Pulled the heads today. Greenish-tan deposits??

[cool 84]

I pulled the heads today and found greenish-tan deposits. A solid 1/16" thick or more on both the heads and pistons. I honestly don't know how the deposts on the pistons didn't hit the deposits on the heads.

Engine has ~20,000 miles and has seen mostly 100LL for it's life. I was forced to drive it as a commuter for a few months at 210 miles a day.

Anyone know what can cause deposits this bad or this color? It always detonated at low boost. 12psi was all I could run on 91 octane and 18 degrees.

 

[charlief1]

You live in an area that has ALOT of fuel aditives. I've noticed a great deal of strange build up from fuel aditive that's in gas these days. It's probibly from that. As far as your det problem it's got to be a combo of fuel and timing. See if you can get some AV gas from the local airport. It might help.

 

[cool 84]

You live in an area that has ALOT of fuel aditives. I've noticed a great deal of strange build up from fuel aditive that's in gas these days. It's probibly from that. As far as your det problem it's got to be a combo of fuel and timing. See if you can get some AV gas from the local airport. It might help.

AV gas was pretty much all it was run on. When I did have it on 91, 12psi was all I could run. Av gas and I could run 16psi.

I have my new heads and I would like to get the problem solved before it goes back together. For what it's worth, rings are Total Seal gapless. I'm not sure if this is an oil burner or not. It never visibly smoked.

 

[charlief1]

Oil wouldn't cause a green discoloring in the combustion chamber. It has to be something with the gas unless you're running an additive of some sort. Do you have water/alcahol?

 

[cool 84]

Oil wouldn't cause a green discoloring in the combustion chamber. It has to be something with the gas unless you're running an additive of some sort. Do you have water/alcahol?

I have it sitting on the floor in the living room lol. No alky before I pulled the heads. I hope you're right that it wasn't oil consumption and just something in the Av gas.

 

[SSedan64]

How did your head gaskets look? Oil & antifreeze deposits?

 

[cool 84]

How did your head gaskets look? Oil & antifreeze deposits?

They weren't blown and the car didn't use coolant. I was thinking the same thing with the green deposits but in my limited experience, usually the cylinder that's burning water is spotless. The fire ring of the 1000s was just about in the cylinders. The 4" bore was just about too big.

 

[SSedan64]

They weren't blown and the car didn't use coolant. I was thinking the same thing with the green deposits but in my limited experience, usually the cylinder that's burning water is spotless. The fire ring of the 1000s was just about in the cylinders. The 4" bore was just about too big.

I was kidding about the Antifreeze. I thought all those fuel additives were supposed to make it burn cleaner. I'll bet the Cat is catching a lot of those deposits too. I've never heard of green deposits before. That's weird. LOL! Probably like the crap they were putting in fuel for the clean air act that wound up contaminating everyones drinking water. Clean air & toilet water.LOL!

 

[gnxtc2]

I used to run AV gas until I was told not to. AV is formulated for air planes that cruise at high altitudes and high rpm. AV gas also has de-icers and formulated to ignite in low oxygen situations.

On the other hand.....street gas is formulated to be used in street applications not at the race track. That's why there is race fuel.

Billy T.
gnxtc2@aol.com

 

[Adam Connell]

No no no... DO NOT run Av gas... that stuff is No good in cars... I can almost guarantee you that your strange deposits are from the AV gas... You should be able to get away with well over 15-16 on pump gas with a proper setup. Something is very wrong with your car if you cant get it past 12...

I had a friend who liked to run avgas in his old GTO... his engines lasted roughly 10-20k and he could never figure out why his oil was so ridiculously dirty all the time... I never saw the heads from his car, but he said there was all sorts of nasty crap inside the last engine he built. The engines kept wiping out cams, but he sold all of it and moved into LS1s so he never figured any of his problems out...

 

[jhanson1750]

Ditto on the AV gas. A friend and neighbor of mine in Oklahoma city got it at his work and ran the crap in his Dodge 360 all the time and every time he pulled the heads (which was about every other month) the combustion chambers were crudded up. I remember once you could see where the crud on the piston was hitting the crud on the head. I moved and he was still running that crap and would NEVER listen. Jon hanson

 

[Chuck Leeper]

"Green stuff"???
Ol Al Gore IS getting this country turned toward the green side, afterall!!
Get off the AV gas crap, and find out wtf is really wrong w/ the engine.

 

[Sleeper-6]

Do you usually use the same brand of fuel? I'm willing to bet there is a green dye in thir products that is leaving a deposit on things. I haven't noticed this in an automotive engine before, but I see it all the time in RC engines, you can tell what brand of fuel someone has been running by the color inside their engine. I have never seen anything as thick as what you have found. Usually it's just the parts tinted with the color of the fuel.

 

[Blazer406]

Av gas also doesn't have the oils in the gas that automobile gas has....

Bad deal all the way around...

Get it cleaned up.... and by Razor's alky kit....... you can run 20 psi on pump gas then.... and never look back.... the alky keeps things nice and clean too...