Question for the gear shift experts: big scrap in R-1st shift plane on side shifter Options

[raynekat]

I've got a 71 914-4 that I converted to a 914-6.
The problem is a very loud annoying squeak when I'm in the R-1st plane.
Something is really scraping badly.
Pulled the shifter which looks to have been changed out from an early shifter to a later shifter.
Greased it very well and that didn't seem to help.

So I looked a bit deeper and put a flashlight in the tunnel where the shifter sits pointing backwards.
Using a small mirror about 6-9" rearward, I see that the shift rod goes through a circular opening in a small bulkhead that is welded into the tunnel.

Looks like the scraping/squeaking is when the rod is hitting the edge of the circular opening in the bulkhead in the R-1st plane.
If you don't pull the lever all the way to the left, then you don't hear the scrape.

Is this typical of a side shifter conversion for an early 914?
Am I shifting incorrectly by pulling the lever hard to the left for the R-1st plane?
Does that bulkhead need to be removed by opening up the shift tunnel from above?

Any thoughts or ideas are welcome.
Thanks in advance.

[BillC]

As part of the conversion to a side-shift tranny, that bulkhead you found needs to have the opening enlarged. Otherwise, as you've discovered, the shift rod will rub against it and make a nasty noise, if it even works at all.

At this point, the most common choices are either live with the noise or pull the shift rod out and open up that hole in the bulkhead. I supposed if you really wanted, you could make a custom-offset shift rod that would clear the bulkhead, but I don't know how much work that would be.

I did a side-shift conversion for a friend a couple of years ago, and I can tell you from first-hand experience that that bulkhead can be a royal pain to get to without cutting an access hole.

[raynekat]

As part of the conversion to a side-shift tranny, that bulkhead you found needs to have the opening enlarged. Otherwise, as you've discovered, the shift rod will rub against it and make a nasty noise, if it even works at all.

At this point, the most common choices are either live with the noise or pull the shift rod out and open up that hole in the bulkhead. I supposed if you really wanted, you could make a custom-offset shift rod that would clear the bulkhead, but I don't know how much work that would be.

I did a side-shift conversion for a friend a couple of years ago, and I can tell you from first-hand experience that that bulkhead can be a royal pain to get to without cutting an access hole.

Thanks BillC.
That aligns with what I am seeing.
I think you are right that the opening in the bulkhead needs to be opened up more or completely removed.
I see a small tube welded to the bulkhead as it passes by bulkhead, so maybe removing the bulkhead will bring other challenges....what does that small tube get welded too now?
Etc, etc.

I thought perhaps I could make an adjustment as to how the shift rod is "clocked" into the shift housing by rotating some splines clockwise or counterclockwise but doesn't seem to be doing much good. Just driving me crazy is all.

Anyone else out there with similar experiences or sage advice at this point?

Think I'm going to have to cut an access panel into the top of the tunnel where the bulkhead resides and get busy making modifications in that area.

[raynekat]

Here's the small hole through the bulkhead that the shift rod goes through.

The diameter of the hole in the bulkhead is barely twice the diameter of the shift rod itself. Not much margin for error there.

In the R-1st shift plane, the shift rod is severely scraping the passenger side of that hole.



Already making plans with Cary at Middleworks to get this addressed.

[raynekat]

Decided I'm going in with scuba gear!

As my main "go to" man is busy plus his shop is knee deep in mud puddles, etc.

I've decided to try this myself.
Have a game plan.
Pretty simple.

Cut a hatch in the top of the tunnel between the seats.
Means seats are coming out and all the carpeting in the rear of the cab.
Will drill a pilot hole and go in with a jigsaw with a short blade.
Cut out a 4"x4" or 5"x5" hatch.
Then go in with a dremel with carbide cutter.
Will open up the opening in the bulkhead (hoop) such that the shift rod doesn't hit it when in the R-1st plane.
I'll put 4 tabs with screws to hold the hatch back in place.
Come in with some new Dynomat and cover back up with the carpeting.
You'll never knew I was in there
Should be an afternoon job at most.
I'll take pics and post how it goes.

