More options for shift coupler bushings

[Elombard]

I ran across these at a local place. ~$20. Myabe in In between brass and plastic? Not as pliable as Will was suggesting mught be nice to avoid ware, maybe a little more pliable then brass?

I will let you know how they feel.

[kstylianos]

What are they made of? Just curious.

If plastic, think of possible cracking.

[RickM]

Look like Nylon...

[gerry100]

They are plastic. Most likely Acetal- used commonly for bushings in low PV ( pressureXvelocity) apllications. Acetal used for lubricity and relatively good wear characteristics versus metal.

Nylon would swell in humid condtions and not wear as well as Acetal.

Delrin is the most common brand name and is likely used in the Porsche supplied bushings also

[chrisp]

Looks like teflon. Nice and slippery.

[gerry100]

Teflon ( PTFE) would be great but very expensive as each bushing would have to be machined.

Teflon can be added to Acetal , and often is for wear applications.

BTW, Teflon, Acetal, Nylon , much of the modern car, some of the 911 is all plastic. Varying types with different properties for different applications.

[Elombard]

Yah I would have called this Teflon, it looks like it was machined, but surely not. Probably molded and "cleaned up".

[chrisp]

Teflon would probably be too soft.

[Wil Ferch]

Most likely Delrin for its shape and inherent lubricating properties..

The fact that the hole is round ( I assume) and tight fitting would...IMHO...make this the ideal choice between fully brass ( not compliant enough because it would be installed in a bushing that is not a true universal joint) ...and a true universal joint ( $). Any plastic would allow a slight amount of "give" that isn't there with a metal like a brass insert.

Wil

[MotoSook]

Erik, are the bore and OD appropriate for our couplers?

[Elombard]

Yes, very snug fit. YOu are right Wil, Delrin - not Teflon. I am almost positive this is Delrin.

I have it in the car, just finished getting the coupler adjusted - back at work :-(( I will give it a drive in a few hours. Not sure I have the adjustment right - feels very strange going into 5th gear.

[gerry100]

When I replaced mine with the new bushings the precision of shifting did improve, mainly because the bore was now round and fit snugly. The original bore had gone from round to oval after many thousands of shifts and the resulting back and forth pressure.

The increased precsion in the shift is a result of the dimensions.

A little give is desirable in the the bushing wiuld absorb some forces that would otherwise be transmitted to expensive and inaccessible pieces of the transmission.

[Elombard]

Gerry I think the stock ones are oval by design. The round hole makes a firmer shift but possibly accelerates wear as you mentioned. There is a great thread on this somewhere..

[gerry100]

I disagree, my original bushings that came out appeared oval from wear. Porche replacements were round. I've been in the plastics business for 28 years and have seen a lot of parts.

Besides , I can see no reason to design in slop in this manner.

[Chuck Moreland]

Though your oe bushings surely did show wear, the factory orginal parts are indeed elongated holes when new and direct replacements are available. The round hole replacements are from the 914 or aftermarket.

The reason for the designed-in slop is to allow the coupler to act as a poor-mans U joint.

[Wil Ferch]

Listen to Chuck.....correct on all 3-4 points he made in that short sentence....

Wil

[Bill Verburg]

Hayden has mentioned the same things that Chuck mentioned. That said I have zero clearance in the bushings and support which have tightened up the linkage a lot it is very nice