Enlarge shift rod hole for side shift conversion? Options

[Jim2]

Folks, I'm installing a side shift gearbox into my 72. Is the hole mid way along the tunnel too small and need to be removed/enlarged? I'm reading opposing opinions about it.

[914werke]

If your referring to the hole for the bushing at the firewall, its the opposite. That is why the conversion bushing is necessary, to adapt the larger hole for use with a smaller rod.

[914Toy]

Folks, I'm installing a side shift gearbox into my 72. Is the hole mid way along the tunnel too small and need to be removed/enlarged? I'm reading opposing opinions about it.

Yes, to accommodate the left to right movement of the shifter rod.

[JamesM]

Folks, I'm installing a side shift gearbox into my 72. Is the hole mid way along the tunnel too small and need to be removed/enlarged? I'm reading opposing opinions about it.

It will work without enlarging the mid tunnel hole, it may work better if you enlarge it. Chances are you will probably wind up with rubbing, especially trying to get into first. worn out bushings will make it worse.

[jcd914]

Two things going on.

The hole in the firewall for the shift rod bushing the larger on 72 and earlier and requires a conversion bushing.

There is also a support bracket inside the tunnel that sometime interferes with the side to side movement of the shifter. The shift rod for a tail shift trans s held in place at the shifter and is rotated by the shift lever where on a side shifter the shift rod is moved sideways a couple inches or so.
Some people have had to clearance the bracket to get the full range of motion the shifter needs.

I personally have converted 10 or 12 cars to side shift transmissions and I have always been able to adjust the shifter without any clearance work except for a shorter seatbelt bolt for the driver side. I have driven some cars that you can feel the shift rod scraping in side the tunnel.

Pull the rear tunnel access plate and use a mirror and look through the tunnel and see where the rod has to go.

Jim

[Jim2]

Sounds like I best deal with this now, instead of trying my luck. Was hoping to not have to cut into the tunnel but now is the time before the interior goes back in. Seems odd porsche added the piece of metal as it doesn't appear to do anything, beside cause us grief 50 years after production.

Thanks all of you for your feedback.

Aside from the gearbox swap, here is today's goings on from some random guy in cowtown.

[a71914]

Oh but that odd piece of metal does do something.
It also holds the clutch cable tube.
Do not cut the whole bracket out and cause the clutch tube to move around.
Just remove enough for clearance of the shift rod.

Ask me how I know.

[r_towle]

Two things going on.

The hole in the firewall for the shift rod bushing the larger on 72 and earlier and requires a conversion bushing.

There is also a support bracket inside the tunnel that sometime interferes with the side to side movement of the shifter. The shift rod for a tail shift trans s held in place at the shifter and is rotated by the shift lever where on a side shifter the shift rod is moved sideways a couple inches or so.
Some people have had to clearance the bracket to get the full range of motion the shifter needs.

I personally have converted 10 or 12 cars to side shift transmissions and I have always been able to adjust the shifter without any clearance work except for a shorter seatbelt bolt for the driver side. I have driven some cars that you can feel the shift rod scraping in side the tunnel.

Pull the rear tunnel access plate and use a mirror and look through the tunnel and see where the rod has to go.

Jim

This ^^^^^^
There is no cutting required.

[SirAndy]

Two things going on.

The hole in the firewall for the shift rod bushing the larger on 72 and earlier and requires a conversion bushing.

There is also a support bracket inside the tunnel that sometime interferes with the side to side movement of the shifter. The shift rod for a tail shift trans s held in place at the shifter and is rotated by the shift lever where on a side shifter the shift rod is moved sideways a couple inches or so.
Some people have had to clearance the bracket to get the full range of motion the shifter needs.

I personally have converted 10 or 12 cars to side shift transmissions and I have always been able to adjust the shifter without any clearance work except for a shorter seatbelt bolt for the driver side. I have driven some cars that you can feel the shift rod scraping in side the tunnel.

Pull the rear tunnel access plate and use a mirror and look through the tunnel and see where the rod has to go.

This ^^^^^^
There is no cutting required.

(IMG:style_emoticons/default/agree.gif)

The only time i have ever seen the part inside the center tunnel rub is when one of its spot welds has come lose.
(IMG:style_emoticons/default/bye1.gif)

[Jim2]

Guys, I didn't see your replies until now and I just finished enlarging the hole. One observation is the heat lever pivot bolt appears to protrude such that the shift rod will make contact with the bolt before contacting the metal hole. I will trim the bolt off and look at the seat belt bolt as well.

What's done is done, though I'd rather have used the hour elsewhere.

[BuddyV]

Jim2......

Thankyou for starting this thread. I also have a 1972 914, and have updated to a side shift trans...... I have been driving this car for YEARS with the shift rod rubbing slightly on the hole in the support bracket.

Today I cut a 4" x 8" rectangular opening in the top of the tunnel...... widened the hole by about 1/16 of n inch...... and.......

THE F-ING CAR SHIFFTS LIKE BRAND NEW!!!!!!

..... whew.

The car before the widening of the opening worked. just rubbed a bit. The squeeking from the rubbing was barely noticeable but was driving me insane.

**** One more observation: Cutting the opening in the top of the tunnel seems to be a MUST for adjusting the connection between the shifter and the rod. Yes, you can probably get hold of the shaft from the access panel near the fire wall..... but,,,,, being able to easily access and manipulate the rod when fine-tuning the connection to the shifter makes the process SUPER easy. I was able to attach the shifter and make the perfect adjustments in about 15 minutes,,,, WAAAAY less time than before cutting the top of the tunnel. The final step will be to make a proper cover.

So.... thank you for your post..... it helped me get my car sorted. Cheers!

Robert

[MM1]

In 20 years, some new 'Teener would probably give $200 bucks (remember . . . inflation) to find this thread and avoid cutting the firewall on his pre-'73 . . . which would be a smokin' deal for the next owner who wants to put it back to oem condition for his concours restoration. . .in 2042 when EV's rule, gas is $15+/gallon and savvy young audiophiles are listening to Rush's "Red Barchetta" for the first time.

@Jim2 - you may not know this - but you can support 914World by donating so @SirAndy can keep this thing running . . .if you do so, you'll even get a benefactor icon attached to your name!

Which, of course, pales in comparison to the priceless knowledge gained here by accessing the wisdom of the 914 Illuminati . . . (IMG:style_emoticons/default/pray.gif)

[MM1]

Other than the Anglicized pronunciation of "barchetta" - Rush nailed it.

[Jim2]

I need to tweak my notifications, didn't realize there were more replies here.

BuddyV good to hear you made an improvement, shifter feel is an element which gives a car soul.

MM1 I sent a contribution to the World, which I had wanted to do a while ago but had trouble figuring how to do it. Thanks for the reminder.

Red Barchetta, I read that story but never knew it's relevance.

[Dave_Darling]

Just confirming--you are using the entire linkage from the side-shift car, including the gear shift lever, right?

And the later style motor mount bar and sold outer and rubber inboard mounts?

--DD

[Jim2]

Hi Dave, yes I harvested the whole linkage and shifter, only need to deal with the custom firewall bushing. It's an aftermarket six installation and I harvested the entire drivetrain.