Crankshaft Rear Main Seal Surface

[Matt Wilson]

Ok, I made it to the machine shop yesterday, where the machinist and I did a test fit of the crankshaft and seal in the block.  It turns out that the pitted portion of the crankshaft does indeed directly contact the rear seal.  The machinist was a little surprised, as he had been thinking that the rough area was a little behind the seal contact area.  He again said there wasn't much that could be done about it, and that most people in this situation just run the engine that way.  I asked him how long the seals last in that situation, and he didn't really didn't have an answer. 

I'm going to buy one of the seals that bolts to the back of the block and cap, and see if it will contact in the smooth area.  If it doesn't, I'll look at the possibility of spacing the seal away from the block to get it to contact a smoother area.

If the above doesn't work, then I may look a little farther for a shop that can weld and polish that area.

Attached are some photos I took yesterday.  The surfaces don't feel as rough as they look, but in my way of thinking, any amount of roughness is going to shorten the life of the seal, but if someone knows otherwise, let me know.  I would be very happy to learn that the seal will run forever like that.

Edited September 2, 2017 by Matt Wilson

[Dartgame]

If you use the bolt on seal, be sure to remove the other seal. I'd guess if you leave it in place the bolt on seal will fail. They need some amount of lube to allow them to slip.

[Matt Wilson]

1 minute ago, Dartgame said:

If you use the bolt on seal, be sure to remove the other seal. I'd guess if you leave it in place the bolt on seal will fail. They need some amount of lube to allow them to slip.

Thanks, Dartgame.  Yes, definitely I will remove the other seal.  In fact, after looking at it and talking with some other folks, I don't think the two seals can be fitted to the engine at the same time, as they will interfere with each other.

[Dodgeb4ya]

I remember there being two styles( brands) of two piece rubber  insert rear main seals. The lip position possibly could of been in a slightly different position.

Also there is a one piece split rear main seal used on the 1-1/2 to 2-1/2 ton trucks too

What brand is your seal? Modern or NOS or NORS? 

[Matt Wilson]

The insert rubber seal I recently purchased, which is shown in the photos I posted earlier, is made by Best gasket.  It's brand-new (not NOS or NORS) made in USA, but I had never heard of them.  The folks at Vintage Power Wagons sell them, and seem to like them better than other brands.  I also have another insert seal from my 230 engine, and it looks identical to the Best seal.  I don't know what brand it is. 

Yesterday, I bought a Fel-Pro seal that bolts to the rear of the engine and main bearing cap, and after careful examination, I believe it puts the seal in the exact same spot as the insert type of seal.  However, since it bolts to the back of the engine, I think it could be spaced farther away from the engine by about 3/16" or 1/4", so that it contacts the smooth part of the shaft.  The concern would be whether or not there is enough distance between the seal attachment bolts and the flywheel attachment bolts to prevent contact between the two.

Can anyone here tell me the distance between the flywheel attachment bolts and the back of the block?  I don't have those parts with me, or I'd measure it myself.  I'm pretty sure the measurement would be the same for a 230, 251 or 265 (and possibly the other engines as well).

Thanks.

Edited September 4, 2017 by Matt Wilson

[greg g]

On a pervious engine the crank was sent to a spray welding facility.  The seal surface was built up then turned down to spec.  When reassembled it still leaked.  Not as much, but it still marked its territory!

[Andydodge]

Matt, as the 230 engine I was building was going to use an aluminium Edgy Head and I had obtained both it and a full set of ARP studs, washers & nuts I realised that the standard copper head gasket would not have been a wise install due to electrolysis between the copper head gasket and alloy head.......I checked with a couple of guys here in Oz who play with hipo Frod Flatheads and they recommended using a gasket set from the Best Gasket Co..........I rang them from Oz and they advised that yes they had plenty of experience in this arrangement and supplied a gasket set with a steel/composite head gasket, they also recommended using a spray gasket glue with it.........as this was a complete gasket set it came with 2 types of neoprene rear crank seal plus both types or shapes of the "ears" that go either side of the crank/main cap and around the oil slinger.......the Best gasket set was a well made and complete set & I'd thoroughly recommend it........as I've mentioned I sold the engine & car before getting to the stage of using it but it was good value for the money............BTW checkout the thread on here titled "1957 230 seals" as it has pics of the "ear" seals............andyd..

Edited September 4, 2017 by Andydodge
more info

[Matt Wilson]

Greg, that's a little surprising and disappointing.  I hope I'll have better results.  Everyone I've taked to says that area is too narrow for a standard crankshaft grinding wheel.  I've spoken to a few shops in the area, and I keep getting the same answer.  And yet you were able to get yours ground, and I assume you're talking about a flathead six?  I was also able to get one ground in that area, many years ago, by a different company, but they're no longer around, unfortunately.  I've had a couple of shops tell me they could weld it, but the only thing they would be able to get in there is one of those polishing belts, and they said it would leave the surface somewhat out-of-round (not circular), since it's a hand-held device.  Maybe that's what they did with yours, and consequently why it leaked(?).

 

Andy, it's good to hear that you have a favorable impression of Best Gaskets.  Maybe I'll call them and see what they say about running the seal on the rough-looking part of the crank, since my machinist says most people just run them that way.  I think I know what they'll say, but it doesn't hurt to ask.

Also, I'm still looking for the dimension between the flywheel bolts and the back of the block, if anyone has that.

