[vnmous93cobra]

A buddy has a freshly built 331 SBF they are using in a road race car. They took it for a few spins around the neighborhood, and it blew a head gasket. He pulled the heads off, and had a machine shop resurface to make sure there was no warping. He put them back on, and took it out to the track today to test some more. It blew a head gasket again shortly into the test session. There is no water in the oil, no water coming out of the exhaust that he can see, but it is losing water and starts to overheat after about 10 laps (2.5 mile hard laps).

This is a basic DSS 331, GT40 heads, nothing exotic. He is using Felpro 8548 gaskets with factory head bolts torqueing to 80 ftlbs.

Any ideas what could be causing this?

 

[vnmous93cobra]

The deck has been checked, and is square. It's blowing on the #3 cylinder each time.

 

[STEVEB]

What year is the engine, factory head bolts were changed in 1991 to torque to yield and are a 1 use only, torque on the factory bolts is 72ft lbs, 80 could be distorting the deck on the block.

 

[vnmous93cobra]

'95 block I believe

 

[strokeme]

The year of the block is irrelevant. Is he re-using used stock head bolts?

 

[vnmous93cobra]

New head bolts, stock replacement nothing fancy, torqued to 72 originally but went to 80 after original issues.

 

[strokeme]

OK he has the head gaskets on correctly, ya?

 

[vnmous93cobra]

I would assume so, he's not a rookie, but I'll ask.

 

[vnmous93cobra]

Yes, head gaskets are on correct.

 

[JWRE1]

How much total timing?

 

[Ben Mens]

Make sure head bolts are not bottoming out in block before proper clamp is applied. Too long of head studs will do same if he is running studs.

 

[vnmous93cobra]

No studs, factory replacement head bolts.

Timing is set at 10 deg initial with the factory EFI computer system.

 

[ordinary builder]

are you retorquing after an innitial warm up / heat cycle....????

 

[vnmous93cobra]

No, I'm not torqueing anything.

 

[mc0311grunt]

Is he re using torque to yield bolts?

 

[ordinary builder]

time for o rings and copper and studs.

can go to 1/2 inch too....

 

[vnmous93cobra]

Is he re using torque to yield bolts?

No he's not.

 

[REDSTANG]

Water pump spinning the correct direction and pumping proper?

 

[REDSTANG]

time for o rings and copper and studs.

can go to 1/2 inch too....

Maybe his torque wrench doesn't....krick krick

 

[vnmous93cobra]

time for o rings and copper and studs.

can go to 1/2 inch too....

Yes, that's what everyone does on a pretty much stock rebuild.