High crankcase pressure?

Posted By: OUTLAWD

High crankcase pressure? - 08/08/12 05:45 PM

I have noticed that I am blowing oil out of the dipstick tube, and pushing the dipstick out. Is this an issue of high crankcase pressure or oil level too high?

The car sat a few years, and I just started driving it alot lately. now that I think back, I used to run the oil a little "low" and picked up a few tenths with no adverse effects.

360
stock pan/pickup
hi volume oil pump
PCV (new valve)
breather in other valve cover

No signs of excessive blowby out of the breather. Engine has ~7k miles, <100 passes. I am worried that sitting may have messed with how the rings are sealing...but it doesn't smoke at all, even at the track. So should I just stop worrying and drain a 1/2 qt out of it??

Thanks!
Dave

Posted By: dartman366

Re: High crankcase pressure? - 08/08/12 05:51 PM

I would dump a little out of it and give it a try.

Posted By: MR_P_BODY

Re: High crankcase pressure? - 08/08/12 05:54 PM

Easiest thing to do is drain a little oil out then
try it again.... but my opinion is the pressure getting
past the rings... but see if they set in... you dont
want to do what I'm doing now unless its needed

Posted By: OUTLAWD

Re: High crankcase pressure? - 08/08/12 06:28 PM

Quote:

Easiest thing to do is drain a little oil out then
try it again.... but my opinion is the pressure getting
past the rings... but see if they set in... you dont
want to do what I'm doing now unless its needed

It looks like I'll be pulling the heads over the winter to do head gaskets...weeping a little water out of the front...figure at that time I might as well upgrade the bumpstick, etc...but I'd really like to be able to leave the bottom end alone for now, and focus time/energy on a new build instead of rehashing this one...

will do comp/leakdown when I remember to borrow the kit from work. but the oil level is an easy check for now

Posted By: Cab_Burge

Re: High crankcase pressure? - 08/08/12 10:27 PM

Pull the breather cap and see if it blows oil out of it when revving it under a load, like a full pass

I have taped a shop rag folded up over the oil filler holes to see if te motor was blowing oil do to crankcase pressure

BTW, some breather caps have very little holes in the bottom to let the crankcase pressure out, I switched my stroker motor over to a set of Mr Gasket breather caps and that cured my oil dipstick from blowing out after several runs with the other breather caps

Posted By: OUTLAWD

Re: High crankcase pressure? - 08/09/12 12:55 AM

Thanks! Can't hurt to try...

I had one of the on the pass side with a baffled gromet

and a PCV on drivers side. Just replaced the fill cap with one of these I had laying around

Posted By: bentwheel43

Re: High crankcase pressure? - 08/09/12 02:55 AM

I had to put a spring on my duster it was blowing the stick out 3" every pass and blowing oil out of Hughes valley pan.I put a pump off of a 2000 firebird it stopped all of it.

Posted By: bentwheel43

Re: High crankcase pressure? - 08/09/12 03:02 AM

this is the other side and I put the stock valley pan back on.

Posted By: MR_P_BODY

Re: High crankcase pressure? - 08/09/12 03:50 AM

Quote:

this is the other side and I put the stock valley pan back on.

Why run a breather on it with a vac pump.... just
put a adjustable relief valve set at a point IF that
pump can pull enough vac

Posted By: bentwheel43

Re: High crankcase pressure? - 08/09/12 04:20 AM

when I pull the breather off and put my hand over it it sucks good and speeds the pump up when the cap is off.It got the pressure out of the motor.It also pull the water out as well as some oil maybe 3 oz in 8 or 9 passes.Stopped all the leaks it problilly would suck harder and maybe hurt the pump maybe becauce it will slow it down alot if I put a cap on it..I thank it cost about $125 for every thing.

Posted By: MR_P_BODY

Re: High crankcase pressure? - 08/09/12 04:34 AM

Isnt that the GM vac pump..... what car/truck is it for

Posted By: bentwheel43

Re: High crankcase pressure? - 08/09/12 05:23 AM

2000 firebird,it works real good keeping the water out of the valve cover.On a friend sb chevy it pulls 5# @ the stick tube.I don't know if he has a breather on it.

Posted By: MoparPitBull

Re: High crankcase pressure? - 08/09/12 03:39 PM

Yes Mr.Body...GM smog air pump used on '99 Corvette.Used them on a few alky motor cars to remove condensation from oil...a poor mans vacuum pump so to speak.Must be mounted in correct position to work best.Advance Auto part #32-2600M @ $95 w/warranty.

Posted By: MR_P_BODY

Re: High crankcase pressure? - 08/09/12 03:48 PM

Quote:

Yes Mr.Body...GM smog air pump used on '99 Corvette.Used them on a few alky motor cars to remove condensation from oil...a poor mans vacuum pump so to speak.Must be mounted in correct position to work best.Advance Auto part #32-2600M @ $95 w/warranty.

Any idea what the amp draw is on them... what size
fuse they run

Posted By: MoparPitBull

Re: High crankcase pressure? - 08/09/12 04:11 PM

No...don't know the amp draw. Had it set up with its own toggle w/20 amp fuse. Only problem ever had was the foam on the inside of pump would get mushy from combination of oil/condensation...started bringing it back at beginning of season taking advantage of warranty. And sorry, its Mr.P Body..lol

Posted By: OUTLAWD

Re: High crankcase pressure? - 08/09/12 10:29 PM

hmm...I may try that pump out regardless of my problem, always wanted to try out a vac pump.

Mr.P, what kind of vacuum should I look for if I am setting a relief valve? Too much is a bad thing in this case, correct?

Posted By: bentwheel43

Re: High crankcase pressure? - 08/09/12 10:55 PM

I suck 3 or 4 oz. of oil on 8 passes with a breather may suck more if I cap it.The cool air gose in the motor it never blow the stick out again,keeps the water out.I drilled a hole and got that fitting from Star mach about $37 bucks toggle with 20amp. pump was about $27 ebay $8 for shippng.You won't want to run it all the time just running it.We do the burnout then turn it on.

Posted By: MR_P_BODY

Re: High crankcase pressure? - 08/10/12 12:34 AM

Quote:

hmm...I may try that pump out regardless of my problem, always wanted to try out a vac pump.

Mr.P, what kind of vacuum should I look for if I am setting a relief valve? Too much is a bad thing in this case, correct?

It would depend on the pump.... on my dry sump I can
get 12"HG with just the pump so I dont run a vac pump
on it... if I were to use that I might set it at 5"
to 6"HG... because I would think (from what the others
are saying it might not like more) but I would have
to see what the pump can do

Posted By: Dave_S

Re: High crankcase pressure? - 08/10/12 12:53 AM

From listening to the radio chatter from the Denver NHRA race, someones crew member reported " data logger on, vacuum pump on" So I assume they are also useing an electric vacuum pump. Not like the one mentioned here, I'm sure, but be looking into one for my car too.

Posted By: OUTLAWD

Re: High crankcase pressure? - 08/10/12 04:50 PM

Doing some msg board searching, it appears as if a similar ford part off a 90's Cobra might be better.
Didn't find it available anywhere though...
F6ZZ-9A486-DA

One guy seemed to be blowing 20A fuses, Buit I'm not sure on his setup. There is some internal foam on the GM units that may restrict it, and it is suggested to remove it.

Posted By: dogdays

Re: High crankcase pressure? - 08/10/12 05:20 PM

First of all, high crankcase pressure only comes one way, past the rings.

Second, decreasing the density of the air inside the crankcase reduces losses. It's surprising how much power is wasted just moving the air back and forth, also rotating stuff through the air.

R.