DocThrottle

Hi guys, new to the forums, hopefully someone can help me with a problem thats been plauging me for a while now. I've got oil leaking from the rear main at WOT. I know that this is due to excessive crankcase pressure, question is what to do about it. When we built the engine we were advised (maybe wrongly) to file the ring gap to .015" because we knew we were going to use a nitrous system. So... To date, I have replaced the seal and installed a header collector type evac setup. I have a breather in each valve cover with hoses running down to H-pipe just after the header collectors. Also still running the factory pcv set-up. no luck... still have same problem. the more I read, the more it seems that the evac setup is not intended to work with full exhaust and mufflers. There is not alot of engine vacuum due to the cam, so, what now? I'm not opposed to running a vacuum pump but I understand they don't last long on the street. Any advice would be appreciated.

Its a 92 LX with a 331, Edelbrock performer RPM heads and intakes, Comp x-treme energy .555/.565 lift (can't remember grind number), 3" exhaust all the way out and a NOS Bigshot

MustangBradley

I must be reading your post wrong. Are you saying you have a pipe running from the exhaust into the valve covers? Are you pumping exhaust gases into the crankcase with this? I would think that would explain your pressurized crankcase problem. The crankcase should be vented into the intake system, not the exhaust system.

DocThrottle

No. Thanx but... the evacuation kit works on the venturi effect created by the exhaust gasses passing thru the collectors to get vacuum. see here...
http://www.summitracing.com/parts/MRG-6002/

luckythirteen13

thats the same kit i use except i only run one side, the other breather is open to atmosphere. works quite well. have you tested to make sure the evac kit is actually pulling a vacuum? if not, i would test that. depending on how you installed the tubes into the headers will effect how well (or if at all) the kit works.


welcome to the forum

MustangBradley

Well I'll be damned, learn something new everyday. I stand corrected.

DocThrottle

Well the weather has finally turned and I found some time to put a vaccuum gauge on the EVAC hose. I get no more than 3in Hg. I dont claim to be an expert, but seems to me this is not enough to EVAC the crankcase. I'm leaning toward a GZ motorsports vaccuum pump.

luckythirteen13

are you running a single hose or two hoses? is this vac reading when the line is hooked up to the motor or just hooked to the gauge?

DocThrottle

Two hoses, one in each cover. took the reading with one unhooked from the breather and hooked to a vac gauge. Also been wondering... What should I be doing with the factory PCV? Cap it? or continue running it?