Possible Reasons for Head Gakskets Blowing.... Come in and share your knowledge!!

[95CobraMike]

Possible Reasons for Head Gakskets Blowing.... Come in and share your knowledge! PICS

Would it be possible to make a list of possible reasons for a head gasket blowing? i have been having troubles and need a list of diffrent possible reasons for it happening alot so i can check off the ones that arent a possibility and narrow down my search.

thanks guys/girls

 

[wytstang]

Detonation(sp?)
overheating
Inproper hg sealing
Inferior gasket
Reusing factory "torque to yeild" head bolts *one time use only*

 

[95CobraMike]

Detonation(sp?)
overheating
Inproper hg sealing
Inferior gasket
Reusing factory "torque to yeild" head bolts *one time use only*

Detonation....nope, timing was at 10* and i ran 93 octane
overheating...my temp gauge never got past the L in normal...
Inproper hg seal....maybe im not sure
inferior gasket....nope run cometics
reusing factory bolts...nope got arp's

Thanks Wytstang
how do you know if the HG didnt seal right?

Keep em coming!!!

 

[wytstang]

Not sure exactly how but if you eliminate all other possibilitys improper sealing becomes the only answer.

 

[JJ95GTID]

The block's deck surface or the surface of the heads to block could be uneven. This will cause bad sealing. Did you have your heads ported or did you do it yourself? If you or whoever did it let the heads sit for an extended time on the surface that meets the blocks deck they can warp. That's why shops store cast heads on their ends.
Are you absolutely sure on the detonation. You are running 10psi, which is not outragous, but does increase compression ratio and could cause detonation. The MSD BTM could be malfunctioning and not pulling enough timing @ certain amount of boost.

 

[95CobraMike]

the heads were ported when i bought the car...
and last time i had the heads off, they were milled down so they were straight again..
on the predet, im not absolutley sure, i never heard any...
going to check the block deck

 

[95CobraMike]

oh BTW the HG blew in the same place almost both times....
top of the 5th cylinder the 1st time and top of the 6th this time...

 

[Joes95GT]

If it didn't detonate, and you 100% positively torqued the head bolts to the proper spec, the only other cause could be a sealing problem...

1) Heads aren't square.
2) Deck isn't square.
3) Combination of 1 & 2.
4) Deck wasn't prepped to the proper spec of the gasket. Cometics seem to be especially picky about this one.

Don't be so sure that your heads are square and flat. That, actually, would be the first place I would look. You might not have a clue as to how many TERRIBLE machinists there are in this world....

Joe

 

[95CobraMike]

this machineist was a highly recommended machineist... people around here told me they wouldnt bring their stuff to anyone but this guy.

if anything my head bolts were over torqued...could that cause a problem?

4) Deck wasn't prepped to the proper spec of the gasket. Cometics seem to be especially picky about this one.

by that do you mean the surfaces being cleaned off?

 

[95CobraMike]

Here are some picts of my cometics that blew....

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[greenlantern]

First off I never trusted the factory temp guage, its got me in trouble before. As far as head gaskets I've always run Fel-pro's, not familiar with cometics.

I think your problem might be surface prep. Either that or change to a different brand head gasket.

 

[VibrantRedGT]

Judging by the pics and that hot spot area it sure looks like detonation to me.

 

[igotyofire]

lol is there anyone without headgasket issues on a 5.0, this makes me want to turn my back on the forced induction route

 

[95CobraMike]

First off I never trusted the factory temp guage, its got me in trouble before. As far as head gaskets I've always run Fel-pro's, not familiar with cometics.

I think your problem might be surface prep. Either that or change to a different brand head gasket.

Felpro's i dont think are going to help me... cometics are multi layered steel and are suppose to be the best gaskets for supercharged cars.....they better be for $89 EACH....
both serfaces were preped fine as far as i know...the heads were milled and the block had all of the old gasket scraped off, then sanded with a really fine sanding paper



COULD the problem be that its not getting enough fuel?

 

[S/CBlack95GT]

Have you had it on the dyno to check your air fuel ratio. Most likely it is just going lean on you.

 

[95CobraMike]

i actually got an a/f ratio gauge in the car when it was acting up, i have only 2 times seen the gauge get into the ideal section....all other times it is ALWAYS lean even at WOT