CV Conversion - a question

[davidallen]

The calculation of the drive shaft length will be one of the major problems,
as this is critical to the whole project.

The Workshop manual has most of the key dimensions of the chassis and
suspension. However one I am missing is the distance from the inner face of
the hub circlip (where the outer bearing butts up to) to the face of the
drive legs. If anyone happens to have a hub out of the car and can measure
this, I would be most grateful.

One assumption I may have to make is that rear lower wishbone is level when
the car is stood. This looks the case from the drawing in the workshop
manual, but is this just artistic licence?

When I have calculated the length of the shaft, I will obviously check it
against the car before cutting metal!

Ta,

David

-----Original Message-----
From: ***@***.***lto:***@***.***
Sent: Tuesday, June 08, 2004 5:34 PM
To: ***@***.***
Subject: Re: [LotusElan.net] Re: CV Conversion - a question


This thread has gotten me thinking as I need to replace my donuts due to
rubber cracking. The later VW beetle with what VW people call the IRS rear
end
used CV joints in the half shafts. These parts are available from the VW
aftermarket in the US for about $60.00 each and there is at least one
company in
California that specializes in VW drivelines that will make new driveshafts
of
any lenght for under $100.00 each. These prices are based on an ad which I
saw
recently and are quoted from memory. All that would be required beyond this

would be adaptor plates to mate the CV joints to the Lotus parts and these
look
like they could be made from flat plate with the sides trued up and holes
drilled including one large one in the center. The VW CV joints uses what
appears to be the same sline as the Lobro racing joints and I believe some
pointed
out earlier that they were the original basis for the Lobro joint. How does

this sound compared to what others have found out?
Jeff Manuel
65 S2





















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[lotuss4s]

Hi,

Sorry for my english...
I am agree about the fact that calculation of the drive shaft length is the
major problem.
But is it not possible to do it begin from the lenght of the intermediary
drive shaf ( 22.2 cm on the elan) +4.65cm (1 rotoflex) +4.65 (1 rotoflex)??
31.5cm
After it , we must withdraw the width of the two adapter to this (say
2cm+2cm=4) or less ....and we have the dimension between the two tripods
27,5 cm...
After it and with the CV joint and the splin axle on the kitchen table it
seems possible to measure where is the position of the center of the CV
joint on the axle and to determine the total lenght of it....?
I hope,
1st: that I can be understandable
2nd: that I am not to far of the of true

jacques
Elan s4/se
france

----- Original Message -----
From: "ALLEN, David" <***@***.***>

Sent: Wednesday, June 09, 2004 9:51 AM
Subject: RE: [LotusElan.net] Re: CV Conversion - a favour


The calculation of the drive shaft length will be one of the major problems,
as this is critical to the whole project.

The Workshop manual has most of the key dimensions of the chassis and
suspension. However one I am missing is the distance from the inner face of
the hub circlip (where the outer bearing butts up to) to the face of the
drive legs. If anyone happens to have a hub out of the car and can measure
this, I would be most grateful.

One assumption I may have to make is that rear lower wishbone is level when
the car is stood. This looks the case from the drawing in the workshop
manual, but is this just artistic licence?

When I have calculated the length of the shaft, I will obviously check it
against the car before cutting metal!

Ta,

David

-----Original Message-----
From: ***@***.***lto:***@***.***
Sent: Tuesday, June 08, 2004 5:34 PM
To: ***@***.***
Subject: Re: [LotusElan.net] Re: CV Conversion - a question


This thread has gotten me thinking as I need to replace my donuts due to
rubber cracking. The later VW beetle with what VW people call the IRS rear
end
used CV joints in the half shafts. These parts are available from the VW
aftermarket in the US for about $60.00 each and there is at least one
company in
California that specializes in VW drivelines that will make new driveshafts
of
any lenght for under $100.00 each. These prices are based on an ad which I
saw
recently and are quoted from memory. All that would be required beyond this

would be adaptor plates to mate the CV joints to the Lotus parts and these
look
like they could be made from flat plate with the sides trued up and holes
drilled including one large one in the center. The VW CV joints uses what
appears to be the same sline as the Lobro racing joints and I believe some
pointed
out earlier that they were the original basis for the Lobro joint. How does

this sound compared to what others have found out?
Jeff Manuel
65 S2





















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immediately by return e-mail and delete this communication. Thank you.

[davidallen]

Yes, I understand what you are suggesting, and had already considered it.
However, (and please someone correct me if I am incorrect) when the car is
stationary, the drive shaft is at an angle, and the donuts deflected.
Consequently, the drive shaft will be a different length than if assembled
on the kitchen table.

