RICHARD MANN'S UPPER LINK AND REAR SUSPENSION MODS TO 7004100119Q

[andy harwood]

"I haven't read the VW conversion, but I am already onto it!! It is the next idea I will explore. See attached exploded view. The stub axles and drive flange are perfect donors, as long as they measure up!"

They measure up closely. Following is part of trimarandan's write up from the knowledgebase;

VW axles are a great alternative. I just uploaded 2 pics of my new VW axles
into the 2474R album. The axles to use come from 68-79 VW IRS Bugs. I bought
mine from a local pull it yourself JY for $11 each. If anybody else pulls a
set, make sure to get all the VW spacers as well, they are far superior to the
Lotus spacers. Many of the sand rail shops sell chromoly bullet proof new axles
on line. However, these chromoly axles will have flanges to use VW bus or
Porsche 930 CV joints which are stronger than bug CVs and able to operate a
greater angles. Our cars are not dune buggys with huge suspension travel, so I
will be installing stock VW CV axles shortly. The VW Bug axles are 30mm so they
go right into stock lotus bearings. The VW axles are dimensionally very similar
to Lotus so there is very little hassle with installation. Leave the first VW
spacer on the axle. This will be the spacer next to the CV flange, the one that
the VW seal rode on. Next, use the small Lotus spacer, the one about .382"
thick. The new axle then goes into the inner wheel bearing, through long
spacer, and emerges through the outer wheel bearing. Next, use the medium sized
VW spacer, it measures about .632" thick. This system will put the CV flange in
about the right spot, and more importantly, it will put the inside of the wheel
flange just where it needs to be (.009" more outboard than where the Lotus wheel
hub set). The wheel hub now goes on followed by the VW axle nut which is
torqued to 230-250 ft pounds. Between the wheel bearings, I used the VW spacer
which is German quality and VERY hard. My upright bearing carriers showed some
wear as I expect they all do. To adjust for this wear, do the following:
install the inner wheel bearing in the carrier and make sure it is all the way
home. Then use the depth measurement rod of a digital caliper to measure inside
the carrier from the inner bearing inner race to the ridge where the outer
bearing seats. Take 4 measurements at 90 degrees. The longest of these 4
measurements is the length that you want the spacer between the bearings to be.
I have TC/TCS carriers, so the stock Lotus spacer was 2.125" long. My adjusted
spacer needed to be shorter, but I don't remember the length (maybe .020-.050"
shorter). The VW spacer is about .100" longer than Lotus. Wearing mechanics
gloves, I held the spacer up against the face of a new grinding wheel in a 4
1/2" angle grinder. The spacer was constantly spun in an attempt to keep the
face square. Grind only one end and measure with calipers each time you need to
cool the spacer with water. With care, I was able to keep the run out in the
ground edge to about .005". When I got close to size, I chucked it up in my
lathe and finished to size. Even without the lathe, I think I could have
finished it square with selective grinding and using an oil stone. Anyway, the
results are spectacular, zero play in the new axles/bearings and resistance free
as the axles are spun by hand. If there is a fly in the ointment with this VW
axle conversion, it is with the wheel hubs. In the bug, the brake drum and hub
are one unit. In my donor car, a PO had bought undrilled drums and had a 4 x
100 bolt pattern drilled using 7/16" 20 threads. This is just the pattern I
want to end up with, so I bought the drums/hubs and cut the drum off. The OUTER
face of the new wheel hub was then machined to Lotus thickness, leaving a step
for the Lotus brake drum to center on. All other steps on the new hub were
cleaned up to use for centering wheels. About 1/4" needs to be removed from the
outermost face of the VW wheel hub where the axle nut rides so that the cotter
pin hole will be exposed. An alternative Wheel hub is the VW type 3 which had
rear disc brakes and a separate hub. These hubs can be bought on line from
MOFOCO for $48 each. They will need similar machining to use in a Europa.

*In re-reading trimarandan's write up, he gives you credit as he copied your twin link design!*

[jbcollier]

The relevant photo album:

https://groups.yahoo.com/neo/groups/LOTUSEUROPA/photos/albums/2080258933

[Lotus 47]

A fellow Europa owner lost his LH rear wheel on the track, probably as a result of constantly applying high torques to his LH stub axle nut, to the point where the end of the stub axle and nut disappeared into the weeds, while his whee,l brake drum and drive flange shot off and hopefully didn't hit anything.

Oooops . . that was probably me.
Hi Richard. 

Hi Gavin!

Why not post some info on your dato conversion?

I found another sketch of the my front trailing arm replacement bush. See below.

Thanks also to Andy for posting the VW info. I need to find a Melbourne wrecker that does Bugs.

Cheers!

Richard

[TCS4605R]

Richard,

The inside attachment point of your new link has the forward side bolted to the aluminum bell housing with two cap allen screws.  Question - did you drill and tap for these two cap allen screws or did you just drill holes and provide a washer and nut inside the bell housing?  Is there enough room inside the bell housing for the washers and nuts without coming afoul with the clutch cover?

