Lotus Elan

Engine - Gearbox torque figure

PostPost by: stuartgb100 » Sat May 30, 2009 6:59 pm

Hi,

Can't see a figure in the workshop manual and factory supplements for bolting the 5 speed alloy gearbox casing to the steel block.

Is there one (I'm blind !) or do it by "feel" ?

Regards,
Stuart.
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PostPost by: CBUEB1771 » Sun May 31, 2009 4:57 am

Stuart,
I just flipped through all my references and I don't think there is a torque value specific to the bell housing / iron block bolts for either four or five speed boxes. I would stick with the 17 to 22 lbf-ft figure given for 3/8 UNC fasteners in the "General - Nuts and Bolts" section.
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PostPost by: stuartgb100 » Sun May 31, 2009 5:41 am

Thanks Russ.

I was a little worried about losing the threads in the soft alloy casing.
Looks like one is gone already through overtightening.

I think I'll go for 22 for the steel and 18 or so for the alloy.

Regards,
Stuart.
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PostPost by: CBUEB1771 » Sun May 31, 2009 6:15 am

sgbooth wrote:I was a little worried about losing the threads in the soft alloy casing.
Looks like one is gone already through overtightening.


Stuart - Good point, I was forgetting that only the top two are threaded into the block. The +2 Workshop Manual lists 25 lbf-ft for the five speed bell housing to gearbox main case bolts. The Service Parts List isn't very clear on what size these bolts are, perhaps M8? Perhaps you can use that as a guide.
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PostPost by: john.p.clegg » Sun May 31, 2009 11:51 am

Stuart

Get them helicoiled....it's not a repair it's an upgrade.....3/8 UNC I think...will be a lot stronger than the ali...starter motor mounts also..

John :wink:
(with helicoiled bellhousing)
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PostPost by: alexblack13 » Sun May 31, 2009 9:06 pm

I totally agree with John.You will be needing a repair to the damaged/stripped out hole in the ally case anyway. Have the rest upgraded (as John said) with helicoils. You can tighten them more then if need be. Normaly 1.25 x the stated torque. Well worth doing.

Alex B..... 8)
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PostPost by: john.p.clegg » Mon Jun 01, 2009 7:48 pm

Stuart
Before you put the gearbox/engine back in,make sure the speedo cable is fully home and aligned,because if it isn't it's a [email protected]@er of a job fixing it later-engiine/box out again -unless you are prepared to remove some of the fibreglass above the speedo angle drive..

John :wink:
Here speaks the voice of experience..

P.S.
also helps if you add a removable access panel under the u/j on the output shaft..
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