For this reason, I was planning to calculate the distance with the car
stationary and make the new shaft this size with the two CV's in mid
position. This will, in theory, give me the maximum bump and droop to avoid
the chance of the system locking up. As the workshop manual also gives the
figures of bump and droop, I should be able calculate the deflection of the
unit in these conditions.

As luck has it, I have access to CAD equipment to lay out the design.

I hope the above is clear, and I you think it is a bit "over the top" please
tell me. I won't be offended!

David
-----Original Message-----
From: J & S Mazel [mailto:***@***.***
Sent: Wednesday, June 09, 2004 12:02 PM
To: ***@***.***
Subject: Re: [LotusElan.net] Re: CV Conversion - a favour


Hi,

Sorry for my english...
I am agree about the fact that calculation of the drive shaft length is the
major problem.
But is it not possible to do it begin from the lenght of the intermediary
drive shaf ( 22.2 cm on the elan) +4.65cm (1 rotoflex) +4.65 (1 rotoflex)??
31.5cm
After it , we must withdraw the width of the two adapter to this (say
2cm+2cm=4) or less ....and we have the dimension between the two tripods
27,5 cm...
After it and with the CV joint and the splin axle on the kitchen table it
seems possible to measure where is the position of the center of the CV
joint on the axle and to determine the total lenght of it....?
I hope,
1st: that I can be understandable
2nd: that I am not to far of the of true

jacques
Elan s4/se
france

----- Original Message -----
From: "ALLEN, David" <***@***.***>

Sent: Wednesday, June 09, 2004 9:51 AM
Subject: RE: [LotusElan.net] Re: CV Conversion - a favour


The calculation of the drive shaft length will be one of the major problems,
as this is critical to the whole project.

The Workshop manual has most of the key dimensions of the chassis and
suspension. However one I am missing is the distance from the inner face of
the hub circlip (where the outer bearing butts up to) to the face of the
drive legs. If anyone happens to have a hub out of the car and can measure
this, I would be most grateful.

One assumption I may have to make is that rear lower wishbone is level when
the car is stood. This looks the case from the drawing in the workshop
manual, but is this just artistic licence?

When I have calculated the length of the shaft, I will obviously check it
against the car before cutting metal!

Ta,

David

-----Original Message-----
From: ***@***.***lto:***@***.***
Sent: Tuesday, June 08, 2004 5:34 PM
To: ***@***.***
Subject: Re: [LotusElan.net] Re: CV Conversion - a question


This thread has gotten me thinking as I need to replace my donuts due to
rubber cracking. The later VW beetle with what VW people call the IRS rear
end
used CV joints in the half shafts. These parts are available from the VW
aftermarket in the US for about $60.00 each and there is at least one
company in
California that specializes in VW drivelines that will make new driveshafts
of
any lenght for under $100.00 each. These prices are based on an ad which I
saw
recently and are quoted from memory. All that would be required beyond this

would be adaptor plates to mate the CV joints to the Lotus parts and these
look
like they could be made from flat plate with the sides trued up and holes
drilled including one large one in the center. The VW CV joints uses what
appears to be the same sline as the Lobro racing joints and I believe some
pointed
out earlier that they were the original basis for the Lobro joint. How does

this sound compared to what others have found out?
Jeff Manuel
65 S2





















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The information contained in this e-mail is intended only for the
confidential use of the above named recipient. If you are not the intended
recipient or person responsible for delivering it to the intended recipient,
you have received this communication in error and must not distribute or
copy it. Please accept the sender's apologies, notify the sender
immediately by return e-mail and delete this communication. Thank you.


































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The information contained in this e-mail is intended only for the
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[c.beijersbergen]

If I can be of any help, I have acces to a mechanical linkage design and
simulation program (it's called SAM, see www.artas.nl , a free demo can be
doenloaded) with which I could calculate the lengthening or shortening on
droop and bump. I do need the basic dimensions then.

greetings,

Cor Beijersbergen van Henegouwen

[Elan45]

Not bad reasoning at all Jacques!



