Lotus Elan

Diff

PostPost by: dr_jayhart » Sat Jun 13, 2020 10:56 am

Hello all. I’m restoring my +2 and having taken the diff out the bolt holes in the case appear to have worn. Is this going to be an issue? Anything I can do? Many thanks.
Attachments
F6BE90A2-D01A-4A06-95F9-EBCB2B758728.jpeg and
dr_jayhart
New-tral
 
Posts: 13
Joined: 25 Aug 2009

PostPost by: Foxie » Sat Jun 13, 2020 11:45 am

dr_jayhart wrote:Hello all. I’m restoring my +2 and having taken the diff out the bolt holes in the case appear to have worn. Is this going to be an issue? Anything I can do? Many thanks.


Doesn't look too bad. Tidy up the bores, and make up and fit a pair of press-fit thin-wall brass bushings,

:)
68 Elan +2, 70 Elan +2s
User avatar
Foxie
Fourth Gear
Fourth Gear
 
Posts: 969
Joined: 20 Sep 2003
Location: Wexford, Ireland

PostPost by: nigelrbfurness » Sat Jun 13, 2020 5:00 pm

A word of warning - on the face of it that seems a good idea but I've seen that repair technique go horribly wrong. First you have to drill out the hole for the brass insert so you have less material left to carry the stress. The fit in old, probably crystalline aluminium is critical. Too tight when you press it in and tbe diff ear will split or break off. Too loose and the brass will fret the hole and you'll be in a worse position than you are now. You will need to heat the aluminium to get a tight fit but then you will need to check the gasket face for distortion. I would check the fit of the long bolts in the hole and get new spreader washers so that when you tighten the assembly through the frustacones the washers are supporting the bolts and assisting the aluminium. With old cast parts like these you need to take extra care.
1970 S4SE/1760cc big valve/SA-AX block, L2s, 45DCOEs, 1978 Jensen GT, 1962 AH Sprite, Alfa-Romeo 159, 1966 Bristol Bus, 1947 AEC Regal bus.
nigelrbfurness
Third Gear
Third Gear
 
Posts: 398
Joined: 04 Apr 2008
Location: Dunmow, Essex, UK

PostPost by: RichardHawkins » Sat Jun 13, 2020 7:12 pm

If I remember correctly the long bolts are 3/8” diameter. In my case I used 10mm bolts to accommodate for the wear in the casting,

Hope this helps,

Richard Hawkins
RichardHawkins
Fourth Gear
Fourth Gear
 
Posts: 772
Joined: 05 Jul 2008
Location: Lincolnshire U.K.

PostPost by: alan.barker » Sun Jun 14, 2020 10:46 am

If your +2 doesn't have a Diff Brace fit one. I have just fitted TTR heavy duty normal "frustacones" they do a nice job. When you fit the Bolts fit correctly from bottom or you will have problems with the Fuel Tank on a +2.
A little smear of Copperslip on Bolt shafts to stop corrosion/action with the alloy.
Alan
Alan.b Brittany 1972 elan sprint fhc Lagoon Blue 0460E
alan.barker
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 2357
Joined: 06 Dec 2008
Location: BRITTANY FRANCE

PostPost by: ecamiel » Sun Jun 14, 2020 10:49 am

Don't put brass in aluminum. Electrolysis! will damage the aluminum.

Eric
64 S1
User avatar
ecamiel
Second Gear
Second Gear
 
Posts: 219
Joined: 02 Oct 2003
Location: Ct. USA

PostPost by: Foxie » Sun Jun 14, 2020 1:23 pm

ecamiel wrote:Don't put brass in aluminum. Electrolysis! will damage the aluminum.

Eric


This would be good advice in a marine environment, where there is plenty of the necessary third partner, salt water electrolyte.

Galvanic compatibility had crossed my mind, but then I remembered that both the filler, drain, and breather plugs are all brass in an aluminium casting, and I have never seen any sign of corrosion in my 50 year old diff casing
:)

I would very much second the fitting of a diff brace.
Attachments
DiffBraceC.JPG and
68 Elan +2, 70 Elan +2s
User avatar
Foxie
Fourth Gear
Fourth Gear
 
Posts: 969
Joined: 20 Sep 2003
Location: Wexford, Ireland

PostPost by: alan.barker » Sun Jun 14, 2020 1:51 pm

In the Diff Ears what's the clearance in the holes with new Bolts. They should be like fitted Bolts + a little more.
I would not want to enlarge the dia of the holes that's for sure.
They are already a design on the limit and fragile.
Alan
Alan.b Brittany 1972 elan sprint fhc Lagoon Blue 0460E
alan.barker
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 2357
Joined: 06 Dec 2008
Location: BRITTANY FRANCE

PostPost by: dr_jayhart » Sun Jun 14, 2020 3:32 pm

Forgive my ignorance how does the brace work?
dr_jayhart
New-tral
 
Posts: 13
Joined: 25 Aug 2009

PostPost by: Foxie » Sun Jun 14, 2020 4:33 pm

dr_jayhart wrote:Forgive my ignorance how does the brace work?


A steel angle section ties together forces on the two 'ears' which are fragile extensions of the main casing, and also transfers some of the force to the iron casting of the diff nose.

The original brace has only one bolt connection to the nose, I have made up a brace which connects to three bolts.

:)
68 Elan +2, 70 Elan +2s
User avatar
Foxie
Fourth Gear
Fourth Gear
 
Posts: 969
Joined: 20 Sep 2003
Location: Wexford, Ireland

PostPost by: dr_jayhart » Sun Jun 14, 2020 5:43 pm

Sounds like diff brace is the answer. I suspect they are not off the shelf?
dr_jayhart
New-tral
 
Posts: 13
Joined: 25 Aug 2009

PostPost by: alan.barker » Sun Jun 14, 2020 6:15 pm

Get a Diff Brace off the shelf from TTR
Alan
Alan.b Brittany 1972 elan sprint fhc Lagoon Blue 0460E
alan.barker
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 2357
Joined: 06 Dec 2008
Location: BRITTANY FRANCE

PostPost by: Foxie » Sun Jun 14, 2020 6:18 pm

dr_jayhart wrote:Sounds like diff brace is the answer. I suspect they are not off the shelf?


Tony Thompson Racing :

https://www.tonythompsonracing.co.uk/pa ... brace-bar/

£25 ex. VAT. nothing wrong with that !

:)
68 Elan +2, 70 Elan +2s
User avatar
Foxie
Fourth Gear
Fourth Gear
 
Posts: 969
Joined: 20 Sep 2003
Location: Wexford, Ireland

PostPost by: jonesa62 » Thu Jun 18, 2020 9:56 am

Col Croucher has a great video on a Diff brace on Elantrikbits.
jonesa62
New-tral
 
Posts: 13
Joined: 07 Nov 2017
Location: Narrogin, WA

PostPost by: Foxie » Thu Jun 18, 2020 11:06 am

jonesa62 wrote:Col Croucher has a great video on a Diff brace on Elantrikbits.


Found the site, but not the diff brace.

Do you have a link ?

:)
68 Elan +2, 70 Elan +2s
User avatar
Foxie
Fourth Gear
Fourth Gear
 
Posts: 969
Joined: 20 Sep 2003
Location: Wexford, Ireland
Next

Total Online:

Users browsing this forum: No registered users and 8 guests