I pulled my heads to change the head gaskets. During a nitrous run (150 shot)I preasurized the coolant system and blew antifreeze out the overflow on the radiator. About 2 gallon's worth. I assume it lifted the heads a little? (stock gm head gaskets - arp head studs) since I have no sign's of antifreeze in the oil and the car has been driving fine NA. Lately I noticed a little smoke on startup and smoke on full throttle. So it was time to pull the heads to put new gaskets on.

This is the part i'm not sure about. In the exhaust ports of the heads I have a very clean "drip" coming from inside the port by the valve UP and out the exhaust port on 6 of the 8 ports. The ports are all black except where this "drip" path goes. Drip meaning if you had a "run" while painting. The drip path is very clean down to the polished port while the rest of the port is black. Is it as simple as the valve seals are bad and oil is leaking out the seals, when I start the car if forces the oil up and out the exhaust port which keeps the path clean? The strange thing is, The exhaust ports travel upward from the exhaust valve, so it seems weird that if it was oil it could run uphill.......

I wish I took a pick before taking them to the machine shop. It would be wasy for you too see... Any thoughts?

 

We see it on a regular basis, it doesn't seem like the oil should do it, but it does. Obviously it is scavenging oil out of the guide while it is running, new seals may help, but I have seen them do this as well. Have your shop check the guides, around .001" will keep you oil and smoke free, and of course new seals.

 

My heads were the same way when I pulled them. I attributed it to excessive blowby from the cracked ring lands on my #7 piston. I guess we'll see once it goes back together. I might have a guide checked just in case.

 

Thanks Brian!