Correct way to mate motor and transmission???

[les_garten]

Originally Posted by SchnellSchweitz

Thanks everyone for chiming in.

I think I need to follow Pete's direction on this since we have similar transmissions (915).

So... Pete are you saying the throwout fork doesn't move more than 5mm by hand (almost seems more like slack than any real movement), but should move a greater distance when the cable is installed and you step on the clutch?

I actually did not think my fork lever was moving at all when I stepped on the clutch after my initial install. It seemed like it just stayed straight. Perhaps that's what it does, but I would think it has to move at least an inch to engage and disengage.

Thanks again for your responses.

IME, you can't move the fork by hand if it is installed correctly or incorrectly.

If you install incorrectly, you can't move it with your foot either. A PITA to get right till you figure it out.

I got mine in the car with the TO bearing and clutch fork not engaged properly. Real pisser!

[Walt Fricke]

Guys - some of this is getting overcomplicated.

First off, what happens with the 911 (or 901) - or G50, for that matter - TOBs has nothing to do with the 915. No rotating of anything, no screw drivers, etc. Haynes failed to point out that various nice pictures it had related to the 911 tranny, misleading a whole generation of DIYers.

Secondly, the most common problem with getting the fork not quite in the right place is that the engine won't slide all the way in. This is a kind of self-correcting problem. It is clearest if the fork points straight back, so it hits the diaphragm spring at about a perpendicular.

That's not too bad, because you know it, and can back the engine out a little and move the fork (by fingers on the bottom of the shaft) more toward the centerline. At least you know which way to go.

Third - you get the fork between the spring and the TOB.

Fourth - you get the fork too far to the centerline, and as you move the engine in the fork gets pushed back so it sits outside, so to speak, of the TOB. Not in the groove.

I can't remember (repression of painful memories is not a bad thing) which of #3 or #4 will allow you to mate engine and tranny fully (putting on all the fasteners etc) without leaving the fork loose such that you can twiddle it back and forth. If you can twiddle it back and forth when mated, something is wrong and try again. There just isn't much "slack" between the fork and the sides of the TOB groove, but the bearings for the vertical shaft aren't all that close a tolerance and there is some wiggle there which can confuse things.

But the difference between getting it in the groove (where sometimes there is just the slightest back and forth) and one of the misalignment options (the most evil one) is very small.

When in doubt, before doing much else, after a successful mating I hook up the lever arm and wiggle that. But I then hook up the clutch, get in the car, and step on the clutch. If things aren't hooked up correctly, the pedal won't move, or will only move a little as it takes up slack. And you know it is back to the drawing board. But at least you haven't hooked up the oil lines, etc.

Of course, the easiest is to have the tranny out on your floor when doing this mating - so you can easily look through the hole and see if the upper ear of the fork is in the groove. But for those of us who tend, at least on occasion, to leave the tranny in this is not so easy. It is one of the reasons I lust after a 5.5" pressure plate with a push TOB that doesn't need to mate with anything.

If you do have the tranny in, start by eyeballing the angle of the fork. You will note that the TOB's engine side groove flange is wider than the one on the tranny side. So you try to, before things get out of sight, get the fork aimed a tiny bit to the center of the engine side flange. So it will miss the tranny side flange, hit the engine side flange at an angle, and slide into the groove.

Sometimes this works just fine for me, sometimes #$#@%#%@ emanates from the garage.

Walt

[SchnellSchweitz]

I guess this is where I become an expert at motor removal and installation... Ha. Perhaps I can get a job on the pit crew when I'm done. I'm pretty fast at dropping and installing now.

Anyway... thank you for the response Walt. I think I've got it in correctly, but what I am learning from you and the others is I will probably have to install the motor and transmission again to find out for sure.

I hate to sound like a shade-tree mechanic here... but it seems like we should be able to hook a ratcheting strap to the fork lever and see if it engages or moves properly before the big install. I don't want to break anything, but isn't there a better way to check it before installing?

[Walt Fricke]

Speedy Swiss

On reviewing this, do I understand that you have engine and transmission out of the car but mated at this very moment?

If so, there simply is no reason to come up with some complex method of seeing if the clutch arm will disengage the clutch. Because you can just look in there and see that the fork is where it should be.

The small LED flashlights are good for this.

I don't know if the hole on the top left (driver's side) of the tranny bell housing is there for vision or for ventillation, but it serves well as a viewing port. If really concerned, pull the starter and look in there.

It is only when you have the tranny in and the engine out that things get trickier. Because on a stock bodied car it is hard to see in this hole. Hence the discussion of using a mirror. Still difficult.

I have no excuse, other than not being tall enough, because my track car (whose engine comes out at least once a year for this or that, and sometimes, alas, more often) has no sheet metal in that area and I can, if a bit awkwardly, look in. But that calls for getting out from under the car, etc.

Look at it this way - it is easier to put the clutch lever arm on with the engine/tranny already in the car than it is to fumble around with it under things on the floor.

Walt

[SchnellSchweitz]

Hi Walt,

Thanks again for the input. It sounds like I should be fine with the installation again.

Although, I did check my throwout fork to see that it was in the proper groove after after my recent removal and it was in the right location, but still did not move.

Hopefully this time it does.

We shall see... thank you again.

Eric J.

[Walt Fricke]

Remember: install just enough to put the tranny and engine holder bolts in, then hook up clutch, adjust, and step on the clutch pedal. With the experience you have gained doing this, whipping it in and out is the quick part. It is hooking up all the other stuff, and unhooking it, that takes the time.

You would think that you should be able to twiddle the upright splined shaft with your fingers, and feel the fork boink against each side of the TOB groove. Sometimes mine feel just like that. But not always. Not much movement to begin with, and unless freshly greased the splined shaft may have some internal resistance. And then there is spline slop to complicate things.

But if your tranny/engine unit is in a fairly stable position, you could slip the clutch arm on (I forget if this is the later clutch with the long and short arm and harp spring, or the simpler earlier style with just one long arm) without bothering, for the moment, with the circlup. Then, while looking in the viewing hole, move the arm back and forth, and watch the top of the fork move a bit one way and the other. Just to confirm.

Walt

[SchnellSchweitz]

Well.... I finally had time to reinstall my motor and transmission. Everything went smoothly, but I don't notice that big of a difference in the clutch.

I am beginning to realize, I may have done an extra removal and install for nothing.

I have never driven a Porsche (bought mine inoperable) so I really don't know what a brand new Sachs clutch feels like.

I would describe the feel of my clutch pedal as a normal clutch when I first step on it. Then when I reach about 1/4 of the way down, it engages the throwout fork and it's all helper spring from there. I believe the throwout fork only moves a tiny bit.

I wonder if I should have the clutch cable tightened even more with a new clutch? My cable is currently tightened at about the halfway point.

On a side note, my transmission seems to shift very smoothly into all gears and reverse with the clutch engaged and not engaged. Is this normal?

Thanks in advance for your responses.

[SchnellSchweitz]

Just got it in correctly. I believe the entire issue was just the clutch cable adjustment. I just needed to tighten it all the way with a new clutch.

Thank you everyone for your help. I must have been standing too close to the forest on this one.