Different Sized Bellcranks? (or is that bell crank)

[Jay Laifman]

Pelican Parts sells the same bell crank bushings for 911s and 912s. I ordered them for my '67 912.

(911 content: My '73 911 was in perfect harmony, as usual, for our drive to Laguna Seca for the ALMS. It was an AWESOME race. We also met all the racers. Such great representatives of the factory.)

The OD of rod out of the 901/902 tranny and the ID of the bell crank on the 912 is slightly smaller than the bushings I got from Pelican. I saw a reference somewhere that there might have been different sizes.

Is this a 911 issue to? If so, does anyone know where to get these smaller bushings???

Thanks,
Jay

[edmayo]

To the best of my knowledge those bushings have been the same size since the 356. I'm not aware of any size difference 911 to 912. Could you possibly find that reference, I'm curious.

[Jay Laifman]

I'll do what I can. There is no doubt in my mind that the bushing it too big to fit in the bell crank - unless it is some sort of press fitting and the metal stretches as it goes in - and there is no doubt in my mind that the ID of the bushing is slightly larger than the post on the tranny - making for a loose, woobly fit.

The original plastic bushing is still decent. Just the lip has chipped a bit. So, worse comes to worse, I can put those back in.

I will definitely report back what I find. I hope that I can get a decent answer.

Jay

[304065]

I'll do what I can. There is no doubt in my mind that the bushing it too big to fit in the bell crank - unless it is some sort of press fitting and the metal stretches as it goes in - and there is no doubt in my mind that the ID of the bushing is slightly larger than the post on the tranny - making for a loose, woobly fit.

The original plastic bushing is still decent. Just the lip has chipped a bit. So, worse comes to worse, I can put those back in.

I will definitely report back what I find. I hope that I can get a decent answer.

Jay

That has not been my experience with the bronze bellcrank bushings- the ID needs a little reaming to fit around the stud and the OD is a press/interference fit in the bellcrank. I have some replated bellcranks and tried to remove the bronze bushings from my existing bellcrank and they will NOT come out. I actually have to order new ones the fit is so tight.

[Jay Laifman]

Ok, I've measured them, and there ARE different sizes. Again, I don't know if this is a 912 specific thing. But, it is the 901 5 speed tranny.

Here are the measurements. The new plastic and the brass bushings I just got are identical, so they are shown as the same:

Shaft - Lever:__9.8mm__13.3mm (OD of the shaft coming out of the tranny and ID of the bellcrank/lever)
New bushing:__10.3 ID__13.7 OD
Old bushing:____9.9 ID__13.3 OD

So, as you can see, the old bushing fits the shaft and lever perfectly. The new bushing is .4mm too big on the outside and .4 mm too big on the inside. While I could see an argument that the old bushing wore on the OD, but the ID can't wear SMALLER! It came smaller from the beginning.

I'd go about jamming the new bushings into the lever. But, the inside ID is still way too big and is a far cry from a decent bearing surface.

So, the question I guess remains, how do I get the right part! And are all those guys who jammed their new bushings into their levers running about with too big ID bushings, and they don't even realize it?

[edmayo]

This is partly why I prefer to use the plastic bushings, even for the pedal cluster, bought from Porsche. Then you're not at the mercy of some incorrectly machined part. All the bronze bushings I've seen are a little loose, the plastic ones from Porsche always fit properly.

[Jay Laifman]

In case anyone is still following this, I decided to squeeze on the plastic ones and see how much it reduced the ID. It did reduce the ID to almost 9.9 mm, which is the measurement on the ones that were on the car. I put it on the shaft. It is not quite as exacting as I think it probably should be. But, it doesn't wiggle around either. The brass ones, however, if I smashed them on, their ID would never change. So, I wonder if someone designed the plastic ones to shrink down and whoever made the brass ones, used the plastic ones for measurements, not realizing that they need to be malleable. But the gap on the brass ones is definitely unacceptable in my book.

I don't know if the plastic ones I got came from Porsche or an aftermarket supplier. I know I can attest that what Ed said is right. When I was working on my 356, and having trouble getting good accelerator pumps for the Zeniths, I got a pair from Porsche and they were obviously and noticeably better quality and fit. So, I might order a pair of bushings from Porsche just to see if they are any different.

Jay