1969 beep beep
Well-Known Member
I tried running 5 quarts and took it out for a test drive. I still found oil in the distributor, but not as much. I am going to try a leak down and see what happens.
Need Help On Excessive Crankcase Pressure
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1969 beep beep
Well-Known Member
What is the allowable leak down percentages on this new engine build with 1000 miles?
70rr-brian
Well-Known Member
"Everyone wants to have a hero engine, but don't believe all the hype you hear about 2 percent leakage engines. No cylinder seals perfectly, especially if the engine is nitroused, supercharged
, or turbocharged where the top and second rings are set with wide ring endgaps. Even for normally aspirated engines, respectable leakage numbers would be anywhere from 8 to 12 percent with a variation between cylinders of 4 to 5 percent, but it's possible the variation could be as high as 10 percent.
So if you test an engine and see leakage numbers even in the 15 to 20 percent range, this is not cause for alarm. "
I will just add that most leakdown gauges I have seen have the "acceptable" range up to 40%.... That's lunacy.
, or turbocharged where the top and second rings are set with wide ring endgaps. Even for normally aspirated engines, respectable leakage numbers would be anywhere from 8 to 12 percent with a variation between cylinders of 4 to 5 percent, but it's possible the variation could be as high as 10 percent. So if you test an engine and see leakage numbers even in the 15 to 20 percent range, this is not cause for alarm. "
I will just add that most leakdown gauges I have seen have the "acceptable" range up to 40%.... That's lunacy.
RustyRatRod
Well-Known Member
We have a member here who made the most torque and HP in a dyno contest with 56% leakdown on one cylinder and at least 10% on all the rest. It was over 700 HP. I'm not an advocate of leakdown.....just stating for the record.
All that said, I think until you get 2500-3000 miles on it, you're over reacting. Drive it some. Clean it up when it gets dirty and go from there.
All that said, I think until you get 2500-3000 miles on it, you're over reacting. Drive it some. Clean it up when it gets dirty and go from there.
70rr-brian
Well-Known Member
Dyno contest is one thing, a street driven engine is quite another. That's like comparing a NASCAR engine designed to go 500 miles to an engine that should otherwise make it close to 100k. Especially when the topic is excessive crankcase pressure. I don't think dyno competitions penalize the builder when the dipstick tube pops out or is spewing oil. Leakdown testing can be quite useful as a diagnostic tool to find the exact source of an issue. Is it intake valve? Exhaust valve? Head gasket? Rings? That said, I am not convinced the real issue here is excessive pressure. Primarily because of all places for it to manifest itself the dizzy is pretty unusual. I would think it is worth doing to eliminate his rings having not seated well across the board or at the very least a few of them. Rings should be seated by now. It only take a couple hours to do... I hardly see the harm in it.
RustyRatRod
Well-Known Member
It depends. If the block was honed with a torque plate, I tend to agree. If not, then it's anybody's guess.
70rr-brian
Well-Known Member
I hear ya. And if nothing else he has a nice baseline test for this point in mileage on the engine. Then I agree with your statement about drive it a couple K and see how she is doing. If the problem persist then do the test again. If nothing has changed and he still has comparable leakdown numbers (assuming they were suspect on this test) then we can probably conclude the rings never seated properly.
1969 beep beep
Well-Known Member
Thanks everyone for all the feedback. Here are my leak down results with engine warm:Cylinder # 1-9%, 3-8%, 5-8%, 7-8%, 2-10%, 4-8%, 6-8%, 8-12% Yes the engine was honed with a torque plate.
70rr-brian
Well-Known Member
Those are decent numbers. I would expect that a functional PCV could keep your crankcase pressure under control even with semi-frequent spirited driving outbursts. I would be willing to bet this isnt a crankcase pressure issue but rather isolated to the dizzy as many suggested previously.
1969 beep beep
Well-Known Member
Thanks 70rr-brian. I am going to look for a used distributor which I can try. What about a deeper oil pan or different windage tray. There could be a lot of splash causing oil to pool beside the distributor. I can't see how it could be going threw the distributor with .001 th spacing on either side of the distributor shaft. Does anyone know what the shaft spacing is on a new msd or new mopar performance distributor?
RustyRatRod
Well-Known Member
I'm really not a frigton familiar with leakdown % numbers, but I would think anythin 10% or greater is high.
70rr-brian
Well-Known Member
I hear ya. I am just saying, like others have mentioned, of all the places for crankcase pressure to manifest itself the distributor is just a very odd place to see it. Usually the obvious place you see it will be a popped out dipstick tube. I think replacing the distributor with a known good one is the best place to start. I mean who knows, there could be a tiny crack in the shaft you aren't seeing but the oil is finding. Ideally you could just borrow one to test with without having to buy a new one or even used one then go from there.
Would you please post specific information about which distributor you are using.
From wikipedia:"Leakage is given in wholly arbitrary percentages but these “percentages” do not relate to any actual quantity or real dimension. The meaning of the readings is only relative to other tests done with the same design of tester. Leak-down readings of up to 20% are usually acceptable while greater than that requires a repair. Racing engines would be in the 1-10% range for top performance."
1969 beep beep
Well-Known Member
Dryheat, I am running the Mopar Performance 3690431
I tested the car again today, after adding another shim and completely blocking the oil port holes at the base of the distributor. Well I set the end play to .010th and sure enough after beating on it again, oil is still coming out of this distributor. I think I need to remove the distributor, and drive the oil pump with a drill so I can see what is happening inside the distributor hole.
I tested the car again today, after adding another shim and completely blocking the oil port holes at the base of the distributor. Well I set the end play to .010th and sure enough after beating on it again, oil is still coming out of this distributor. I think I need to remove the distributor, and drive the oil pump with a drill so I can see what is happening inside the distributor hole.
RustyRatRod
Well-Known Member
Then on hes kinda high on a lot of them, isn't he?
I was in the garage yesterday staring at my naked 383 block trying to figure out how medium or high veloctiy oil could be spraying in that area. I sure hope you detect something.
70rr-brian
Well-Known Member
"Most leak down testers use 100 psi as the standard input pressure. But most any pressure from about 20psi and up can be used for measuring the percentage of leakage. Using a higher pressure like 100psi will make the sounds of leakage louder and easier to identify."
383man
Well-Known Member
I just wanted to let you know that I used to run a PCV valve in my old 440 with the MP .557 cam but when I built this 493 I used a stouter cam that has .264 & .270 @ .050. So I run two breather caps like you see here on each side. I used heater hose and run it down to the wheelwell and tie them there just leaving the breathers open. I did not tie them into my headers as with a full exh system out to the rear bumber I was not sure it would work good. This has been perfect for me with no leaks anywhere and no oil ever drips from the hoses.
I was thinking why not pull the dipstick up a little out of the tube (to create an open area) and drive it hard again to see if any oil comes out the dipstick tube and if it still comes out at the dist ? I know you must be pulling your hair out. Good luck to you , Ron
I was thinking why not pull the dipstick up a little out of the tube (to create an open area) and drive it hard again to see if any oil comes out the dipstick tube and if it still comes out at the dist ? I know you must be pulling your hair out. Good luck to you , Ron
1969 beep beep
Well-Known Member
Thanks Ron, I will have to try pulling the dipstick out and going for a blast. Yes this problem is driving me crazy, I will keep everyone posted on this problem.
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