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1950's LSD - possibly GKN


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#1 andybrad

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Posted 07 February 2019 - 18:50

I am restoring a lotus eleven which has a LSD diff from new it has a Lotus MK9 diff case and an austin Healy BN 1 nose piece crown wheel and pinion

The car is a series one from 1956 it was entered in the 56 Sebring race Bought by Briggs swift Cunningham for Colin Chapman and Len Bastrup to drive Bastrup rolled the car in practice.

The car then was rebuilt by Mo Mo with a Maserati 1500 engine and ran in America for a few years. I am looking for Information on the LSD as i can find no maker on the LSD unit Just interested to know its origin. I think  sterling Moss won in an Austin Healy with LSD in 55 Hence the eleven being shipped out there with a LSD Diff unit. andy



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#2 David Birchall

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Posted 07 February 2019 - 23:07

I don't know about the diff-although I do know that Stirling (note spelling) Moss did not win Sebring in a Austin Healey-he took third in 1954 (I think).

If you need an original close ratio, straight cut gear set for your Eleven I have one with the modified casing to fit to an angled FWA-it came out of an Eleven I believe and is one of the sets made by ELVA afaik.  PM me if interested.



#3 Eric Dunsdon

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Posted 08 February 2019 - 09:39

Stirling Moss and Lance Macklin  finished 6th overall and won their class with the Austin Healey in 1955. He had won the race in 1954 with an OSCA shared with Bill Lloyd.



#4 andybrad

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Posted 08 February 2019 - 10:37

I don't know about the diff-although I do know that Stirling (note spelling) Moss did not win Sebring in a Austin Healey-he took third in 1954 (I think).

If you need an original close ratio, straight cut gear set for your Eleven I have one with the modified casing to fit to an angled FWA-it came out of an Eleven I believe and is one of the sets made by ELVA afaik.  PM me if interested.

Thanks for pointing out the typo my eleven has a 1500cc so it ran a close ratio MGA box. 

andy



#5 andybrad

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Posted 08 February 2019 - 12:49

Page-461-Bottom-Momo-in-Lotus-Maserati_z

 

Here Is a picture of Briggs Cunningham's eleven with i believe Mo Mo warming it up 



#6 Tim Murray

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Posted 08 February 2019 - 15:44

Here’s a potted history of Andy’s car:

http://www.lotuselev...chassis_156.htm

#7 Lee Nicolle

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Posted 09 February 2019 - 03:46

I am slightly confused here. What diff is it? A90/Healey/ J Van or B series BMC? 

I feel both had LSDs available in later years for MGBs or big Healeys.

Both of which came with a fair array of ratios.

The A90 diff had 3.9 or 4.1 and J Vans were 5.6 and I have seen a new set of 6.1 gears advertised on Ebay in recent times with a tiny pinion.

I use these diffs in my Classic Speedway Supermodified though they are welded.  Using second gear on a Holden 3 speed I get 6.5 or 6.88. Many of the V8 super mods or stockrods ran 5.6 though the pinion gear is too small to me. Though they seldom break and if so it is usually hitting a wall or another car with the wheels. The axles were they are turned into the 'hats' at the end and sometimes break there. And we are talking 500+ horse power! When decades ago I used to go to the street drags there was an A90 running with a strong LS7 454 Chev. He was gentle on it off the line but it was a low 11 sec car. This early 70s.

Ratios I know of are 3.5 from  Wolsley, 3.9 and 4.1 for A 90s and or Morris Isis. 5.6 normal for J van. The 6.1? Who knows.

I have heard but never seen a 4.5 [or so] for Healeys

MGBs had ratios from about 3.5 to mid 4.1s.


Edited by Lee Nicolle, 10 February 2019 - 02:20.


#8 andybrad

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Posted 09 February 2019 - 08:48

I am slightly confused here. What diff is it? A90/Healey/ J Van or B series BMC? 

I feel both had LSDs available in later years for MGBs or big Healeys.

Both of which came with a fair array of ratios.

The A90 diff had 3.9 or 4.1 and J Vans were 5.6 and I have seen a new set of 6.1 gears advertised on Ebay in recent times with a tiny pinion.

