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Lotus Europa Spiral Pins

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Mike Stobbe

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I've got an Europa mystery. The spiral pins on my Twin Cam have started backing out. This has never happened before. The pins are about 1/4" longer than the U-Joint yolk diameter. I'm careful when installing them to have 1/8" sticking out on each end, but now in about 50 miles of driving both pins move 1/8", flush on one end and sticking out 1/4" on the other. I haven't dared drive farther to see if they will continue moving; I assume they will. They aren't loose. It takes a ball peen hammer and a drift to reset them. And I thought I was being very careful to shim out the yolk with no end float or even a bit of interference fit. Have any Europa owners out there experienced this? I've got maybe 10,000 miles of Europa experience, but never this problem before.
 
Hi Mike...YOu posted your question in the Forum that is meant for discussing our new forum platform. I'm going to move this to the "Lotus" forum. I'll leave a pointer in the original forum you posted in. If you are reading this then you are now in the Lotus forum.

Each major make has it's own forum for discussion.
 
It sounds like you have maybe:

1. Shimming issues. The yoke needs to be tight against the transmission, just a bit of looseness can allow enough movement of the yoke to start walking the pins out.
2. Pin issues, are the pins old or new? and you do have the small pin that goes inside the big one?
 
There are 2 kinds of pin for the TC. One is a roll pin, for the early gearbox (336?) which is the 2-part roll pin. The later 352, 4 speed and 365, 5 speed are a one-part spirol pin.
Do you have the right one? They are slightly different diameters I think.
 
The pins are the spirol type, for a 352 transaxle, and are new. Somewhatspritely, you are thinking the shimming is too loose? Have you ever experienced the pins moving?
 
I have an S2 with the dual pins, (currently in pieces) It had opin movement before I did a rear-end rebuild. I replaced the deformed OEM spacera and reshimmed, the rebuilt assembly didn't move for the 3000 miles I managed before the next set of issues . . .
 
Thank you, Roger and Somewhatspritely. I've added 0.010" more shim to each side, and reinstalled the pins. They took about twice the effort to drive home, so I know they are an interference fit now. Just returned from a 75 mile test drive and the pins have not moved. I'm going to trust that the problem has been solved.
 
Folks often safety wire through the pins to avoid issues if pins do move. As noted above, they shouldn't move, but it could be ugly if the work there way out unexpectedly.

TonyWa
 
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