famous bob
mopar misfit
And use plenty of sealer between it and the gasket .
Well It Leaks AGAIN!
- Thread starter superchargeddrt
- Start date
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famous bob
mopar misfit
Hey off topic and a thread jack , kinda.
Does anyone know where u can get the old solid side seals for a big block ?? We never had trouble w/ them --------
66jim
Well-Known Member
Any oil leak always seem to migrate to the same spot where it appears to be
coming from the rear main seal. Eliminate other possible sources first, I stuff
rags in spots and drive the car around then see leak(s) on ground or rags. Check
dist. O ring, oil sender,back of intake manifold, back corners of valve covers, oil pan
fuel pump,oil filter gasket area..etc. Seems long highway driving aggravates oil leaks
and so does synthetic oil in my experiences. Good luck and PLEASE report back
on any success
coming from the rear main seal. Eliminate other possible sources first, I stuff
rags in spots and drive the car around then see leak(s) on ground or rags. Check
dist. O ring, oil sender,back of intake manifold, back corners of valve covers, oil pan
fuel pump,oil filter gasket area..etc. Seems long highway driving aggravates oil leaks
and so does synthetic oil in my experiences. Good luck and PLEASE report back
on any success
harrisonm
Well-Known Member
I have got to say that I have NEVER heard of a "pressure" situation that would force oil out the rear main seal.
famous bob
mopar misfit
Never heard of crankcase pressure ?
MOPAROFFICIAL
Oogliboogli
Also, the rear cap...when its milled on a 360...the thinner rear pan seal that insets becomes too long and bunches and swells out when torqued. You have to be careful.
harrisonm
Well-Known Member
Certainly, but I never heard of it being high enough to blow oil past a good seal. Can that really happen?
MOPAROFFICIAL
Oogliboogli
67 gt
A Wog boy who loves his Mopars !
Mine was doing it decently aswell replaced seal than same same engine builder told me to put some miles on it and while I was at it I read a thread on here where some one had ran 2 pcvs and had helped so I purchased and plumbed another on the other side bingo not one drop.
famous bob
mopar misfit
I did that on a hot 406 sbc . Tried it on this 440/505 , and didn't seem to work, think I might have done it before my rings started seating. ???
famous bob
mopar misfit
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
no one ??
Daves69
Well-Known Member
famous bob
mopar misfit
Price not very intreging , lol
furrystump
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Chasing a oil leak on a friends 400 chevy stroker. He thought is was bad oil pan gasket install. He re-did it. Still leaking. This thing has a star machine vacuum pump on it and it was STILL leaking! Leak down test was bad 60-70%. Pulled it apart nothing glaring, Off to the machinist to check the bores. Have you run a compression test on it?
yellow rose
Overnight Sensation
Where did the leak down air go? If it was into the pan, that's ring seal. It's almost impossible in 1985 to get rings that don't seal.
I'll be interested to hear what the conclusion of the matter really is.
Think how quickly you will be able to change it in the future with all this practice!
As for pressure in the block. IMHO if you did not even have a PCV the crank case should not build pressure if the valve cover breathers are open to the atmosphere. If it does have enough blowby greater than the amount of air that can pass through the breathers openings you have a major ring sealing issue.
You stated you have a NEW crank. so I would be measuring the crank to be sure the dimensions are correct to the stock crank.
We are all assuming you have installed the seal correctly with appropriate lube and sealer in the appropriate places.
Is it pushing any oil out the dip stick tube?
superchargeddrt
Well-Known Member
No the dip stick is staying put. This will be the third main seal.
The first one leaked on the dyno and we thought it was a oil pan gasket issue. We changed the pan gasket and while doing so managed to break a grade 8 bolt in the oil pan. This was surprising because we didn't put any serious torque on them. We had already put permatex on the gasket area and it had started to dry because it took us about an hour to get the bolt out. We decided to install the gasket anyway and we reinstalled the engine. When we started the engine we had the same leak. This was really frustrating and I was about to quit and let it go until the next year. We put dye in the oil and used a ultraviolet light to see where it was leaking. It looks like the oil pan again so figuring that it might have been because it took so long to get the oil pan gasket tightened down that it might have caused the pan gasket to leak. Remove the engine again and we put yet ANOTHER pan gasket on. My buddy Larry suggested the we install a main seal but I didn't have one and it looked (according to the dye) like it was the oil pan gasket. We reinstalled the engine AGAIN and guess what?......It leaked again! I ordered a new seal from Superformance, installed it and the leak was fixed for several months and I thought I had it beat. Now I was only driving it to and from our local car show and the speed was kept to around 60 MPH or lower. I think that the combination of extended 70 PSI oil pressure and heat caused another failure. I ordered the adjustable PCV and we're gonna pull the engine one more time.
The specifics on the engine are:
418 Stroker
Molnar Crank
10.55 Compression Ratio
Superformance Main Seal
Stock style PCV
Breather on the other valve cover.
For what is worth, mine runs 60-70 psi on highway, or any rpm above 1500. My car mostly only sees highway drives due to where we live. Other than minor sweat at times, there are no oil leaks. I think it is something else going on, not oil pressure.
yellow rose
Overnight Sensation
I hate that you have to pull the engine again, but this time, be very purposeful in your disassembly. When you pull the rear main cap, look at the seal. I'm going to bet (if you don't have a ring seal issue) that the problem is going to be you didn't trim the ends of the seal.
Some guys LOVE to clock the seal with the ends above and below the parting line. I've never done that, nor will I ever.
It won't fix anything. If you did clock it off the parting line, slide the seal around until the ends are at the parting line. Then measure how proud the ends are above the parting line. You only need .010 or so proud on the block and cap. For a total of .020 at most.
If you have more than that, it will push the seal out of round and make it leak. You see this with line honed blocks. I started with a brand new block and by the time it was ready to go, I had to trim my seal.
I still prefer a rope seal. It takes more torque to turn on assembly, but it takes less when you get a few minutes run time on it. If you are pulling crankcase vacuum, you have to use a rubber seal.
67 gt
A Wog boy who loves his Mopars !
It was from one of your posts you put up when I was having issues with the rear leaking and putting another pcv on that I tried as a last resort the car has been perfect since, 2500km on the new motor oil, the same height on the stick not burning oil and plugs are clean running (EFI) . I feel everything has settled in as it runs way better now.Mine runs 70psi off idle once hot 50psi same as yours 1500rpm 70psi.
furrystump
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It has weird patterns on the cylinder walls. To get it to 420 CI. The piston is almost a hockey puck! Not much skirt with gapless rings. Not to hijack. Didn’t smoke just a bunch of crankcase pressure.
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