Graphite Seal Failure
 

Boy, this wrecked my flawless record of installing seals that didn't leak. The new graphite seal made it through the break-in run and a few subsequent starts while I did some tuning. Then today I find melted strands of seal on the pavement. Just to be sure, I cleaned up the cement and ran it for another five minutes. A few more strands and a spray of oil on the clean cement, and a few drips from the rear main. The previous asbestos rope seal was in the car for twenty years and survived. Nothing was done to the crank or the seal area. I followed directions with the cutting and all went well, I also coated the rope with assembly lube prior to setting the crank. Anyone else melt one of these, or am I "special"?:confused2

In fairness, I have always slightly preloaded the old asbestos seals rather than just drop them in the groove, and something tells me that the graphite doesn't tolerate as much pressure as the old ones.

Good grief! I think you may be the first to have this happen. Just curious, what type of crank is in the car?

Original 455 crank with very smooth serrations. Old seal had no problems, and this failure was probably operator error. Something tells me that the old rope seals have a larger tolerance on pre-loading against the crank. If I try another one, I'd just lay it in the groove rather loose and cut the ends after beading it down. I had really good luck with expanding the old rope type while feeding it into the groove. Never had an old seal rotate in the groove or leak with this method. Oh well, lesson learned...

Have you talked with the manufacturer Best Gasket Company?

Naw, it just happened this afternoon. Good idea though - see if I can't contact them on Monday.

That's pretty wide material for that kinda seal. Plus how can it pull all that out as it is a spun matt. Plus it is graphite. Rather slick material.
What part number. There are two different thicknesses and if you try and use the wider 400 seal. It will rip it up.

Hummmmmmmmmmmmmmmmmmmm.


I really compress it with a 1" deep well 1/2" drive socket.
I have installed over a hundred of these and never seen how that can happen installed properly?

"I really compress it with a 1" deep well 1/2" drive socket."

Same deal here, but have only installed about a dozen of them with zero issues anyplace.

I spend considerable time packing them into the groove with chrome deep well socket. I cut the seal with the spacer and knife provided, apply a small amount of lube to the crank sealing surface, some RTV from the edge of the seal to the outside of the cap, and install the cap.

At first most of them turn sort a hard, but free up quickly. Very little if any noticable drag by the time you've rolled them thru a half dozen times or so.

If you had a lot of drag, it was simply too tight and burned it up......Cliff

My vote would be that you got a 400 seal vs a 455 seal from Best Gasket or if they sent both gaskets that you had a brain fade and used the wrong one.

I have never seen a properly installed graphite seal tear apart in 45 years of messing with Pontiacs.

Tom Vaught

Pontiac jack sez: Have you talked with the manufacturer Best Gasket Company?

My experience. When I contacted Best a couple years ago to inquire why they list a 1967 428 seal as the same as a 1967 400 seal while the 1968 428 seal is listed as the same as a 455 ????? they said in so many words to mind my own business, unless "I thought I was smarter than Felpro"

Tom V sez: My vote would be that you got a 400 seal vs a 455 seal from Best Gasket or if they sent both gaskets that you had a brain fade and used the wrong one.

I wonder too. Im really not "smarter than Felpro", but I know a big journal seal is different from a small journal seal. Not just the diameter but the thickness of the rope. At least on factory type seals they are and folks have actually cracked rear main caps when tightening over the wrong rope seal. You can hold them in your hand and see they are different. I thought it might not be too good to get them mixed up. Maybe the Best is a one size fits all with different part numbers for different main diameters? I dont think so.
Best seal product might be great but I dont trust the Best humans at all.

Hey wait a minute. They only brought out this new seal a year ago.:-ohwell: That's okay, in my 44 years of messing with Pontiac's I never had a rear seal tear apart either - until now.

I'm thinking that while the older organic rope based seal would burnish in and work, this new space age material does melt if the tension is pushed too high. I had lubed it up good, and this is probably why it made it through the engine break-in and several additional runs while I sorted things out. Assembly lube must have finally dissipated enough and the fun began. I use a short section of round stock with a 3-1/4" outside diameter to shape the seal. I always torque the rear main with the seal in place - then remove it and apply the thin silicone bead before torquing things back to spec. Nothing out of the ordinary was noticed.

Best only include one rope seal pair in the package, and at least the package was marked correctly. I believe that I would have recognized the fatter 400 rope if it had been mis-packaged. Regardless, I guess it's time to start unbolting everything and get the engine pulled out.

