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Re: Time to decide between donuts and CV joints

PostPosted: Sun Sep 08, 2019 12:08 pm
by Tmac897
I’d be keen to see what could be done; but in the interest of full disclosure, I already have a new set of interleaved donuts that I bought back in the day. For my restoration timeline and budget, I’ll probably stick with those for now.

I need (almost) an entire new engine, which will eat up a good chunk of my budget.

Re: Time to decide between donuts and CV joints

PostPosted: Sun Sep 08, 2019 12:42 pm
by Andy8421
lotusjohn wrote:
I am sure the Elan would have had CV's if they were around in 1962. The first production use was 1969 in the VW beetle. Donuts were "state of the art" and used on many formula cars of the era.

John


John, just as a point of correction, the multi ball CV design dates back to Alfred Rzeppa who patented it in the 1920s. Its use in the outer driveshaft joint of the Mini (1959-) made front wheel drive cars with reasonable lock and no driveline vibration possible.

It is open to question why Chapman didn't use them in the Elan - my guess is price.

Re: Time to decide between donuts and CV joints

PostPosted: Mon Sep 09, 2019 12:16 am
by seniorchristo
Plus 1 on the Trik Bits CV axles

Re: Time to decide between donuts and CV joints

PostPosted: Mon Sep 09, 2019 3:29 am
by StressCraxx
lotusjohn wrote:Decided I would put my 2 cents in here. My name is John Kouba and I am been manufacturing the CV kits that RD, JAE and DBE have been selling since the 1980's.

No limiting straps are needed. The Elan has way more droop than it ever needs. The CV kits do limit the travel but do not bind up like the sliding spline kits.

I am sure the Elan would have had CV's if they were around in 1962. The first production use was 1969 in the VW beetle. Donuts were "state of the art" and used on many formula cars of the era.

Many people find the "donut windup" an unpleasant attribute of the Elan design.

The donut failure issue is something to seriously think about. Many of the cars I have worked on over the years show the damage of donut failure.

With the common low yearly miles on these cars, time will be a bigger factor on replacement intervals. Poor rubber quality and environmental factors will lead early replacement.

I am open to group buys if anyone is interested.

John


John,

"Many people find the "donut windup" an unpleasant attribute of the Elan design." I wish you could have seen my wife first learning how to drive a manual transmission in my Elan. It looked like she was launching a frog. It was quite entertaining.

So glad you spoke up. You build a great kit. Thanks.

Regards,
Dan Wise

Re: Time to decide between donuts and CV joints

PostPosted: Mon Sep 09, 2019 4:07 pm
by S2Jay
This is a Big +1 from me for possible group-buy info from "lotusjohn".

For those who are not familiar with John Kouba, I first met him sometime in the 1980s at a small shop in the NW corner of the infamous San Fernando Valley North of LA. He struck me as a bit of an obsessive/fanatical perfectionist at the time, and I considered that a good thing. There was a Spyder chassis strapped to the wall of the shop [where it did not take up valuable space, but was an attention-grabbing display] and a smattering of Elans & 7s littered the shop in various stages of repair.

Maybe more important to this discussion is the bit about not needing any droop limiting device/feature. I had not heard that before about these CVs, and it was only recently that I learned [from info posted on this site] that these were the units being sold by all of the major U.S. Lotus specialists that I have been using for my current rebuild.

Disclaimer: No connection, personal or financial with any of the suppliers/manufacturers [I have not spoken with, met or communicated w / J. Kouba in more than 20 yr]. No direct knowledge of any of the CV conversions being discussed here, only respect for those who have used the various CVs & then posted their opinions. I do suspect that most [and likely all] of these CV axle conversions are well designed & well made and that a discount on any of them in a group buy would be a great bonus & benefit to me, on a somewhat limited budget.
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Re: Time to decide between donuts and CV joints

PostPosted: Mon Sep 09, 2019 4:18 pm
by snowyelan
I have John's CV's on my rolling chassis and can confirm that they do not bind at full droop with Spax adjustable dampers. To the best of my knowledge these are the same length as stock dampers, and maybe slightly longer when the small diameter billet spring perch thickness is added . What sold me on them was the included diff output shafts made specifically for CV's.

Re: Time to decide between donuts and CV joints

PostPosted: Wed Sep 11, 2019 6:08 pm
by groucho
ericbushby wrote:Fitting Kelvedon/Sue Miller CV shafts made a great improvement to the feel of my car.
Before then I had to be cautious engaging the clutch to pull away as the engine would rock a little and sometimes the carbs would tap on the footwell.