Sorry for my english...
I am agree about the fact that calculation of the drive shaft length is the
major problem.
But is it not possible to do it begin from the lenght of the intermediary
drive shaf ( 22.2 cm on the elan) +4.65cm (1 rotoflex) +4.65 (1 rotoflex)??
31.5cm
After it , we must withdraw the width of the two adapter to this (say
2cm+2cm=4) or less ....and we have the dimension between the two tripods
27,5 cm...
After it and with the CV joint and the splin axle on the kitchen table it
seems possible to measure where is the position of the center of the CV
joint on the axle and to determine the total lenght of it....?
I hope,
1st: that I can be understandable
2nd: that I am not to far of the of true

jacques
Elan s4/se
france

----- Original Message -----
From: "ALLEN, David" <***@***.***>

Sent: Wednesday, June 09, 2004 9:51 AM
Subject: RE: [LotusElan.net] Re: CV Conversion - a favour


The calculation of the drive shaft length will be one of the major problems,
as this is critical to the whole project.

The Workshop manual has most of the key dimensions of the chassis and
suspension. However one I am missing is the distance from the inner face of
the hub circlip (where the outer bearing butts up to) to the face of the
drive legs. If anyone happens to have a hub out of the car and can measure
this, I would be most grateful.

One assumption I may have to make is that rear lower wishbone is level when
the car is stood. This looks the case from the drawing in the workshop
manual, but is this just artistic licence?

When I have calculated the length of the shaft, I will obviously check it
against the car before cutting metal!

Ta,

David

-----Original Message-----
From: ***@***.***lto:***@***.***
Sent: Tuesday, June 08, 2004 5:34 PM
To: ***@***.***
Subject: Re: [LotusElan.net] Re: CV Conversion - a question


This thread has gotten me thinking as I need to replace my donuts due to
rubber cracking. The later VW beetle with what VW people call the IRS rear
end
used CV joints in the half shafts. These parts are available from the VW
aftermarket in the US for about $60.00 each and there is at least one
company in
California that specializes in VW drivelines that will make new driveshafts
of
any lenght for under $100.00 each. These prices are based on an ad which I
saw
recently and are quoted from memory. All that would be required beyond this

would be adaptor plates to mate the CV joints to the Lotus parts and these
look
like they could be made from flat plate with the sides trued up and holes
drilled including one large one in the center. The VW CV joints uses what
appears to be the same sline as the Lobro racing joints and I believe some
pointed
out earlier that they were the original basis for the Lobro joint. How does

this sound compared to what others have found out?
Jeff Manuel
65 S2





















CONFIDENTIALITY NOTICE
The information contained in this e-mail is intended only for the
confidential use of the above named recipient. If you are not the intended
recipient or person responsible for delivering it to the intended recipient,
you have received this communication in error and must not distribute or
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[saarhus]

David,

I suggest a different, crude but effective, approach. Rather than laboriously calculating the length of the shaft, I prefer to measure it. How? Simple. With the complete suspension and the various adapters and Lobro joints in place its simply a matter of measuring a dowel or piece of broom stick that fits inside the splines of the joint. Cut it a little long so that everything will go together. The dowel should be as large in diameter as possible, preferably a slip fit in the joints. This allows observing the joints at full droop to verify that you have joints that accommodate the angular deflection of the suspension without the balls falling out. With everything in place and the suspension in full droop, mark the stick on the outside of each joint and you have the minimum keyway to keyway length needed. Add a bit for clearance and voila, you have the dimension you need. With the spring removed, verify that the length is correct with the suspension in full bump. Just for peace of mind, verify that the measurements on the stick are correct for the other side.

Cheers!

Stan (switching to brick-bat dodging mode)

<snip> The calculation of the drive shaft length will be one of the major problems,
as this is critical to the whole project. </snip>

[c.beijersbergen]

I did a quick calculation in an Autocad drawing I made before of the rear
suspension.
I took the dimensions for droop and bump as given in the Elan manual. I
measured the distance between the doughnut faces of the 3 eared spiders on
both diff and hub.
I found this: bump 293.5 mm., normal ride 301.5 mm. and droop 313.5. The
decimal digit indicates a degree of accuracy that is not realistic of
course.
I also measured the deflection at the diff side, which is the largest of the
two.
bump 10.8 degree, normal ride -3.5 degree, droop -18,5 degree.
Jacques calculated a length for the drive shaft and two rotoflexes of 315
mm. This coincides with the required length I found of 313.5 for droop. I
can imagine that in the droop situation, where the deflection is largest,
the rotoflex is allowed to work without lengthening or shortening.
I hope my approach helps.

greetings,

Cor Beijersbergen van Henegouwen

["e s"]

I used lancia scorpion axles on my plus two, very slightly too short, had to use thicker adapter plates. Still way too long for an elan. Nothing is that short.

