[scott70]

I wanted a replacement clutch fork for my 70 to but the 69.00 one you have is not in stock at the moment so I bought a good mark one. When I received it I noticed the part that goes against the throw out bearing was flat compared to my original that was curved. If you think about it you would want it curved so the bearing can rock on the curved part when the fork goes through its arch as you push on the clutch peddle. If it sits on flat metal it has to tip one way or the other. So I looked at the pic of your 69.00 dollar fork and it looks like it’s flat also. Actually any brand of aftermarket fork claiming to be Pontiac specific looked flat in the pics online. But pics of oem forks are all curved. Am I missing something here?

[scott70]

I thought maybe an Ames tech would chime in and say whether they knew they were flat and supposed to be curved? How much would it take for the manufacturer to make the correction?

[Ccass]

If I remember correctly, the Chevy fork was flat and someone had it reproduced for the Chevy market. since the flat one seems to get the job done, nobody in the Pontiac world wanted to buck up for tooling to make it exact.

[scott70]

Ok,,, I just assumed these forks are Pontiac specific since that’s what it sounds like in the descriptions online. I would assume that if they were formed to Pontiac specific that at the same time they could have put the curves in. I didn’t realize Chevy forks were all oem flat and seem to work ok.

[AMES-TECH]

Originally Posted by scott70

I wanted a replacement clutch fork for my 70 to but the 69.00 one you have is not in stock at the moment so I bought a good mark one. When I received it I noticed the part that goes against the throw out bearing was flat compared to my original that was curved. If you think about it you would want it curved so the bearing can rock on the curved part when the fork goes through its arch as you push on the clutch peddle. If it sits on flat metal it has to tip one way or the other. So I looked at the pic of your 69.00 dollar fork and it looks like it’s flat also. Actually any brand of aftermarket fork claiming to be Pontiac specific looked flat in the pics online. But pics of oem forks are all curved. Am I missing something here?

scott70 you are correct, these are the correct contour but the area where it contacts the bearing is different. I'm not aware of Chevrolet being different originally, Chris could be correct on this though. We've found that this does not cause any issue concerning functionality. Sadly there is not a correct reproduction with the curved surface.

Thanks!
Kyler @ Ames

[Joe]

Currently converting a 66 GTO from auto to 4 speed. One of the items I am search of is a correct 66 GTO clutch fork. As stated above," this does not cause any issues concerning functionality".
What about service life of the bearing? Is it shorter due to what you are offering vs. an original?
Curious.
Thank you

[64-3Deuces]

Originally Posted by scott70

I wanted a replacement clutch fork for my 70 to but the 69.00 one you have is not in stock at the moment so I bought a good mark one. When I received it I noticed the part that goes against the throw out bearing was flat compared to my original that was curved. If you think about it you would want it curved so the bearing can rock on the curved part when the fork goes through its arch as you push on the clutch peddle. If it sits on flat metal it has to tip one way or the other. So I looked at the pic of your 69.00 dollar fork and it looks like it’s flat also. Actually any brand of aftermarket fork claiming to be Pontiac specific looked flat in the pics online. But pics of oem forks are all curved. Am I missing something here?

The curve vs. straight is not important. What is important is the angle of the fork and the overall length. First, the curve vs. straight. The first picture is an OEM Pontiac fork that I purchased new back in the 80’s. You’ll notice that the ends are straight. Please, no comments on the yellow color. The next is used OEM for a mid-60’s GTO. Also has straight edges. The one thing I noticed is that the straight portions on the aftermarket are a lot longer than the OEM but maybe that’s just the angle in the picture.

The angle of the fork is part of the clutch geometry that allows the throwout bearing to move in a straight line on the input shaft housing. Compare the two forks and see if everything matches up. If so you should be good to go. It appears that the bent up portion was initially done to keep that spring steel piece against the bearing and later determined to be no longer needed? The “unbent” portion still appears to be against the front part of the bearing to hold in place. The bearing will “rock” about 1/8” in the OEM fork.

[GtoFM]

64-3Dueces I believe the OP is referring to the curved edge where it contacts the TO bearing, not the end of the fork. Look at your 1st pic of the yellow fork where it is resting on the rattle can lid.

[64-3Deuces]

Originally Posted by GtoFM

64-3Dueces I believe the OP is referring to the curved edge where it contacts the TO bearing, not the end of the fork. Look at your 1st pic of the yellow fork where it is resting on the rattle can lid.

Yes, he is referring to the curved edge which is at the bearing end of the fork. Not sure what you mean by “not the end of the fork.” I thought my pictures and commentary explained that some OEM Pontiac forks did not have the curved edge at the bearing end which is the OP’s concern. Again, pictures showing straight edges (or flat per the OP) as opposed to the curved in the OP post. If I did not make that clear that’s on me.

[scott70]

GTOFM is correct,,,,Im referring to where it contacts the the throw out bearing. I would assume the throw out bearing has to rock some through its slight arch of movement and thats why the originally done with a curve in them. When theres a flat spot only if it has to rock its going to have to rock up on the corners instead . How much it rocks in that arch I dont know and if they say a flat arm doesnt bother anything then I guess thats it. The curved metal makes more sense to me but what do i know.

[scott70]

Originally Posted by AMES-TECH

scott70 you are correct, these are the correct contour but the area where it contacts the bearing is different. I'm not aware of Chevrolet being different originally, Chris could be correct on this though. We've found that this does not cause any issue concerning functionality. Sadly there is not a correct reproduction with the curved surface.

Thanks!
Kyler @ Ames

OK thank you. So it sounds like most or all GM originals may have been curved and then repops they made them flat but seem to work. So when they made pontiac specific forks (whenever that was) they just didnt add in the curve. So yes whoever has the tooling to stamp these adjusted to make them pontiac specific but the tooling for the curves were never there for aftermarket so they kept them flat.

[Rachelsdad]

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