915 grind? must read...

calling911 · 08-02-2012, 05:48 AM

So my 3rd gear has been grinding in since I bought my 76 6 years ago.. But I've learned how to finesse it.. In MY situation, a blip before engaging usually does the trick... I've read other successes of increasing engine RPM helping with this.. However, forget to do it and Id really grind the hell out of it... and I always blip down, bad racing habit.. so it would not grind on a downshift...

Now to my story....

Last week my clutch cable broke.. I have the odd ball throw out arm where the cable goes in a slot and makes a 90 degree before the adjuster.. I ordered a cable from our host for the 76... I think said 75-76... well, wrong cable, it was too short.. but I wasnt sure what to get to solve that so saw a thread where someone drilled a hole into the throw out arm rather than buy a standard one... so that is what I did.. I also needed to move the arm one spline further away...

Worked like a charm... so then read about how to adjust.. book says 1" of play on the pedal.. set it for that... What I first noticed was the clutch engaged just as leaving the floor.. I was not used to this at all.. clearly my pedal was adjust for a full throw.. as I released the pedal it took a good 1-2" before the clutch would grab... didnt like the feel of the immediate grab but the book said to do it that way so I did...

Im sure you know where this is heading... my grind is gone.. I've driven it on back roads for over 30 minutes and I cant get it to grind.. chugging alone, or spirited driving..

I'm a very let down with myself that I didn't fix this earlier because Im sure I have done damage over the years.. What I don't understand is why??? Why would a new cable, perhaps a new adjustment fix a 3rd gear grind.. something to do with the clutch disk being closer to the flywheel when adjusting the gear?? Now it is SURELY closer.. not further when my pedal is to the floor right? Surely the cable wasn't "stretching" or Id have trouble holding the pedal to the floor without the car moving...

I suppose this could have to do with me turning my "angled" throw out arm into a straight shot arm too.. but not sure why.. the fulcrum point would not have changed more than 1/2"... which would make the pedal slightly harder to push.. other than that???

If you look in waynes book you can see both arms... fwiw.

Oh, after driving.. my pedal is no longer 1" play.. more like 1/2" or so.. which makes no sense to me.. seems like it should be more play... more confusion.

I'm confused, and let down with myself, but mostly happy that my 915 does not appear to need to be torn down.... and I wanted to pass this on to my felllow p car enthusiasts..

T77911S · 08-02-2012, 09:38 AM

i had a karmann ghia when i was in high sclool and several years after that always had clutch chatter when accelerating from a stop. one day i was jacking it up and noticed how much the tranny lifted off the support. i replaced the tranny mounts and it was all better, then sold it. all those years driving it, then someone else got to enjoy it......wish i still had it.

911dean · 911dean's Garage

Thanks for posting this. I've got a clutch cable,springs and wevo shifter sitting on my work bench waiting to be installed. I've already done the ed's coupler. I'm hoping this corrects my second gear grind, but not holding my breath. Maybe I'll do it this weekend. Once again thanks for posting your experience, gives me hope.
Dean

James Brown · James Brown's Garage

interesting, you would think that 1st and 2nd would also grind if it was the transmission. I was thinking someone just rebuilt the 1 & 2 syncros but your fix makes more sense. Good job!

calling911 · 08-03-2012, 08:58 AM

Quote:

Originally Posted by James Brown

interesting, you would think that 1st and 2nd would also grind if it was the transmission. I was thinking someone just rebuilt the 1 & 2 syncros but your fix makes more sense. Good job!

I did not intend to fix anything but the cable but thanks.. I drove the car 1 hour yesterday with normal upshifts into third.. not one grind.. no blipping, nothing.. just smooth shifting like the 915 normally seems to need.. Im still baffled as to why this solved the grind.. but I'll take it.

Steve@Rennsport · 08-03-2012, 09:28 AM

It solved the grind because the clutch was no longer dragging.

In other words, it was not fully disengaging when the pedal was depressed.

calling911 · 08-03-2012, 09:40 AM

Quote:

Originally Posted by Steve@Rennsport

It solved the grind because the clutch was no longer dragging.

In other words, it was not fully disengaging when the pedal was depressed.

So it must have been a tiny tiny drag... because it did not try and move the car while in gear.

80-911SC · 80-911SC's Garage

It is amazing that people will drive these cars with the clutch and/or shifter poorly adjusted and convince themselves that it is "normal" for an older PORSCHE to shift poorly ...

Answer ... they should shift properly .... if they do not ...FIX the issue ..