Quick backstory-built 2.3 (arp 625+ headstuds) with a 6466. Made 800 on dyno with no issues. Tuner took it out, did a fourth gear pull, and blew front cylinder 3 freeze plug out.

Obviously, I have to replace freeze plug. Plans were to do that and retorque head studs, as this engine has 250ish miles on it. Should I be worried about the headgasket? I dont really want to do extra **** I dont have to. My issue is I know a compression/leakdown wont really show if the head is lifting under boost.

Other question-being told I should oring the head for anything over 700, while the last engine I had in the car wasnt and made more power/boost. Really just looking for guidance. Thanks!

 

I would at least do a leak down test.

 

My worry is the car runs perfect, and that this test wouldnt actually test under boost. Any ideas?

 

OP, I don't think you need to oring the block or head. What does need to happen is the block deck and cylinder head need to be checked for straightness using a precision straight edge and feeler gauges. Once you have verified that and installed a new OEM MLS head gasket after thoroughly cleaning the surfaces, you should be golden. The head studs you are using are solid as well.

 

So, with the freeze plug coming out, are you saying for sure head gasket? Again, the engine head was planed 250 miles ago and the engine has the same amount of miles.

 

99% of the time it is, or your radiator cap isn't working properly. Most start to release coolant into the expansion tank at 1.3 bar. Check this tank to see if it is overflowing. It takes a lot of pressure for a freeze plug to come out. Plugs are really only supposed to come out if the coolant had too much water in it and it froze in the block. If the head was resurfaced 250 miles ago, it's possible the block deck itself isn't straight. You could take a chance and install a new freeze plug to see if it happens again, but I think it's worth a check even if you find nothing is wrong with the surfaces. What torque pattern and torque spec are you using with the head studs?

 

Freeze plug is a misnomer, they are casting plugs. The engine block has internal cavities and the mold the molten block metal was poured into had sand cores. These cores have to be positioned somehow and the air needs a pathway to escape as the liquid metal goes in. After the block is cast it goes onto a shaker to knock out the sand. Then the holes are machined for 'freeze plugs'. So, the only thing the engine maker is interested in is inserting the cheapest possible plug that doesn't leak.