I have a GSR motor fully built with a turbo, the motor was recently rebuilt with new pistons and rings. When the motor was fired, after breaking it in there was still oil on the pistons while sitting at idle, which is causing it to misfire under boost. Can anyone help???

 

is the motor smoking? Who built the motor? Tolerances? Were the valve stem seals replaced?

 

after you fire the motor it's smokin, all the seals in the head were replaced, it has new rings that were filed down to spec. There is no oil in the intake manifold either.

 

Hey Adam, are the cylinders round? It almost sounds like the bores have ovalled to me

 

There are only a few ways oil can get into the cylinder. Getting past the rings, seals, or from the turbo thru the intake.

 

I have had similar occurences with my built motor. Pulling the plugs I can look down and see oil sitting on top of a few of my pistons from time to time... but the car still runs great, doesnt smoke, and oil consumption is very low. Also compression and leakdown numbers are good. Im sure its possible the oil is coming up through the oil control rings.

I replaced the valve seals on piston #1 and it seemed to clear up the problem for a while, but then it came back lol so it most likely wasnt the valve seals. Besides it seems like guite a bit of oil to get past the valve seals and still not be burnt up during combustion.

At this point I stopped worrying and just drive the car.

 

could it just look like oil because of the carbon on the tops on the pistons....are you sure it isn't over fueling and just leaving stuff wet when you shut it down.

 

I belive these are fresh pistons he jsut put in his motor...

I wanna say thier CP Pistons.... g2turbo... what kinda pistons were you running?

 

CP pistons here as well.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by BoostR41 &raquo;</TD></TR><TR><TD CLASS="quote">could it just look like oil because of the carbon on the tops on the pistons....are you sure it isn't over fueling and just leaving stuff wet when you shut it down. </TD></TR></TABLE>

My oil is very fresh and still has the golden appearance. And the top of the pistons definitely appear to be oil and not fuel.

I thought it was fuel at first, and left the plugs out overnight and the fuel was still there in the AM... shouldn't it evaporate?

 

I had that happen on my hotrod car. The cylinders were getting out of round.

 

You make any progress yet Adam?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SpeedDreamz.com &raquo;</TD></TR><TR><TD CLASS="quote">There are only a few ways oil can get into the cylinder. Getting past the rings, seals, or from the turbo thru the intake.</TD></TR></TABLE>

and spark plug seals on the valve cover

 

thanks for the help everyone. we've got the oil situation fixed, now the miss fire is still their. works great until we go over 23psi of boost then we get the miss fire back any idea's?

 

So what was the cause of the oil getting into the cylinders?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by adam1027 &raquo;</TD></TR><TR><TD CLASS="quote">thanks for the help everyone. we've got the oil situation fixed, now the miss fire is still their. works great until we go over 23psi of boost then we get the miss fire back any idea's?</TD></TR></TABLE>

Are you running stock ign? I am breaking up around 8-9k at 450 whp right now. It might be ignition im not sure yet.

Can the car running overly rich cause misfires?
How about lack of timing? Could this also cause misfires?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by eg:R &raquo;</TD></TR><TR><TD CLASS="quote">

and spark plug seals on the valve cover </TD></TR></TABLE>

That will not get oil in the cylinder unless you pull the plugs out. That will only get oil in the plug holes.

 

looks like we got the miss fire fixed and some good numbers at the dyno ,so we are off to the track tomorrow. thanks again everyone for the help

 

not sure what the cause was, but we added the pcv valve back onto the car and let the motor run for a while thinking maybe it didn't hav eenogh time to seat

 

as for the misfire problem we went to a bigger injector, and a new distributor and that seems to have fixed the problem there, and yes I'm still running a stock ignition for now