Question: With the mains pulled but the timing chain still on, is it possible to lift the rear of the crank far enough away with the rods still attached to fill the anti-rotation holes and install a BOP seal? Never had reason to try it before, and just trying to get around popping out all the pistons.

Sorry for your issues, truly.

With 44 years of Pontiac experience the issue has to be with the seal except Now you are asking can you lift the crank up enough with the rods attached and the timing cover on to install a BOB seal. That sounds like a 'rookie" question if I ever heard one and I know you are not a "Rookie"

TAKE THE ENGINE APART. CLEAN THE CRAP OUT OF THE ENGINE. ROPE SEAL WENT OUT ROPE SEAL WENT IN. INSPECT EVERYTHING, TAKE THE PUMP OIL APART. INSPECT EVERYTHING.

You will be much happier as will the engine knowing that you do not have other issues awaiting around the corner.

Fitting a BOP seal is not easy to do right. You need to inspect the block and make sure that the centerline of the crank is in the center of the block bore for the bop seal to work properly.

I know that you are frustrated. It happens to all of us. Take a few deep breaths and then work your way out of the hole vs try and take shortcuts.

I guarantee later you will be a lot happier.

Tom Vaught

yep, take it apart and clean everything

Yeah, I know, I know. I'm sitting here dreaming up shortcuts tonight, but tomorrow I'll do what I always do and rip the SOB down to the bare block. I'll post up pictures of what I find.

The short answer is yes. On the 3-inch motors the holes do not need filled. On the 3.25-inch motors we have a new procedure for doing it without pulling the crank that it working very well. The instructions for this can be downloaded at our website where the seal is sold. While the concentricity issue can be a factor, I still maintain these cases are few and far between. I sell and support thousands of seals per year and have very few issues.

Update
 

Engine is out, and have some pictures to post. The most unnerving one was the discoloration of the crank from the heat generated by the seal. Note that the serrations didn't have anything to do with the failure. All together there was only half the seal still in place, other half was in the pan and on the ground. I'll repeat that the previous rope seal lasted 24 years and wasn't leaking when the engine came out for freshening up and a cam upgrade. Also the pickup screen was clean, but that doesn't mean that the pieces weren't drawn up against it when the engine was running. Mains are clean with no pollution found. Pictures of the seal on the crank was just after lifting the cap off - there was that much seal missing. The intact piece of seal looks to be the correct size.

Ran out of time and haven't cut the filters open yet.

You did good, Mick! Lot of work doing things right BUT now you know.

Personally I would be having a serious conversation with the "Crank Seal Boys" about this issue.

Talk to them on the phone, send them the photos or the link to this site, document your time in taking this deal apart, repair, and reinstallation, etc.

The part obviously failed. The deal is WHY???

I have seen rope seals with 100K on them that did not look that bad.

The Black crankshaft marks may simply be carbon tracks as Graphite is carbon.

Graphite IS NOT A LUBRICANT so I still do not understand how the seal is supposed to live as a crank seal. Graphite also causes severe corrosion of aluminum parts so any graphite from the seal washed into the oil would cause corrosion of the aluminum parts inside the engine (PISTONS). The Military will not allow Graphite around their airplanes.

Tom Vaught

Graphite comes in a fine powder and is used as a solid phase lubricant, works great.

http://en.wikipedia.org/wiki/Graphite

"Graphite and graphite powder are valued in industrial applications for its self-lubricating and dry lubricating properties. There is a common belief that graphite's lubricating properties are solely due to the loose interlamellar coupling between sheets in the structure.[9] However, it has been shown that in a vacuum environment (such as in technologies for use in space), GRAPHITE IS A VERY POOR LUBRICANT. This observation led to the discovery that the lubrication is due to the presence of fluids between the layers, such as air and water, which are naturally adsorbed from the environment. This molecular property is unlike other layered, dry lubricants such as molybdenum disulfide. Recent studies suggest that an effect called superlubricity can also account for graphite's lubricating properties."

Tom Vaught

Mick, Sorry for your troubles....what a PITA!!

I'm not sure what your game plan is at this point for a new rear main seal, but I'm fairly certain I have a couple of very old (asbestos) rope seals out of some very old, like 1979, fel-pro gasket kits. I'm CERTAIN I have a 3" version, and will check on a 3-1/4"....

Would be glad to help you out and send you one for the cost of shipping if you are interested.....

BTW, If I don't get time tomorrow am, then it'll be on Monday as I'm leaving for the Uprising Friday afternoon (driving the Lamnas) and won't be back til late Sunday.

Lemme know either way...

Jim

This thread is scaring me Mick.Thanks for the pics of the damage