A note. if you have not replaced your early diff ooutput shafts, you will break them with cvs, so the kit from any of the Lotus guys may not seem so expensive after all.
--

--------- Original Message ---------
DATE: Tue, 8 Jun 2004 10:08:19
From: "Franklin R. Jones" <***@***.***>
To: ***@***.***
Cc:

On Tue, Jun 08, 2004 at 03:47:36PM -0000, Steve B wrote:

which brings to mind something that has rattled through my
head before. I owned a '74 X1/9 (well several up though '78s) and it
had dual CVs in its rear shafts. Anyone investigated that system as a
donor?
I no longer own anything Fiat as I've been 'clean' for about a
decade now. I've now got a wife and kids and don't want to go back
there.. . it was a ugly part of my life that I would just as soon
forget.
but I do recall that the CVs were low maintenance except for
the Italian rubber boots, similar sizing etc.

fj..

[gjz30075]

--- In ***@***.***, ***@***.***e:











Thanks Jeff. Great prices, however, my axle length is shorter than
12", either 11 3/4 or 11 5/8", can't remember which. Worth the
inquiry though.

My adapter plates are aluminum and the bolts holding the joint to the
plate need to be locktited and safety wired or they work themselves
loose.

Greg Z.
'72 Sprint

[poiuyt]

Jeff,

Thanks!

We just completed a major engine rebuild and use the car for
shows/club events. In December it will be in for new donuts, rear
suspension bushings and we'll probably replace the springs and
shocks. I didn't expect any problems with the donuts, but all this
talk about replacing with CVs got me to wondering.

Steve B.
1969 Elan S4



--- In ***@***.***, ***@***.***e:

[davidallen]

Mmmmm. This is something I had not bargained for. Is this likely? Anyone
else had the output shafts fail after fitting new drive shafts?

David

-----Original Message-----
From: e s [mailto:***@***.***
Sent: Wednesday, June 09, 2004 2:36 PM
To: ***@***.***
Subject: Re: [LotusElan.net] Re: CV Conversion - a question


I used lancia scorpion axles on my plus two, very slightly too short, had to
use thicker adapter plates. Still way too long for an elan. Nothing is that
short.

A note. if you have not replaced your early diff ooutput shafts, you will
break them with cvs, so the kit from any of the Lotus guys may not seem
so expensive after all.
--

--------- Original Message ---------
DATE: Tue, 8 Jun 2004 10:08:19
From: "Franklin R. Jones" <***@***.***>
To: ***@***.***
Cc:

On Tue, Jun 08, 2004 at 03:47:36PM -0000, Steve B wrote:

which brings to mind something that has rattled through my
head before. I owned a '74 X1/9 (well several up though '78s) and it
had dual CVs in its rear shafts. Anyone investigated that system as a
donor?
I no longer own anything Fiat as I've been 'clean' for about a
decade now. I've now got a wife and kids and don't want to go back
there.. . it was a ugly part of my life that I would just as soon
forget.
but I do recall that the CVs were low maintenance except for
the Italian rubber boots, similar sizing etc.

fj..

[roadterror]

Have converted mine with no such failures but then again, I've been driving
the classic minis for so long (good training for smooth clutch work)....
Bottom line is having some car sympathy. If the output shafts don't break,
something else along the drive train will! Diff, prop shaft UJs, first
motion shaft..... guess some drivers are better off replacing donuts every
so often.....

BTW, have also used the TTR uprated diff mounts and brace so that everything
feels that much firmer.

Cheers,
Brian

Easy on the gas... especially now that fuel prices have soared!

----- Original Message -----
From: "ALLEN, David" <***@***.***>

Sent: Thursday, June 10, 2004 12:19 AM
Subject: RE: [LotusElan.net] Re: CV Conversion - a question


Mmmmm. This is something I had not bargained for. Is this likely? Anyone
else had the output shafts fail after fitting new drive shafts?

David

-----Original Message-----
From: e s [mailto:***@***.***
Sent: Wednesday, June 09, 2004 2:36 PM
To: ***@***.***
Subject: Re: [LotusElan.net] Re: CV Conversion - a question


I used lancia scorpion axles on my plus two, very slightly too short, had to
use thicker adapter plates. Still way too long for an elan. Nothing is that
short.

A note. if you have not replaced your early diff ooutput shafts, you will
break them with cvs, so the kit from any of the Lotus guys may not seem
so expensive after all.
--

--------- Original Message ---------
DATE: Tue, 8 Jun 2004 10:08:19
From: "Franklin R. Jones" <***@***.***>
To: ***@***.***
Cc:

On Tue, Jun 08, 2004 at 03:47:36PM -0000, Steve B wrote:

which brings to mind something that has rattled through my
head before. I owned a '74 X1/9 (well several up though '78s) and it
had dual CVs in its rear shafts. Anyone investigated that system as a
donor?
I no longer own anything Fiat as I've been 'clean' for about a
decade now. I've now got a wife and kids and don't want to go back
there.. . it was a ugly part of my life that I would just as soon
forget.
but I do recall that the CVs were low maintenance except for
the Italian rubber boots, similar sizing etc.

fj..

