Board index Flathead Power-Technical Questions, Answers, and Suggestions 45 Flatties Crankcase oil seal??

Crankcase oil seal??

Moderators: Curt!, Pa

Post Sat Apr 04, 2015 7:24 pm

Posts: 246
Location: Orlando
I bought a new type crankcase oil seal that has rubber instead of the reverse thread. I was wondering if anyone experienced any problems with this new type seal.


Thanks Brendan

Post Sun Apr 05, 2015 12:07 am
GuS

Posts: 368
Location: Bergen, Norway
Hi.
I see no reason why the old cant be used. The crancase have an average pressure below the atm. Pressue and there is a reverse spiral drawing any oil back in that reach the seal. And if there is a drop coming out it will just help lubricate the chain.
All that being said I have used the new rubber lip type with no issues. The do seal 100% and leaves no worries for oil spill to the belt drive. Check the OD. If too loose it might rotate in the race. I have had a couple with sloppy OD dimmension. To make a slight press fit, the OD was increased by squeezing the outer ring in a press and then cut the OD in the lathe.

I assume they have improved quality an you should have no issues.
My only thought is the old thype must have an additional functional as it is being open and playing a factor in the crankcase pressure balance. If only maybe lowering the average crankcase pressure wich maybe compensate itself by drawing a bit moore air through the crancase vent.

GuS

Post Sun Apr 05, 2015 9:06 am

Posts: 265
I believe the rubber seal is for late (post 1944) engines, dont remember the exact reason, but it had to so something with pressure difference indeed.. Maybe it will not give you any problems, am not sure on this matter..

Post Sun Apr 05, 2015 3:15 pm

Posts: 246
Location: Orlando
I bent the spring ring taking it out and found the seal difficult to remove. I then realized "better is the enemy of good enough".
I didn't consider the air pressure in the system.
I moved the seal a little by tapping it pretty hard with a wooden dowel.
I read a lot about this seal and the fit differences on the knuckle but not much on the 45's
I am trying to decide weather to order an OEM spring ring and tap the seal back in place or pop it all the way out and fit the Colony seal.

I am leaning toward tapping it back in place and putting in a new retaining spring ring based on your posts.

However, The Colony part says " Improved design guaranteed to stop oil leakage. Fits 1939-73 Harley 45's.".

First I will try and put it back in place.

:?

Brendan

Post Sun Apr 05, 2015 5:01 pm

Posts: 1659
Location: Interlaken, NY USA

The reverse spiral seal was developed before lip type seals were. As long as there was a primary chain there that needed oil anyway, they sufficed. My experience with the lip seals has been that they are the biggest they could fit in the space allotted. They don't seem to last too long. Look at what Harley uses on Shovels, Evos, etc. Larger circumference, double lip.
I still use the Colony seal, but live with the limitations.
DL

Post Mon Apr 06, 2015 9:26 am

Posts: 3061
Location: Central Illinois, USA
Brendan!

The only problem with modern seals on the sprocket shaft is that when the motor sumps oil from sitting for a while, it has no escape route, filling the cases "to the brim". This causes quite a mess when started, not only fouling plugs, or blowing out gaskets, but I have even heard hear-say of where the hydraulic pressures lifted the rear cylinder from the cases.
(Must have been a Big Twin....)

I have never encountered a seal on a 45" (or a Big Twin through '66+) other than Colony's (or Dixie's?)

If your shaft shows wear from the original "slinger", then the seal won't last long anyway.
If your mainrace has been honed for oversized rollers, the Colony seal may drop right through. It can be carefully expanded with a press, and then re-cut to size upon a proper lathe-mandrel.

....Cotten

Post Tue Apr 07, 2015 3:30 pm
GuS

Posts: 368
Location: Bergen, Norway
Cotten.
Ive had the seal drop through a Std bore race. But fixed by expanding and cut to size. And you're right. A worn shaft will eat the rubber. The first rubber seal i installed was 10 yrs ago. Still keeps the front drive and belt dry.

I have experienced one serious wet-sumping. Result was 1/2 of it puked out of the crancase vent before I ealised what was happening and could shut down and drain through the bottom plug.
GuS

Post Tue Apr 07, 2015 6:16 pm

Posts: 246
Location: Orlando
I put it in because i couldn't get the original back in place. It turned out I had to make a tool to insert the new seal anyway.
It fits good and seals the case. I will be very careful not to let the oil sump when sitting. If I do let it sit i will be sure to drain before starting.
I probably should have left it alone but since it was all apart I thought I would try it.

Post Wed Apr 08, 2015 4:08 am

Posts: 265
You people do realize that the races can be replaced right? Why fiddle around with oversized or even damaged ones.. all you need is a hydraulic press and a piece of tooling to support crankcases

Post Wed Apr 08, 2015 8:58 am

Posts: 3061
Location: Central Illinois, USA
Samsup!

I was referring to a race honed for oversized rollers.
Even a decent fresh race should still need to be line-honed, so why spend for one if it still has life in it?

....Cotten

Post Wed Apr 08, 2015 7:36 pm

Posts: 246
Location: Orlando
I was hesitant to push the races out. I was reluctant to push the oil seal out , but I did. . I was afraid I would crack or mess up the case in some way.

