Dave Farr

Throttle body sealed needle bearings?? GM/Ford/Dodge don't have service parts for their TB's, had my TPI TB ported out and bushings installed but when fully hot gets sticky. I want to install the newer style bearings but am having trouble sourcing them. davefarr@telus.net

titchener

Dave, I'm assuming there were some bushings installed in your throttle body when it was ported. Replacement bushings will work fine (probably better than needle bearings) when there are installed correctly. After the bushings are pressed in they need to be reamed for correct clearance with your shaft.

You just need to have the reaming done correctly on yours, I'd contact the guys that did your TB and have them do it over. The alternative is to buy the reamer yourself from a place like mscindustrial.com but this could run in to some dough. You need a reamer about 0.001" larger than your throttle body shaft.

Good luck-

Paul T.

Dave Farr

Yes the bushings were installed by the same guy- funny thing is, this is the second job he's done for me and both are/were sticky. Do you think it was reamed to tight? Penetrating oil works for a little while. Why are bearings NOT the way to go- OEMs are doing it

titchener

I would think that if the bushing were well fitted that you would have less air leakage than with a needle bearing, although the needle bearings probably have rubber seals also to cut down the leakage, so maybe its a push.

Yeah, they were probably reamed too tight, you don't want to ream any larger then you have to or you get air leakage. You could probably do a "quicky hone" of your bushings by rolling up some 320 grit wet/dry sand paper and working it back and forth in the bushings, but go slow at this, you don't want to take off more than you have to, and you need to do this with it fully disassembled so you can blow it out well with compressed air or carb cleaner.

Before "honing" I'd mark the throttle shaft with a magic marker, stick it back in and work it open and closed several times and then carefully pull it back out. The worn away marker spots will show you where it its rubbing and you should focus your "honing" at those locations in the bushings.

While you have the shaft out, you should also check it carefully to make sure its not bent, if you can roll it on a piece of plate glass or if you can't do that spin it between your fingers to see if it wobbles.

I'd also call your porting guy and get his input into the situation.

Paul T.