The Stovebolt Site Forums The Shop Area Engine Shop Seal replacement , bearing, and debris (with pictures)

I'm replacing the rear main and front seal on my '54 235. I was surprised to find out that the rear seal in my truck was not rope, nor was the front seal leather. I can only assume someone replaced these in the past, which is kind of a bummer because I wanted to see the original worn out rope and leather.

Anyway, now that I've looked at everything, I have some questions for the experts:

1) Bearing wear.
Here is a picture of my rear main bearing. Note the pitting. I was expecting it to be totally smooth. How should I interpret this wear? Does the bearing need replacement? Here is another angle.

2) Debris.
I also found some debris in the main bearing cap, near the oil hole. What could this be? Could this be bearing (Babbitt?) material? It is metal, but pliable like solder. Here is another picture that shows its size in relation to the bearing cap.

3) Crank condition.
Here is what my crank looks like under the bearing cap. How does this look? The surfaces seem pretty smooth. The surrounding area sure is messy, though. Does anything here look wrong or in need of attention?

4) Upper rear seal.
Here is how the upper (rubber) seal is sealing with the block and crank. I know people say the newer-type seals won't work well because of the machining tolerances of the day, but to my untrained eyes that looks like a pretty good seal. Looking at it, I would like to assume that my leaks were coming from the seam where the two halfs meet up. I'm now re-thinking what I want to do. I have new rope seals, but now I'm wondering if a little RTV between these rubber pieces will fix it up. Thoughts?

5) Front seal.
Here is the front seal. I didn't have much luck getting it out, but it was also very late and I was getting tired. Here you can see where I tried to get it out with pliers. Before I go beating on it some more, is there a better way to do this? Also, I noted the seal was very very hard--the plastic was not pliable at all. Should I expect this hardness to happen with the new seal, or will a new seal last for 10+ years?

Finally,
here is the page that has all the pictures and a few more


Thank you for looking at my pictures and giving your suggestions. This is my first time through this stuff, and I feel a lot better going with others' experience and knowledge than my own guesses and assumptions. Especially when it comes to subjective evaluation of a part's condition. Thanks.

I know that someone will probably jump in and disagree, But I never pull bearing caps to just look. If the engine is that far apart already and you found metal where it shouldn't be, I'd rebuild it. For me, "patch" jobs never work and cost twice in time and parts. If I had to guess, I'd say that what you found came from the pitting you see in the bearing, but it could be a collection from all the bearings. I think it would be wise to check the cam bearings as well. Good luck!

Les

I believe the pitting in your bearings is corrosion. Your crank looks good to me especially compared to what I found in MINE.

No clue on the scrap of metal but it should be a cause for concern. The neoprene/rope seal issue is argued to death and I have nothing to add there.

So is the amount of pitting on my bearing normal? How long do bearings typically last?

Greg,
The pitting on your bearing surface could be caused by antifreeze contaminating your oil, head gasket leaking or cracked head? I'd take a look at the thrust bearing and see if its got a piece missing, maybe that is the source of the piece of metal you found. If you find excess end play in the crankshaft that may be the bottom line to your oil leaks. If it does have excess end play no matter what type seals you put in its still going to leak and be a problem. As to if the pitting is normal wear, I would say its not normal in my opinion. From the looks of the sludge in your motor its been a long time since its been opened up. If you plan on using your truck on the road I'd consider pulling it apart and going thru it. If you just want it to run and move around while you do other things to the truck, then just do a minimal repair on the motor.
Good Luck
Don

Your main bearing is definitely danaged and it should be replaced. The material has failed. It almost looks like it ran short of oil at some time for a few seconds. Also there appears to be a lot of sludge in the motor. It looks like it has been run on non detergent oil and maybe a long time without a change.

Take your time with the seal. I like to use a pair of wire cutters and splt the lip. Then I peel it right out.

I would drop some of the other caps and have a look at the bearings. Maybe the rear main suffered a blockage. It wouldn't hurt to look at the rod bearings too.Your crankshaft looks pretty good to me.

I'm trying not to beat a dead horse here, but I got my "Best Gasket" rear main seal, which, by the way, seems of much better quality than the fel-pro seal I also have. Plus, it comes with a blade and spacer. Anyway, my real problem is this:

The instructions with the gasket explicitly say, "Coat all cap-to-block mating surfaces with sealant. DO NOT apply sealant on rope ends"

Ok, so what gives? I hate it when instructions go against my instinct and research. I've read elsewhere that you SHOULD but a dab of sealant on the rope ends, and my gut tells me to NEVER put sealant on the cap to block mating surface.

Experts, please advise!! Thanks.

Greg,

I could be all wet here, but I think it's because the woven rope weeps oil which lubricates the seal to crank boundary and prevents it from burning. If you put sealant on the end, you basically 'cauterize' it and shut out the ability for it to pass minute amounts of lube and it will cook and wear!

Don't quote me on this though.

Stuart

Well that is a good thought Stuart... makes sense to me. The original shop manual makes no reference to putting stuff on the end of the rope (not that they had RTV back then, though), so I figured putting a drop on there would be good "insurance" that the rope wouldn't leak at the joint where the two halves mate up. I've also heard the tip of offsetting the rope joint so one seam is in the block half, and the other seam is in the bearing cap. Anyway, I'm willing to try leaving the rope ends as they are...

But what do you make of the instructions about putting sealant on the cap-to-block mating surfaces? That seems dangerous to me.

I am anxiously awaiting my "Best Gasket" rear seal. They apparently have a new design with different material. One gasket supplier says that since asbestos was banned, the rope seals just aren't very good. I hope this new one is the answer.

I wouldn't put sealant on the cap faces. In my case I have shims in there.

I would appreciate knowing how you make out with this.

Greg,

Again, this is all shade tree guessing. The rope seal is malleable and will mold to a imperfect surface. The mating surfaces of the block and main cap aren't hand scraped for a dead flat fit so a bit of sealant would guarantee no drip, runs or errors.

Stuart

The rope should be packed in the block side and pressed in the cap, if its like most rope seals. The block side will try to unpack or uncompress as the motor runs and it will conform to the cap side of the seal. It will form a continuous seal around the crank. You don't want anything on the ends that will keep them from blending together. All the Pontiac's I have built use the rope seals and when done right, last forever. Since they took the asbestos out of the seal material, its very hard to get one to last or even to go in right. Hope your "Best Gasket" works ! Joe