The Stovebolt Site Forums The Shop Area Engine Shop 235 rear main oil leak with new rope seal

Hi-

I have just fired of my 235 that has fresh rings, bearing and seals. I was very careful on following the steps suggested on the rope seal, I did put oil on it during assembly and it has been maybe 4 months since the rebuild. My question is will a rope seal leak for awhile till it swells or should it seal right away? This is a leak that I don't think I can live with. I leaks more than just a couple of drips. The drip enlarges to about the size of the bottom of a pop can on the floor.

This is a 54 235 that does have shims, I put a thin film on sealan between the shims, block and rear cap before I torqued everything down.

Thanks,
Brent

The newer shims that I bought for my rear main didn't have the cutout in the seal area like the originals. Did yours have a cutout in the seal area ?

I ended up using my original shims, it all spec'd
out with em. I'm pretty sure my shims had notches in them. good thought though...

Thanks,

Brent

Is this a new or NOS rope seal? The New Old Stock rope seals work better than the new fiberglass ones. But as I tell everybody: Hey, its a 235, they all leak oil.

good luck

chip

Run it a while, and see if the drip stops on its own. If not, I'd redo the seal, and be sure it's firmly packed into the groove prior to cutting off the excess seal material. The older seal material seems to work better than the "new, improved" type.
Jerry

This seal came from a new set, it seamed like a decent seal, this set even had a copper head gasket. felpro was the brand. I would agree that all 235's leak to some extent. My 216 in my 37 truck leaks less than this one. It just is a little bothersome that you put all that time in cleaning/painting the 50 years of road grime and dirt. Then it leaks on the first 20 minutes of running. I will run it for awhile and see if it seals up. I did remember that I rolled the seal into the grooves with a socket, then cut the seal slightly above the deck and cap.

We will see what happens.

Brent

You mentioned putting oil on the seal,did you soak the seal or just lightly oil it?. I soak the seal halfs in oil for about 24 hours before installing but since my 235 sat a couple of years after initial break in before being driven it leaks now so it looks like the rope seal dried even after being soaked.

Nope...

I did not soak it like that.. just lubed it up good. Maybe that is what I missed. Maybe it will swell, the gasket is pretty fresh.

I will keep my fingers crossed, but won't hold my
breath

Thanks,

Brent

Yup, gotta soak 'em !!

JS

The new rope seals suck.I put in a NOS rope seal in my 261 , leaks zero oil after 2 years.I never soaked the seal,just used oil on it during assembly.The proper way to insure a good rope seal job is to do the seal when the crank is out.My 2 other engines have the rubber lip seals,they never drip on ground, but there's a little oil on the clutch inspection pan.Of course a 54 engine won't take a rubber seal.

I've mentioned this before, but I will mention it again because it happened to me and I didn't realize it at the time.

There are some flywheel alignment pins on the back of the flange of the crank shaft. If those pins are missing, even one, you will be putting oil right out the back of the engine and it will look exactly like a rear main seal leak. Those holes go through the flange into the engine cavity. I have seen some people cut off bolts to use them to make pins. They will generally leak because they are too loose. Pins need to be used and pressed or driven in. They need to be tight to prevent the oil from coming through.

Of course, there is that other thing - the valve cover not being tight enough and letting oil run down the back of the engine.

Just a couple of thoughts!

As I recall, there were 2 alignment pins when I installed the flywheel. The valve cover gasket was leaking a little, I tighten everything down again, pulled the inpection cover, cleaned everything up and see what we get. As much oil that was on the floor, it did not seem the seal and rear cap where that wet. I will just have to keep and eye on it.

Thanks for the tips.

Brent

The "freshly rebuilt" 235 in my 3800 when I bought it soaked the clutch with oil in the first few miles. It turned out that one flywheel bolt hadn't been installed, and it filled the bellhousing with oil!
Jerry

That'll do it just like leaving one of the alignment pins out!

Well, that is bad new about the clutch assembly.
I'm positive that the pins and bolts are there. I have driven it enough that if they weren't I would have the soaked disc blues... I will post one I get the results are in..

Well, I think it was the valve cover gasket, I have driven ~10 miles and no leaks so far. The oil was clear enough I could not see it leaking from the valve cover until I started wiping my finger around to feel if it was wet back there.

Thanks for all the suggestions.

Brent

I used one of the new rubber/plastic/neoprene seals in my 235 and so far so good. It is true that oil leaking from the valve cover will make you think the RMS is leaking. The same with the oil pan. I replaced the front seal on another 235 and there was still oil dripping on the ground. I pulled the pan to tighten the two bolts that go thru the bearing block and discovered that my gasket making left a small void in the semi-circle part of the front of the pan. I think it is best to clean everything off before you start wondering where the oil drip is coming from.