Donny vestal Posted August 17, 2010 Share Posted August 17, 2010 can anybody tell me why my 400 is building pressure in the bottom end.i can drive it around town it aint that bad but get out on a long run it blows oil out the valve cover oil cap[vented]and the front seal. Quote Link to comment Share on other sites More sharing options...
Mike 57 Posted August 17, 2010 Share Posted August 17, 2010 What type of PCV/breather setup are you running Donny? Quote Link to comment Share on other sites More sharing options...
Donny vestal Posted August 17, 2010 Author Share Posted August 17, 2010 standered pvc off my 600 holly and crome vented oil cap Quote Link to comment Share on other sites More sharing options...
BAMC1369 Posted August 19, 2010 Share Posted August 19, 2010 I have the same problem with my 400sbc. Quote Link to comment Share on other sites More sharing options...
Winston Wolf Posted August 19, 2010 Share Posted August 19, 2010 Get a new PCV valve, your's is probably just shot. They are cheap <10$ Quote Link to comment Share on other sites More sharing options...
BAMC1369 Posted August 20, 2010 Share Posted August 20, 2010 That might work for donny. I dont have one, if i get that set up should that take care of it? Quote Link to comment Share on other sites More sharing options...
Winston Wolf Posted August 20, 2010 Share Posted August 20, 2010 A PCV setup is the difference between the breather leaking oil on top of everything and it not leaking a drop. (in my car at least) It will also help your oil last longer, drawing out the caustic fumes from the crankcase. Unless you have a drag only car, I would run one for sure. Cheap, easy and they work. Quote Link to comment Share on other sites More sharing options...
monte70car Posted August 20, 2010 Share Posted August 20, 2010 We have a pcv/air breather on a small block and it blows oil out between the bottom of the timing chain cover and oil. Quote Link to comment Share on other sites More sharing options...
wallaby Posted August 20, 2010 Share Posted August 20, 2010 Every motor has leakage past the rings. Older high-mileage engines are worse. The PCV will do its best to vacuum out the excess pressure from inside the crankcase, but if the rings don't seal well, the pressure problem is too much and it's going to escape (with oil) from somewhere. Your problem seems to be with high speed running. Most of the time pressures build when the engine is heavily loaded. If you have oil pushing out of you breathers with light load and high speeds, I'd check the location of the breather openings in the valve covers: are they aftermarket covers without baffles and the breathers are positioned directly over a rocker arm? That is a recipie for problems. Quote Link to comment Share on other sites More sharing options...
kc8oye Posted August 25, 2010 Share Posted August 25, 2010 make sure you have baffles in the valve covers too.. Quote Link to comment Share on other sites More sharing options...
Heckeng Posted August 25, 2010 Share Posted August 25, 2010 make sure you have baffles in the valve covers too.. I second that one. It will make a big difference on oil drippage. Quote Link to comment Share on other sites More sharing options...
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