Renshift, Springs Options

[Randal]

I totally blew my last two runs yesterday missing shifts.

I know part of this is the driver, but I also think the Rennshift springs are suspect.

When we first installed the Rennshift it took some getting used to, but it worked all the time. I've run 8 events now with the new shifter and it was fine for the first four, but not for the last four.

Saturday and Sunday at Alameda I was hitting reverse, shifting from first to second. Typically this was during cornering, but that is the way course work; you just can’t sit there on the rev. limiter waiting to the corner to complete.

Also during very heavy cornering (like in a slalom) shifting from second to third, it was going into fifth.

On down shifts from third to second it was hitting reverse. I destroyed a great run on Saturday on the second to the last corner....just couldn't find second. (Like Grind Me A POUND!) Very ugly.

So what are the ratings on the standard springs? Is there somewhere I send my existing springs to have them tested? What heaver springs are available?

At Alameda I was shifting up/down 8 times. Miss any shift and you blow the run.

BTW the 911 guys don't have to shift more than once.

[maf914]

I want to weld one up and machine it down so it fits that shift console bushing perfectly. The ideal situation would be to run a heim joint there and let the rod slide through it. This would give us PRECISE shift rod action.

I purchased a bronze bushing (the type held by a c-clip) from the bird and found that the inside diameter was about the same as the stock plastic bushing and the shift rod still had plenty of loose play. Like the plastic bushing the inner diameter of the bronze busing appears to be tapered, i.e. the inner diameter is larger at one end than the other.

I went to a local hobby shop and bought a piece of brass tubing that fit smoothly over the machined end of the shift rod where it rides in the busing. This was to be used to sleeve the bushing down to match the shift rod. I took the brass bushing and tinned the inner surface with solder. I cut a piece of the brass tubing the same length as the bushing and placed it inside the bushing. It was almost a perfect interference fit. I cleaned both pieces, added flux, hit it with the propane torch, added a bit of solder, polished it up and now have a bushing that is a fairly snug fit. The bad news is it is not yet installed, but I hope it works well. I'm concerned about possible binding though. Just in case I have a new plastic bushing standing by.

After doing this, it occurred to me that the shift rod itself could be sleeved with either a brass or other metal tube to achieve the same thing, a rod and bushing combination that fit with less play. This sleeve could be epoxied onto the shift rod which means it could be ground off if necessary. Then either the plastic or bronze bushing could be used with a snug fit.