The V8 Owners Forum -

Can anyone give me some help and advice please, I have a rv8 circa 1980 sd1, it is completely rebuilt and slightly tuned with a piper fast road cam, stage 1 heads, lightened flywheel, offenhauser intake with a edelbrock 500 carb, the sump leaks oil only when running which I believe to be sump pressure, no oil is leaking from the valley gasket, I have changed the sump gasket twice but still leaks, my rocker covers are the ones with a small pipe coming out of the top and linked together via a t piece to the bottom of the air cleaner, there are no flame traps or pcv valves, I have read up on solutions and believe that the way forward is to install on the near side rocker cover an inline pcv valve direct to the pcv valve input on the front of the carb and the off side rocker direct to the air cleaner, I have read that there different types of valves that restrict flow etc so if this is the way forward what types and where is the best place to get them from, am I missing anything or is there a better solution, thanks in advance.
Regards Steve

As long as you have some sort of vent to stop pressure building up in the crankcase ,and it sounds like you have ,there should be no pressure build up.(the various breather systems are really to control the crankcase fumes once they have left the motor, old days there used to be a hose dangling off the side of the block venting straight to atmosphere ).n Another possibility for only leaking when running is that the oil is being flung about rather than sitting still in the pan . Where abouts is the leak comming from? front , back , sides of sump ? Is it even comming from the sump ?
I had an instance where oil was leaking from mechanical fuel pump ....only when running , The wind from forward motion caused drips to flick back onto the sump flange on the side of the block, ergo ,the sump only leaked whilst running , also cured a leaking steering rack boot .....that the last drop of oil off the fuel pump landed on after car was parked . ( 2L pinto in a capri ). Oil can be sneaky stuff, and an oil pan with a distorted flange can be a bastard to seal , they can be fixed tho . Sometimes you have to get your face right in there from underneath , car on axle stands ,with a rag, torch and a can of degreaser , helper controlling the motor , while you track the leak .Good luck

Thanks for your reply, its definatly coming from the rear 2 bolts area of the sump, ive been under this car so many times, the engine was completly rebuilt and I have installed it in to a mk3 Capri that I have completely restored, all flanges etc are as flat as you can get them which then led to thinking there must be some unerline problem, not ever working on an rv8 before you dont no of any common problems and fixes so after more investigation work I've moved from sump pressure to the crucifix seals, I've whipped the sump of again and removed crank cap 5 and installed new seals, lets hope this fixes it if not gearbox out and change the rear crank seal.

If you remove the oil filler cap engine running, there should be a slight vacuum there.

I've always tried to make the sump gasket a 2 day job, fit a new gasket with a smear of RTV both sides and fit it with the screws finger tight, following day or overnight nip them up to desired torque, I've done loads of engines this way