E36 325is Track Car Stock Manaul to M3 Manual Transmission Swap Question

[jvredz]

Hi All,
I did a search first and did not find any information on the topic I am about to ask. I have a 1994 E36 325is that was converted to full race car a number of years ago. Been a great car but in the last race at Mid-Ohio the stock transmission gave up the ghost (and lots of metal). Bought an E36 M3 transmission supposedly from a 1995 car and have not been able to get the transmission to mate up to the engine. It gets to about half an inch gap and then is just stuck and no amount of wiggling, bouncing or hammering on a 2x4 moves it. Have tried it with the stock flywheel, clutch and pressure plate and an M3 flywheel, clutch and pressure plate and tried a few brands of pilot bearings, throw out bearing, etc. all with the same result. There are no witness marks inside the case or on the pressure plate except from where we have been jiggling it around. The car is on a lift and using a transmission jack so have been able to try various angle of entry as well and always same half inch gap and then stuck.

Anyone with experience doing this swap have any words of wisdom or tricks or know something I have overlooked? Thanks in advance or your advice. It has been frustrating having something this simple take so long.

[jayjaya29]

does the pilot bearing slide onto the input shaft of the transmission easily?

[olemiss540]

This sounds like a frequent issue I remember where alignment was oftentimes the cause. As wierd as it sounds, there was always a hangup possibly either at the small dowel locations or with the flywheel alignment (using a flywheel alignment tool) if memory serves. Had to have a pretty specific and aggravating angle/wiggle to get that last bit to slide in. Hehe

[jimmypet]

I am assuming you did an out of the car test fit of the pilot bearing over the pilot shaft of the trans and it fits perfectly?

If yes I have this issue every single time I put my trans back in my race car. The trans slides in all the way to the last engagement of the pilot shaft into the pilot bearing.
In my case every single time I climb into the car, push the clutch pedal in (thus floating the clutch disk) and the trans slides easily into the pilot bearing.
Only thing I can figure is those plastic alignment tools just are not quite precise enough and leave just enough misalignment to not let it slide right in.
I want to get an actual trans input shaft to use as an alignment tool, I assume that will help the situation.

If your clutch arrangement allows for that I'd tray that. On my car (E30M3, S14 w. separate bell housing and trans) the slave cylinder can be mounted up to the bell housing while I am installing the trans so this is possible. I dont know how the E36s are. If its all one piece this solution might not be possible.

If you are using a plastic alignment tool see if any one you know has an actual input shaft laying around. I am 99% sure that is / has been my issue. The slight imperfection of the plastic alignment tools. When I float that clutch disk I can literally push the trans in with two fingers.

I'm not sure about yours but I know on mine when I am reassembling the clutch I put the alignment tool through the clutch disk into the pilot bearing then the hat over the disk and try to square it as best as I can put its pretty easy to tow that cutch disk a few degrees without even trying. Then as you tighten the hat down it can pull the disk a nudge either way. The trans and input shaft allow for no such towing. Its got to be perfect. Thats what floating the disk helps me with. No matter how perfect and square I try to get that alignment tool to the mating surface 9 times out of 10 its just enough off that I need to float that disk and then it slides right in.
Hope that helps.
Jimmy P

[ScotcH]

I use the plastic alignment tool with our 2 disc clutch, and the alignment there needs to be even more precise. Jimmypet is right in that the tool is kinda crappy ... what I do is put it in, then tighten the clutch PP nuts just so I can barely move the disc around ... then really make sure the tool is perfectly centered in the PP tines. Just make sure you eye ball it dead on, not on an angle. If done right (and of course as suggested you have the right pilot brearing), it should just slide right in.

good suggestion on making a tool from an old tranny, we have that for our 5 speed (haven't killed a 6 speed recently to cut one off yet )

Other tips:
- loosen the motor mounts so you can tilt then engine down a bit. Makes the angle easier to get right, and to get the top bolts later
- Try a fit without the pilot bearing to confirm this is your issue
- try without the PP and clutch in place
- Make sure the metal gasket/shield is properly fitting over the alignment rings on the big bolts
- make sure the starter is not in the way of re-install

[jvredz]

Thanks all for your suggestions. Great stuff.

The pilot bearing does go on fairly easily as long as the angle is correct. Tried it with the existing pilot bearing, and two new ones from different manufacturers. We do have the engine angled to help with this.

That is very interesting about the alignment tool. We will take a look at this and see if we can find a more precise alignment.

Thanks very much for the replies.