Is there any definative 915 to G50 threads?

[adomakin]

I cant seem to find any. ive looked about but with no luck.
can anyone help?

Andy

[ZCAT3]

Andy - I just did a G50 conversion on my 930 and there really is not much out there. There are few guys here than have done it - such as Dean (formerly user ID "Blown"). If you get ahold of the diagrams for the G50 hydraulic system is is pretty straight forward - but lots of work. I know for the 930 the bell housing on the G50 needs to be shortened so that the engine does not need to be moved back. You need to find a machine shop that has done this, such as Patrick Motorsports, to have it doen properly. You will need the following in addition to the transmission itself:

All the new hydraulic parts - fluid reservoir, new pedal box with master cylinder, the 3 lines that run the fluid from the master cylinder, through the tunnel and out to the slave cylinder, and a soft line to plum from the reservoir to the master cylinder.

A G50 shifter, shift rod, and coupler. Assuming the 915 is similar in size to the 930 tranny and the G50 bell housing is shorted, you need to get the shift coupler modified so that it is a few inches longer. The shop that sets up the transmission modifications should be able to do this as well.

A G50 clutch package that is designed to mate to your engine. Once again there are many shops who can help with this such as Patrick and Kennedy Engineered Products. You will likely need a standard 915 flywheel with a modified pilot bearing (it is modified so that it is not as deep as the original pilot bearing), and then can use a G50 clutch disk, pressure plate, ring gear, and throw out bearing. You will also need the updated clutch release fork and release fork pivot, plus the pivot needle bearings, and end cap.

A G50 speedo sensor.

A G50 starter

I think that is most of it. I would try to source the clutch kit from a place that has done this before so you are sure you have the right parts.

Hopefully others will fill in what I have missed.

[Geary]

Because both the bellhousing and the mainshaft require shortening, a rather complete disassembly of the G50 trans is required.

[adomakin]

thanks bill and geary, great info. are your cars still running the torsion bars? Im up for ditching the torsion bars so could i not just run a standard length g50, cut out the torsion tubd and modify the metal work at the other end where it is going to fail? please tell me if im missing something here but im assuming that the shortening of the box is to allow it to run with the standard susp, right?

thanks,

Andy

[935PROJECT]

Yeah shortening the tranny is for running t bars, but scrap those and run coilovers.

[dean]

I used a combo of SS braided hose and hard line to plumb the hyds. I also used my SC starter and an early 930 clutch set up in my shortened box. And depending on what car you are putting it in you might have to move the motor back a little to make it fit. That applies to SC's and early 930's when keeping the torsion tubes. I think if you are going to go coil overs you are all set. But I don't know for sure cause I've never done that.

[adomakin]

thanks Dean and Dave, has anyone done the g50 swap using coil overs? is it just a case of offering up the engine and g50, cutting out whatever is in the way and using the origonal g50 mount ?

Andy

[ZCAT3]

Andy - I have coil-overs in my 930, but still went with the shortened G50 as I did not want to push the engine back or cut the torsion tube. 930s are tail happy as it is without putting more weight toward the rear. I think it is worth the extra $1000 or so in machining costs to have the bellhousing shortened. The car will handle better and you have many more suspension options.

[adomakin]

fair point Bill but Im not bothered about cutting the torsion tube and there is also a distinct lack of experianced engineer shops over here for me to farm out the machine work. don't get me wrong, there are lots of good enginner shops, they just aint too hot on g50 box conversions! so assuming im going to cut the torsion tube, is it basically a case of doing what I said in my previous post on this thread?

Andy

[Jack Olsen]

The torsion anchor is important, structurally. On my car, we removed a portion of it (to move the drivetrain 1.25 inches forward), but then did pretty extensive reinforcing (including diagonals in the rear footwells) to prevent the chassis from slowly twisting itself apart. If you go to coil-overs, you'll need to gusset and reinforce the rear crossmember anyway. I'd talk to someone who's done the same thing and find out what needs to be done to preserve the rigidity and strength that the torsion anchor piece normally provides.

[ZCAT3]

Andy - Jack points out the other reason not to cut the torsion tube - strength. Not to mention that in a wet climate if you start cutting and welding under there you are going to be more likely to expose areas to rust. There has to be someone over there that can machine a G50 case for you. If I knew my G50 transmission was machined to fit your car as well as my 930 I could take some pictures and measurements for you as the transmission is currently out of the car.

[adomakin]

Thanks Jack and thanks for the offer Bill. I understand that its not just a case of lopping a big chunk of torsion tube out to get the box to fit. I was looking to go along the fully fabbed cage route for the car and would like to run the cage through the rear bulkhead/seat area to pick up the rear crossmember. Jack, do you have any pics of the diagonals that you fabricated to add strength?

Andy

[Jack Olsen]

Originally posted by adomakin
Jack, do you have any pics of the diagonals that you fabricated to add strength?

I have some. See the second page of this thread.