[Judge not]

Hey all, I have a 1970 GTO with a fresh 455. When I hammer on it on the freeway I smell oil in the car, when I get home and investigate there is oil all over the left side of the engine. It seems to be coming out of the dipstick tube. I have a pcv valve in one valve cover hooked up to the manifold. I have an an-6 line hooked up to the right valve cover, it goes to the air cleaner base. I also have an aluminum after market valley pan with no provision for venting. Is there any way to seal the oil dipstick, there is no "o" ring on it. Or is there something else wrong? It only happens on the freeway at high rpm.

[Judge not]

Hey all, I have a 1970 GTO with a fresh 455. When I hammer on it on the freeway I smell oil in the car, when I get home and investigate there is oil all over the left side of the engine. It seems to be coming out of the dipstick tube. I have a pcv valve in one valve cover hooked up to the manifold. I have an an-6 line hooked up to the right valve cover, it goes to the air cleaner base. I also have an aluminum after market valley pan with no provision for venting. Is there any way to seal the oil dipstick, there is no "o" ring on it. Or is there something else wrong? It only happens on the freeway at high rpm.

[Ty - 68]

Have you done a compression check on the 455? How many miles on the 455? Sounds like ring blow-by. My dipstick will sometimes move out about an inch when I get on it but I never get oil out the tube. I'd look for a cause before trying to seal the dipstick tube.

[goatseeker]

John,
Fairly common problem with high crankcase pressure under higher rpms. Don't know if you race the care or not, but it would probably do the same thing there.
My advice would be to get a PCV bung placed in your valley pan to assist in relieving the pressure.
My '66 did the same thing with my '462 despite vented breathers in both valve covers and a PCV in the valley cover. Mine only did it under full throttle track conditions though. Something worth trying first is to insert the dipstick 180 degrees turned from the way you've been doing it. i.e., if the opening on the finger loop of the dipstick is facing away from the engine, insert it so the loop faces the opposite direction when it's inserted. Sounds incredibly simple but it fixed my dipstick blowout problem.

[Lerry: The Body Ventura..]

I was blowing oil out of the dipstick big time. Plus leaking oil out of rear seal and oil pan/timing chain cover gasket. Too much crankcase pressure as previously mentioned. Mufflers were not letting evac. system work.Plus I had the pcv system plugged off. I now run the pcv system with evac system on the street. When at track I plug off pcv and uncap headers to run the full evac. Seems to work well with no leaks....

[FantomPoncho]

Without proper crankcase ventilation, the pressure will push oil anywhere it can go. Including through the rear main seal (learned the hard way). All of the suggestions above should do the trick. If not, do a compression test. Hopefully your rings are ok.

[cchapman@papadocs.com]

I had the same problem with a 455 after I installed pvc valves in both valve covers and in the valley pan the blow by quit. I did put a small piece of hose around the dip stick just to make sure. I have about 2-300 miles on it since and it still seems alright. Good Luck.

[Darrell]

vent your valve covers into your air cleaner. I was suprised on how much power I picked up by doing that.

[Judge not]

Thanks Guys, I will try to vent her better.

[Brian Baker]

PCV valve ain't going to do much under WOT conditions, which sounds like where his problems lie.

Higher than stock HP engines require better crankcase ventilation than what the factory offered. Try a pair of breathers, one in each valve cover.

I had the same problem you have with my old 455 pump gas engine whenever I hit it with nitrous. Installed a pair of K&N breathers on the valve covers and that cured it.