Sweet shifting a 915

Ignatzcatz · Post by **Ignatzcatz** » Sat Feb 16, 2019 11:20 am

I was a bit fearful if doing this job in case it evolved into additional problems. The gear shift on my SSE has always been a bit notchy especially the third to fourth change where you had to pull it out of third to neutral then make the tiniest movement of the lever to the left before pulling it into fourth. Never a nice nor fast change. My fear was having to fit new bushings if nothing could be done to improve the operation. I was on the Pelican forum and noticed a how to sort your gear selection on a 915 gearbox post. It seemed a very simple operation so I got my spanners out. Two 13mil spanners to be exact, but first you access the shift coupler under a small panel just in front of the rear seats. The carpet pulls back easily and this panel is secured by four self tap screws. I undid the 13mil nut and bolt on the coupler and, with it nice and free, moved it as far as poss to the right or offside of the car. Then I moved the gear lever to the left, the nearside, just light movements and keeping it central between first and second. Without moving any parts carefully tighten the 13mil nut and bolt, screw the cover back on and voila, job done. That was so easy but what a difference in gear selection performance, third to fourth a straight through path now and snicking into fifth was a breeze. A simple job with a great result. Perfect.

hot66 · Post by **hot66** » Sat Feb 16, 2019 1:31 pm

That’s what we like to hear

The 915 box is much misaligned by those who have only ever driven a bad one. I love mine in my 2.4

PMNorris · Post by **PMNorris** » Sun Mar 10, 2019 11:15 pm

I've not used one myself, but I've read these make a huge difference:

http://www.rennline.com/Precision-Shift ... 333-SR010/
https://www.porscheshop.co.uk/our-brand ... -1989.html

They are made by Stomski racing.

jwhillracer · Post by **jwhillracer** » Tue Mar 12, 2019 8:50 pm

hot66 wrote:That’s what we like to hear

The 915 box is much misaligned by those who have only ever driven a bad one. I love mine in my 2.4

+1

JW

Ignatzcatz · Post by **Ignatzcatz** » Tue Mar 12, 2019 9:07 pm

Following a shrewd purchase at the swap meet I'm going the whole hog now with the installation of factory option M241 which is the official Porsche short shift kit. I'm just waiting for a new ball socket and friction ring from Design 911 and I shall be getting on with the job. A review of the, hoped for, gear shift improvement will follow.

911hillclimber · Post by **911hillclimber** » Thu Mar 14, 2019 8:50 am

I await with interest your conclusions about the short shift kit.

That set up method works v well.
I have zero play plastic bushes in the gearbox end coupling which removes a LOT of the fore aft play and after 2 short shift kits now settled on a Rennsport gear lever tower for the last 3 years.

I found this to be too short so extended the lever 60mm and now have precision and a low effort and for me, no stretch to get the lever to hand for 1st and 3rd.
The box can still be reluctant at times esp going into 2nd from 1st or 3rd.
The box is totally rebuilt alum cased 915 by the best box man in the UK.

By and large, a nice box and selector system.

There is a lot of play in the system when the box is in any gear, the detention design is not tight.
I think this is most important to the clean gear location in the gate or it will jump out of gear....ouch.

Lightweight_911 · Post by **Lightweight_911** » Thu Mar 14, 2019 9:09 am

.
I've never understood the criticisms of the 915 gearbox (or the 901/911 dog-leg boxes either) - when adjusted correctly & with new bushing in the linkage it's as good as just about any contemporary road car gearchange (although Alfas were better).

You need to remember it's a 45+ yr old design ...

Gary71 · Post by **Gary71** » Thu Mar 14, 2019 9:20 am

Agreed Andy, If in good condition and with the linkage adjusted correctly (not hard!) it’s just fine.

Any jumping out of gear or major reluctance to change is due to something (dog teeth/syncros) being worn.

It’s not a sweet little MX5 box, it’s old school and slower to syncronise than something modern, but absolutely not a problem.

911hillclimber · Post by **911hillclimber** » Thu Mar 14, 2019 7:25 pm

I have 2 boxes, one a 73 and the road box is 85.
Both extensively rebuilt by the same specialist who we all admire.
Both boxes can bulk going to second, the selectors could not be more different.

Only common denominator is me setting the shifters up and operating the lever...

Both boxes will go into 1st at very high speeds, esp the one in the Lola as I know all too well.