Thanks. 

[Branded]

Don't have the measurement you need but, recollection tells me that if you space the seal flange away from the block to reposition the seal on the crank your flywheel nuts are going to rub. There's not a lot of clearance.

[Matt Wilson]

That's what I was afraid of.  I should have done a test fit of the flywheel bolts while I was at the machine shop last week.

[Dodgeb4ya]

A picture of a 265 crank flange to block dimensions (.8305")

 

Edited September 4, 2017 by Dodgeb4ya

[Matt Wilson]

Thanks, Dodgeb4ya.  Do you happen to know how far the flywheel bolts protrude from the flange toward the block, when installed through the flywheel and through the flange of the crankshaft?  In other words, how much gap is there between the block and the end of the installed bolt?

[Dodgeb4ya]

All i have is a fluid drive coupling with studs for checking... not what you need.

I don't have a flywheel easily available to put on the crank to check this measurement.

Another thing is factory flywheel cranks I think had a machined relief on the block side of the crank flange to prevent the flywheel bolts from turning. The special flat sided bolts where installed with the main cap off... threads to the rear of the vehicle.

You will probably be using grade 5 or 8 bolts with nuts and lock washers or star washers which will decide your clearance dimension.

The bolts will probably be inserted through the flywheel with the nuts and washers towards the block. The thickness of the nut and washer and the stickout of the bolt through the nut will determine your clearance dimension for the external seal plate housing.

Shown is the factory Ply/ Dodge flywheel mounting bolt that is installed from the block side of the crank flange... threads to the rear.

These are the special bolts that require the machined relief on the back side of the crank flange so the bolts will not turn upon assembly of the flywheel nuts and bolts.

[Matt Wilson]

Thanks again.  I think the bolts on mine insert through the flywheel, with the threaded end toward the block.  I probably need to go look at mine to be sure if the dimensions.

Meanwhile, I found a local crankshaft shop that says they think they can weld and machine my seal area.  I told him it's only an inch wide in that area, and he seemed to think he could do it, so I'll probably go get my crank from the machinist and take it to this shop later in the week.  Keeping my fingers crossed....

[Dodgeb4ya]

Your'e bolts will have to go thread first trough the flywheel.

That's how I've done these jobs.

[Matt Wilson]

Here's an update for everyone:

I found a small place that came highly recommended by a much larger shop that deals in larger engine crankshaft repair, especially diesel cranks.  The smaller place is called Tripple 'N'Gin  (yes, this is the correct spelling) and is located in Irving, TX, if anyone needs a place to do this kind of work.  It's a one-man show (George is his name) and he does all kinds of crankshaft repair, except he doesn't do balancing.  The larger shop doesn't handle the small crankshafts, so they referred me Tripple 'N'Gin, saying he does excellent work.  I took my crankshaft there, and George repaired the seal surface for $80, and what a nice-looking finish it has now!  It looks brand-new, if not better.  He has been in the business for 36 years, and has all kinds of grinding wheels to fit numerous different journal widths, including mine, when other shops had said it was too narrow for their wheels.  I dropped off the crank yesterday morning and he had it ready for me yesterday afternoon.  I picked it up and took it back to my machinist, where they will balance it, along with the flywheel and pressure plate.  Interesting, George at Tripple 'N'Gin said he does not pre-heat or post-heat the crankshafts.  I think my machinist said the same thing about the shop he used to weld repair the thrust flange.  Both shops use Submerged Arc Welding, with some kind of welding wire that's made for forged steel and cast iron crankshafts.  George told me he's never had a problem in his 36 years.  A shop I used many years ago on a previous flathead rebuild did not pre- or post-heat either, so I get the impression it's fairly common.  On the other had, I have read numerous times on various forums over the years that you should always pre-heat and post-heat, so I'm not sure who is right.  My machinist told me that there is special wire that negates the need for this, so maybe that's the answer.  I don't know too much about it, but in any case, George at Tripple seems to have proven his technique over a number of decades.

As a side note, when I arrived with my crankshaft, George told me the pitting at the seal surface was nothing to worry about, and he knows many people who have run shafts in that condition with no problem, and no significant shortening of the seal life.  I really appreciated his honesty, but I told him I would feel better about it if was re-worked, so of course he did it.  I figured I might as well get it done while I have it all apart.

Again, if anyone needs this kind of work done, here's his contact info:

 

George

Tripple 'N'Gin

331 N. Rogers

Irving, TX

(972)259-2474

Edited September 10, 2017 by Matt Wilson

[Andydodge]

Matt............sounds like this is the go to guy.........does he do house calls?..............lol................you have had a win........andyd

[Matt Wilson]

I think he wpuld do house calls, Andy...if you built your house right next to his shop.  :-)  I lucked put in finding this guy.  Although I guess it wasn't completely luck.  There was some persistence involved as well, along with someone at the larger shop who was willing to share his info.  Whatever the case, I'm glad I was able to find such a guy!

[Dodgeb4ya]

How about a picture?

[Matt Wilson]

1 hour ago, Dodgeb4ya said:

How about a picture?

After I dropped off the repaired crankshaft at my machinist's shop, I realized I hadn't taken any photos of it.  I expect to get it, and all of my other engine parts back from the shop soon (maybe this week), and when I do, I'll take some pics and post 'em here.  Sorry I didn't do that already.