Reply With QuoteHave you ran a leak down test. Greg
I'm at the end of my rope. I don't know what to do. The las straw is to pull the engine, but before I do, I thought some of you might offer insight in order to save mega bucks.
Here's the problem. 76 sleekcraft, 460 Ford.
The engine is building crankcase pressure to the extent that it is blowing oil out everywhere!
I have added another breather to the valve cover, now have one on each. I have moved the pvc to the center of the valve cover to accomodate the extra breather. The motor has good oil pressure. It does not smoke or knock. It does appear to have good power, although it isn't turning as high as I thought it should. The motor is stock and orig, with the exception of the aluminum low rise intake and the holley. It blows oil out around the distributor. I have replaced the o ring ( i got it from ford, they say it is special for the 460) on the distributor twice. I have already spent a ton on the boat, new paint, new interior, new steering, and had the trailer completely redone. I am out of money and out of ideas. The water has finally returned to North Carolina and I have only had it in the water 3 times. Each time I take it out, the oil problem is still there, I would make changes and take it back out, but no luck. I don't know what to do. The money is about gone, the ideas are gone, somebody help before whats left of my sanity is gone! Any imput is greatly appreciated!
Have you ran a leak down test. Greg
you need to know what you are working with. you need to do a compression test and a cylinder leak down test then this will tell you what to do next. you probably have a winter engine project just like I do. My boat got in the water twice this year before the mains let loose. So you are not alone.
I have not ran a leak down test. Is this the same as a compression test?
No it is not.A compression test uses the engine's own compression to determine whether all cylinders are sealing evenly.It is performed by cranking the engine over with a presssure guage screwed into the spark plug hole.A leakdown test uses an apparatus with a guage that pipes compressed air into the cylinder while the engine is not running and you watch the guage to measure the leak rate.You have to find out what is normal leak percentage for your particular engine.A trick that is helpful while doing a leakdown test is to remove the exhaust and put duct tape over all of the exhaust ports.That way if there is something catastrophic like compression leaking into an adjacent cylinder through a crack you will notice the tape bulging.
iam with the rest i woud perform a leak down test! it will show you were you problems lies!
i knowon my old motor it did the same thing!
and it was a stock 460
i upgraded lol!
wink
I have to agree with the rest of these guys! wink Sounds like the rings have lost their seat and you have the compression leaking past the rings back down into the crank-case which is creating your crank-case pressure problem and blowing your oil out of any place it can find vent to do so..Sounds to me like you don't really know how to go about doing a leakdown test but are knowledgable enough to do your own compression test.
SO, pull all of the plugs out of the motor and check the compression one at a time. I will usually spin the motor over 5 revolutions on each cylinder, write down the PSI of each one and check to see how much variation there is between each one. If it turns out there is quite a bit of difference in the PSI from one cyl.to another you will have determine whether or not you have a head gasket leaking, but with your situation of excessive crank-case pressure I would say the motor is in need of a new set of rings and/or pistons and rings
Hey 76, You should run the leakdown as suggested in the gear head thread also. It may be something relatively easy to fix (like a blown head gasket) which will save you a bunch of money over a full rebuild you might not need. Compression and leakdown will take all the guesswork out of it. Just my .02
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