There are several boxes that are far better from the same period, Ford Mk1 Escorts come to mind.

I found the works short shift terrible, kept it for 2 weeks / 2 hill climbs, went back to standard asap.

hot66 · Post by **hot66** » Thu Mar 14, 2019 7:28 pm

My box has been built by Mike Bainbridge and shifts perfect from 3rd to 2nd .( mike installed the box and set up the shift too )

1st to 2nd is always a slow shift , but I never do full throttle 1st to 2nd shifts anyway so not an issue ... all other upshifts at the redline and done quickly are loverly as are all down shifts. I’ve never liked 2nd to 1st shift if moving

Ignatzcatz · Post by **Ignatzcatz** » Sat Mar 30, 2019 6:54 pm

After waiting a week to obtain new cup bush and sleeve bush for the shift rod on my wide body, I was able to complete the installation of my factory short shift kit which I learnt was a factory option M241 back in the day. It was all straightforward removing the existing assembly but I did encounter a little difficulty when assembling the new kit. There are two springs within the main gear shift body that have to be compressed over the, I think it was the latch carrier plate. When compressing these two springs, there is nothing to retain them before the top plate can be secured with a couple of 10mil nuts. With the minimal aid of a large G cramp I eventually got the springs locked in to where they should be and started re-assembly. No problems here apart from the two self tappers which hold the base of the centre console had rather feeble speed clips which I exchanged for a much beefier pair then secured the console with 7 mil headed self tappers as the drive angle for the old screws was inward and difficult to tighten. A minor point I know but it made life a lot easier. The very worst part of this installation was hammering back the gearshift knob onto the lever top. It's what you are supposed to do, but I was somewhat reticent to go bashing away so used my nylon hammer and a block of soft wood but it still took a fair old belt.
So to performance and to be totally honest there isn't much difference. OK, the shift is a little bit closer especially first to second and it is a nice movement from second to third, however it's still notchy third to fourth and finding fifth gear is far from a sweet change. The change is quite precise but certainly not a fast movement of the lever. It's almost a Germanic sort of change if you get my drift and I really feel I should pull it all apart and gently grind off all the sharp edges from the various plates and pieces and snip a few milimeters off the two springs, thus relieving the assembly of it's Teutonicness. However, it is early days and as I have driven only a few miles with it, it might just ease somewhat. I'll give it a couple of hundred miles of use and decide further operation then, but, on first impressions I have to say that if you might be contemplating a short shift installation into your beastie, save yourself two hundred quid and stick with what Mr. Porsche supplied in the first case.

911hillclimber · Post by **911hillclimber** » Sat Mar 30, 2019 9:39 pm

Yes...not surprised.
My experience was worse.
The Rennshift is on a different level.

anglophone1 · Post by **anglophone1** » Sat Mar 30, 2019 9:55 pm

911hillclimber wrote:Yes...not surprised.
My experience was worse.
The Rennshift is on a different level.

+1 even better than Wevo

911hillclimber · Post by **911hillclimber** » Sun Mar 31, 2019 9:23 am

Went out yesterday to the Welsh Boarders in my 915 box' 73T, the Rennshift slices very well from 2 to. 3rd to 4th so nicely, and 5th shifts like you really are going into cruise overdrive.
Helps when you have a 3.2 behind it mind, so full of torque.

Also it goes into reverse so cleanly!

Enhances the car without robbing too much character, and for what you get, not expensive.

Best of all the shifters I've tried over the years, had mine for 5 years or so now, lost count.

jwhillracer · Post by **jwhillracer** » Sun Mar 31, 2019 10:49 am

We have had the 3.2 short shift on our Hillclimb car since the kit came out in the 80's, and have always been pleased with it. It's probably on its 3rd or 4th 915 gearbox now, as we have worn out at least one, broken another in half on the Loton Park start line, etc.....

Never had a problem with the shift, it's never going to be as fast as a modern one, but neither is the car or driver!
If the linkage is correctly set up, the change is perfectly smooth, precise and relatively foolproof, and will also allow 3rd to 1st and 4th to 2nd shifts that some of the aftermarket ones don't.
It helps having a friendly local expert who feels his way around a Porsche gearbox in the same manner as my osteopath does my back!

Here's hoping said gearbox stays in one piece for another season!

Cheers!
JW

DDK - Die Deutschen Klassiker