Looking forward to some squeak/scrape free shifting.

Wish me luck.

[Montreal914]

Good luck! (IMG:style_emoticons/default/smash.gif)

...while you are at it, you might want to clear up the driver side too? (IMG:style_emoticons/default/idea.gif)

[mepstein]

Wont a jigsaw blade come close to the metal tubes?
What about a die grinder with a small cutting disk?

[raynekat]

Wont a jigsaw blade come close to the metal tubes?
What about a die grinder with a small cutting disk?

Yeah, I'll likely try that.
Certainly don't want to cut anything valuable inside the tunnel.
I'll be looking a lot inside with my mirror as I go.
Should be quite doable.
Will happen this weekend.
The scraping while shifting is driving me crazy on this car.

[raynekat]

Good luck! (IMG:style_emoticons/default/smash.gif)

...while you are at it, you might want to clear up the driver side too? (IMG:style_emoticons/default/idea.gif)

Absolutely.
Only want to be in there once. Ha

[ChrisFoley]

Is it possible to move the base of the shift lever to the left a little bit by slotting the mounting holes? Not sure that would provide enough clearance, but worth a look.

My precision shift adjuster has a small offset that I think goes the right direction, but again, its probably not enough to eliminate the contact. It might be possible to build one with additional offset. I don't think it has any effect on shift action but there may be other obstructions in the tunnel to consider when moving things to the left.

What's your firewall bushing like? Is it an old conversion bushing? That's another place where you might improve clearance in the tunnel without actually going in there.

[Cairo94507]

I have ridden in a very nice 914-6 that seemed to have that exact issue. My car has the RennShifter with the side-shifter conversion done to my 6 transaxle and I have no rubbing or noises. (IMG:style_emoticons/default/beerchug.gif)

[mepstein]

I have ridden in a very nice 914-6 that seemed to have that exact issue. My car has the RennShifter with the side-shifter conversion done to my 6 transaxle and I have no rubbing or noises. (IMG:style_emoticons/default/beerchug.gif)

Similar here. Rennshifter, Renshifter linkage, Tangerine precision adjuster. No rubbing. Maybe I just got lucky.

[gereed75]

My original six with side shifter did this. From memory it went away once I refurbished the shifter with a Weltmiester short shifter and Tangerine firewall bushing.

Never realized this clearance hole was different in early cars vs side shifters and how lucky I was that this worked itself out.

Now wondering what will happen as stuff wears. At least I will know what it is

The other thought I had was that you could maybe cut the shift rod in this area and weld a smaller diameter section into it at this area. Lotsa work, but maybe no more than accessing the tunnel to clearance the hole.

[Krieger]

I am glad you posted this. I have had this issue for years on my 72 six conversion. I haven't bothered to fix yet. I have a carbide bit that is 6" long. I think I am going to use a small hole saw and see if get it in the correct location for grinding some clearance. If it's not I have a viewing window for doing my work through another correctly placed hole. I don't think I will repair holes since it is a track car. I do have carpet that does cover the area.

[Superhawk996]

Wont a jigsaw blade come close to the metal tubes?
What about a die grinder with a small cutting disk?

Yeah, I'll likely try that.
Certainly don't want to cut anything valuable inside the tunnel.
I'll be looking a lot inside with my mirror as I go.
Should be quite doable.
Will happen this weekend.
The scraping while shifting is driving me crazy on this car.

@raynekat

I'll tell you from experience that there is only 2-3 mm of clearance between the floorpan and these control tubes near that bracket.

Be careful in there

I have a picture of that are in sideview in my build thread.



Thin grey on bottom is floorpan edge view. Closest tube is the clutch cable tube, the smaller one behind it is the throttle cable tube and there is only 2-3mm clearance to the floorpan.

