jkim

It seems there are a few of these cars around that has 3.3L motor with a 915 tranny. I am considering buying one of these, knowing that I will eventurally have to replace the tranny so that I can drive the car like a Turbo. One car I am considering is a 77 with a 86 motor in it. Not sure of the year of the tranny.

1. Does anyone have experience with 3.3/915?
2. Is chaning back to the 4-spd fairly straightforward?
3. Where can I get a 4-spd?

Also, I would like to see what the best way (economical and safe) is to jack up the car for removing the engine/tran. I plan on doing this not more than once a year, and cannot afford a permanent hydraulic lift which will require capital for garage modifiction and the lift purchase.

Thanks.

jonn

Geoffrey

Removing the engine yourself in your garage is fairly easy and straight forward. You need 2 large jack stands, and a good hydraulic jack (I'd advise against one of the aluminum ones for this purpose). You can remove the bumper and intercooler if you need additional clearance (I do with my car). I jack the car up and put the stands under the jack pads at the corner of the rear chassis. Or you can put them on the torsion bar tubes if you can get enough height. I also made a cradle out of 3/4" plywood that supports the engine by the center of the case and the heat exchangers, although I've also done it with only a jack which is much harder by yourself.

I can do it in 2 hours with hand tools.

4spd boxes are fairly easy to find, the trick is getting one with an LSD.

PorschePhD

John,
Keep in mind that the 915 will bolt up and is fine, but will only like to live with a HP limit of apx 300-350. After that things get bent, broken or worse. If the chassis is a turbo chassis changing back and forth is easy. If it is a NA chassis the turbo 4 speed will not fit with out cutting the torsion tube and running coilovers, cutting the tranny, or running a 75-77 Turbo Carrera 4 speed. This was the same as the 930s, just had a short bell housing. This is my choice as it makes the install a snap to a NA body.

jkim

Thanks for the insight, Geoffery.
I was anticipating taking a day to take the engine/trans off. (I talked to a BMW mechanic, and he quoted me 16 hours to lower and reinstall engine/trans.)
2-hour sounds awesome!

How far up do I need to have the car before I can lower the eng/trans? I heard that I needed to get it up as high as 4 feet. Also, am not sure about how tall the jack stands need to be. (I am having difficulty visualizing this).
Is there a picture I can look at?

jkim

Thanks Stephen. The car chassis is a '77 Euro Turbo. Do I need a Turbo Carrera 4-spd for this car?

Geoffrey

My jackstands are 16" at their lowest position and I extend them to about 18" when I put them under the jack pads. You don't need 4 feet of clearance, only the height of the engine + however high your jack is at its lowest position.

cowtown

John,
I'm running a '77 Turbo engine in a '75 911S, with a mag-case 915 (also from the '75).

I don't know if the car you're looking at has a magnesium or aluminum cased transmission, but if it's magnesium, at the very least you should bolt up an aluminum side plate to it, especially with all that power from the 3.3T engine. I found an Al plate for around $50. It cuts down the flexing.

There are also fancy aftermarket billet cover plates available. Bring cash for those.

Good luck!

A930Rocket

Here's a pic of my car when I removed the engine last time. I have to jack it up a little more than usual due to my front air dam. I leave the bumper on.

PorschePhD

Yes, you do. It wasn't until 78 that the tranny was the longer version.

Rob S

I don't ever remove the rear bumper to pull the engine. I think the best trick is to use two floor jacks. If you don't own two, perhaps you can borrow one for a day to get the job done. Use one jack to raise the car and place it on jack stands. The height isn't that critical -- just high enough to get yourself comfortably under there to undo what needs undoing. Then lower the engine and trans to the floor, while leaving it on the jack. Now, using the second floor jack, raise the car off the stands so the lowest point of the chassis clears the highest point on the engine. Voila, you can roll the engine rearward out from under the car. When raising the chassis with the second jack, I use a 4 foot long 2 by 6 under the rearmost portion of the floor pan, just forward of the torsion tube, so I don't bend any of the undercarriage sheet metal.

When you do it this way, you never need to elevate jacks or jack stands on wooden boards as shown in the photo earlier in this thread. But then again, you need a second jack for that brief moment of raising the car off the stands to clear the engine...