferguson
Messages: 3447
Registered: May 2006
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As many of you know, Kerry Tandy's 502 powered Ken Rose coach ingested
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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| Re: [GMCnet] 502 post mortem [message #67121 is a reply to message #67116] |
Thu, 10 December 2009 16:12  |
powerjon
Messages: 2446
Registered: January 2004
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When I talked to him at the Bluewater Lunch Bunch meal we had last
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
On Dec 10, 2009, at 4:43 PM, Rob Mueller wrote:
> 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
>
> -----Original Message-----
> From: gmclist-bounces@temp.gmcnet.org
> [mailto:gmclist-bounces@temp.gmcnet.org] On Behalf Of Gary Casey
> Sent: Friday, 11 December 2009 3:34 AM
> To: gmclist@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.
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J.R. Wright
GMC GreatLaker
GMC Eastern States
GMCMI
78 30' Buskirk Stretch
75 Avion Under Reconstruction
Michigan
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| Re: [GMCnet] 502 post mortem [message #67181 is a reply to message #67170] |
Fri, 11 December 2009 10:57 |
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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! 
| Steven Ferguson wrote on Fri, 11 December 2009 08:36 |
Here is more info:
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 <defconfx@gmail.com> wrote:
>
>
> s the 502 a bored out 455, or a chevy/caddy based motor?
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
--
Steve Ferguson
'76 EII
Sierra Vista, AZ
Urethane bushing source
www.bdub.net/ferguson/
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73 Canyon Lands, (a.k.a. The Yellow Submarine) West Los Angeles CA
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| Re: [GMCnet] 502 post mortem [message #67186 is a reply to message #67181] |
Fri, 11 December 2009 11:26 |
powerjon
Messages: 2446
Registered: January 2004
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Shan,
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
>
>
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J.R. Wright
GMC GreatLaker
GMC Eastern States
GMCMI
78 30' Buskirk Stretch
75 Avion Under Reconstruction
Michigan
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| Re: [GMCnet] 502 post mortem [message #67187 is a reply to message #67181] |
Fri, 11 December 2009 11:30 |
Ray Erspamer
Messages: 1707
Registered: May 2007
Location: Milwaukee Wisconsin
Karma: -3
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Senior Member |
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Looks like this would be a blast to have in the GMC.........LOTS of low end torque.......what would be the guesstimate on mileage ??
Ray
Ray & Lisa Erspamer
78 Royale Center Kitchen
The Malosco Cruiser (TZE368V101144)
Wauwatosa, Wisconsin 53226
Email: 78GMC-Royale@att.net
414-745-3188
Web Site: http://ray-lisa.page.tl/
________________________________
From: Shan Rose <defconfx@gmail.com>
To: gmclist@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
> Here is more info:
> 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 <defconfx@gmail.com> wrote:
> >
> >
> > s the 502 a bored out 455, or a chevy/caddy based motor?
> > _______________________________________________
> > GMCnet mailing list
> > List Information and Subscription Options:
> > http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
> >
>
>
>
> --
> Steve Ferguson
> '76 EII
> Sierra Vista, AZ
> Urethane bushing source
> www.bdub.net/ferguson/
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
_______________________________________________
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Ray Erspamer
78 GMC Royale Center Kitchen
403, 3.70 Final Drive
Holley Sniper Quadrajet EFI System,
Holley Hyperspark Ignition System
414-484-9431
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| Re: [GMCnet] 502 post mortem [message #67241 is a reply to message #67187] |
Sat, 12 December 2009 07:13 |
Steven Ferguson
Messages: 3447
Registered: May 2006
Karma: 0
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Senior Member |
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It is not as much a dream engine as you would think. When the Dyno
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.
On Fri, Dec 11, 2009 at 9:30 AM, Ray Erspamer <78gmc-royale@att.net> wrote:
> Looks like this would be a blast to have in the GMC.........LOTS of low end torque.......what would be the guesstimate on mileage ??
>
> Ray
>
> Ray & Lisa Erspamer
> 78 Royale Center Kitchen
> The Malosco Cruiser (TZE368V101144)
> Wauwatosa, Wisconsin 53226
> Email: 78GMC-Royale@att.net
> 414-745-3188
> Web Site: http://ray-lisa.page.tl/
>
>
>
>
> ________________________________
> From: Shan Rose <defconfx@gmail.com>
> To: gmclist@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
>> Here is more info:
>> 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 <defconfx@gmail.com> wrote:
>> >
>> >
>> > s the 502 a bored out 455, or a chevy/caddy based motor?
>> > _______________________________________________
>> > GMCnet mailing list
>> > List Information and Subscription Options:
>> > http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>> >
>>
>>
>>
>> --
>> Steve Ferguson
>> '76 EII
>> Sierra Vista, AZ
>> Urethane bushing source
>> www.bdub.net/ferguson/
>> _______________________________________________
>> GMCnet mailing list
>> List Information and Subscription Options:
>> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
>
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
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>
--
Steve Ferguson
'76 EII
Sierra Vista, AZ
Urethane bushing source
www.bdub.net/ferguson/
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| Re: [GMCnet] 502 post mortem [message #67280 is a reply to message #67024] |
Sat, 12 December 2009 16:28 |
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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!
73 Canyon Lands, (a.k.a. The Yellow Submarine) West Los Angeles CA
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| Re: [GMCnet] 502 post mortem [message #67283 is a reply to message #67280] |
Sat, 12 December 2009 16:48 |
Mr ERFisher
Messages: 7117
Registered: August 2005
Karma: 2
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On Sat, Dec 12, 2009 at 2:28 PM, Shan Rose <defconfx@gmail.com> wrote:
>
>
> 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
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| Re: [GMCnet] 502 post mortem [message #67299 is a reply to message #67282] |
Sat, 12 December 2009 21:06 |
Dennis S
Messages: 3046
Registered: November 2005
Karma: 2
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Senior Member |
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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 <scottyforsail@hotmail.com>
To: GMC <gmclist@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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Dennis S
73 Painted Desert 230
Memphis TN Metro
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| Re: [GMCnet] 502 post mortem [message #67305 is a reply to message #67299] |
Sun, 13 December 2009 01:30 |
 |
ljdavick
Messages: 3548
Registered: March 2007
Location: Fremont, CA
Karma: -3
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Senior Member |
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Does anyone know how many horsepower Jim K's twin turbo Caddy produced
when it ran?
Ljdavick at comcast.net
On Dec 12, 2009, at 7:06 PM, dennisfsexton@aol.com wrote:
>
> 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 <scottyforsail@hotmail.com>
> To: GMC <gmclist@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
>
>
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
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>
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> ligible CDN College & University students can upgrade to Windows 7
> before Jan 3
> or only $39.99. Upgrade now!
> ttp://go.microsoft.com/?linkid=9691819
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Larry Davick
A Mystery Machine
1976(ish) Palm Beach
Fremont, Ca
Howell EFI + EBL + Electronic Dizzy
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