If you cut a hatch flap, it needs to be biased toward the passenger side to avoid the tubes.

[ChrisFoley]

Never realized this clearance hole was different in early cars vs side shifters and how lucky I was that this worked itself out.

I'm not sure the hole is any different. The early shift rod was a larger diameter but was supported by bushings at both ends so it only rotated and moved fore/aft. The sideshift rod moves left and right at the shift lever so requires more room around it.

[raynekat]

The sideshift rod moves left and right at the shift lever so requires more room around it.

This is definitely the issue.
When you move the shifter left into the R-1st plane, the bottom of the shifter and the attached shift rods moves in the opposite direction to the right...and quite bit right. Enough obviously to hit the passenger side of that hole in the bulkhead or hoop as Cary calls them.
Even in the neutral plane you can hear the shift rod bang up against the inside of the hole in the hoop.
Then when you move into R or 1st, you hear the big scrape.

I'll definitely get in there with my small flashlight and mirror from both ends (through the shifter hole and also the small access cover back by the rear fire wall.
I'll measure from both directions to find exactly where the bulkhead/hoop is located.
My access hatch that I will cut needs to be located aft of this just a bit.
I'll also look at where everything is located to make sure I don't mistakenly cut into something by accident.

[Retroracer]

So I just went through this recently - here's my findings, but obviously, as with most things with these 50 year old vehicles: YMMV.

My 1970 chassis had been converted to sideshift when I bought it. I only drove it home before stripping the car down for the -6 and GT conversion, so vaguely remembered it must have got into the gears....

On getting the car back on the road, I replaced the firewall bushing with a new nylon one, as well as getting a new PMS rear shift linkage (which misses the -6 headers) + brass bushing for the console. The shifting was OK but I - like you report - did detect a slight scraping in the R/1st plane. This never baulked any changes and was fine for a few thousand miles; until I noticed this scraping sharply deteriorating after WCR2020. To the point where I needed SERIOUS effort to move fore and aft when the lever was in the R/1st plane.

The fix for that appears in another thread on the world here http://www.914world.com/bbs2/index.php?showtopic=350350

but to summarize, the main (scraping) issue was solved by the combination of:

1) replacing the front shift linkage rod (which was an early one modified) with a proper sideshift one (special thanks @mepstein for his generosity), and
2) replacing the firewall bushing with a decently engineered one (Tangerine Racing in this case)

The combination of the above meant that no scraping is felt anywhere, and once adjusted, shifting is much more predictable. Main point here is that the front linkage rod diameter was larger than the later (sideshift) skinnier one - which MAY be your issue too.

- Tony

[raynekat]

What a pain to remove the seats.
I've got GTS Classic seats in my car and the bottom of their seats wasn't perfectly flat plus I don't think the mounting holes in the seats for tracks are in exactly the right spot.
Tough to put them in (they don't slide so great) and much tougher to get them out.
I moved them forward enough to get access to the bolts that hold the seat bases to the car and removed the seats that way.



With the shifter out of the way, and a mirror & flashlight in the tunnel, this is what you see:



Pretty apparent that the shift rod takes up a lot of room in that opening of the bulkhead/hoop.
My estimate was the diameter of the opening was about twice the diameter of the rod.
Not nearly enough for these side shifter conversions.

I do have the updated Tangerine Racing firewall bushing already in place, so that wasn't going to be the solution to my problem.
Possibly a perfectly bent shift rod could do it, but then you'd be up against the side of the opening in the 4th-5th shift plane and have possible scraping there....which I don't at this point.
Still planning to open up the top of the tunnel so I can get a die grinder in there.
It will be tight, but doable I'm thinking.
Luckily I'll be working in the part of the tunnel away from the wiring, tubes, cables, etc.
Most of that stuff is well over towards the passenger side were as the shift rod looks like it's mostly situated in the driver side of the tunnel.

More to come later.....

[914Toy]

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