I'm involved with a drag machine with
The engine is a 351 Cleveland stroked to 380 cubic inch, bored 30 thou and fully balanced.
Competition forged pistons, closed chamber 4V flowed heads, triple valve springs, Yella Terra roller rockers, with guide plates and 60 thou over push rods, pushed by a Crow 21806 solid cam.
2 x 650 double pumper Holleys sit on a Weiland tunnel ram manifold with a Big Shot 2102 Nitrous system.
and it keeps building up too much pressure in the sump, pushing out the dipstick, and throwing oil every ****ing place. Any solutions
Every day above ground is a good day
Are you sure it's oil pressure? I would suspect a non-PCV unvented engine and crankcase pressure from the significant blow by gas pressure. If you haven't got one try an appropriate crankcase ventilation system; if you have one check it is working.
Its not uncommon for a real weapon of an engine with a big dose of NOS to have some blow by, but there is a limit. Too much is probably ring blowby possibly caused by block distortion (or bad rings), or possibly heads lifting..
Hi, a few tips, but you didnt mention if it happenes just idling or going down the track, so, first assuming if your car has a hight lift long duration cam, you might not have enough intake manifold vacuum for your pcv to even function properly at idle.
Second, all pcv.s are calibrated and flow differently, so you might want to try one that flows better.
Doesnt hurt to do a compression test either, just to check. Try doing the test both when cold and again when engine is hot.
Some racers i've noticed forget the pcv altogether and just use the old fashioned baffled road draft tube.
Alot of people just either shake the pcv valve or put their finger over it to see if its working, that just checks the valve itself, to fully check to see if the vacuum from the valve is sufficiant to exhaust the crankcase check the valve when running by taking off the oil cap (or another entrance to the crankcase) and place a piece of paper over the opening, the vacuum from the pcv, should still be active and cause the paper to stick to the opening because the vacuum is healthy in the crankcase. If the paper doesnt hold witht the pcv installed, you either have the wrong pcv, blockage either in the line somewhere, or just to much blowby. This test also works great for quickly checking a engine condition when looking for a used car.
Hi, thinking about your problem a little more and i have a question after your comment about oil on the racetrack.
Is it LIQUID oil coming out of the dipstick or oil vapour, After 1 run and not always? Since i'm not there this might sound silly but is it possible that the churning of the oil might be going up the tube and pushing the dipstick out maybe because of a poor aftermarket windage tray, or the lack of one? or is it actually blowby (vapour looking, not fresh liquid viscous oil) Is it not also noticably chugging vapour like a train from the breather like bad blowby should? leaving oil film under the bonnet and windscreen?
You actually didnt think it was blowby at first, did you, and you might be right.
you should have a breather somewhere, if that is working and clear all the blowby vapour should be coming out of there if blowby is excessive, not the dipstick. If the crankcase blowby vapours havnt been coming out of the breather it could be plugged, a plugged breather wouldnt help the pcv vacuum in the crankcase either and the dipstick might even come out if the breather is blocked.
once you check that out, including the stuff on the previous post and still dont have a solution you should go over what you all checked during the measuring and fitting of the pistons and rings, like ring end gap, ring to land, are compression rings right side up, piston to cyl clearance (that would possibly be heard when cold) possible broken ring on installation, poor ring break in, list goes on... Fastening down the dipstick without solving the problem (if blowby related) would just blow a seal or gasket.
or why dont you just try a run without nitrous, if its blowby due to that extra pressure that would be a quick way to tell. on top of all that , probley wouldnt hurt to make sure ther are no other other external oil leaks. good luck.
Will put all of your ideas to the test this weekend.
Installing Vacupans, two breather caps, and give it a couple of runs before we start ripping heads off (on the motor I mean)
Sorry, thanks to everyone for your feedback, youv'e all been a great help.
Will post results after weekend as to the outcome.
Every day above ground is a good day
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