bill h
coastal reconquista
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Joined: 08/02/2001
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Daveinet wrote:I purchased my 502 from http://www.crateenginedepot.com/store/nbspnbspBig-Blocks-C54.aspx. If I had to do it over, I would either order the ZZ502 and put a different cam in it, or just buy the Ramjet. The reason is that the ZZ502 has oval port heads, which will still flow decent at low RPM, but are faster burn heads than the HT502. The Ramjet just has enough torque over the full RPM band that it would do just fine. What you want to stay away from is the HO502 with rectangular port heads, as they will not do much in the low end.
The HT502 has peanut port heads, which are designed for low RPM torque, but they are an old design cast iron head. The ZZ an aluminum head and has a better chamber design that promotes a faster burn. Faster burn helps efficiency as well as discourages detonation. They can get away with higher compression because of the faster burn. So, the best of both worlds is the faster burn head, but put a high torque cam in it, such as the HT cam. You can custom order any configuration of these engines.
The RamJet is also a serious contender as well. With longer intake runners, it will help the low end torque. The biggest advantage of port injection is that it allows for longer intake runners, without the fuel falling out of the air at lower RPMs. That has always been the limit with TBI or a carb, is that if the runners are too long, the fuel falls out of the air, and puddles in the bottom of the manifold. So this limits the length of the runner which hurts the bottom end. Port injection will do better in the low and midrange because of the intake design.
Dave, have you considered different heads on your 502?
84 Barth 30 tag powered by ht502/Thorley, Gear Vendors OD
Siamese Calvin and Airedale Hobbes
4WD Toyota toad
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Jim83Itasca
La Quinta Calif
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Joined: 09/16/2003
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Bill, I can sniff out a rebuild here.....A 1/4 stroker kit would be a very nice addition IMHO along with some decent heads and cam..
Jim
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Daveinet
il
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Joined: 10/29/2003
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bill h wrote:Dave, have you considered different heads on your 502? Yah, but I'm done spending money for a while. I'd go for Edelbrock if I were to change.
Dave
FMCA F298817
'83 Revcon Prince 31' FWD
502 w/Howell/Edelbrock MPFI, Thorley's & Magnaflows,
Koni FSD, Class A built for gear heads 
??????
Revconeers Forum
There is nothing compassionate about taking someone elses money and giving to the poor.
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West Coast FT
California
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Joined: 11/24/2005
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jpancini wrote:Thanks for all of the info.. I'm rethinking my decision and plan on talking to my mechanic tomorrow about doing a rebuild of the current engine. I just finished a trip in early October from Indianapolis to Bar Harbor and back, that is when the problem started. Large amounts of oil was being blown into the breather which created a lot of white smoke. The mechanic said there was no sign of water in the oil. This engine has always been strong and solid - even on the trip back from Maine.
I think you're headed in the right direction. This is definately sounding like my Ford problem last fall. Could be a blown head gasket, or burnt/damaged valves, cylinders 4 and 6 on mine, if I remember, Either way you won't know until tear down.
Please keep us informed. I'm sure a valve job is cheaper in your neck of the woods than mine. My heads were pulled from the top through the "doghouse" on mine, which is probably the incorrect term on a class A. Anyway, if the bottom end and block are good. I would really consider the valve job, water pump, and possibly timing chain if its being torn down anyway. Unless you know the water pump and chain were changed out eariler in the engines service life, Its cheap insurance for the next 100K
Almost forgot, If you overheated in any part of your trip. Compression test the radiator cap. My spring while still working tested at 5 lbs but wouldn't hold 13 lbs as spec'd. Spend most of this summer trying to figure out why I was losing coolant near the expansion tank.
* This post was
edited 11/03/09 12:44pm by West Coast FT *
TV 02' Chevy Silverado 3500 8.1 liter 4X4, Rancho 9000, Airlift Airbags 2 Honda EU3000,plus paralleling kit (6000 Watts peak!)
Old Rig (03' Lance 1161) Boy I missed it!
New Rig (05' Cedar Creek 37RDQS)
Second new Rig 1996 Damon Intruder 325B
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BULLETLS1
Guatemala, C.A. (NOT Dakotas, Wyoming, Iowa...)
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Joined: 11/29/2008
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for ease of installation and back to service time Ill go with engine rebuild w/overzise pistons, and few upgrades....
but only one tread of "dieselization"?
this should be a "project" mor than a "repair"
I I HAVE A DATE WITH ETERNITY, AND I DON´T WANT TO BE LATE!
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Lariat trucker
Sticksville, TX
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Joined: 11/18/2005
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An alternative would be a Jasper Remanufactured Engine, it is enough cheaper with a better warranty. They are actual done close to your HB in Indiana. I'm sure your mechanic is familiar with them and can quote a turnkey job cost.
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olds468
WV
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Joined: 03/24/2009
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If you are considering a different motor Steve Schmidt engines of Indy. His shop builds all kinds of motors. Nothing can beat cubic inches.
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bill h
coastal reconquista
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Joined: 08/02/2001
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If you choose a rebuild,and want more power, consider a stroker kit. Lots of poop for not too much extra money.
I think the crate ht502 is pretty neat. Mine has Thorleys, X pipe and turbo mufflers, and really gets up the hills.
Some of the above will be related to your tolerance for slow hill climbing.
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patnchris
Gurnee, Il. USA
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Joined: 08/06/2002
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Another vote for Jasper. I got my engine from them in 2004. Make sure you specify that you want a medium duty truck engine. The car/light truck engine makes more horsepower, but the medium duty truck engine makes gobs of low end torque. Motorhomes were actually built with both, which may explain the different performance claims for the "same" engine......
Patrick and Christine
and Maggie May, the cocker spaniel
1995 Damon Ultrasport 3470
Rallies Attended "21"
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wny_pat
Western NYS
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olds468 wrote:If you are considering a different motor Steve Schmidt engines of Indy. His shop builds all kinds of motors. Nothing can beat cubic inches. My mechanic is also a custom builder - http://www.stevesautoandmachine.com/index.html
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