Rear Drive Train

[stelz]

Guys,

I have been advised that the diff output shafts, drive shafts and
wheel hub shafts are a weak point on the Elan that should be upgraded
if more power is likely to be put through it. I have an S1 with bolt
on hubs. Any thoughts on this one ? Obviously the damage for a
failure in this area is v bad.

Thanks,
Ben

[rodney]

Ben

The diff output shafts are definitely a weak point, mine both have twisted
due to torque loadings, and both have been replaced with stronger units
supplied many years ago by CN, but that is another story.

I don't think you would have any problems with the drive shafts or the wheel
hubs and shaft.

Rod

Rodney Stevens
CSIRO Minerals
http://www.minerals.csiro.au

Ph. 61 2 97106701
Fax 61 2 97106789

Personal Home Page
http://mywebpage.netscape.com/rodjohnst ... mePage.htm


-----Original Message-----
From: stelzerbe [mailto:***@***.***
Sent: Wednesday, 27 March 2002 10:02 AM
To: ***@***.***
Subject: [LotusElan.net] Rear Drive Train


Guys,

I have been advised that the diff output shafts, drive shafts and
wheel hub shafts are a weak point on the Elan that should be upgraded
if more power is likely to be put through it. I have an S1 with bolt
on hubs. Any thoughts on this one ? Obviously the damage for a
failure in this area is v bad.

[ecamiel]

The outer rear axles are a definite weak point, especially with sticky tires and 30 years of use. So are the front stub axles. When I raced in the 60's, I magna fluxed 14 new ones. Just 2 passed.
Eric 64 S1

***@***.***e:

[Foxie]

Hi Rodney,

I enquired at CN a few years ago about high strength diff output shafts, but they told me they no longer supplied these "because of too many claims" on this product. This doesn't make a lot of sense to me, no product can be guaranteed completely unbreakable. I see these listed in the Dave Bean catalogue, but the cost, including shipping from the US, gives me pause, (for the time being)

Sean Murray

----- Original Message -----
From: ***@***.***
To: ***@***.***
Sent: Wednesday, March 27, 2002 12:35 AM
Subject: RE: [LotusElan.net] Rear Drive Train


Ben

The diff output shafts are definitely a weak point, mine both have twisted
due to torque loadings, and both have been replaced with stronger units
supplied many years ago by CN, but that is another story.

I don't think you would have any problems with the drive shafts or the wheel
hubs and shaft.

Rod

Rodney Stevens
CSIRO Minerals
http://www.minerals.csiro.au

Ph. 61 2 97106701
Fax 61 2 97106789

Personal Home Page
http://mywebpage.netscape.com/rodjohnst ... mePage.htm

[rdssdi]

I purchased "billet" type diff output shafts from SJ Sportscars in the UK. I
have not driven the car yet so I have no experience regarding their strength.

I believe they are similar or the same as those supplied by Tony Thompson in
the UK.

I recommend SJ Sportscars. They are knowledgeable and friendly. Ask for Steve.

Bob
1969 Elan +2

[cliveyboy]

Tony Thompson sells new shafts machined from billets which will be stronger
than the originals.
Clive

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[StressCraxx]

I have worked with flexible drive couplings on turbomachinery in
refineries that are installed on tapered shafts(4000 to 10,000 HP). In
order for the taper to provide drive it must have both adequate "pull up"
of interference fit and the mating pieces must have perfect contact.
Otherwise fretting of the mating tapered surfaces will occur and the
drive will eventually fail.

To achieve perfect taper contact we used tapered lapping mandrels and
lapping paste to get the desired result. After lapping, the compound was
cleaned off and prussian blue was applied to the tapered shaft and the
coupling hub test fit. Absolute minimum allowable was 85% contact area.
95 to 100% was usually obtained with a bit more patience. We did not use
loctite.

On Elan hubs, too much lapping and the hub pulls up too far on the taper
for the nut to load the hub on the taper for adequate interference fit.
The loctite serves to fill the imperfections on the taper and provide
additional contact. The loctite also serves as a lubricant when you heat
it up to melting point to expand the taper from its interference fit.

When you have the puller mounted on the hub and tightened up for removal
there is an enormous amount of potential energy stored in the puller.
Stand clear, don't have anything valuable in the way.

The keyway is on the shaft to provide drive if the hub to taper
interference fit fails. It will easily shear if the taper is not pulled
up tight enough. The Dave Bean recommendations to round and fillet the
end of the keyway are accepted practice to reduce the chance of stress
risers at a very critical area.

Some of the service shops who subscribe to this list are capable of
safely removing the hubs, replacing the bearings, non-destructive
inspection and proper reassembly. If in doubt about what to do, use
their services. Having a wheel/hub assembly come adrift at speed is very
exciting.




________________________________________________________________

[ddddumas]

Bravo! Now, this man is a machinist to be respected.