cam seal leak

[funky technician]

Ok, so I need some input on a snag I'm having. I'm getting ready to put my lil festiva on the road for winter, with its new lil b6 head, but there's a problem, when i rebuild this motor, the lower half came out of the woods, and I couldn't get new rings so i used the old ones, they all were within tolerance after a good hone, but the number 3 cylinder was pitted a bit because the valves were open on that cylinder, so i honed as much as i could before the ring gap became too much, needless to say, there was still a bit of roughness on the wall after maximum honing.....ANYHOW, the engine runs very well, but during the first few test runs, it was leaking oil from the cam seal, I then realized that i never put a new one in when i rebuilt the head, so I replaced it, BUTTTTTT!, when i went to tap the new one in, it went right into the engine! SO, I pulled the valve cover and using strategically place alen keys, i managed to re-seat the seal into place, and am pretty sure it was not damaged during the procedure, but the car still leaks oil there, not as much, but still. I'm suspecting too high crank case pressure due to the looser rings in the number 3 and this is overloading the PVC system and slightly pressurizing the engine crank case forcing oil out. Sorry this was so long but i wanted everyone to know all the facts to help me find the problem

[mooseheadc]

Re: cam seal leak

I'm suspecting too high crank case pressure due to the looser rings in the number 3 and this is overloading the PVC system and slightly pressurizing the engine crank case forcing oil out. Sorry this was so long but i wanted everyone to know all the facts to help me find the problem

If the fit is that bad, you may get leaks in other spots, like the
valvecover. With the Oil fill cap off, and engine running, you should see
some steam/vapor if its in bad shape. If it still leaks with cap off,
its probably not ring blowby. For a beater, you could fit an old fashioned
road draft tube to let off extra pressure. But thats not a fix, it just get you by

[funky technician]

strangely enough, the problem was the poor quality of the aftermarket seal. I have just gone out and picked up a true mazda seal and I noticed that it has directional oil vectoring lines on the inner race that help channel oil back into the head, the seal that i got from autochoice didn't have these channels, and that's why it was leaking. Ya, I kinda re-thought my suspicions of it being blow-by after thinking that if the if there was that much blow-by that it was overpowering the PVC system that the motor probably wouldn't run at all, just like if you pulled off a vacuum line, and ya, there isn't that much gaseous blow-by coming out of the fill cap, so I think I just learned my lesson about cheap aftermarket seals :roll:

[mooseheadc]

Ya, I kinda re-thought my suspicions of it being blow-by after thinking that if the if there was that much blow-by that it was overpowering the PVC system that the motor probably wouldn't run at all, just like if you pulled off a vacuum line, and ya, there isn't that much gaseous blow-by coming out of the fill cap, so I think I just learned my lesson about cheap aftermarket seals :roll:

Sucks to have to take all that stuff off to replace that seal.

Ive had car with rings so bad, it would burn a quart a week :shock: , but
didn't leak from the valvecovers and such. Now also had a Ford
302 with a holed piston, and that leaked oil from every possible gasket
even with the fill cap on loose to release pressure

[funky technician]

:lol: It's funny how bad an engine can get and still run eh? lol

[mooseheadc]

:lol: It's funny how bad an engine can get and still run eh? lol

About the worst one I knew of was a mopar 383 that had really
torched a piston to where the whole top was gone, see clear thru
to the wristpin.

Had to keep it running, no time to get another BB from the junkyard,
dropped the pan(to see what metal bits were floating around.
looked ugly, sides scored so bad it wasn't worth dropping in another
piston,pulled a lot of crap off the oilpump screen too. So pulled
the rod off the crank, used an old dog collar 8) to block the oil hole
on the crank to keep pressure up. Pulled the pushrods to that
cylinder to eep the valves closed, and shoved a hole into the sparkplug
port to make a road draft tube, as the old chrysler had its seals so bad
it leaked from both ends of the crank and spewed oil from the
valvecover breather into the airfilter, making it look like
an old oilbath filter.

So yeah, it missed at idle pretty bad, but it ran good enough
that the guy decided not to replace the motor. Ran for at least
another year :shock: that I knew of, daily driver.

[miami man]

i guess if you can see through the top of the piston to the wristpin that means it is a open chamber...right. just joking

[funky technician]

LOL that's wicked! Man that poor motor must have suffered :lol:

[mooseheadc]

LOL that's wicked! Man that poor motor must have suffered :lol:

And the most half-assed job I done. reused the headgasket,
and others with silicon. threw it together to last a couple
weeks, tops. Didn't even use fresh oil, just dripped in some
from an oilchange from another truck that I hadn't got reclaimed yet.

Had real rebuild motors :cussing: that didn't keep going as long as that POS
did.