Bushing dances again - Alfa Romeo Bulletin Board & Forums
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post #1 of 20 (permalink) Old 03-23-2016, 09:02 PM Thread Starter
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Bushing dances again

2 and 3 sloppy, but 1 will get done too -- if I can find the right bushings
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post #2 of 20 (permalink) Old 03-24-2016, 08:14 PM Thread Starter
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Ya here it is -- everything over by 4 or 5 thou, interestingly enough mains haft diameters are 4 ish thou lower on this box than the last one-- and centerline doesn't have the spiral cut machined bushings ( see my last year bushing clearances post) only the dimpled ones...
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post #3 of 20 (permalink) Old 04-25-2016, 12:14 PM Thread Starter
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I had an extra of the spiral cut bushings from last time that I slid into 3rd gear -- its beautiful, needs tiny, tiny relief on one end. I got another 2 of the dimpled type from Spruell and pressed em in on Sat for 2nd and 1st. They are about 0.014" diameter too small -

I just now went over to a precision machine shop -- the stuff these do is incredible -- and pleaded my case to the general manager. He's a car guy at heart so he took em in and now I wait. I explained the exact concentricity needed and I'd like em 1 to 1.5 thou over--and what he said about how to do it sounded correct to me -- mount up in soft jaws on the lathe, true it up, and go for it. I told the guy I felt kind of like asking Picasso to draw me some stick figures and he laughed-- said they would take care of me and get me back on the road!

Now we wait.

74 GTV with 10548's and Ingram pump
71 Spider 1750 BOMBER ; 1995 LS 78K tight fast car
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post #4 of 20 (permalink) Old 04-27-2016, 01:38 PM Thread Starter
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Update -- the machine shop called and basically said that they have no way to do this to hold concentricity and perpendicularity. Back to searching on someone/somewhere that can do this -- seems simple I know but I also know it isn't!

74 GTV with 10548's and Ingram pump
71 Spider 1750 BOMBER ; 1995 LS 78K tight fast car
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post #5 of 20 (permalink) Old 05-24-2016, 08:04 AM Thread Starter
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I did finally succeed in getting the bushings turned/honed and matched to 0.001 ! I went over and talked to the machine shop lathist and we agreed he would give it a go with no guarantees -- when I got these back and put on the mainshaft I was blown away -- 2nd gear might even be less than 0.001, it barely (and I mean BARELY) slips onto the shaft but it does turn freely with ZERO slop. Interesting to note that the dimples on the inside of the bush show the non-concentricity of the raw gear, after machining, ie the dimples now are not all the same depth, one side has more material removed than the other inside the bush. Not by much but a probably 5 thou anyway


Spent last night assembling the mainshaft. I bought a 5 dollar toaster oven off craigslist and used it to heat up the tripods. Worked great!

Only a couple things bothering me -- 1. there is axial (left and right) play in second gear about 12-15 thou or so. I did put the two .11 mm spacers back in (between first gear and bearing) but there is still play. With second gear pushed all the way left (towards third) I get right in the middle of the range specified in the book (cant recall 1.558 inches???) but when I pull it all the way RIGHT its over (ie the whole gear is moving toward first gear). My first thought is that I didn't get everything squashed together properly (don't have a press). However,

2. There is an ever-so-slight binding on reverse gear layshaft to mainshaft. I mean slight. And, when I drop the mainshaft into the bearing pockets, it doesn't visually look like the bearings are fully seated in the case -- but the case halves go together no problem. It is worth mentioning that the main and layshafts are not native to this gearbox case, the originals were in pretty bad shape. Also note that everything is pretty dry right now with only a minor amount of assembly lube on the bushings/bearings, nothing on the gear faces themselves.

So I am wondering -- for the axial play, is it just that I need to squeeze everything down a little more with a press? (ie move everything towards 4th gear) Thoughts and expert advice from all the gurus here? I don't relish taking everything off again but if need be then OK.

TIA goats

74 GTV with 10548's and Ingram pump
71 Spider 1750 BOMBER ; 1995 LS 78K tight fast car

Last edited by goats; 05-24-2016 at 09:27 AM. Reason: typo confusing
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post #6 of 20 (permalink) Old 05-25-2016, 07:21 AM Thread Starter
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Real measurements --left-to-right slop between 2nd and the shaft hub = .007, 3rd .008 and first .009. Will see if I can get it closer by pressing with hydraulic press but even if not I think I'm OK -- book says 2 and 3 not more than .0083 ; not sure about first tho....... 2nd to 3rd measurement "A" is spot on when these two gears are mated up next to each other as noted above......

No binding left --- I cleaned the snot out of the bearing pockets , although there is no visual change, the gear train is very smooth now.
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74 GTV with 10548's and Ingram pump
71 Spider 1750 BOMBER ; 1995 LS 78K tight fast car
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post #7 of 20 (permalink) Old 05-31-2016, 10:27 PM Thread Starter
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What I hope to be the final learnings on this trans.

1. Cleanliness is key. Everything clean. Spotless. Then use assembly lube on bearing surfaces (a tiny bit) to help everything go together easier
2. Toaster oven at 350 for tripods and reverse on reassembly is your friend = $5 on craigslist
3. DO NOT take your "A" measurement until you have everything on the mainshaft torqued down. This means put the drive fork on and torque to 87 ft/lbs. I chased the measurement 3 times until I finally figured this out (and I;m kicking myself because RJ mentioned this in one of his posts!). I lost 6 thou on the A measurement after tightening the drive fork! And, let it sit awhile and relax into position. I finally (at least as of this moment) ended up with an average of 1.556" with a range of +1, -1.5 thou around the circumference of the gear teeth. Same true for the end play 3rd 2nd first. I ended up with 7, 8 and 9 thou respectively
4. I found an extra .5mm shim in my parts stash! Good for next one I suppose



Still a few things pending but I;m feeling way better about this. I would guess I am close to 25 hours on this box right now. Don't ask me where it went. Fiddling more than anything else. If I was good at this I bet I could get it done in 4 to 5 not including cleaning.