I use these diffs in my Classic Speedway Supermodified though they are welded.  Using second gear on a Holden 3 speed I get 6.5 or 6.88. Many of the V8 super mods or stockrods ran 5.6 though the pinion gear is too small to me. Though they seldom break and if so it is usually hitting a wall or another car with the wheels. And we are talking 500+ horse power! When decades ago I used to go to the street drags there was an A90 running with a strong 454 Chev. He was gentle on it on the line but it was a low 11 sec car. This early 70s.

Ratios I know of are 3.5 from  Wolsley, 3.9 and 4.1 for A 90s and or Morris Isis. 5.6 normal for J van. The 6.1? Who knows.

I have heard but never seen a 4.5 [or so] for Healeys

MGBs had ratios from about 3.5 to mid 4.1s.

 

Thank you for the responce. The diff nose is Austin Healy 100:4 Using the crown wheel and pinion from the same diff unit. the crown wheel is bolted to a LSD internals it works on spring loaded plates expanding when getting hot thus reducing slip. I have managed to work out how to put pictures up now. in my next post. andy



#9 andybrad

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Posted 09 February 2019 - 12:46

lsd%20diff_zpsisi7itwt.jpg



#10 56Lotus

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Posted 09 February 2019 - 21:53

Hi Andy

 

my eleven has a Detroit Locker in the diff.  Not sure of the originality but that type seems to have been around for some years.  Looking on google images there are similarities with yours.

 

Maybe a line of investigation

 

Jon



#11 Catalina Park

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Posted 09 February 2019 - 23:13

Could it be a Salisbury unit?

#12 Lee Nicolle

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Posted 10 February 2019 - 02:17

lsd%20diff_zpsisi7itwt.jpg

To me it appears to the A90. Healey diff. I suspect for info and parts the  place to go is a Healey specialist. I doubt any 50s cars used them so near certain an aftermarket item. Though I know there is all sorts of items available now for those diffs as spme people are very serious racing them.

The MGB style also find a MG specialist.

The MGC used the A90 style diff as well. V8s too maybe?



#13 David Birchall

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Posted 10 February 2019 - 02:19

Hi Andy

my eleven has a Detroit Locker in the diff. Not sure of the originality but that type seems to have been around for some years. Looking on google images there are similarities with yours.

Maybe a line of investigation

Jon


Jon I would urge you to get rid of that Detroit locker! They were never intended for a vehicle as light as a Lotus Eleven and will cause very sudden snap oversteer - usually mid corner.
The Detroit Locker may work in a dragster but it has no place in a light road race car.

#14 Ray Bell

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Posted 10 February 2019 - 11:42

Which A90, Lee?

#15 56Lotus

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Posted 10 February 2019 - 11:59

Jon I would urge you to get rid of that Detroit locker! They were never intended for a vehicle as light as a Lotus Eleven and will cause very sudden snap oversteer - usually mid corner.
The Detroit Locker may work in a dragster but it has no place in a light road race car.

 

 

You're right, although I don't race my Eleven it can be bloody horrible on the road.  I've got another diff to swap over it's just a matter of finding the time to do it.



#16 andybrad

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Posted 11 February 2019 - 20:39

Thank you everyone  for your comments the LSD  diff was fitted in 1956 it is documented in the history i have researched over the years. Mostly due to the internet i might add. There is a picture from 56 Sebring as the car was upside down and you can plainly see a large air scoop on the floor pan under the diff to cool the unit.



#17 David Birchall

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Posted 12 February 2019 - 02:43

I just received this response from Ian Wood here in Vancouver, who is originally English and with a huge amount of racing experience, and running a  shop here in Vancouver that specialises in Rear Ends Only  (plug) said:

"David,

Looks  to me like a stock carrier, they put 4 springs and 2 plates that press out against the side gears to get some resistance.
We’ve done that here, we call it a semi-posi it works better than nothing.

Cheers, Ian
 
Hopefully that helps.


#18 andybrad

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Posted 12 February 2019 - 17:13

 

I just received this response from Ian Wood here in Vancouver, who is originally English and with a huge amount of racing experience, and running a  shop here in Vancouver that specialises in Rear Ends Only  (plug) said:

"David,

Looks  to me like a stock carrier, they put 4 springs and 2 plates that press out against the side gears to get some resistance.
We’ve done that here, we call it a semi-posi it works better than nothing.

Cheers, Ian
 
Hopefully that helps.

 

Very interesting that makes sense thanks for going to the trouble andy