kasturbo

Just as the title says. Will new rings allow enough blow by to cause enough pressure to make a rear main seal leak? How long does it typically take for new rings to fully seat?

What else would cause a rear main to leak if the crank was in perfect shape with no grooves? Trying to figure this out on a friends new motor. We are stumped.

KuHL 951

I don't know the particulars of your friends motor but was the rear seal done at the same time as the new rings? If anything should leak from excess crankcase pressure it would be the oil pan gasket, it's the weak link IMO. There was some talk on here years ago about the black rear seals (Victor Reinz?) sometimes leaking where the red or brown seals always were leak free. Any chance the spring inside the seal got rolled out of it's seat on installation? Again, rings should have no effect what so ever on a rear seal.

Ski

I had a new one leak and we thought we did everything perfect - seated at the right depth, no problems going in but as soon as we fired it up, leaked. PITA, took it out, installed another one with just a tiny bit of high temp silicone on it, put it all back together and no leaks. The wire retainer was on the old one we took out.

kasturbo

Everything on the motor was brand new, so yes the seal was done at the same time. It was a red seal.

caster951

I would think that if the rms was leaking due to too much crankcase pressure, it would have progressed to worse once the oil found its way across the seal. As you know I had my own issues with a leaking rms and tried 3 different times with 3 different seals to get it right. The rings obviously were not new. I would think that the pan gasket would seap as well, is it?

tyro

It's not installed properly. I went though the same ordeal with mine, ended up buying an oil seal arbor from Pelican, an Elring seal from Paragon (black and orange color), some Curil T for the OD and it's been 100% leak free ever since.

In short, you need to replace the seal..again.

KuHL 951

+10 That's the way to do it. The Curil is very important. I think sometimes the block gets scratched from prying the old seal out and creates a path for oil unless sealed. It's usually assumed that the crank surface condition or a faulty seal is the culprit

Chris White

Rear mains can be a pain in the ***. I have seen some quality control issues on the new ones. Sealing the sides is a good idea.

fastmover

Depth of the installed rms is very important. Some times you have to put them in with a slightly different depth. Because where the previous spot the lip rode against can become slightly polished, and will not seal correctly.Make sure the crank is nice and clean and try to install the new one .5 - 1.0 mm before the original position. Also check the gap between the crank and engine with a micrometer in several different postions around the radius of the crank to determine if the crank is centered in the engine. Also check if there is lateral freeplay at the rear of the crank, try to pry it side to side to see if there is any freeplay.

I have seen several cars with engine crank work was done and the crank was not centered in the engine while rotating, basically the crank was beating the rms while the engine was running .

Also check crankcase pressure while boosting with a pressure gauge coming off the oil dipstick tube. If you are building excessive pressure then check the air oil seperator, since the aos acts as the pcv.
To rule out the rings (which I highly doubt is the cause) just do a cylinder leakdown test to determine if you are getting blowby pressure past the rings.

Semper fi

kasturbo

Thanks everyone for the the good ideas.

Fastmover, what sort of pressure should I see when boosting?

fastmover

There should be very little or none at all. as far as I know there is not a spec on pressure limitations in the crankcase. I would think a pound or two would be acceptable, but if it reaches 4 or higher I would be concerned. (This is just my opinion).

Semper fi

tyro

I wouldn't even mess with checking crankcase pressure. The seal isn't in correctly.

Here's a photo of a proper seal installed to the proper depth by a proper tool with Curil T on the OD :

xsboost90

after having to tear a motor back apart due to a new rms leaking after a new clutch job, i always put the rms in as far as possible. I used to put them in flush but now they are all the way in-no leaks since.

mtnman82

Yup, went thru this dilema myself when doing my clutch. I didn't actually get everything together to find a leak, but could tell from the first two seals that they weren't going to do the job properly just from looking at them. It's been a while, but I believe I got a black seal first and just didn't look like it was going to do the job. Then got the Victor seal which looked better, but even that had some anomolies looking at it (if I remember correctly, it just barely was going to cover the notch in the pan - I put it in and didn't like the fit). After some searching on this forum and searching on the net, finally came to the conclusion and found an Elring seal. Muuuuuuuch better thatn the other two. I also did the Curil T and bought the press for installing the seal to make sure it was done correctly. If I recall, there was a problem with the press too - I think it was drilled wrong or something and could only get one bolt in, but it still worked great. Have almost 1000 miles on since the clutch job and no leaks (knock on wood). I definitely put the seal in all the way - not flush. If you put a Victor seal in flush, IMHO you will have a leak for sure ...

Rock

The oil pan gasket would go first because of blow by. I burnt a valve to shreds on my motor and it caused the pan gasket to blow out nasty.