serious overheating at race speeds, 95gt

[mike stevens]

I'm blowing headgaskets on the first day of track time. No external leaks, no coolant in the oil, no oil in the coolant. Has sve aluminum rad. stewart waterpump, gutted thermostat. arp headbolts, felpro gaskets. I have a stock block and heads, stock cam.
I'm down to either a blockage in the flow, hot spot internally, airflow thru the radiator issues.
I've heard the radiator draws its air primarily underneath. Is this true? What aero mods have any of you used? I welcome any thoughts on this. I'm missing something.

Last time out, I used another short block, scored the pistons and cyl. walls on the last one.

Mike

 

[ttocs]

do you have the air deflector under the core support? It is just an L-shaped piece of plastic but it helps to create a low pressure system behind it to help suck the heat out of the bottom of the car. If you are overheating while just idling, then it is a different problem but it it is only when moving then take a look.

 

[mike stevens]

I ordered an air deflector today

 

[Musturd]

damn that’s rough . I’ve gotta sve radiator and stock fan on my car never gets above 203 even in 105* heat

 

[ttocs]

you might also check to be sure the fan is going into high speed mode and not staying low speed.

 

[RAU03MACH]

was the engine recently built
head gaskets can be put in the wrong way blocking important passages
just asking if engine was rebuilt
and just a thought

 

[Musturd]

Very good point ^

 

[RAU03MACH]

something else you may want to try
check timing
and for the hell of it run a compression test
make sure all cylinders' are close to even
this will tell also if a gasket is leaking internal

 

[RAU03MACH]

i also in your statement a gutted thermostat
if its a open thermostat never open or close
that will run hot constantly
change it

 

[mike stevens]

running a used engine, compression hovering around 130 lbs. thermostat us gutted to prevent having a stuck closed one. This is a stock engine, maybe 250 hp. The class that I run requires stock engine. Can delete smog and exhaust is free.

 

[RAU03MACH]

A gutted thermostat won't help you

 

[ttocs]

As he said if the coolant does not stay in the rad long enough it will just keep heating up as it cycles endlessly. I missed that in the OP, I would fix that as well asap.

 

[Daryl]

Same problem a while ago. Same responses… and solid advice mind you. I swapped in a new Mishimoto radiator with brackets, upper and lower hoses and T-stat along with the lower air deflector. And the proper lb radiator cap. Only thing NOT Mishimoto is the coolant. I’m running Preston’s pre-mix + Water Wetter.

 

[cobrajeff96]

You should have no problems cooling down the motor with that setup. However, if the track you're racing on is one of those tight/technical ones with not a lot of straight shots, cooling will then depend almost entirely on the fan.

 

[Rod]

Replace your Tstat. Also burp the cooling system. It is really easy to miss getting out all the air in the system. Pull the water pump and make sure the vanes are not shot.

 

[mike stevens]

Rod there is no thermostat, only a restrictor. new waterpump already. thorough burping the system is a definite thought.

 

[RAU03MACH]

why would you run without a thermostat
makes no sense

 

[ttocs]

the thermostat is the first thing I would replace. I think stock is 192 degrees IIRC?

 

[Frank.JD.Perez]

Post pictures of your setup.
Are there not multi layer gasketd for thr sbf?

 

[Frank.JD.Perez]

If youre worried about the tstat run thr mishimoto race one that opens at like 162 or something. Ive never had a issue with my car overheating and ive ran some hot ass days