PTE Miata Head Gasket and Head Work

Our little PTE Miata that Aaron bought last year only made it a couple track days before it overheated severely and ended his season. With a supposedly fresh motor in it when purchased, I didn’t think we needed to go over it with a fine tooth comb, but that was a big mistake. The engine builder who put the motor together used thin vacuum caps to block off some coolant ports that were no longer needed. The problem is that thin vacuum caps don’t hold up to the heat and 15psi pressure of the coolant system. A cap split, driver didn’t notice until it was too late, and we had a blown headgasket (or at least we hoped as that would be best case when they check the description). Ouch. A better solution if you can’t close the ports off with metal plugs, is to use heater hose of the same size along with a bolt for a plug and hose clamps. Much stronger solution that will not fail. It isn’t pretty, but race cars aren’t always pretty. With it overheating pretty bad, I wasn’t sure what else we hurt in the motor, but you won’t know till you open her up 🙂

I pulled the head at the end of the year, and sent it off to the machine shop to check for warpage/cracks/ etc. What we found was the head was ok, but the fresh headed needed valves/guides/seals as nothing was sealing up like it should. Easy enough, it just costs money right? Luckily the cylinder bores looked great, and the motor turned over like butter, so we took a chance and threw the head back on with a new gasket set and hoped for the best. The radiator and block had significant rust in it from running straight water (which we initially thought was oil), so I pulled the radiator, treated and cleaned it, and flushed the block and system 5-6 times while warming up the new motor. Luckily, everything cleaned up great and the motor is running well. Our 3 offending coolant ports are fixed to prevent that from happening again, so off to Hallet on the 28th for some testing.

More from the Blog

Leave a Reply