is this safe to run?

[norbs]

Those are NGK UR5's and if you notice the ground electrode is burned off,but the center electrode is unburned, and the ceramic is gone all the way up, the piston is not melted either. No big pops, smooth as silk.

 

[my85grandnation]

Those are NGK UR5's.

Well theres your problem right there. IMHO NGK's are major POS's. I ran other supposidly high performance plugs like NGK's and they worked for a bit but then they made my car start missing. Went back to AC Delco plugs and havent had a problem since. Just my .02 cents on the matter.

 

[norbs]

Which plugs should i use next time?

 

[my85grandnation]

Id use AC Delco plugs. Find the ones that are best suited to your set up and try them out and Im sure youll love them.

 

[turbolc2]

Spark Plug

I wonder if your root cause could be an injector dribble that was lit off on waste spark? If the improper combustion was quiet it makes me think the ignition took place when the piston was not at the proper position prior to TDC on the compression stroke.Thats why I wonder about waste spark & a dribbling injector.

 

[norbs]

It could be, i will find out very soon on the status of the injector. from the spark plug ground strap being melted off and the inuslaor gone, it appears it detontated, even though i there was no knock "silent detontation" possible? It could be the waste spark, but so many cars use it i Don't see it happening

 

[Cheeseburger]

Time for a R.T. rebuild, lol.

 

[norbs]

Time for a R.T. rebuild, lol.

Good idea, i'll just use the $500 they owe me as credit!, but there tolerances on boring and line honing are +/- .002. Here's the report on the stage 1 they machined. Great specs for a Lawnmower maybe


Mains honed .002 undersize, taper in cyl bore .0015

 

[norbs]

Had the injector flowed it was fine. It appears it was an act of God. Who else had problems with NGk's?

 

[bruce]

"silent detontation" possible?

It's called preignition.
And no a knock sensor has no way of sensing it, since there is no acoustic signature.

While detonation can kill a cylinder in few combustion events, preigntion can in just 2.

Often it's detonation that leads to preignition. But, the detonation may be of such short duration, and minor amplitude that a *normal* knock sensor might miss it.

On the J+S Knockguard site (if they're still around) they spend some time talking about the GM C5 project and the effort that they and Bosch put into detonation detection.

 

[norbs]

I have aleady emailed them, just waiting for the response.

 

[my85grandnation]

Ive had problems with Bosch and heard nothing but bad about NGK's so I went back to AC Delcos at the advice of the guy that put my engine in my T-Type. He is a GM Master Mechanic that works on mainly Vettes so I figured he knows whats best for GM cars.

 

[83ttypecooled]

detonation

Hi,
This has to have been caused by a detonation episode. No if ,ands , and buts about it! Not enough fuel for the huge amount of air your engine pumps IS the cause of this damage.The sparkplug damage is a result, not a cause.
One suggestion as to this cause has not been mentioned.Is your ECM letting you down? I think it is possible. Don't know what you are running, but you had better check it, or lose another motor. Oh, and by the way, I would go through the whole thing, unless you are really strapped for cash. In that case, I would pull that piston and take a good look at it. You mentioned a block score, so it's f%^&*d , anyway. Sorry to be a crepe hanger. These are all suggestions, and I could be wrong. Good luck with your troubles!
Dale

 

[norbs]

The car was run with Razor's alky kit and 94 octane fuel @28 psi boost. The ecm is a gen 7 and I don't think it has issues as the duty cycle is under 50%. Timing is at 23 and the piston or head gasket is not metled. Only thing that i can think of is uneven distribution in the plenum or the alky, but if that was the case, all the buicks with the alky kits would be having similar problems!

 

[Cheeseburger]

The car was run with Razor's alky kit and 94 octane fuel @28 psi boost. The ecm is a gen 7 and I don't think it has issues as the duty cycle is under 50%. Timing is at 23 and the piston or head gasket is not metled. Only thing that i can think of is uneven distribution in the plenum or the alky, but if that was the case, all the buicks with the alky kits would be having similar problems!

28psi+23 degrees of timing+94 octane= BOOM, alky or not..........thought you would know better???????

 

[norbs]

People have run more boost and more timing with alky, ask Razor

 

[Cheeseburger]

People have run more boost and more timing with alky, ask Razor

Ok, i will phone him right now.