1939/40 Harley trans questions

It was oh so well fitted in the '39 tranny case ... the main clutch gear/thrust bearing race . Had a perfect fit , rolled smoothly ,
everything was going oh so well . But then I found a 1940 trans that was pretty much complete , and a lot of the parts were in better shape than the '39 trans I had . Two factors influenced my decision to swap to the '40 case , there's a (non-critical) piece broken off the '39 , and the '40 has a spring loaded ball and detent system to lock the shifter drum . So I pressed the race out of the '39 case and into the '40 . And all at once the rollers didn't fit so well . Clutch gear wants to walk into the case when rotated one way , out of it when turned the other . Turns out the hole in the case is egg shaped , .0015" wider than it is tall . So here's the question : I want to set the case up in the milling machine and use my boring head to make it round . This will take about .00075" from the top and bottom , and I'm worried I won't have as tight a press fit as I think is needed . So I'm wondering if using a Loctite sleeve retaining compound will be acceptable to keep things stationary . Having that race spin in the case would be a Very Bad Thing ... My other option , is to repair the '39 case and re-machine the shift cam plunger hole to accept the '40 spring plunger assembly . Shift cams are the same except for the locking area and will swap . I'm finally getting to a point that I have room to work on at least the sub-assemblies to get this bike back on the road . I'm not worried about "ruining" original parts , this bike is a mutt anyway and a modified part that I can use beats a broken part any day .
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Snag
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On Sat, 13 Apr 2019 11:50:09 -0500

Could you build the worn egg-shape area up via TIG and then machine to proper size? Even if not perfect it would give you solid material on four sides for the press fit and maybe some loctite too for insurance...
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Leon Fisk
Grand Rapids MI
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On 4/13/2019 12:30 PM, Leon Fisk wrote:

fit now , and I'm hoping that it will still be tight enough after rounding the hole out . A thou and a half split between the sides leaves a mighty fine cut . A couple of things concern me about the build up and re-machine approach . Well , actually 3 things . Finding zero on the hole , this thing has to be dead nuts . Welding on an 80 year old casting in a critical area - it's gotta have some oil soaked in and that means weld grind weld grind repeat until you get a clean repair , welding will also draw whatever temper that casting has , again in a critical area . Whatever I end up doing , pulling the race and miking that hole to make sure I'm right is the first step . If the hole is actually round that means the other one ain't . That's not likely , the race was ground in the lathe while gripped lightly and ran well after installation . Just a very light touch-up to clean up the bearing surface . It ain't likely I'll get to this very soon , just want to have a plan when I do start . Then there's the crankshaft rebuild ... got new bearings and crank pin , by the time I'm done the motor and trans will be completely rebuilt . Now if I could find a set of hi-perf cams for a 45 Flathead ...
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wrote:


Modify and repairthe '39 - which you KNOW works
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On 4/13/2019 7:25 PM, Clare Snyder wrote:


father got this bike in 1952 and it had a broken countershaft in the trans . As far as I know he never even fired it up much less rode it . It sat around in Grandad's chicken coop (half was storage) until 1965 , when Dad pulled the trans and had a countershaft made - somebody in the machine shops at Hill AFB musta owed him a favor or six . But alas , he never put the bike back together . And so when he passed in 1998 I put all the pieces in a trailer and hauled it home to Memphis from Utah . I've been collecting parts since I got it , very little left to buy now , just gotta put it all together . And it looks like in the fairly near future I'll have room to work on it . If I had a bucket list , getting this machine back on the road would be at the top .
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wrote:
"It was oh so well fitted in the '39 tranny case ... the main clutch gear/thrust bearing race . Had a perfect fit , rolled smoothly , everything was going oh so well "
This is what I meant by "you know it works" The parts fit and turn as designed.
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On Sat, 13 Apr 2019 19:50:08 -0500
<snip>

Oh man, great back story and good luck getting this machine up and running again.
You'll have to make a small video of it tooling down the road, preferably in the near future ;-)
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Leon Fisk
Grand Rapids MI
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wrote:

