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Bell Housings: Would you?

Already rebuilt 4-speed long bell housing is out of the car as part of my motor rebuild. Someone suggested having the long housing machined down to short bell housing specs (this is on a 1988 930) in order to move the engine up to improve weiht balance.

Thoughts? Would you?
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Rob Montgomery
'88 Blk/Blk 930 ('Lucy') - Not Stock & Not Running
Old 07-31-2014, 04:51 PM
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Something tells me its not quite that simple.

What else is involved aside from machining the bell housing? Off the top of my head, you need a different pressure plate, and maybe some other clutch related components. Something has got to change on the front of the engine where it bolts to the chassis as well...maybe a modification to the engine mount itself?

Is moving the engine forward 2-3" going to make all that much difference in the performance? I honestly have no idea, but I think you could find better ways to spend your time and money on improving the car.
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Old 07-31-2014, 06:26 PM
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The shaft driving the gearbox would then need shortening the same amount the housing is shortened. That necessitates disassembly as well.
Plus you can't shorten gearboxes that don't have the reinforcement around the mounting holes. You'd have to variety that yours is even able to be shortened.
It's all kinda complicated. As stated above, you'll need the compatible clutch set as well. $$$$
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Old 07-31-2014, 11:48 PM
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28mm is the difference between "short" and "long" bell housing on a G50, think it's the same deal on 930 box (you only machine down to the reinforcing rib).

As 25.4mm is an inch, that's not actually very much. And as already pointed out, then you need the 3.0 clutch setup and shorten (then re-harden) the shafts to match.

No changes to the engine mount are required to move the motor 28mm, but that's the least of your issues...

Moving the oil tank (say) would probably be far more cost-effective for changing weight distribution/CoG. It's lighter, but you can move it a lot further - pretty sure a number of folks have a kit to move the oil tank to the trunk..

For a street car, it wouldn't seem to be a good ROI. For a race car, your competition likely already did everything that complied with the rules for your class, and everything they think they can get away with

If you're mentally prepared for the cost of shortening a 930 box, you should maybe consider shortening a G50 and just put the unmolested 930 box to one side - either to sell to defray expenses, or keep to return to stock later, depending on your plans/intentions.

If you go the G50 route, then you have more choices. Re-gear the internals to G50/50 (1st probably isn't worth touching, for the $$$), or just swap 5th for shattering acceleration to the top of 4th, followed by relaxed cruising/180MPH top gear? Swap in a taller R&P and raise all the gears in one swell foop? Fight the Ultima/GT40 guys for a G50/50 ($$pendy and probably pointless on a "strength" basis unless you're planning very high - over 700 ft/lbs or so - numbers)

It's all trade-offs, so you need a clear plan to get it right first time - doing it over probably won't make you happy.
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Old 08-01-2014, 03:29 AM
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Quote:
Originally Posted by spuggy View Post
28mm is the difference between "short" and "long" bell housing on a G50, think it's the same deal on 930 box (you only machine down to the reinforcing rib).


If you're mentally prepared for the cost of shortening a 930 box, you should maybe consider shortening a G50 and just put the unmolested 930 box to one side - either to sell to defray expenses, or keep to return to stock later, depending on your plans/intentions.

If you go the G50 route, then you have more choices. Re-gear the internals to G50/50 (1st probably isn't worth touching, for the $$$), or just swap 5th for shattering acceleration to the top of 4th, followed by relaxed cruising/180MPH top gear? Swap in a taller R&P and raise all the gears in one swell foop? Fight the Ultima/GT40 guys for a G50/50 ($$pendy and probably pointless on a "strength" basis unless you're planning very high - over 700 ft/lbs or so - numbers)

It's all trade-offs, so you need a clear plan to get it right first time - doing it over probably won't make you happy.
Total waste of time and money for the desired affect on a 4spd box..

Both Jacob and quattrorunner are correct in what needs to be shortened and then procured to make it work.

Additionally, I had not read spuggy's post but he is spot on too.. and took the words right outta my mouth!
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Old 08-01-2014, 08:44 AM
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thanks...
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'88 Blk/Blk 930 ('Lucy') - Not Stock & Not Running
Old 08-01-2014, 08:59 AM
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