Post Wed Apr 08, 2015 10:12 pm

Posts: 83
Location: Long Island New York
Brendan don't worry these old girls withstand a good bit of strong arming, if you can turn a screwdriver and hold a wrench, you can do almost everything on these machines yourself.

Leo

Post Sat Apr 11, 2015 7:02 am

Posts: 3061
Location: Central Illinois, USA
I almost agree, Leo...

But there's always a way to get in trouble, if you don't put some thought into it.

Samsup mentioned supporting the case when pressing bushings in an out.
Here's what a custom shop did when they put the cases straight on the press:
BRKNCAS2.JPG

The incredible part of it is the fellow cracked one case, and then proceeded to destroy the other!

.....Cotten
PS: The owner brought them to me for last rites I guess, which was to support them and easily move the races in and out.
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Post Mon Apr 13, 2015 4:02 am

Posts: 265
Cotten wrote:
Samsup!

I was referring to a race honed for oversized rollers.
Even a decent fresh race should still need to be line-honed, so why spend for one if it still has life in it?

....Cotten


Because for some it feels better to know that the engine bearings are all 0 overzise... At least for me it does. It is how the engineers intended the engine to be so to say.. And I have never line honed the new bearings, I just lap them with the HD lapping tool ( agian, thats how the engineers decided it must be, that is how I do it) .. I am sure there are better ways nowadays, but there is also a lot of ideas that are less thought through..

As for the oilslinger, I would suggest to stick to the original plan, others will swear by the improved designs out there. It is all up to you what you want, and what you trust..

Post Mon Apr 13, 2015 4:35 am

Posts: 1659
Location: Interlaken, NY USA

You might be interested to know that the factory had available UNDERSIZE bearings and would use them to fit up bearing assemblies when new at the factory. So, I believe there were some design tolerances when they laid down the original designs. (These undersize bearings weren't available by part number to dealers) They did make it easier to fit up new connecting rod races for instance, though. Just something to consider....
DL

Post Mon Apr 13, 2015 7:31 am

Posts: 3061
Location: Central Illinois, USA
Samsup!

You can't possibly believe that the Factory could make production with lapps! They were a "field repair" tool.
I have never encountered an NOS race with a lapped finish, but I have encountered many low-mileage machines with a cross-hatch that I would call honed.

And DL!
I knew Indian produced undersize, but not H-D.

The bottom line is often a fresh race is puckered or slightly out of true, especially if there have been weld repairs, etc.
Most quality races I have encountered were undersized purposely.

Besides my Sunnen, I have a Sidley diamond hone (Caterpillar salvage) that is precisely set for BT .001" rollers.
It has allowed me to align the bores of some drastic case repairs.

....Cotten
Last edited by Cotten on Fri Apr 17, 2015 9:59 am, edited 1 time in total.

Post Mon Apr 13, 2015 3:56 pm

Posts: 265
Cotten, the revision handbook that harley provided to workshops ( military or civilian) is quite clear on the lapping part. They even sold the tools for that. Thus I believe it is sufficient for good operation. Ofcourse it can be better to hone, but not everyone has this equipment available, and I do not think it siginificantly improve the lifespan or performance of the engine..

Post Mon Apr 13, 2015 4:34 pm

Posts: 3061
Location: Central Illinois, USA
Samsup!

That's exactly my point that it was a "field repair" tool.
They could never expect every service shop to have a hone like a Sunnen.
But the Factory would need many.

Not only does it cut the labor to a fraction of the time, the finish is honestly much better for oil dispersion/retention.

Nowadays, a shop should have nothing less.
My decrepid machine is barely "post-War".
LINEHONE.jpg

....Cotten
PS: Hope that photo doesn't show up in the next V-TWIN catalog like the one of it honing a carb!
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Post Mon Apr 13, 2015 9:15 pm

Posts: 246
Location: Orlando
I had a feeling I would become conflicted concerning how far to take the Bottom end.
I fitted rollers .0002 over in the case races, .0002 for the female rod and .0004 for the male rod.
everything meets the clearances in the book but one case is slightly larger than the other. neither will take a .0004 roller but by measuring, I can tell one is at least .00015 larger.
I don't have line honing equipment.

I bought new rods, bearings, cages, and a pin thinking I might bring everything back to 0 but the new rods need to be honed to take the std rollers.

So, I have to decide on staying with what I have currently fitted, which feels pretty good, or start over by sending off my cases, Rods, and bearings to someone with the equipment and expertise to line hone, lap and fit my rollers. :?:

That cracked case just scares me to death. They obviously held it by the casting rather than the insert, but still.

I think I will think on this for a bit.
Brendan

Post Tue Apr 14, 2015 6:49 am
Pa Site Admin

Posts: 5673
Location: Ohio USA

Try temporarily assembling the assembled flywheels and rods to the cases Brendan. Assembled as if you would a completed final assembly, minus tappet block, cams, etc.. Grasp the rods in your hands and roll the flywheels over. If they roll smoothly, are not loose, and no binding, I will bet you are ok.

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