Tom
74 TCS - 4605R

[blasterdad]

Richard,

The inside attachment point of your new link has the forward side bolted to the aluminum bell housing with two cap allen screws.  Question - did you drill and tap for these two cap allen screws or did you just drill holes and provide a washer and nut inside the bell housing?  Is there enough room inside the bell housing for the washers and nuts without coming afoul with the clutch cover?

Tom
74 TCS - 4605R

They are bolts, he posted a pic in reply#4.

[TCS4605R]

This photo shows the two cap allen screws into the aluminum bell housing - are there nuts inside the bell housing or has Richard tapped and threaded the aluminum bell housing?  Is there actually enough room inside the bell housing for washers and nuts?

Tom
74 TCS - 4605R

[BDA]

I think this is the picture Blaster was referring to:

[TCS4605R]

Richard - can you comment on my last post?

Tom
74TCS - 4605R

[jbcollier]

Photo showing nuts inside the bell housing:

http://www.lotuseuropa.org/LotusForum/index.php?action=dlattach;topic=1724.0;attach=9612;image

[Lotus 47]

Richard - can you comment on my last post?

Tom
74TCS - 4605R

Hi Tom,

I drilled through the bell housing and fitted nuts on the inside. There is very little room. I even deleted the washers due to the tight cluster of bolts/nuts. I do not trust threading into the bell housing. I fitted a larger 215mm clutch. There is heaps of clearance to these bolts/nuts, because they are so far rearwards - much further rearwards than the face of the throw-out bearing.

[TCS4605R]

Thanks Richard -  could you use a self-locking nut plate inside the bell housing?  I have used them elsewhere on the frame - they get pop riveted in place, then you can remove the bolt while the nut plate stays in place.  The nut on the nut plate is also self-locking.

Tom
74 TCS - 4605R

[BDA]

I was going to say that I don't think you'd get the clamping support with a nut plate that you'd get with a nut and washer especially in a situation where you're not clamping against a flat surface (and if you happened to have seen this post before I edited it, that's what you'd see. After looking at the pictures again, I still think that's true but I don't think it's as serious an issue as I imagined.

I wouldn't think it's a joint that you're likely to have to take apart after it's been correctly put in place so you'd be going to more trouble to make it something you can take apart and put back together with minimal fuss. In fact, I think it wouldn't be a bad idea to use red loc-tite - just a belt and suspenders way of thinking about it. After all, if the mount for the upper link were cast into the bell housing, you'd probably like that even better!

Just my $0.02.

[GavinT]

Why not post some info on your dato conversion?

Well, it’s not much more than an idea but I’ve done some rough measuring.

Losing a rear wheel at a fair clip does tend to focus the mind.
Probably the main cause of that incident was the compression of the outer 3/8” spacer. It was somewhat mushroomed - obviously too soft.

Having obtained a couple of Hillman Imp axles I had some alloy spacers machined up which were installed on the wheel mounting face. This allowed the elimination of the outer axle spacer and gained 3/8” more spline engagement as well. This worked fine but I reckon the axles are marginal in any case particularly if one ventures onto the track. Two pics attached.




The next pic shows a Datsun 240Z axle which is pretty much the same as a Datsun 1600/510.



This axle uses 2 x 6206 bearings on a 30mm shaft . . . similar to the Europa TCS but could also accept a 6206 and 6006 bearing of the S2 and the Europa spacer. The Datsun spacer is only a little longer.

The features I liked were the one piece axle & outer flange with no external threaded portion to break off. The outer bearing is also hard up against the wheel mounting flange without the cantilever feature of the Europa axle.
That’s all fine but it does mean that the wheel mounting face is ~ 25 mm further inward. A 25 mm spacer outboard of the outer bearing would bring this into line I reckon. I’ve yet to fit the arrangement into a Lotus upright but it should work.

The Datsun inner end uses a four bolt flange with a factory torque spec. of 181-239 ft-lb.
Obviously this would require new half shafts. A good opportunity to upgrade to bigger UJ’s or go the whole hog with CV’s . . perhaps VW Type II or Porsche 930 half-shafts.
CV adaptors for the four bolt flange are already available and used by the Datsun 510 crowd.

Still interested to see the VW stuff too.

Cheers,
Gavin

[andy harwood]

Here is a quick snap of the Lotus stub axle beside a VW stub axle, including spacers and nuts. The VW axle nut torque spec is 350 ft. lbs., VW axle uses stock Lotus bearings. Seems the VW axles/drive shafts are used in fairly high horse power drag cars, so should be up to a Europa load. I'll get some bearings, mount everything up in a carrier, get some measurements soon, and post. Finally getting where I can spend some time on the Lotus...

[BDA]

That's pretty interesting, Andy! When you get everything together, maybe you can provide a parts list and any instructions or required mods.