hey!
I am running a rebuilt engine and my compression tests:
1. 180
2. 190
3. 180
4. 180

This is in my gsr with 9:1 JE pistons. Car runs quite good.
I noticed while retuning my car today that at idle every once in a while, I get some grey smoke coming out the exhaust. Clears once I have been driving and I don't see it in full boost (up to 13psi) and I am tuned quite well.

I pulled the plugs and notice that in the #2 cylinder the plug had a slight oil stain and if I look inside the cylinder I can see the top of the piston and it looks like there may be oil on the top. There is no oil in the plug chamber (meaning its not dripping from around the valve cover seals).

I had my head reworked with the valves polished and lashed and new valve seals put in.

How can I narrow down where this is coming from? What should the tops of the pistons look like when you peer down into them with a flashlight from the spark plug hole?

I'm assuming its the head. I'm tempted to buy a head and have it totally reworked by portflow.


It seems like its just one thing after another
Thanks!

Torin

 

ttt

oh, also, after 1000miles I change from castrol gtx 10w30 to mobile 1 10w30 and that made the smell of burning oil noticeable on rare occasions. especially coming off throttle to a stop. is that diagnostic of anything?

 

ttt

 

Dude...I wouldn't sweat it too much...Your compression is good...and if your not losing power then it should be ok...you might be getting some slight blowby, or maybe your valve cover is leaking into the plugs a bit...try toning down the boost a bit, and changing that one plug to see if it happens again..

 

thanks Miraiz.
thats what i was hoping. i cant believe it would be the valve cover cause i would see the oil along the spark plug and down the threads of it, right?

It must be valve guides or the shop just screwed up the new valve seals!

anyway, no harm in some oil getting past the head onto the tops of the pistons??
wont it crud them up? i hope the lower compression pistons will help resist detonation.

Power seems to be just fine though.

torin

 

I've heard that Mobil 1 (due to it being a synthetic) has a smaller molecular structure that allows it to get past seals easier. (Could be why you're smelling oil more now)

X2