Flipping the ring and pinion on G-50?

orbmedia · 02-26-2002, 03:13 PM

Let's say you wanted to run a G-50 in a mid-engine configuration like in one of those super kit cars. What's involved in flipping the ring and pinion? Is it something that requires lots of machining and parts or is it mosting labor? Any clues?

PorscheDV · 02-26-2002, 07:38 PM

sorry man..cant be done! only way to reverse its rotation is to flip it upsidedown...but you lose about 5 inches of ground clearence...

ChrisBennet · ChrisBennet's Garage

Quote:

Originally posted by PorscheDV
sorry man..cant be done! only way to reverse its rotation is to flip it upsidedown...but you lose about 5 inches of ground clearence...

PorschDV,
I remember they flipped the ring and pinion (and ran them upside down) on the 935's. Do you happen to know what changed on the later transmissions (G50's) to preclude flipping the R&P?
-Chris

finadict · 02-27-2002, 06:47 AM

I know that the 901,915,930 can all be flipped, G50s, I've only heard of them being run upsidedown. 'Renegade hybreds or Patrick motor sports may tell you something different though..... Good luck

rob911 · rob911's Garage

Seems like flipping the whole unit over is the only way.

That is what Ultima do in their Can-Am and GTR. One fine day I will have one.........
How much do I get if I sell a kidney?

orbmedia · 02-27-2002, 07:15 AM

EEEnteresting. So if you have to flip it what else has to be done? DO you end up machining a new drain plug?

matt_d · matt_d's Garage

From my readings in the Starkey book "930 to 935: The Turbo Porsches," the later 935s used a flipped 930-based transmission. Special upside-down case castings were used with well-lubed 930 trans internals. I don't think it's possible to just flip the ring and pinion in a normal case, but I could be wrong.

Early 935s used a well-lubed normal 930 trans. 935/78 (Moby Dick) was the first to use the flipped trans because it was a much lower car and the CV axle angles were too severe for durability reasons - replacing CVs and axles on 935s was a common and lengthy pit proceedure during endurance races prior to the flipped trans.

Thinking about it, if you just flip the trans 180' about crank centerline, the car will run backwards in the forward gears. If you flip the trans and rotate the engine/trans combo w/engine in the front (mid-engine), the car should run forwards in the forward gears. Clutching should be easy to do with hydraulics, but the shift linkage would be a challenge.

For my project, I've been wondering if another OEMs R&P/carrier could be adapted affordably to create and upside down, forward running 930 trans, but I haven't torn apart my 930 trans yet to figure it out. I'll get to that thought someday ...

rob911 · rob911's Garage

Ultima cars supply the G50 flip kit.
Consists of breather kit, new drain and fill plugs/blanks.

PorscheDV · 02-27-2002, 11:26 PM

ive done a bit of reasearech on it..and 901's 915's 923's and 930's can have the ring and pinion flipped to run in mid motor applications (or reverse rotation motors)

G50's or any of the hyrdro trannys cannot (the reason escapes me..i think its ring and pinion are configured different or one peice) anyway the only way to run it in reverse is to flip it (with above mentioned kits)

matt_d · matt_d's Garage

PorscheDV - can you provide any specific info on flipping the R&P in the 930 trans? Or is it supposed to be just as simple as it sounds?

For a normal position case/flipped R&P, I'm wondering what that would do the wear surfaces of the helical gear teeth. My initial thought is that the opposing side of the teeth would now be in contact in the flipped config as compared to the normal config. If so, the loads would definetly be transfered differently. My gut feeling is that this is bad, but I'm not sure - it's been awhile since I did a gear design.

Any info would be appreciated and save me some research.

Thanks ...

PorscheDV · 02-28-2002, 04:28 PM

hey matt...geez..wish i could provide first hand experience...but trying to do so would be a lie...i was going to do it..but found an alternative..alot of naja places have alot of experiences with it..also, try kennedy..they can put you in touch with guys that do...

using a flipped R&P 915 is popular with the sand rail guys (the reason i looked into it)