Head gaskets lifted with boost spike?

[counterman]

My bastard transmission caused an unexpected downshift into 2nd at wot in 3rd, causing a boost spike and over rev to the limiter. The car popped, then started right back up. Afterwards, I noticed an elevated water temp. The car would not run over 180 before the incident, but it wil run 215 or so with any throttle now. I saw the telltale bubbles in the coolant jug indicating a blown head gasket. I just tore it down today, and no signs of any colateral damage exist. No bent pushrods, no piston to valve contact. I could not find an obvious fault with the gaskets, either. No blown out spots. Could it just have lifted the gaskets without any obvious tracks? Once adhesion is lost with the head, I suppose that it will not reseal, especially under boost. I have seen this before in 5.0 liter Fords running nos, so this seems plausible in this case too. What are your thoughts and experiences? Thanks, Counterman.

 

[86 TR]

How much boost were you running?

I had a similar problem with my car last year. I let a buddy make a pass in it and he forgot to shift into 3rd gear. My car ran 12.20 @ 90 in second gear!

I though for sure it was blown up. But everything appeared to be ok. It was running just as good as before. After the race day I noticed it wasn't taking the coolant back from the reservoir once it cooled off. Also I noticed a little glittery graphite material in the coolant tank. I ran it a couple of more times and the last outing both headgaskets let loose. Blew both firing rings right out! I never seen the notorious bubbles in the coolant tank on my car though?

Before the gaskets blew completely I did notice an increase in coolant temp. so that should have been my indication along with the graphite material in the reservoir to swap out the headgaskets. My fault. But the main reason I think my gaskets blew was running 24psi boost then hitting the rev limiter and all of the fuel shut off but not the air coming in. Maybe the heads lifted off the block at that boost?

I think you made a wise decision to change the gaskets because down the road it could have come back to get you. Yes, I have seen instances were the head can distort and lift but you should see some of the graphite backing of the gaskets starting to deteriorate. Once the process starts it just keeps whittling away the backing of the gasket until in finally goes.

 

[counterman]

I had my boost set at 15psi with an RJC controller. I know it spiked into the mid twenties at least when it downshifted causing the revs to jump to 6k with no load on the engine, before the wastegate could react and before the limiter killed the ignition. I suspected something was amiss, and maybe drove it 5 miles or so since the over rev, mainly to investigate whether or not it would overheat under throttle. I don't have any water in the oil at all, either, just the elevated temp and the combustion gases in the coolant jug. The heads are new Champion irons, and this is a new build. I am just hoping that their isn't a cracked head or block causing the trouble. I am not thinking along those lines because of the symptoms and how they began. At this time, I am betting a gasket lift. The leakage was comparatively minor, and the car would idle around town at 200 degrees or so as long as no boost was involved. Same at idle with just a little bubble trail into the coolant tank until the throttle was winged. That would get the medium burst of bubbles in the jug. I had probably 100 miles on the motor prior to this with no trouble, so that is why I am discounting a cracked block or head. My problems started with the boost spike. Thanks, Counterman.

 

[Ed Valvo]

I lifted a head once and I ran my car for quite a while with the intent to change it but never did. Mine resealed. I later lifted it again.

It never "blew" but it did leak. No coolant in oil. I did have bubbles in the overflow bottle. I even raced it a couple times. Temps did go up.