Lotus Elan

Elan Race Prep circa 1973

PostPost by: lance54 » Sat Jun 20, 2020 3:59 pm

There was no instruction book for this in 1973. It was all seat of the pants engineering and what looks right might just be right.

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Just add 180HP 8 inch wide slicks and have some serious fun.

In those days the gearbox was the weak link. The now common ultra-close ratio dog-engagement box was a unknown. Outer rear stub-axle was another weak point. Break one of those and the wheel parts company with the car.

In the early 1970s $5,000 would put an Elan into SCCA C-Production trim including the car, all mods and the ex-Formula Atlantic Twincam.

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PostPost by: jabingb » Sat Jun 20, 2020 4:02 pm

Hmmm, that car looks quite familiar!
Jerry:
'65 S2 Elan 26R | '69 S4 Elan FHC | '00 S1 Elise Sport 190
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PostPost by: lance54 » Sat Jun 20, 2020 4:13 pm

Indeed, perhaps evidence of our miss-spent youth.

Easily $50,000 or more to replicate today.
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PostPost by: webbslinger » Sat Jun 20, 2020 10:07 pm

So what box was being used, a stock one of the day? I'm particularly interested in this, and as you mention misspent youth, I'll tell you why.
In 1969 I had my second '65 S2 which had a close ratio box and an 8k redline, or at least that's what the guy who sold it to me claimed. An insane car for a 21 year old to have huh? Having no sense at all we drove it to redline all the time.
The "we" is one of the mispent parts. I was sharing a big house and garage with 3 hot rod, drag race, street race guys and we were swapping cars all the time and trying different things.
My friends called the Elan "the spit wad" because of the rubber launch system, but they fought to drive it.
One day my buddy Ted told me why; they'd learned to power shift it and lacking any better judgement, he talked me into trying it. Well, I had too, was I going to be the only one who hadn't floored my own car?
It felt like it was meant to be driven that way!
Did I say that it felt like it was meant to be friven that way? In that mode there weren't many cars around that could keep up with it. Power shifting turned the car into a beast.
I can't imagine racing an Elan without popping a few shifts like that, once in awhile, you know, when you have too. Risky, but too much would be left on the table if you didn't go for it. Is that part of the reason for the failures? Have I said too much already?
Fortunately for the car, and probably me too, my drivers license was the first thing to fail in the drive train.
Tell us about driving race boxes.
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PostPost by: lance54 » Sun Jun 21, 2020 11:05 pm

In the 70s I used a stock close ratio with the 2.5 first gear. Than means helical gears and synchro engagement. The weakness was neither the helical gear design or the engagement type. The weakness was that 2nd and 3rd gears rotate on the main shaft without any bearings while 1st gear uses a steel bushing keyed to the shaft. Sustained high engine RPM under racing would easily weld 1st gear to the its steel bushing. First being the gear with the greatest speed differential when not engaged.
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Modern dog engagement boxes have the benefit of needle roller bearings on 1st, 2nd and 3rd in addition to the stronger straight cut gears and the faster shifting via dog engagement.
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Via the ongoing development of the 2000E Bullet Gearbox you can now have a synchro box with needle bearings on 1st, 2nd and 3rd. Both helical and straight cut versions are available from Burton and TTR....
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Regarding ratios most modern dog boxes use a 2.25 first gear that is useful for rolling starts but not very useful at most circuits. Even taller first gear ratios are available like up to 1.83 which would make first a useable gear at the slower corners of some circuits

Another weak point of the 2000E box is case flex and rotation of the countershaft in the case. I use a cast iron case and the countershaft is pinned in place to eliminate rotation.

I would say a properly assembled straight cut dog box in a Elan is just about unbreakable. Noisy for sure but very durable.
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PostPost by: webbslinger » Wed Jun 24, 2020 3:43 am

Thanks for all of this information.  I hope to run into one of those gear trains sometime to learn what they would be like.  My car is primarily a cruiser now so I don't want to add to the noise, but a helical-synchro-dog clutch sounds very interesting.  That is also interesting about the box itself, the flexing aluminum vs cast iron, and your comment about there not being a manual showing the ways forward then. The manuals have been written, but those days will never be repeated.
My S2 had slippery little Gold Seals and no limited slip so flogging it didn't subject it to a fraction of the forces a race car would see.  Even so, at the time the capabilities of the car placed it in the U for unicorns run group.  Occasionally I imagine that my experience with that car gave me insight into what racing an Elan would have been like, but I keep getting reminded that it wasn't even a hint. 
There should be an archive for information on period racing and preparing Elans.
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