QUESTION
I am contemplating purchasing a CV drive-shaft conversion and its a choice between your CV's and the UK supplied UJ shaft conversion.
I don't have enough technical knowledge to fully understand shaft "lock up" and concerns on the forums about limiting suspension drop, my only understanding is that cvs have a better articulation.
What did concern me was the general belief in the forums that 140 bhp will wreck the diff output shafts or the hub shafts.
My TC doesn't run well enough to put out the stock 115 let alone 140 and I don't have enough pennies to drive hard enough to break anything, I have a cheap little 7 replica for that!
Given that I am not so hung up on the desirability of the TC (distributor under the manifold, engine out to change the water pump, not firing properly on cylinder 1 etc) I have always wanted to Zetec the car with a 5 speed when my engine is worn. That is going to give over 170 bhp in even reasonably mild tune.
So I guess I need to factor in beefing up the drive train as well.
Do you have a view on that?
J.S. - UK
ANSWER
Not sure if you have read the technical paper I have written regarding modifying the Elan rear suspension?
If you have not seen this article then you can read it here -
https://www.lotusmarques.com/info/technical/32-lotus-elan/172-modifying-the-elan-or-elan-2-rear-drive-train-and-suspension
The only comments I can make are, with all the installations and development we have carried out here there are no known lock-up problems with the conversion we manufacture
A while ago I did see a CV conversion from a UK supplier that obviously does not fully understand the CV lock-up problem.
The same UK supplier offered additional componentry to limit suspension travel so as to over-come a relatively simple problem.
The standard (off-the-shelf) CV joints and boot assembly will lock-up on extended suspension travel.
This is caused by insufficient clearance between the shaft and the steel casing that supports the rubber boot.
The CV conversion manufactured by Lotus Marques has been redesigned so it overcomes this problem.
I would suggest if you frequent forums and seek advice about the reliability of diff and hub shafts, then you will get many different opinions rather than the facts.
The facts are - the differential internals, output shafts and hub shafts all share common bearings, shaft diameters plus a common ancestry - the Ford Cortina.
What is not well known is, Colin Chapman developed the IRS suspension using the live Ford rear axle with solid axles and outboard drum brakes.
What needs needs to be recognised is that Ford actually over-engineered the Cortina/Elan differential.
The same differential is subjected to current day Historic race cars fitted with Lotus twin cam engines developing 200bhp - a testament to the original differential design and durability.
However, if you modify your Elan +2 and install 14" diameter wheels fitted with modern day low-profile sticky tyres then it would reasonable to expect problems with the driveshafts.
If you want to have high performance fun, then your seven replica is a much better vehicle for this purpose.
Many of the "TC engine hard to live with features" can be overcome by installing modern day components (and it doesnt have to cost a lot of money)
I have very few mods on my Elan +2 but have treated myself to a removable water pump and contactless electronic ignition
For the last 38 years of ownership I have made it my mission to engineer out many of the inherent design problems so as to breath additional reliability back into my Elan +2
If you are anticipating upgrading to a Zetec engine then you may want to start by first upgrading the brakes and cooling system.
Copyright © 2018 Lotus Marques
I am contemplating purchasing a CV drive-shaft conversion and its a choice between your CV's and the UK supplied UJ shaft conversion.
I don't have enough technical knowledge to fully understand shaft "lock up" and concerns on the forums about limiting suspension drop, my only understanding is that cvs have a better articulation.
What did concern me was the general belief in the forums that 140 bhp will wreck the diff output shafts or the hub shafts.
My TC doesn't run well enough to put out the stock 115 let alone 140 and I don't have enough pennies to drive hard enough to break anything, I have a cheap little 7 replica for that!
Given that I am not so hung up on the desirability of the TC (distributor under the manifold, engine out to change the water pump, not firing properly on cylinder 1 etc) I have always wanted to Zetec the car with a 5 speed when my engine is worn. That is going to give over 170 bhp in even reasonably mild tune.
So I guess I need to factor in beefing up the drive train as well.
Do you have a view on that?
J.S. - UK
ANSWER
Not sure if you have read the technical paper I have written regarding modifying the Elan rear suspension?
If you have not seen this article then you can read it here -
https://www.lotusmarques.com/info/technical/32-lotus-elan/172-modifying-the-elan-or-elan-2-rear-drive-train-and-suspension
The only comments I can make are, with all the installations and development we have carried out here there are no known lock-up problems with the conversion we manufacture
A while ago I did see a CV conversion from a UK supplier that obviously does not fully understand the CV lock-up problem.
The same UK supplier offered additional componentry to limit suspension travel so as to over-come a relatively simple problem.
The standard (off-the-shelf) CV joints and boot assembly will lock-up on extended suspension travel.
This is caused by insufficient clearance between the shaft and the steel casing that supports the rubber boot.
The CV conversion manufactured by Lotus Marques has been redesigned so it overcomes this problem.
I would suggest if you frequent forums and seek advice about the reliability of diff and hub shafts, then you will get many different opinions rather than the facts.
The facts are - the differential internals, output shafts and hub shafts all share common bearings, shaft diameters plus a common ancestry - the Ford Cortina.
What is not well known is, Colin Chapman developed the IRS suspension using the live Ford rear axle with solid axles and outboard drum brakes.
What needs needs to be recognised is that Ford actually over-engineered the Cortina/Elan differential.
The same differential is subjected to current day Historic race cars fitted with Lotus twin cam engines developing 200bhp - a testament to the original differential design and durability.
However, if you modify your Elan +2 and install 14" diameter wheels fitted with modern day low-profile sticky tyres then it would reasonable to expect problems with the driveshafts.
If you want to have high performance fun, then your seven replica is a much better vehicle for this purpose.
Many of the "TC engine hard to live with features" can be overcome by installing modern day components (and it doesnt have to cost a lot of money)
I have very few mods on my Elan +2 but have treated myself to a removable water pump and contactless electronic ignition
For the last 38 years of ownership I have made it my mission to engineer out many of the inherent design problems so as to breath additional reliability back into my Elan +2
If you are anticipating upgrading to a Zetec engine then you may want to start by first upgrading the brakes and cooling system.
Copyright © 2018 Lotus Marques