Differential clearance.
21 posts
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My car is an early Plus 2 with a Spyder sheet metal chassis. I?ve fitted a diff brace and after a bit of juggling of washers and mounts I have a few millimetres clearance between the diff and bottom chassis rail as shown in the photo.
Change is inevitable, except from a vending machine!
- Bigbaldybloke
- Fourth Gear
- Posts: 894
- Joined: 16 May 2017
Russ Newton suggested to me that my diff should be angled same as the transmission so the drive shaft u-joints should perfectly cancel their errors. I suppose that is right, but I'll swear there was and is very little wiggle room for the diff, so I am leaving it where it is.
John
John
- baileyman
- Third Gear
- Posts: 371
- Joined: 17 Aug 2017
Place an angle finder on the front crankshaft pulley and record the angle. Then place the angle finder on the differential pinion flange. The angles should be the same.
Rob Walker
26-4889
50-0315N
1964 Sabra GT
1964 Elva Mk4T Coupe (awaiting restoration)
1965 Ford Falcon Ranchero, 302,AOD,9",rack and pinion,disc,etc,etc,etc
1954 Nash Healey LeMans Coupe
Owning a Lotus will get you off the couch
26-4889
50-0315N
1964 Sabra GT
1964 Elva Mk4T Coupe (awaiting restoration)
1965 Ford Falcon Ranchero, 302,AOD,9",rack and pinion,disc,etc,etc,etc
1954 Nash Healey LeMans Coupe
Owning a Lotus will get you off the couch
- prezoom
- Coveted Fifth Gear
- Posts: 1358
- Joined: 16 Mar 2009
The bottom plate on the Spyder chassis is the same location as the Lotus chassis. The top plate where the diff mounts is also the same. What is different I believe is the depth of the top plate structure which is less on Spyder with it space frame tubes compared with the bent sheet metal Lotus used.
Thus more clearance with the Spyder chassis to remove the diff.
Where you locate the diff versus the top and bottom plates in not critical except for getting at least one washer or the brace above the diff to spread the load from the mounts and at least 4 mm below the diff to stop it hitting the chassis.
The range between the two is small especially if the chassis bottom plate has been bent by jacking in the past. Bending it back down again can help and is easy to do.
cheers
Rohan
Thus more clearance with the Spyder chassis to remove the diff.
Where you locate the diff versus the top and bottom plates in not critical except for getting at least one washer or the brace above the diff to spread the load from the mounts and at least 4 mm below the diff to stop it hitting the chassis.
The range between the two is small especially if the chassis bottom plate has been bent by jacking in the past. Bending it back down again can help and is easy to do.
cheers
Rohan
-
rgh0 - Coveted Fifth Gear
- Posts: 8962
- Joined: 22 Sep 2003
Just for the record, I have fitted the diff with approx 4mm clearance between the lower edge of the diff flange and the chassis. I used two thick washers and the diff brace and 4" bolts, 1/4" longer than standard. From this I guess the Spyder chassis has 1/4" higher more clearance than the standard chassis.
Cheers.
Cheers.
- davidj
- Third Gear
- Posts: 465
- Joined: 09 Apr 2008
More diff woes
1972 Sprint. Lotus replacement chassis in mid 1990s.
Prior to fitting new driveshafts I removed the diff. to attend to a slight leak. Refitting has shown up a very tight clearance issue at the bottom. I’ve replaced the original fit 3mm spreader washers with new 1.7mm ones but my cardboard feeler gauge is still a very snug fit at 0.57mm.
The diff mounts were of course replaced at the same time as the chassis but have virtually no road use, maybe 1200 miles.
Could they have deteriorated to such an extent just by sitting? They appear to be fine.
I have read comments regarding the build quality/accuracy of replacement chassis ( mine needed to be relieved to ensure the exhaust manifold didn’t knock) and I’ve measured the distance between top and bottom chassis rails at the diff mounts as 250mm left side and 260mm right side (approx).
The bottom rail isn’t deformed by jacking.
Can anyone with a Lotus chassis confirm those figures as it isn’t detailed in the manual drawing.
![Sad :(](https://lotuselan.net/forums/images/smilies/icon_sad.gif)
1972 Sprint. Lotus replacement chassis in mid 1990s.
Prior to fitting new driveshafts I removed the diff. to attend to a slight leak. Refitting has shown up a very tight clearance issue at the bottom. I’ve replaced the original fit 3mm spreader washers with new 1.7mm ones but my cardboard feeler gauge is still a very snug fit at 0.57mm.
The diff mounts were of course replaced at the same time as the chassis but have virtually no road use, maybe 1200 miles.
Could they have deteriorated to such an extent just by sitting? They appear to be fine.
I have read comments regarding the build quality/accuracy of replacement chassis ( mine needed to be relieved to ensure the exhaust manifold didn’t knock) and I’ve measured the distance between top and bottom chassis rails at the diff mounts as 250mm left side and 260mm right side (approx).
The bottom rail isn’t deformed by jacking.
Can anyone with a Lotus chassis confirm those figures as it isn’t detailed in the manual drawing.
- persiflage
- Second Gear
- Posts: 208
- Joined: 24 Jul 2005
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