Another overheating question
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Burning Brakes
Joined: Jan 2009
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From: Delta BC
Another overheating question
A friend of mine just put a freshly rebuilt 383 stroker motor into his 63'. He has a new Dewitt's rad (which he had with his old motor) and new 160 thermostat, etc., etc. He is running the AFB carb and manifold off his 327. After 100 plus miles the motor is still running very hot. About 222 on the IR gun. I told him to pull a plug to see if it was running way too lean. He said it looks fine. I told him that maybe his timing is way too advanced which I believe would also make it run hot. Any other thoughts.
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Burning Brakes
Joined: Jan 2009
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From: Delta BC
He put back in all the old stuff from his 327. It has the factory correct shroud, fan clutch, etc. It ran fine with his old engine in 2 weeks ago. I'm also going to tell him to check that he didn't put his fan in backwards.
Le Mans Master
Joined: Aug 2009
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From: Houston Texas
St. Jude Donor '10-'12-'13
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Burning Brakes
Joined: Jan 2009
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From: Delta BC
He believes the timing is correct. I think it is tight clearances on the new motor and he needs to put a few more miles on it. I spoke with him again and he said that it is only overheating when it is idling. It is fine when he is moving. I suggested he richen his idle mixture screws to see if that changes things.
Race Director
Joined: Jan 2002
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From: Close to DC
C2 of the Year Finalist - Modified 2020
That motor is about 10% broken in at 100mi. It's not unreasonable too have that motor run hot for a few hundred more miles. Has he changed the oil and filter yet? If not, better get it done, then again at 500 miles. I agree with all the above. As they say, "you can pay me now or pay me later"! 
Dennis
Dennis
Le Mans Master
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From: Rocklin California
I agree check timing and carb. Sounds like cooling system is fine. Was water pump replaced? I had an LT-1 350/370hp motor that I sold for a crate 383 stroker 450hp 450tq and the timing on the stroker is 32-34 VS 36 on the LT-1. BUT, I don't think 220 is all that bad if the motor does not get any hotter. I have A/C also so I had to replace the mechanical fan with a Spal 16" electrical puller fan. I never get over 200-210 in 100+ degrees ambient temperatures and the A/C blowing. Normal temps when 80 degree out, it runs no more than 190-195 with A/C on. 
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Burning Brakes
Joined: Jan 2009
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From: Delta BC
I went and checked his car out last night. It runs right at 180 when it's moving. When he stops and lets it idle it slowly climbs beyond 220. After he shut it off I could hear a lot of boiling and gurgling inside the manifold and top rad hose. I think he has a vapor lock condition. I suggested he undoes the top rad hose from the rad, bend the hose up and fill it some more through there to remove the air.
Le Mans Master
Joined: Mar 2005
Posts: 7,631
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From: Rocklin California
I went and checked his car out last night. It runs right at 180 when it's moving. When he stops and lets it idle it slowly climbs beyond 220. After he shut it off I could hear a lot of boiling and gurgling inside the manifold and top rad hose. I think he has a vapor lock condition. I suggested he undoes the top rad hose from the rad, bend the hose up and fill it some more through there to remove the air.
Melting Slicks
Joined: Jul 2004
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From: Maryland
Is he using a VAC that is connected to manifold vacuum? If he has a IR thermometer has he verified that the gauge & IR T. are in synch? Also if he has a IR T what is the temperature of the exhaust manifold after it overheats @ idle?
Last edited by Donald #31176; Jul 28, 2010 at 10:52 AM.
Le Mans Master
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From: Rocklin California
Team Owner
Joined: Oct 2000
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From: Washington Michigan
I went and checked his car out last night. It runs right at 180 when it's moving. When he stops and lets it idle it slowly climbs beyond 220. After he shut it off I could hear a lot of boiling and gurgling inside the manifold and top rad hose. I think he has a vapor lock condition. I suggested he undoes the top rad hose from the rad, bend the hose up and fill it some more through there to remove the air.
The gurgling is perfectly normal - that's hot-soak after shutdown. I've never seen "trapped air" as a problem on a midyear; all you have to do is loosen the expansion tank cap to bleed off any air.
Pro
Joined: Feb 1999
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From: Myrtle Beach South Carolina
Double check the lower radiator hose for kinks and make sure it has the internal spring still installed. That's the suction side of the pump and it will collapse if the spring is missing/weak.
Thread Starter
Burning Brakes
Joined: Jan 2009
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From: Delta BC
63' doesn't gurgle and burp after I shut it off so just assumed he must have an air pocket in there.
Cartoon Character
Joined: Jun 2006
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From: Can't be more than 114... Arizona
Get a fan that you can direct connect without a clutch and see if that works. If you force air through the rad by driving and it is cool then the problem is that you do not have enough air flow at low speed. An incredibly long shot would be that the blades in your water pump are damaged and you are not getting enough flow at low speed...
Here is a mechanical fan that I know for fact pulls so hard that it will deform the shroud:
http://www.stockcarproducts.com/fan1.htm
I had the mother of all cooling problems last year...
Here is a mechanical fan that I know for fact pulls so hard that it will deform the shroud:
http://www.stockcarproducts.com/fan1.htm
I had the mother of all cooling problems last year...
Last edited by Tintin; Jul 28, 2010 at 08:23 PM.
Le Mans Master
Joined: Mar 2005
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From: Rocklin California
The only problem with mechanical fans is they don't turn fast enough at idle to pull good airflow. That is why I switched to the Spal 16" puller. It pulls way more air at idle than a mechanical fan. Then shuts off when cruising at highway speeds as it not needed because you are getting plenty of air flow to keep the system cool. 
Le Mans Master
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From: Houston Texas
St. Jude Donor '10-'12-'13
The only problem with mechanical fans is they don't turn fast enough at idle to pull good airflow. That is why I switched to the Spal 16" puller. It pulls way more air at idle than a mechanical fan. Then shuts off when cruising at highway speeds as it not needed because you are getting plenty of air flow to keep the system cool.
Unless you are running a 7 blade fan. I chose the spal and to keep the 5 blade clutch fan.
Le Mans Master
Joined: Mar 2005
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From: Rocklin California
