Detonation?

[homestyle]

Hey everyone!

How do I know for sure if I have a detonation problem? I have a 94' Cobra with a 9psi Powerdyne. The head gasket blew last year. I have a boost retard, but don't use it. Why?, because I either do not have detonation or don't know what it sounds like. The engine sounds fine to me. What is it, how do you identify it, and how do you get rid of it? Oh, I found out the gasket was blown after it sat thru last winter. Pitted a cylinder wall a bit. Anyone know of a filler metal to touch up the pitted area?
Only small pitted area, about half the size of a postage stamp.

Anyway, I am trying to find out if replacing the head bolts with some ARPs' will help. What's the best gasket to use? I do not want to change these head gaskets again.

Thanks in advance.

Homestyle

 

[Booyah]

Well you might not have detonation. A blown head gasket isn't always caused by detonation. It could be just from the extra stress caused by the forced induction. Detonation isn't very subtle, it's a audible popping that DOESN'T sound normal. Believe me if you have any detonation you will know.

 

[GR8WHITE]

It sounds like a handful of firecrackers muffled going off under your hood! :shocked: Some people say it sounds like marbles bouncing off your pistons. Very distinctive sound.

 

[HO93LX302]

:xpl:
Detonation sometimes sounds like golfballs hitting your windsheild as your driving.. Not a good sound to hear cause you'll know something bad is happening to your motor.. I think MSD makes something thats detects detonation.. Goes by 3 colors.. red, yellow, and green.. Red being detonation happening, yellow is on the verge of detonation and green would be ok of course.. Not sure what it's called but it's a nice peice to have.. see ya

 

[Greg@SVTOA]

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[homestyle]

Hey Nice!

You may be right. It looks like it blew between 6-7 but also had antifreeze build-up in 2. I run stock #24 injectors, 40-45 psi fuel, 190 lph pump and I am not sure on the base timing when it blew. Timing should have been stock (which I can't recall while typing). No tuning device used.

I don't know if the pistons are damaged, but they look ok from the top. The reason I think it is from the anti-freeze goo is because the pitting was located right where the goo stuck to the cylinder wall. Is there anyway to tell if the pistons and rings are alright short of yanking the motor? It seems to me that the rings would have to have melted to cause the scenario your talking about.

It did start to emit a single backfire when I let off the throttle after going to WOT, but I think that might have started right when the gasket was starting to go. The gasket did not blow suddenly. It just got progressively worse over time (over-heating began and white smoke out of the drivers exhaust).

Any advice appreciated.

Homestyle

 

[Greg@SVTOA]

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[Booyah]

Originally posted by homestyle
Hey Nice!

You may be right. It looks like it blew between 6-7 but also had antifreeze build-up in 2. I run stock #24 injectors, 40-45 psi fuel, 190 lph pump and I am not sure on the base timing when it blew. Timing should have been stock (which I can't recall while typing). No tuning device used.

I don't know if the pistons are damaged, but they look ok from the top. The reason I think it is from the anti-freeze goo is because the pitting was located right where the goo stuck to the cylinder wall. Is there anyway to tell if the pistons and rings are alright short of yanking the motor? It seems to me that the rings would have to have melted to cause the scenario your talking about.

It did start to emit a single backfire when I let off the throttle after going to WOT, but I think that might have started right when the gasket was starting to go. The gasket did not blow suddenly. It just got progressively worse over time (over-heating began and white smoke out of the drivers exhaust).

Any advice appreciated.

Homestyle

Man oh man :shocked:, go with what Nice Asp told you. You definately need more fuel.