74 GTV with 10548's and Ingram pump
71 Spider 1750 BOMBER ; 1995 LS 78K tight fast car
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post #8 of 20 (permalink) Old 06-01-2016, 08:06 AM
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Goats, FWIW,I just noticed at AFRA (GTV parts),they show the spiral gear bushing,maybe they still have them.Classicalfa also had that photo up a few months ago,but when I called,they were NLA,and I believe they changed the photo to the dimpled original type.Phil D
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post #9 of 20 (permalink) Old 06-08-2016, 08:45 AM
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Great thread, Goats. Lots of good tech.

Scott

72 GTV; 66 Fairlane GT convt, 428, 4 sp; 68 GTO Convt, owner built 455 and TH400; 71 Javelin road race project, owner built 401, T10
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post #10 of 20 (permalink) Old 06-08-2016, 09:17 AM Thread Starter
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Guys I am done with the trans ; everything is back together. I'm going to Starbucks today and buying my machine shop guys a gift card for the expert precision work they did for me. My last trans came out beautiful, I think this one is going to be every bit as good. Good work does take time. Attention to detail is important. One thing to make sure of when you reassemble is to check the studs in the case halves and make sure they are cinched down tight. Mine were very loose and unless one took the time to check, over time I am sure leaks would develop between the case halves. Some locktite blue on the studs where they mount into the alum cases is not a bad idea.....

74 GTV with 10548's and Ingram pump
71 Spider 1750 BOMBER ; 1995 LS 78K tight fast car
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post #11 of 20 (permalink) Old 06-09-2016, 12:17 PM
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It's always great to be able to to take the time to "blueprint" an assy of machinery. Everything ends up working so smoothly, whereas with a standard assembly line, you get what you get, depending on how careful the assembler was or how much time he was allowed to do the job.

With our Milano, the transaxle had to be torn apart and reassembled properly on warranty when the car was brand new, since it must have been a Friday or Monday product, having very obvious loose clearances everywhere inside, ie, just thrown together. Far too much on and off the throttle slop.

Del

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1989 Milano, Shankle Sport
1991 164S, stock
1994 164LS (~Q)
1972 Morgan 27

previously owned since 1964:

62 Morris MiniMinor 850, 67 Austin 1275 Cooper S (Downton 3/4 race), 64 Giulia Sprint GT (1st red one made), 72 Fiat 128 Sedan, 75 Alfetta Sedan, 78 Alfetta Sedan, 78 GTV, 81 GTV6, 86 GTV6
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post #12 of 20 (permalink) Old 07-13-2016, 04:00 AM
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Originally Posted by goats View Post
Guys I am done with the trans ; everything is back together. I'm going to Starbucks today and buying my machine shop guys a gift card for the expert precision work they did for me. My last trans came out beautiful, I think this one is going to be every bit as good. Good work does take time. Attention to detail is important. One thing to make sure of when you reassemble is to check the studs in the case halves and make sure they are cinched down tight. Mine were very loose and unless one took the time to check, over time I am sure leaks would develop between the case halves. Some locktite blue on the studs where they mount into the alum cases is not a bad idea.....
Loctite + aluminum (even the less aggressive blue loctite) makes me nervous. Have had bad experiences here.

Question about the bushings -- are the spiral bushings superior to the dimpled ones? If so, how?

Thanks,

Scott

72 GTV; 66 Fairlane GT convt, 428, 4 sp; 68 GTO Convt, owner built 455 and TH400; 71 Javelin road race project, owner built 401, T10
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post #13 of 20 (permalink) Old 07-13-2016, 08:37 AM Thread Starter
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Hi Scott

Take a look at your bellhousing to case mating surfaces and all mating surfaces Alum to Alum. There may be evidence of fretting and this is due to vibrational and rotational movement surface to surface due to loose studs -- Mine were very loose

Spirals are machined bushings that seem to have perfect ID / OD and thus only need to be pressed in and secured. No extra machining was needed in my case. DImpled bushings are not machined, they are pressed/punched and wound. They need to be pressed into the gear, expanded (if needed) and then machined. Finding qualified machinist with soft jaw lathe to make sure its centered/perpendicular/no taper/etc can be trying. If I was building another box, I'd try to get the spiral cut bushings. Same price as dimpled essentially but no need to post machine.

74 GTV with 10548's and Ingram pump
71 Spider 1750 BOMBER ; 1995 LS 78K tight fast car
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post #14 of 20 (permalink) Old 02-19-2019, 12:55 PM Thread Starter
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bump for crackie ! You can also go find the other post I did referenced above

74 GTV with 10548's and Ingram pump
71 Spider 1750 BOMBER ; 1995 LS 78K tight fast car
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post #15 of 20 (permalink) Old 05-17-2019, 10:58 PM
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Goats, thanks for the bump on this thread.

Curious your take on this. In the pictures below it seems my bushings have spun in the gear. The bushing filing for the oil galleys don't match up with the oil galleys on the gear itself. But it's odd, because the gear clearance on the shaft is in spec at .0045, so not sure why that would have happened.

I don't have a great desire to go through the bushing machining odyssey that you and so many on your threads have gone through given the clearance is in spec. Is it acceptable to keep these and just file the bushing at the galley and go on with my build?

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--Scott
Current: 85 GTV6, 69 Duetto, 17 Giulia, 74 GTV
Past: 65 Giulia Sprint GT, 77 Alfetta, 79 Alfetta, 87 Milano Gold, 74 GTV (Euro)
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