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Lotus Europa Forums => Garage => Topic started by: jpane on Tuesday,March 09, 2021, 07:50:58 AM

Title: 365 Linkage, Heim Joint
Post by: jpane on Tuesday,March 09, 2021, 07:50:58 AM
Is the Heim joint in the middle of the 365 linkage (reasonably) replaceable ?
I have the Tom Berkley modification to the middle pivot. His drawings show that as a 1/2" Heim joint. Any other dimension I need to know to order a replacement?
Thanks,
John
Title: Re: 365 Linkage, Heim Joint
Post by: Pfreen on Tuesday,March 09, 2021, 03:26:33 PM
It is easily replaceable.  I used Mcmaster part number 2458K16.  https://www.mcmaster.com/2458K16/
Title: Re: 365 Linkage, Heim Joint
Post by: jpane on Tuesday,March 09, 2021, 03:35:17 PM
Pfreen, Thanks for the confirmation. It appeared simple, but I never assume anything on this car.
Title: Re: 365 Linkage, Heim Joint
Post by: Pfreen on Tuesday,March 09, 2021, 04:15:02 PM
The only trick is the ball is loctited to the shaft.   If you have problems un screwing the two shafts after driving out the roll pin, the threads are probably loctited as well.
Title: Re: 365 Linkage, Heim Joint
Post by: Bainford on Wednesday,March 10, 2021, 06:45:29 AM

I have the Tom Berkley modification to the middle pivot.
I'm curious, what is the Tom Berkley modification?
Title: Re: 365 Linkage, Heim Joint
Post by: jpane on Wednesday,March 10, 2021, 07:01:16 AM
Go to the "Master Documentation Menu", below
http://lotus-europa.com/manuals/

Scroll down to the section on Transmission. You will see a link to:
352/356 Shifter Middle Pivot - Thanks to Tom Berkeley
    Drawing 1
    Drawing 2
    Drawing 3

It is a less complicated, and I believe smoother, bracket for the middle of the shift linkage.
Others may chime in on their opinion of it.
Title: Re: 365 Linkage, Heim Joint
Post by: Bainford on Wednesday,March 10, 2021, 08:17:24 AM
Go to the "Master Documentation Menu", below
http://lotus-europa.com/manuals/

Scroll down to the section on Transmission. You will see a link to:
352/356 Shifter Middle Pivot - Thanks to Tom Berkeley
    Drawing 1
    Drawing 2
    Drawing 3

It is a less complicated, and I believe smoother, bracket for the middle of the shift linkage.
Others may chime in on their opinion of it.
Thank you jpane. Very interesting.
Title: Re: 365 Linkage, Heim Joint
Post by: Pfreen on Wednesday,March 10, 2021, 10:10:38 AM
I tried many different isolation methods for the shifter's center pivot.  The stiffer the isolator, the better the shift accuracy, but the more the shifter vibrates and drives you crazy.  My car has an aluminum flywheel which further aggravates the problem. 

The original design isolated the vibration, but the bushing disintegrates from the exhaust manifold heat and the shifter is vague.

I first tried varying degrees of stiffness silicone isolators (also from Mcmaster).  The middle stiffness one was a good compromise between shifter accuracy and vibration.  However, the isolator ripped in half on a speed shift. 
I went back to the original design but changed to a silicone bushing.  This compromise make the shifting precise and the vibration is enough to hear at certain rpms, but not too annoying.
Another issue I found was with the shifter spherical bearing.  The bearing available domestically from the usual Lotus supplier is a non lubricated bronze race type which has a lot of play.  This helped the vibration issue.  I found a teflon race spherical bearing and machined an adaptor to make it fit the Lotus spherical bearing holder.  The bearing is from Pegasus Racing part number 3070-8.
Title: Re: 365 Linkage, Heim Joint
Post by: MRN I J on Wednesday,March 10, 2021, 12:02:54 PM
I changed mine on my S2 to the highest spec PTFE rod end joints, never used Loctite just the locking nuts as I wanted to replace them as quickly as possible as the rod ends often broke in competition, sprinting & hill climbing in the UK