Window regulator & motor advice

[bmwm3owner]

Hello,

I have a '72 3.0CS and have some questions regarding the front window regulators and motors - for now.

I have been researching the forum and see that many folks have done the e28 rear window motor conversion. Looks like a nice upgrade. My car has the sardine can style motors. My questions are:

1. Can I upgrade the regulators to the later style? I believe from the '74 up? Will they bolt up and operate the same as the early regulators?

2. I read somewhere that you can use the early Porsche window motors. I ended up getting a couple of new motors for early 911's, up to 1985 I believe. When I received the new motors, it looks like the shoulders where the mounting screws go through the motors are taller than the e28 motors. This make it so that the gear on the motor does not reach the large gear on the regulator. I suppose I could grind the shoulders down a bit so that the gears will mesh but before I destroy some new motors, I wanted to check and see if anyone else has done this before. If I upgrade to the later style regulators, will I have to do this anyway?

I did clean up the sardine can motors and will be greasing up the existing regulators, tracks, etc. to improve performance. Ultimately, I want to do the upgrade, including adding the relays, but before tackling this project, I wanted to check and see if there are available used regulators, just in case my project takes the wrong turn.

Thanks

 

[HB Chris]

You can modify your regulators to accept the e28 motors, it will be very hard to find mid-73 and newer regulator. The procedure is documented in a thread on our forum. Porsche motors will not work, only e28 rear door motors can be used.

A few tips on installing e28 window motors

OK, so why does e9coupe.com need yet another thread about installing e28 window motors? Well, I thought I could pass on a few tips that I learned while converting both front doors on my 1970 2800CS from the original "sardine can" style motor & gearbox to the e28 style with integrated motor/...

e9coupe.com

 

[jmackro]

Porsche motors will not work, only e28 rear door motors can be used.

The issue is the # of teeth on the gears. The sardine can motor-gearboxes' output gear has 8 teeth. So you need an 8 tooth gear driving the large gear on the regulator, which is what the e28 rear motor-gearbox has. I think you'll find that the Porsche motor-gearboxes have 10 tooth output gears.

 

[bmwm3owner]

The issue is the # of teeth on the gears. The sardine can motor-gearboxes' output gear has 8 teeth. So you need an 8 tooth gear driving the large gear on the regulator, which is what the e28 rear motor-gearbox has. I think you'll find that the Porsche motor-gearboxes have 10 tooth output gears.

Hi Jay,

The Porsche motors that I have are also 8-tooth. The later ones (I believe '86+) are 10-tooth. They mesh up fine with the gearing on the sardine can style regulator. The main issue is that the threaded ears on the motor have a shoulder to them, which makes it so that when you mount the motors, the gear does not reach the large gear on the regulator. I presume I could grind the ears off a bit so that the gears would mesh. I wanted to see if I could get another set of regulators, just in case I butcher things

 

[jmackro]

OK, as long as they have 8-tooth gears, they should be adaptable to the e9 window regulators. If you have read through the threads on this conversion, you've seen that a few things need to be cut/ground/drilled to make it work. So yea, shortening those threaded stand-offs is probably something you'll need to do.

 

[bmwm3owner]

OK, as long as they have 8-tooth gears, they should be adaptable to the e9 window regulators. If you have read through the threads on this conversion, you've seen that a few things need to be cut/ground/drilled to make it work. So yea, shortening those threaded stand-offs is probably something you'll need to do.

Thanks Jay. Always nice to get some confirmation from the group. I hate to start hacking things up, especially since parts cost a lot to replace or are made of unobtanium!