911 Engine to Transmission Mating

rsheridan · 06-19-2008, 10:15 PM

The engine was removed to replace the clutch on a model 915 transmission on a1981 911SC. The new clutch, pressure plate, seal, throw out & pilot bearing and all the flywheel bolts were replaced and the flywheel machined locally. All went well. All stock parts.

Upon re-installation, the engine and transmission casing mate well up to the last 3/16 of an inch and it stops. I can put the four nuts and washers back on the four studs that protrude from the engine and tighten them fine, but when the bolts are tight, the casings remain 3/16" apart. I am afraid to over tighten to "pull" the two together.

I actually took the engine back out again to make sure nothing was binding or in between. Nothing appears damaged or scratched and the spline lube was nicely showing on the transmission spline, indicating it had mated. I took off the starter as well to ensure it was not interfering with the starter ring around the flywheel. Is there something I am missing?
Second re-install, same exact problem.

SP2 · 06-19-2008, 11:49 PM

It has been a while since I did this, but I remember there is a fork that needs to mate with the clutch properly. It is that fork that, when you depress the clutch pedal, it pulls on the clutch to separate it from the flywheel. Could that be the problem?

Peter Zimmermann · 06-20-2008, 06:55 AM

The fork can definitely be a problem, you have to use the hole in the bell housing to guide (with a screwdriver or similar) the fork's fingers into the TO bearing's outer groove. Your instincts are good - DO NOT try to pull the engine tight to the trans using fastener hardware.

Elombard · 06-20-2008, 07:37 AM

Do you have the tranny on the floor too? Might as well if you dont. +2 on the clutch fork. It almost could not be anythng else, post pics tranny off and bolted up. Somebody will be able to see the problem.

Those Germans engineered it to be pretty easy if you have everything lined up.

mackskibum · 06-21-2008, 11:19 AM

#3 on the clutch fork. You can do it if you find the spot in the fork travel where it falls together.

Britwrench · 06-21-2008, 11:57 AM

Did you make sure the clutch release bearing will go over the guide tube?

rsheridan · 02:08 PM

Thanks.. I did not know you have to use a screwdriver thru the "window" on the edge of the transmission to get the fork into place over the throwout bearing!!!
I thought the fork would slide over the first lip of the bearing by itself. I will recheck this before hiring a towtruck.
I assume this would have to be done from the TOP of the engine, looking down over the trans with your head in the engine compartment???
Any more tricks to this? Thanks to Peter for the most info. I'll give 'er a try!
This is my first engine removal and Pelecan has not instructions on REPLACING the engine. R

Elombard · 06-21-2008, 04:00 PM

No looking in the engine compartment. Mate the tranny and engine together on the floor and then put them up in the car. Watch the shift arm when you do it (sticks out of the front of the tranny..

Komenda Fan · Komenda Fan's Garage

Is the tranny still in the car? I have never done it that way, I've always dropped both together and then separated them.

When I align the two, I usually just move the fork back and forth and watch through the inspection hole to align. I would assume you can do this without actually seeing the fork by paying attention to the movement of the fork arm (it should have a little travel back and forth when it is in the throw out bearing).

Also, if you are installing the engine with the tranny in-situ, is it possible you are hanging up on a wire off of the starter?

dentist90 · dentist90's Garage

There is a hole on the upper surface of the tranny that you can peak into to assure the shift fork is properly engaged in the TO bearing.

efhughes3 · efhughes3's Garage

Quote:

Originally Posted by Elombard

No looking in the engine compartment. Mate the tranny and engine together on the floor and then put them up in the car. Watch the shift arm when you do it (sticks out of the front of the tranny..

No need for this...what Pete and the others have said about the fork is the ticket. I've done the drop both ways, it really isn't tough sticking the motor on the trans when it's in the car. I think leaving the trans in the car saves a fair bit of time, not having to screw around with CV joints and such.

SP2 · 06-21-2008, 08:13 PM

+1 on doing this out of the car. If you seem to be having a hard time already, make it easier by doing it on the ground. It is especially easy if you are guiding the fork into place while a colleague is doing all the maneuvering of the tranny. But FWIW I was able to do it solo. Good luck!

efhughes3 · efhughes3's Garage

Quote:

Originally Posted by SP2

+1 on doing this out of the car. If you seem to be having a hard time already, make it easier by doing it on the ground. It is especially easy if you are guiding the fork into place while a colleague is doing all the maneuvering of the tranny. But FWIW I was able to do it solo. Good luck!

-2

Guys, it will not be any easier on him if he yanks the trans out of the car JUST to engage the shifter fork while it's on the floor. Please, all he has to do is cock the fork enough to clear the throwout bearing, and when it gets to the right spot, simply spin it in a bit to engage. Done.

How could removing his transaxle and then doing this same exact process on the floor be ANY easier at this point than him doing it in the car? Trust me, I've done both. There is no magic to mating the engine to the trans while it's in the car.

Peter Zimmermann · 06-22-2008, 06:20 AM

Quote:

Originally Posted by efhughes3

-2How could removing his transaxle and then doing this same exact process on the floor be ANY easier at this point than him doing it in the car? There is no magic to mating the engine to the trans while it's in the car.

So true, when you don't have to disconnect CV joints - don't! I think that the process is actually easier to do with the trans in the car; the trans is stable, and the installer is controlling the engine from the back of the car. Once the lower studs are engaged, establish the angle of the engine (line it up square to the trans), push in until the fork can engage the TO, then push it home. Something to note that should be obvious, but sometimes isn't, is to be sure that the floor under the engine is clean. Nothing is worse than getting a jack wheel hung up in a concrete crack, or on one of the nuts/washers that you put under there anticipating that you will need them to secure the engine!

Kroggers · Kroggers's Garage

I did this recently on my car. Installed the engine with the transaxle still in the car. What I did was get a high step so you can look over the back of the engine and down to see the engine align with the transaxle and the fork with the TO. As it gets closer you will no longer see the arm against the TO, so you will have to use the view hole on the top of the transaxle to make sure the arm is engaged. As the transaxle is in the car, you can not get your head in there to look down the hole - for this I used a digital camera. Move engine and take picture all is small steps until it is aligned and installed - I did it all on my own and in total it took maybe 45min.

If I was to do it again, I would still do it this way - saves playing with the CV joints. Additionally, the more you have to disconnect and move the more you have to potentially brake!!

Peter Zimmermann · 06-22-2008, 07:11 AM

Quote:

Originally Posted by Kroggers

As the transaxle is in the car, you can not get your head in there to look down the hole - for this I used a digital camera.

Sorry! I should have mentioned that I use a mirror and small flashlight for that part!

rsheridan · 06-22-2008, 09:32 PM

Thanks to everyone. Instead of doing this solo, I have asked a friend to come in wednesday and help redo this line up using all the tips from all of you!
-Clean floor line up of the engine to tranny using two jacks
-flashlight and mirror to see the fork.
- use the great picture from the dentist90 as a guide.
I will let you know how it goes! Thks
Rob from Vancouver