Bad news upon pulling motor today

[Alky V6]

I should add something else. Another reason why I prefer to run as cold of a plug as I can is due to the fact that a colder plug has less porcelain area exposed to the combustion chamber. With that, there is less chance of a detonation or preignition event shocking the porcelain and causing a crack, or worse, causing the porcelain in whole or part to break off and wander around in your combustion chamber for awhile before deciding to exit the chamber and slam into your turbine wheel.
Racing is so much fun.

 

[murphster]

You can see some info I posted up in a post here:
http://www.turbobuick.com/forums/general-turbo-buick-tech/307197-autolite-103s-ar103s-gn1s-maybe-ngks.html#post2385549

I'm running the AR103s but was considering switching to the AR3932 if I run more boost. The ground is cut back more on the AR3932 and its not a projected nose plug. The AR3932 is colder, but there is an AR3933 that might match the AR103 better. There is also an AR3934 that even hotter.

Here is what my AR103 looks like after some highway runs and driving back home. Looks rich but I think the heat range is ok. You can clearly see the projected nose, but the ground is cut back some.

 

[Alky V6]

The thing about a cutback side electrode on a projected nose plug is that it's still a LONG ground strap. You're hanging that marshmellow deeper into the fire.
I understand why you guys might want to use a projected nose for street use, but for racing, I would not even consider running them, unless the tune was pretty mild.

 

[Alky V6]

A question for you guys. Let's see if anyone knows their stuff.

What else can affect a cylinder to cylinder plug read besides a/f ratio and ignition timing setting?

 

[Phoneguy]

Temperature , voltage , indexing , gap, blow by ,

 

[Mike Licht]

Compression ratio, cam timing
Mike

 

[Alky V6]

Temperature , voltage , indexing , gap, blow by ,

Very good.
What is the heat generator in the cylinder besides the combustion event?
What will blow-by affect?

 

[Alky V6]

Let me put a diagnostics scenario to you.

You've finished an engine that's running good, the tune is set, and all the plugs read even. Over time you start noticing #6 plug showing less signs of heat. You don't hear any difference in the way the engine sounds. In other words, no obvious missing. What could be happening?

You guys are real close.

 

[L8TRH8R]

I think I am the only one running one. No headgasket issues or burnt up plugs. I would like to see others input about it. We don't do dyno's either. Could it be something in the "Fast" system ?? We are still on a chip with a maf.

I run a power plate and XFI. Pump gas (91) and alky made 730 rwhp @26psi car ran 730's at over 101 in the 1/8 1st time on a track EVER for me or the car, horrible 60ft. And reaction times. The turbonetics controllers are garbage, that's the weak link here, although the Information shared is excellent! When this combo was first put together I had a turbonetics Deltagate and a turbonetics bc. The car would hole at 15 for about 1 second then spike to 30+ psi. Tried several things including running tuner style off the Deltagate and got the same results. Bought a precision 46mm gate and tuner style holds steady at 18. The turbonetics controller is on it's way out as I'm also going to control boost through the factory solenoid and the xfi. Just need a new solenoid! XFI tuned by Cal...

 

[L8TRH8R]

As far as dissipating the alcohol isn't that why it's recommended to stagger the nozzles, rather then have them directly across from one another? Sorry for the carnage... We've all felt that pain.

 

[SloGN]

Let me put a diagnostics scenario to you.

You've finished an engine that's running good, the tune is set, and all the plugs read even. Over time you start noticing #6 plug showing less signs of heat. You don't hear any difference in the way the engine sounds. In other words, no obvious missing. What could be happening?

You guys are real close.

fuel distrubution? what about valve lift ( cam lobe going flat, bent push rod)

 

[Alky V6]

fuel distrubution? what about valve lift ( cam lobe going flat, bent push rod)

I'm sorry. I should have set some conditions.
The fuel delivery is even for all cylinders and the timing is the same for all.
Cylinder cooling has not changed.
No major mechanical failure.

 

[SloGN]

Very good.
What is the heat generator in the cylinder besides the combustion event?
What will blow-by affect?

Blow-by can affect the effect the cylinder walls due to blowing the oil down off the skirts of the pistons.


Compression is a source of heat. very high compression diesels don't even use glow plugs as a source of heat to ignite the fuel. of course about 22:1 ratio is hot!!

 

[Alky V6]

Something that commonly and inevitably develops over the life of a racing engine. No escaping it.

 

[SloGN]

Something that commonly and inevitably develops over the life of a racing engine. No escaping it.

ring wear.

 

[Alky V6]

Blow-by can affect the effect the cylinder walls due to blowing the oil down off the skirts of the pistons.


Compression is a source of heat. very high compression diesels don't even use glow plugs as a source of heat to ignite the fuel. of course about 22:1 ratio is hot!!

This is close enough.

The loss of ring seal over the life of an engine. Particularly a hard charging racing engine.
One or more cylinders can develop more compression loss than the others throughout the life of the engine. Those low cylinders will show less heat on the plugs.
A cylinder compression and leakdown balance check will confirm this suspicion.

I have one particular cylinder at the moment that will not burn the plating off the top of the threads. Unless you're really tuned into the sound of your engine, you would not even know you had a low cylinder. I can barely detect it myself with my engine. Yet, a leakdown test clearly shows the low cylinder.

 

[Alky V6]

ring wear.

Ahh! You hit the nail on the head before I could get the last post on here. Very good!

 

[1chance]

Good info here, but I still run A/C delco's!

 

[Alky V6]

Good info here, but I still run A/C delco's!

Nothing wrong with that. The manufacturer is not important. The design is what's important. Finding the plug design that will work for you.

 

[lazaris]

This is close enough.

The loss of ring seal over the life of an engine. Particularly a hard charging racing engine.
One or more cylinders can develop more compression loss than the others throughout the life of the engine. Those low cylinders will show less heat on the plugs.
A cylinder compression and leakdown balance check will confirm this suspicion.

I have one particular cylinder at the moment that will not burn the plating off the top of the threads. Unless you're really tuned into the sound of your engine, you would not even know you had a low cylinder. I can barely detect it myself with my engine. Yet, a leakdown test clearly shows the low cylinder.

This is what I was eluding to that can happen when you start melting plugs as you have done. Overheating the cylinders enough to melt the plugs can cause the loss of ring tension and ring seal, along with other issues.
If your melting the plugs theres a problem.