Slightly OT but make sure you have the correct motor mounts. The carb side mount should be higher to prevent the airbox hitting the fiberglass. I know because my car had the wrong mount for years and it cut a ditch in the glass deep enough to occasionally let a little fuel drip out of the carbs, through the porous glass in the bottom of the "ditch", and onto the passenger's foot.

On topic - I would be interested in the group buy for John's but I already have a pair of Lotus Marques CVs sitting next to my Elan awaiting install (where they've been for a year or so... I will install them before the engine goes back in, hopefully in the next month or two!) They appear to be comparable in quality to the Elantrikbits ones. The US ones are very nice also from what I've heard. I quite like the feel of the doughnuts but the stories of weak modern rubber and the frightening damage that can happen if one fails make the CVs a no-brainer in my book.

Re: Time to decide between donuts and CV joints

PostPosted: Wed Sep 11, 2019 6:26 pm
by ericbushby
Jeff, yes I am aware of that, in fact at my recent annual condition and safety check I noticed the carb side mount is just starting to peel. I do this myself as we no longer have a compulsory test in UK.
I did it anyway, just that I am more thorough now.
Even with this deterioration the carbs are not touching the footwell yet. It will be on the next order list.
Thanks
Eric in Burnley
1967 Type 45

Re: Time to decide between donuts and CV joints

PostPosted: Wed Sep 11, 2019 6:29 pm
by mbell
I have a set of John's shafts on my +2. Only done 1k miles on the car since I put it on the road but have been issue free. One less thing to with about with the car, was very nice thing to see under the car when I was buying it!!

Personally I think they are the best of the CV conversion available because of the diff output shafts. Which remove a known weak area for some cars and increase the shaft length which lowers the angles for the CV joints.

Re: Time to decide between donuts and CV joints

PostPosted: Wed Sep 11, 2019 7:03 pm
by tdskip
Great discussion gentlemen.

I believe we have three people signed up for the group buy. Anyone else?

Re: Time to decide between donuts and CV joints

PostPosted: Wed Sep 11, 2019 8:40 pm
by RogerFrench
A question for John, or for someone who has already fitted these shafts - can they be installed with the diff. housing left in place?

Re: Time to decide between donuts and CV joints

PostPosted: Wed Sep 11, 2019 9:55 pm
by steve lyle
RogerFrench wrote:A question for John, or for someone who has already fitted these shafts - can they be installed with the diff. housing left in place?


Yes.

Re: Time to decide between donuts and CV joints

PostPosted: Thu Sep 12, 2019 1:34 am
by lotusjohn
We seem to have three people interested. Are there there anyone else who would like to get in the group buy?

And, yes, they can be installed with the diff in place. A very careful use of a propane torch on the diff housing and the original shafts will easily slide out.

If you install the shafts with the diff on the bench, make sure to orient the circlip ends so the clips can be removed with the diff in the car. The stub axle circlips can be rotated with a punch but it can be tedious.

John

Re: Time to decide between donuts and CV joints

PostPosted: Thu Sep 12, 2019 10:13 pm
by mwisch
I would be intterested as well. It is unclear to me what are the differences and pros and cons between John's kit and the elantrikbits pieces. Can anyone explain that?
Mike

Re: Time to decide between donuts and CV joints

PostPosted: Thu Sep 12, 2019 10:26 pm
by lotusjohn
As some of you know, I have selling my kits through Dave Bean, RD Enterprises and JAE for many years. I know I offered a group buy on this thread. Regretfully, I am going to have to back out of that offer and refer any sales to one of my vendors. I do very little retail business. If I start undercutting my vendors prices, it will discourage them from selling my kits. Undercutting my vendors prices is just bad business practice.

Some technical details on my kits.

My kits include the inboard stub axle which is approximately 70% stronger (tensile strength) than the stock part. They are available separately at about 50% of the upgraded stock part.
Including the stub axle also allows me to lengthen the halfshaft for more available droop.

They DO NOT require any limit straps and should not be used.

All new Lobro CV joints and boots

Chromoly halfshaft.

Bolts that connect to outboard stub axle and brake rotor are special manufacture(similar to NAS spec) which provide full shank diameter through rotor and stub axle --NO threads in shear.

Further technical questions can be asked here or directed to my email: [email protected]