Mating engine to transmission problem
 

I am having great difficulty getting the engine and transmission to connect. I have the engine under the car on blocks, eye-balled alignment on the engine studs. When I go to slide the engine past the point where I can no longer view the clutch fork and throw out bearing (all four studs enter the correct tranny holes)... that is point when I can no longer get the engine to move further on the studs. The engine can move closer on one side, which of course creates a larger gap on the other side. The engine is sitting at close to the same angle as the tranny is leaning. I can slide the engine back out easily and slide the clutch alignment tool into the open are easily....

Here is some additional information;

Car is 1980 911SC
Crank is from a 1978 911SC.
Flywheel replaced with new 1978 SC version
Pilot bearing replaced with 1978 version - pressed into the flywheel from engine side
Clutch is new Sachs unit

If anyone has any tips or information, I will be extremely grateful.

When you took the clutch disc out from the box did you try it on the input shaft to check spline fitment?? Believe it or not I've had the proper app clutch set-up and the disc would not fit onto the shaft (boxed wrong or manufactured wrong) So I do this now out of habbit.

Also try to have a socket/ratchet on the crank nut and while you're mating the trans and engine gently turn it so as to engage the input shaft into the disc.

Yes, the new release bearing will not fit on the old style guide tube. Check the fit and if it doesn't buy the new updated guide tube.
Note that the new style release bearing and guide tube should not be lubricated.

I did this just the other day, however the engine and transmission were out of the car. If you say that the clutch is all lined up I would check the clutch fork. It needs to line up in the groove in the throwout bearing (I think, I am still not sure of all the terms). -- the bearing on the front of the clutch. If it doesnt line up you may be pushing against that. Other than that I cant think of anything that will bind.

Anyway, I had a similar problem that you do, where I could mate the engine and transmission together but there was about an inch or so gap all the way around. I couldnt see anything that was blocking it. To solve the problem I just kicked the front of the transmission and it mated up perfectly, I guess it just needed a little more force. If you have your engine on some sort of cart you could probably try kicking the front of the engine, or getting a moving start to build up momentum.

I really like duke3282's answer!!!

However, it is easy enough at this point to remove the clutch assembly and perform a test fit.

With this damn car it is @#$!%(&%#@(%& ALWAYS something....

Shoulda kept my first Porsche....

Note that the use of excessive force at this step (slamming the engine into the transmission to get it to go together or forcing it together with the connecting bolts and stud) can result in a bent clutch release fork and ruined clutch release bearing. One should really find out what the problem is: splines out of alignment, mismatched guide tube and release bearing, clutch release fork out of position, etc. Good luck, Jim

Thank you for this. I was having problems mating the transmission to the engine today. I did try rotating the transmission input shaft by turning both transmission output flanges (in the same direction), but that didn't help, so I didn't' think that the problem was alignment of the splines, and was starting to think that the guide tube was hanging up on the throw-out bearing.

I searched Pelican for some clues and found this thread. I tried turning the crank and that solved the problem :). The transmission was probably in neutral which is why turning the output flanges didn't work.

Hey guys, I'm about to send my trans out for a rebuild, and am researching potential issues. Which nut is the "crank nut"?