Kevlar pilot bushings
 

Anyone have experience with these? Obviously, the bronze bushings don't last. I currently run the needle bearing style but they have somewhat limited life as well. Just curious if the kevlar bushing is the answer. I'd like to hear if anyone has actual experience with these, not just something that you read in a magazine.

Jim Caughlin
SS 6019

Re: Kevlar pilot bushings
 

Jim, if you do a search, a lot of people have suffered failures with the so called "Kevlar" pilot bushing.

Since I am familiar with the material, I did an internet search and what they are calling "Kevlar" is actually a Nylon bushing and the reason why they do not last. So in a nutshell, I believe they are selling a Nylon product by giving it a flashy name.

Kevlar's properties are not conducive for such application. Delrin or Polyether Ether Ketone (PEEK) materials would be.

Re: Kevlar pilot bushings
 

GM had roller bearings for the 6.2 diesel that would interchange with a "stock" bronze Chevy bearing- not sure what you have been using but worth a look-- they would last a season or more at high rpms too with no difficulty--- machining one from delryn or other products should not be a problem for a good machinist you only need to get a source for some material to make the bushings---
FED 387

Re: Kevlar pilot bushings
 

#14061685 is the GM part number for that bearing about $11-14 dollars--FED 387

Re: Kevlar pilot bushings
 

Didn't think about PEEK, we use it at work and it works very well as a wear surface, good idea. I currently use a GM size needle bearing unit, they last for a full season but do wear out. I had one come apart once and it was a royal pain to remove. Maybe it is best to just accept that they wear out on a yearly basis and need to be replaced. Just thinking about better ideas.

Re: Kevlar pilot bushings
 

PEEK will take the abuse and loads better than Delrin or Nylon.

Re: Kevlar pilot bushings
 

We have run a kevlar bearing and it has done well. I think RAM sells or markets it. 3 seasons on it.
I would say that if you have the crank out, do it all the way and install a sealed bearing. Never ever had a failure there. From a 10,000 rpm modified to a stocker.

Re: Kevlar pilot bushings
 

PEEK is a great resin, way better than nylon and better than Delrin and also much more expensive. However I think there are some newer composite resins like Hydlar which I think is a Kevlar filled nylon that gives both strength and lubricity. The old glass filled nylons had good strength but also caused wear on the shafts they were supporting. (I'm speaking as a plastics guy, not specifically about transmission applications)

Not sure how easy it is to machine or suitable for a pilot bushing.......there is getting to be an awful lot of engineering resins on the market with special purpose fillers in them.

Re: Kevlar pilot bushings
 

South Bend Clutch used Kevlar bushings for a while in diesel applications.
Use your dial indicator to make sure the bellhousing is dead centered, and the trans surface is parallel to the block/crank flange. It is very common for them to be out. Lakewood etc. offer offset dowel pins.

Re: Kevlar pilot bushings
 

Maybe I'm missing something here, is there a sealed bearing (as opposed to an open cage type bearing) that will hold up? In my case, I'm using the open cage type. I pack it full of grease when I first install it but obviously a few 10,000 RPM launches and I assume all of that grease exits the bearing in a short period of time and the bearing is in an unlubed state and eventually fails. In additon, the grease flings into the bellhousing and makes a big mess. As the sealed bearing would not be a press fit onto the pilot, does it spin free enough to be effective or is it just going to gaul the pilot? I'm thinking of either machining a bushing out of PEEK and/or utilizing a sealed bearing that spins adequately free, either should improve my situation. Any thoughts?

Re: Kevlar pilot bushings
 

I use a sealed bearing in my SBF. It was installed with green loctite. It may take some research , but I would think there has to be a bearing that would be close enough for your application.

Re: Kevlar pilot bushings
 

I been using the sealed bearing for years,picked it up from truck pullers, Mc Leod, I think sales them Jerico used to I know they have them for Chevrolets,I don't know what your application is.
Had some made before,can't remember bearing # make bushing to adapt OD to crank
BTW they fit in the bigger hole where converter pilot goes
Remember made one for Windsor in pulling truck once.
These bearings will last for years and if ever do go bad just go buy bearing and put in bushing.
Mike Taylor 3601

Re: Kevlar pilot bushings
 

YES McCloud sells the sealed roller bearings many types look on the web site

Re: Kevlar pilot bushings
 

Thanks for the info. I run a 2.3 Ford motor with an adapter plate to run a SBF flywheel and bellhousing, the crank has been modified to accept the standard GM dimension pilot bearing so there is probably something off the shelf that would work.

Still wondering about gauling on the pilot. It would seem to me that there would be enough friction in the bearing seals that it would not turn free enough to avoid slippage and subsequent damage to the pilot. Might be overthinking this...

Re: Kevlar pilot bushings
 

BTW they fit in the bigger hole where converter pilot goes.

Hi Jim, I could not get the bronze pilot bushing to last even with the bellhousing aligned near perfect. I use the sealed bearing which inserts in the back of the crank where the converter nose goes. It clears and no gauling on pilot shaft. Looked great after 60 passes. High rpm launches are hard on those stock bushings I think. Happy holidays to you. Gary Howe,

Re: Kevlar pilot bushings
 

Never seen any problems,truck pullers are way harder on them than we are they bring rpm up high and then ride pedal for 50-75' depending on track.
Sealed bearing will end your pilot bearing problems
Mike Taylor 3601

Re: Kevlar pilot bushings
 

As long as we are on the subject of manual trans component life, how long are people getting out of throw out bearings? In my case, they are pretty trashed by the end on one season and due for replacement. The other issue that I hate is that they fling grease into the bellhousing. I've always just accepted these issue (limited life and the grease issues) as the cost of racing a manual trans. Any better ideas?

Re: Kevlar pilot bushings
 

I had about 150 passes on mine at last inspection but dont turn much over 6K,I say yours is seeing quite a bit above 6K. I wonder if the extra harmonics of 4cyl shortens life of pilot bearing,throw out bearing.etc
Use to get BCA bearing to use w/long style press plates,were looked up for early 60's GMC truck that had the big GMC V6 w/long style pressure plate if remember correctly took bearing off the (don't know name of part) housing maybe well any way bearing presses on it and it goes in clutch fork and press back on regular chevrolet piece.
One in my car now is Ram.
Mike Taylor 3601

Re: Kevlar pilot bushings
 

Jim,
I have been using the same TOB since 2008. I have a spare, but when I pull the trans to check the clutch I check it and have not seen any issues. Same way with the pilot bearing. I run an SKF sealed bearing for the pilot.

As for bearings, if you have a bearing distributor in your area, with the dimensions you need for the pilot, the distributor will be able to match the ID and OD. It may be metric but most likely they can find something for you. A place like IBT would be who I am referring to.

The reason for having bearing issues, comes back to alignment of the bell housing. I align pumps and cooling towers and it is critical that the less misalignment that you have the longer things will live. .005 and less is required and that would be both parallel and angular. It could be the bell housing is aligned on the parallel plane, but the angular is not. Something to check if you are having issues.

Sean