Lotus Elan and Lotus Elan Plus 2 Forums

Sadly we didn't go racing today after our gearbox sychro's cried enough but I did get some footage from our car on Friday. Enjoy: https://www.youtube.com/watch?v=XgL8K3Fx1Q8

Looks to be going well Chris!!

1.07 is a good time. Presume you're not on Dunlops.... Was this practice for the CSCC meeting?

I sympathise with your gearbox problems - there's a systemic problem with straight cut CR gear set and the early Elan type tail housing/bearing carrier.

Paul

I was at Silverstone today and heard your car was a non starter.

The gearbox issue is very topical for me as I'm currently trying to decide on a synchro or dog box. From speaking to four of the Elan owners in the swinging sixties series today the dog option seems the more popular choice.

What's the reason for running synchro, fia/hscc regs?

toomspj wrote:1.07 is a good time. Presume you're not on Dunlops.... Was this practice for the CSCC meeting?

I sympathise with your gearbox problems - there's a systemic problem with straight cut CR gear set and the early Elan type tail housing/bearing carrier.

Paul

We are running Dunlop 'm's. Lap time is getting there but plenty more to come as I really dont have the setup nailed yet.

It was the baulk rings that failed, 3 of them actually snapped. The later ones do look much stronger.

PaulFinch wrote:I was at Silverstone today and heard your car was a non starter.

The gearbox issue is very topical for me as I'm currently trying to decide on a synchro or dog box. From speaking to four of the Elan owners in the swinging sixties series today the dog option seems the more popular choice.

What's the reason for running synchro, fia/hscc regs?

As I understand it a dog box doesn't comply with Fia regs. Cscc are sensible and allow them (clearly it does help reliability!!). We are now contemplating what to do, we will build a spare regardless but might build one dog and one synchro. We want to ultimately do spa 6 hours, Nurburgring etc though so I think maybe we need to learn how to get the compliant synchro box to hold up.

I don't understand the problem with synchro racing boxes. I have had a Quaife syncro gear set in my competition Elan for about 15 years now and never had issues or failure or need to rebuild it. The synchro is certainly weaker than it was when newly built but it is still effective and only really needs just a little more care to roughly match revs on the shifts. I have used Redline MTL for its entire life.

What is the actual direct cause of failure e.g. synchro ring wear or breakage? What is believed to be the root cause of the wear or breakage?

cheers
Rohan

3 of the 4 rings have broken up into three pieces. I've not had a really good look as it was stripped late Friday night whilst attempting to fix for a race on sat so once I realised I didn't have the bits to fix it I parked it on the bench. I'll take some pics etc in the week. I would really appreciate your input to understand what you have done differently in your box to make it work. Do you have late or early style sychros as I think this might be a factor?

I use the late style synchro hubs and rings which my 68 Elan originally cam with. The design certainly appears to be stronger. I have never broken a ring in 35 years of racing.

cheers
Rohan

Very enjoyable clip - I adore seeing Elans racing. Do you do special leg exercises to ram the accelerator into the bulkhead so hard! I hope you resolve your gearbox problems and I wish you the best of luck for the rest of the season. Please post more videos, especially when you go to Spa.

John

I've run synchro boxes mainly with the early rings. I had 3 years running in my S1 Roadsports car (640kg), using the original helical CR gears and Yoko A048 tyres and never had a problem.

In fact the only problems I have had with the Helical gears have been as a result of incorrect assembly (and I won't make that mistake again).

As for the Quaife SC gears, you can't simply drop them into an early box with the early tail housing - the positions of the gears are wrong. I have had broken baulk rings(and I've worked on plenty of other people boxes with them too) but that has been a result of wrong clearances. I have also had to mistreat the box to make it work at all which in turn causes failures. The other problem i have had is the aftermarket layshaft wearing through the case hardening and then rotating in the case - I now only use original (good used) Lotus/Ford layshafts for the race boxes.

I finally spent time with Brian Hill (BGH) and we got both my SC synchro boxes assembled with all clearances just right. I haven't had a problem since.

I've been tempted to go the dog box route but both the FIA and HSCC have made it crystal clear this year that they will not be permitted.
Paul