[Elan45]

Not after fitting replacement shafts, but I just had the RH inner stub axlefail on my 67 Elan S3-SS. This was an original to the car. I'm 3rd owner and know everything that has happened to this car since 1974. Prior to that,#1 owner autocrossed (Sprints to those east of the pond) it hard enough toinstall small diameter race springs and larger front sway bar and rolloverbar. 2nd owner did no competitions.

The car still had original donuts when I bought it in 1974. Changed to Sprint ones next year. Taken off road in 1978 w/ front turret problems and restored on galv. frame 1982 to 1985. Diff was totally rebuilt at the time by me. Stub axles perfect. But the axle didn't fail in normal torsion mode, with the little pie shaped fragments. Instead, it failed in a clean flat surface, just inboard of the radius reduction to the minor diameter. Since I hadthe donuts out, I replaced the RR wheels bearings too. And now I shouldn'thave to revisit this for a few more years. (Did the LR bearings 2 years ago.) Since the failure was a strange one, I checked very carefully the installation of the replacement axle. There didn't appear to be any out of center condition that would cause bending or shear. All I can think is there wasa stress riser in the lathe turning marks on the axle and it has just taken 37 years and 80,000 miles to break it.

Yes, the donuts were their normal uncooperative selves and it seems I spentmore time re-installing them than all the rest fo the work. I even have a wonderful "T"-bolt clamp that is a quick relase handle to compress the donut and hard steel 7/16" diameter pins about 3-4" long, pointed on one end todrive in to align the bolt holes and off course I had the special hub puller I had made to remove the bolt-on hub. I think this car is especially difficult to fit donuts to since it has the small diameter race springs and itis impossible to get the inner and out shafts to line up. That would certainly help, but eventually all went back in and I'm wearing a Lotus smile again.

Roger


else had the output shafts fail after fitting new drive shafts?

David

-----Original Message-----
From: e s [mailto:***@***.***
Sent: Wednesday, June 09, 2004 2:36 PM
To: ***@***.***
Subject: Re: [LotusElan.net] Re: CV Conversion - a question


I used lancia scorpion axles on my plus two, very slightly too short, had to
use thicker adapter plates. Still way too long for an elan. Nothing is that
short.

A note. if you have not replaced your early diff ooutput shafts, you will
break them with cvs, so the kit from any of the Lotus guys may not seem
so expensive after all.
--

--------- Original Message ---------
DATE: Tue, 8 Jun 2004 10:08:19
From: "Franklin R. Jones" <***@***.***>
To: ***@***.***
Cc:

On Tue, Jun 08, 2004 at 03:47:36PM -0000, Steve B wrote:

which brings to mind something that has rattled through my
head before. I owned a '74 X1/9 (well several up though '78s) and it
had dual CVs in its rear shafts. Anyone investigated that system as a
donor?
I no longer own anything Fiat as I've been 'clean' for about a
decade now. I've now got a wife and kids and don't want to go back
there.. . it was a ugly part of my life that I would just as soon
forget.
but I do recall that the CVs were low maintenance except for
the Italian rubber boots, similar sizing etc.

fj..

[Lincoln62]

What a great idea, use a stick, brilliant.

My car was restored in the mid 80's and has done about 30000 miles
since. I bought 3 new donuts (that's all they had in stock) for spares
when I was in England in 1989 after hearing how fragile they were and so
far I have installed only one of them (in 1997). I check them from time
to time and they are still fine. I am pleasantly surprised.

I did break an output shaft in 1990 though, even with the donuts.

Peter
66S2
==================================================================
With everything in place and the suspension in full droop, mark the
stick on the outside of each joint and you have the minimum keyway to
keyway length needed. Add a bit for clearance and

[frearther]

Actually, mine failed with doughnuts (twisted splines). I was assured that
the new ones that came with the CV unit are much stronger - I certainly
hope so.

<Mmmmm. This is something I had not bargained for. Is this likely? Anyone
else had the output shafts fail after fitting new drive shafts?>

Art
26/4934

Arther H. Frederick
Initial Reaction - embroidered and decorated apparel
3869 Route 66, Chatham Centre
Valatie, NY 12184
518-392-4287