Loctite, the correct part number and used properly, will hold the race in place. It can even help centralize the race in the hole because the Loctite will try to form an even film on the race and bore surfaces. Loctite has developed many new retaining compounds since I first started using the stuff over 40 years ago. They now make at least one retaining compound that works very well on bronzes. I have been using #638 for the last few years when the parts are made from steel alloys. You should check their website to see which compound is best for steel in aluminum. Eric
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On 4/14/2019 1:38 PM, snipped-for-privacy@whidbey.com wrote:

the guys there suggested line lapping it ... that may well be how it was originally fitted in 1939 , I don't know . But that would definitely make sure alignment was spot-on . Several years ago when I discovered this problem I started to make an adjustable lap system , several sizes since other stuff may also need to be lapped in place . I abandoned that project because my skills at that time were not up to the task I set for myself - accuracy wasn't even close to the precision called for . I'm a better machinist now , and have decided on a different approach to making laps for these bearing races . I'll still use the same mandrel and the slugs I was going to use , but I'll machine them smaller then cast a "skin" of maybe lead but more likely wheel weight alloy which will then be machined to the size I need . I've been out in the shop today working on that original lap system , checking it out and cleaning things up . The center drilled in the drive end ain't centered , but dialed in with the 4 jaw chuck and supported with a live center at the other end it has way less than a thou runout . I'll cast a couple of laps and see how that goes , but I'm pretty sure this is the way I'll go with this .
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wrote:


I guess I don't understand what you are trying to do. I thought you had a bore that was out of round and so a bearing race would walk out of it. Are you just going to lap to roundness instead of bore to roundness? Once you do have the bore the way you want it will you still need to Loctite the bearing race in? Or bush and then press the race in? I don't know anything about Harley transmission cases and where the bearings are located. Eric
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On 4/14/2019 5:15 PM, snipped-for-privacy@whidbey.com wrote:


pressed into the left side of the transmission case , it carries the clutch gear (main input shaft to trans , carries the clutch on the outside) and thrust for the clutch . When this race was pressed into another case I have the bearings rolled perfectly - these are loose rollers with retaining washers on both ends . In the case it is currently pressed into , it ain't workin' so well . The race now measures .0015" larger horizontally than it is tall - it's oval now . What we're talking about lapping is the inside diameter of the race , to make it round IN THIS ORIENTATION in the case . If it's R&R'ed it will have to be indexed to the exact same orientation . Or I can make the hole it's pressed into round . Six of one , half a dozen of the other . I can go either way with what I have on hand except for loctite sleeve retaining stuff .
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<SNIP>


OK, now I think I see what you are trying to do. If the race is pressed into an out of round hole and then takes on this out of roundness condition the ID of the race will be out of round. Then if you lap the ID of the race roundness is then restored. If the race is lapped into roundness it will now be a larger diameter. Is this OK? The rollers will now be able skid. Maybe they could in the original configuration. I don't know how the bearing was designed. If the race is lapped round after pressing it in is there a possibility of the race moving in the bore? That would be bad. How much of a press fit is the race in the bore? It seems to me that the shaft that rotates in this bearing will rattle around if the race is lapped oversize. That would bother me. Maybe I should look online at Harley transmission cases. Maybe there's a good drawing or two showing how everything works. As an aside, today I had to remove the distributor from my 1939 Ford 9N tractor. To adjust the points. Sheesh! At least the distributor drive slot is off center so that it only goes on one way. Still, needing to remove the distributor to adjust the points??? Eric
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On Sun, 14 Apr 2019 17:05:33 -0700, snipped-for-privacy@whidbey.com wrote:


Didn't HAVE to remove the distributor on a slant six, but it was less agravation and took less time that way
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On 4/14/2019 7:26 PM, Clare Snyder wrote:


distributors .
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wrote:



On v8 distributors only though.
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On 4/14/2019 9:30 PM, Clare Snyder wrote:



early Tempests . Basically the right bank of their 389 V8 , it displaced 189 CI and a lot of internals would swap . Like camshafts ... Ever try to buy half a set of headers ?
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wrote:




You are correct - and I BELIEVE, but am not cetain,that in a pinch you could run one with an 8 cyl cap.
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wrote:



That little metal door where you could put the allen key? Yeah, that was one of GM's few engineering good strokes.
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and that we can do nothing to change it look before they cross
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On 4/14/2019 7:05 PM, snipped-for-privacy@whidbey.com wrote:


oversize rollers for just that . I don't recall for sure but I think the rollers in there now are stock or .0004" oversize . Yup , that's four tenths . Not much chance of a roller skating as long as I get the clearances right . As it is now the race is a tight press fit , I just remember it was fun getting it in without a press . Nuts and bolts and washers and sleeves will work , but not that easy .
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wrote:



Let the race "rest" for a while so the out-of-round case doesn't force it farther out of shape after you lap it.
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