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PostPosted: August 23, 2012, 11:43 pm 
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I'm so frustrated!! I paid a local driveline guy to fab a flange for my project, and now that the car is running (at least around the block), I've found the fabbed piece is not 'true' at all and will be downright dangerous to run as-is..

Here's the short of it- My BEC has a transversely mounted VFR engine and a driveline that goes down the center of the car between the seats... there sits a T5 tranny- and the problem... Driveline guy made a flange (at the arrow in the pic) that slips over the splines on the input shaft of the T5 (where the clutch disc would ride- under the bell housing (by the way, my T5 sits there to give me reverse and overdrive). Anyway, he's made a flange that is all cattywampus and I'm afraid to go over 20mph with it...

I'm ready for a 'true' solution to this unique problem (notice the set screws- this design was likely never really ideal anyway).. I'm going to pull it back apart and remove the T5 input shaft and have a machinist respline/taper/pin/weld/ whatever to make this crucial part run true and give me peace of mind... It's actually likely the flange part will need to be redone entirely.. I know there's a way to make it work "correctly."

I sincerely hope it's ok to do this on our forum-- If you're a machinist and think you would like the work and can help, I would really appreciate it. Of course I will pay you- I just need it done by someone that gives a damn how their work turns out.

I appreciate it guys- I'm just so frustrated to have paid for this, checked it off the list, and be here talking about it at all.. :roll:

thanks-

ccrunner


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PostPosted: August 24, 2012, 12:23 am 
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Wow. I think I'd probably be taking the part back to the guy, have him spin it up on a lathe, and ask him if he sees anything wrong with his work...then have him re-do it.

If I had a shaper to do the splines, I'd do the job for you myself. Once the splines are done, the rest is simple lathe work...accuracy to .0001" should be no problem for even a relative novice machinist, like me. And, since it's aluminum, balancing (when made to such tolerances) would be essentially perfect.

Failing that, I don't see where it couldn't be made out of steel using, say, the center out of a clutch disc to provide the splines, and making a flange on a lathe.

I suspect if the guy won't give you satisfaction, you need to find an old guy, with a lathe. That'll fix it.

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PostPosted: August 24, 2012, 8:16 am 
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Did your driveline guy spin balance the whole assembly including the adapter? If so, it should eliminate the machine-work as the primary fault. Did he cut a proper step in the adapter's face to center the driveshaft u-joint? I can't tell from the photos. Relying on bolts to keep it centered is not a good plan.

I'm not sure that this will system work as designed. I don't see any support bearing in your design that would replace the function of the pilot bearing in the flywheel. I would think that this is very important to support both ends of the input shaft. there is a lot of leverage at the end of that shaft. Your design eliminated that pilot bearing support. Perhaps you could re-design and add some sort of pillow block bearing in your adapter.

The slip joint length appears to not have enough engagement of the splines to maintain center of the driveshaft. I'm not a driveline engineer but I would think that there needs to be 2-3x the diameter of the spline of engagement length min to keep things from wobbling about.


Just some thoughts.

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PostPosted: August 24, 2012, 10:18 am 
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[quote="rx7locost"]
I'm not sure that this will system work as designed. I don't see any support bearing in your design that would replace the function of the pilot bearing in the flywheel. I would think that this is very important to support both ends of the input shaft. there is a lot of leverage at the end of that shaft. Your design eliminated that pilot bearing support. Perhaps you could re-design and add some sort of pillow block bearing in your adapter. [quote]

This^ and it should NOT be made out of aluminum if it's spline to spline. As mentioned before, bolting is a terrible way to center one axis to another. Look for a rear driveshaft flange that has a machined landing on it and have your new steel, splined flange, machined to fit. Find another "machinist", preferably an old guy that is building his own car also, he'll know how to solve your problem.

Tom

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PostPosted: August 24, 2012, 11:25 am 
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Thanks for the thoughts guys..

I can clarify a few things on this piece- maybe it'll help the next guy trying to mod a tranny into the build downline...

The flange/adaptor was in fact fabbed using 2 clutch centers (to match the splines-- this particular spline pattern didn't conveniently match a production driveline yolk as I had hoped for).. Anyway, both clutch centers were placed side by side (making the spline contact area about 4" long) and sleeved externally with some .120 tubing... Then an OEM Toyota driveshaft flange was cut down and pressed/welded to one end, making the all-steel part you see. The low resolution pics don't show it, but it is 'hub-centric' as it should be, to assure it spins true (which it does not :( )

I believe the trouble came in welding the lathed-down Toyota flange to the clutch center spline tube... I think maybe it's heat warped or wasn't perfectly centered to begin with.. I also have a problem with the design.. the splines don't engage as snuggly as I'd like, which is where I felt the need to drill/tap 6 set screws.. with my set screw anchor system, I think it's impossible to have that 4" contact area align perfectly...

In the big picture, I think I'll be ok with a revised/alternately mounted flange hanging out there.. Where the pilot bearing would have supported the end of the T5 input shaft, I've given it support with that aluminum cone seen on the right side... it goes from the face of the T5 all the way out to the flange and at the end is a sealed bearing (maybe not obvious in the pic).. So now for the fix..

I like the idea of abandoning the exsisting splines/clutch center/sleeve and using a production flange from a differential (read no welding!).. I'm off to the wrecking yard next week to source something.. Any ideas on a good donor diff to yank one out of? maybe just find a Toyota? My only real issue is the 'new' diff flange ID splines/taper need to be smaller than the T5 shaft that needs to be machined to match (I think the T5 is like 7/8"-ish)...

thanks again for your thoughts-

ccrunner

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My '72 Honda N600 build log (bike engine in a microcar)...
http://www.locostusa.com/forums/viewtop ... 36&t=14452

My '63 Volvo 1800 with a turbo inline 4 build log (LNF Ecotec compliments a Svelte Swede)
http://locostusa.com/forums/viewtopic.php?f=36&t=16309

My '59 Berkeley SE492 build log (bike engine in a microcar)... "A Berkeley With Bite!"


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PostPosted: August 24, 2012, 1:27 pm 
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My machining ability and experience far outweigh my welding experience and ability. As such, in order to achieve anything resembling precision in the final product, my advice is to always weld, then machine.

Bill


Last edited by BBlue on August 24, 2012, 10:16 pm, edited 1 time in total.

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PostPosted: August 24, 2012, 5:54 pm 
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Another option is to part the bolt circle from the flange then true what is left, machine another used flange to fit over what you have with some press fit but a lot of wetted area between the flanges, bake the assembly at 350 F then braze with an 80,0000 psi rod by someone who does gas welding and brazing. There should be plenty of wetted area for the shear loading between the two and no warping in comparison to welding.

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PostPosted: August 25, 2012, 10:42 am 
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I disremember diameters but. .. Maybe a pinion yoke off of a Dana 30/35/44 will fit the trans input shaft?
In your neck of the woods I'd call Fresno Driveline, several friends of mine have had a good experience with them for custom work.

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PostPosted: August 31, 2012, 9:57 am 
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Another method:


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