G64 awd conversion

[stulad]

Hi
my build is a Minotaur www.minotaurkitcar.co.uk anyways I bought a G64 gearbox the question i have is does anyone see a prob converting this to 2wd serial no G64003L07394 i believe its a porsche 964 year 1990 ,awd i have stripped the top end of the box down so i could check the main gears as i found a broken tooth , everything is good and the tooth came from the front wheel drive part of the box.
the confusion i have is that the shaft that turns the diff is inside the main gearbox shaft if that makes sence so when i turn the diff crown gear it doesnt turn the box. im very confused and am going to have to reassemble the whole box before i spend £100 on gaskets. any thoughts or help would be great
thanks guys...--
does anyone know how the power from the engine gets to the rear wheels if these 2 shafts are free to rotate?
any help or thoughts would be great im assuming if i can make a 2 splined top hat to tie the 2 shafts together it will solve the problem?
thanks stu [email protected]

 

[Fran Hall RCR]

Stu,

I checked out your build over on pistonheads the other day.....your are dedicated thats for sure.....nice work.
You may want to get hold of California Motorsports or Powerhaus 2 they can both give you good reliable info.

 

[Martin]

Stu,

That's so coooool. I was looking at the Minotaur before I plumped for the GT40. I like it. You're doing a fine job on it to. Great stuff..Thanks for sharing the link.

 

[stulad]

many thanks, your better doing the GT40 my build is a proper nightmare,
i have a solution for gearbox now and will show everyone how just as soon as i can get it down on a web page many thanks to Joel (jmracecar) from this great forum btw i would have built a GT40 if a)i could afford it and b) i wasnt 6 foot tall, keep up the good work everyone ,love seeing GT40's sooooooo cool ,many thanks Martin it does help when ppl appreciate it (im very much on my own with this one) stuepper:

 

[stulad]

Hi Guys , i promised a guy called Joel R (jmracecar) that if i solved this problem i would post the answers here so im back to say yepp ive as good as sorted it, ive had 2 adapters made that lock the splines together pics and drawings on my web site, so ive now got a strong 200mph gearbox that will take the torque from a 450bhp LS engine for about £600 all in will soon be selling my UN1 renault box and adapter bell housing for small block chevy (watch ebay or mail me). hope this helps any questions or drawings needed ? i would be more than happy to repay the help ive received from you guys many thanks stu www.minotaur-kitcar.co.uk

 

[Randy V]

Mean looking car there Stuart.. I've sent Joel an email with a link back here since he doesn't make it by here very frequently...

 

[BruceA]

Thats a great build you have going on there. Not to mention the very clever wee adapter you have for the 4-2 conversion. I did look at your build logs and photos, and I dont know why, but I have nightmares about failing rod end bearings on suspension joints due to being undersize. None of my business - but they do look a little on the 'small' side.
I'll keep checking back on the build though - its looking good!

 

[jmracecar]

Good job, nicely done! Be careful though, the car this box was designed for made 247 flywheel hp and 228 foot pounds of torque. If you are careful I think you'll be Ok, but if you try hard enough with gobs of V8 torque you could probably break it. Also the diff plates will wear out. The diff itself is a variable-lock design. It was set to use an extra slave cylinder that would mount to the bottom of the bellhousing (before inversion; top on this forum), and apply variable pressure to the diff plates (for variable lock). In your photos, there is a round hole there, with a black seal, and a pair of studs sticking out, right side of gearbox, just above the axle drive flange. You can simulate the variable-lock input with a big bolt through a fixed threaded plate. Use a wrench instead of computer-driven hydraulics to set the lock percent. But start looking now for a spare diff. The discs wear out and cost more than your entire gearbox project to replace if new from Porsche. Check the diff with a torque wrench. With one side held in place, it should hold at least 10 to 15 foot pounds for street use, and at least twice that for track use. Without some lock pressure applied it will fail the test, so handle that first, then we can come to a conclusion about the diff plates. Or if you don't care, it should be good to go as is, as an open diff that weighs too much.

 

[stulad]

Many thanks guys.
to Big foot many thanks much appreciated.
to Rambo I hope youre wrong The car designer John has done this set up before, but no one has ever used an Ls engine,. if theres a problem ill swap them out, nothing is impossible.
To Jmracer thanks for all your help , im not building this car as a track car so hopefully ill be ok but if nothing else its been interesting modding this box, and if it blows by then i will have enough money saved to replace it with a more suitable box, bearing in mind this has cost me £650 all in cheep im sure you will agree, As far as the diff im not using a limited slip diff, i have had it replaced with a standard diff , hope you agree that this wont cause me problems. i was told that it was the way to go , i just need to swap the crown gear over with the original.
thanks for your time guys will post pics of the end cover once its done
cheers stu :drunk:

 

[jmracecar]

A standard G50 open diff is lousy for a high-torque application. With all due respect, one-wheel drive is hardly worthy of the rest of your project. The open diffs fail to bring $50 at auction here on eBay, which is reflective of what they are worth. They direct power to the wheel with the least resistance, i.e. the one that will more readily slip than the other. Use it for a book-end. Put the original back in there and put in the bolt plate as I described, or better get a real LSD. Problem there is you will have to double your outlay to get a healthy one. Don't forget to shim the diff correctly or bad things will happen. The factory workshop manual is the only place to get this info. This is another reason to run the original as it came. If its plates are worn out, or if you don't do the bolt-plate, you are no worse off than with a real open diff, but at least it is shimmed correctly (assuming it was done by the factory).