swapping back - 912E conversion to stock

Nditiz1 · 10-06-2018, 05:03 AM

So my 77 Targa was converted to a 912E. It is running all the 912E bits, 923/02 Tranny, special rear sway bar and mounting block (welded mounts). The 914 is fine, but I want a 6 back in the car. I am trying to decide if I need to remove the 923 transmission to get everything to work properly or I can mate the 2.7 (or 3.0) up to it and have gear ratios like the 73 RS. Help me out Guru's what things will I need / watch out for if leaving the 923/02 in my 77. Thanks!

uwanna · 10-06-2018, 09:55 AM

Quote:

Originally Posted by Nditiz1

So my 77 Targa was converted to a 912E. It is running all the 912E bits, 923/02 Tranny, special rear sway bar and mounting block (welded mounts). The 914 is fine, but I want a 6 back in the car. I am trying to decide if I need to remove the 923 transmission to get everything to work properly or I can mate the 2.7 (or 3.0) up to it and have gear ratios like the 73 RS. Help me out Guru's what things will I need / watch out for if leaving the 923/02 in my 77. Thanks!

I remember reading that the 923/02 will not work with a 6cyl motor.
Seemed to be a problem with the 923 mainshaft not being compatible
with the 6cyl motor. Can't recall the exact problem, perhaps someone
with better knowledge will reply.

Nditiz1 · 10-06-2018, 11:49 AM

I am hoping it is only a matter of the correct clutch package. Didn't early cars mate to the rough splines? 70-73?

inaminit · 10-06-2018, 04:23 PM

I think if you can keep the current clutch parts, it will work. But this is a weak work around. You will be happier with a 915.

Matt Monson · 10-06-2018, 04:31 PM

Quote:

Originally Posted by inaminit

I think if you can keep the current clutch parts, it will work. But this is a weak work around. You will be happier with a 915.

Rubbish. There's nothing weak about it. The input shaft is splined like a 914 and requires the esrlier clutch stuff. Internally it is a 915 gearbox.

Trackrash · Trackrash's Garage

Quote:

Originally Posted by Matt Monson

Rubbish. There's nothing weak about it. The input shaft is splined like a 914 and requires the esrlier clutch stuff. Internally it is a 915 gearbox.

What you mean is the '70-'71 disk?

Nditiz1 · 10-06-2018, 06:22 PM

Ok so if i get a 70 - 71 clutch disk package it will bolt up to a 2.7/3.0 flywheel and everything will be good.

Is there anything needed for mounting that may be different? Engine and transmission mounts.

Matt Monson · 10-06-2018, 06:28 PM

Quote:

Originally Posted by Trackrash

What you mean is the '70-'71 disk?

No, I said what I meant. The 912E's 923 gearbox uses the same 215mm clutch assembly that a 914 or 1969 901 uses. It does NOT use the 225mm 70-71 911 gearbox style clutch assembly.

As long as someone uses one of the 6 bolt 911 engines everything in the car can be retained when swapping the car back. That's part of why you see so many 914-6 conversions using the 2.7. It's fairly straight forward on the clutch piece of it, whereas the later 3.0 and up engines have a different crankshaft bolt pattern.

Nditiz1 · 10-06-2018, 07:00 PM

Now I understand.

Thanks a lot Matt!

Trackrash · Trackrash's Garage

Matt, so you are saying that if one installed a 2,7 or 3,0, with a flat flywheel, that a 225mm pressure plate and disk would not fit in the bell housing of the 923?

So the 923 trans won't accommodate the later 225mm pull type pressure plate?

Matt Monson · 10-07-2018, 09:23 AM

Gordon,
I don’t know anyone who has ever tried. What I’m saying is that every 912e I’ve seen turned into a 911 and every 923 gearbox I’ve seen used in a 914, used the stock clutch. How would you address push versus pull?

Trackrash · Trackrash's Garage

Matt, I guess there are a couple of things to consider.

Since all the pressure plates on 911s are the pull type from '70 on and mate to a flat flywheel, I assumed that set up would work in the 923 trans.

I am assuming the release mechanism is the same in the 923 as in the 915. Maybe that is not the case?

For example when I changed from a 901 trans to a 915 trans in my '71 911 I could use the PP and flywheel that was on my 2,2 motor. I only had to change the disk and the throughout bearing to match the newer trans.

So for example if the OP installed an SC motor couldn't he use the PP and flywheel from the SC, but use a '70-'71 disk? The '70-'71 disk is 225mm but has the smaller spline as was used on the 901 trans. I am assuming that the 923 and the 915 share the same release arm.

Matt Monson · 10-07-2018, 10:11 AM

Trackrash · Trackrash's Garage

So the release arm is different on the 923 compared to the 915. I would guess that that could be changed? The shaft is the same? Change the fork and the arm on the bottom? Possible? Otherwise using an SC motor would require a custom flywheel?

Flat6pac · 10-07-2018, 10:39 AM

From 1970 on all pressure plates are matched to
A flat flywheel
The 923 mainshaft will be the same clutch. 215!or 225 pre 72
You probably change guide tube then a 915 pp and TOB with a 911 disc should
work
Bruce

Nditiz1 · 10:49 AM

915 from an 86

Flat6pac · 10-07-2018, 10:45 AM

That guide tube is already larger than Matt s
Picture
Bruce

Nditiz1 · 10-07-2018, 10:48 AM

901

Flat6pac · 10-07-2018, 10:51 AM

Gordon. I don’t see a. Reason for a custom flywheelfor a 3.0 because except for bolt holes every thing is the same
Bruce

Nditiz1 · 10-07-2018, 10:53 AM

Bruce

The guide tube has no affect on the PP, clutch, flywheel. It is solely for the TO bearing correct? So that will all stay the same on the 923. Are all surface area of the TO bearing made the same, meaning they will all touch the fingers at the same point no matter which guide tube you use?