Lotus Elan

Quaiffe Helical Gear set for 4 speed

PostPost by: rgh0 » Wed Apr 17, 2019 1:13 pm

ceejay wrote:While I am in the process of rebuilding my twin cam engine, the gear box is just sitting there, so I thought that it might be of help to someone if I took the cover off the box and took a shot of the internal helical gears, this is the bullet box, very tall first gear, close ratio gears... this gear box is a delight on the road, or up in the aussie alps in the summer, I run a 3.55 diff ratio, and while it does make first gear very tall and takes a bit of gentle clutch feathering to get it off the line, to me it is the perfect elan gear box.

And runs very quiet.

Shot is taken between the shifter rails, and the angle of the gear teeth are quite evident, If I ever required replacements, I would certainly look to the same gear design.

I don't know the early history of the gear box, whether it was built from parts obtained from the UK, (This would have been in the 1970s) Or if the likes of local Aussie gearbox manufacturer's, Peter Holinger or perhaps others machined/supplied the bits.

There are several engineering places around who would be capable of the CNC machining process, but at what cost I would not know, its a fact that gearbox parts are not cheap, but it is, what it is, I guess.


You can get anything made at a price. i currently have a large ( it weighs around 3 tonnes) industrial gear box under repair. The quote for cutting 2 new gears plus a rebuild of the box is around A$150k the cost for a complete new gear box is around A$250k . The box failed because of poor assembly and to much shaft end float the last time it was rebuilt at another re-builder. Still trying to decide the best option as we also have a spare gearbox of another make and to adapt the drive to use this spare is less than either option around the current gearbox. Its just like an Elan except on a larger scale in both weight an $.

Also don't get me into a debate as to the oil and oil cooling that should be used in these boxes :lol:

cheers
Rohan
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PostPost by: ceejay » Wed Apr 17, 2019 10:01 pm

Interesting conundrum you are facing Rohan with the industrial gear box repair, it has presented more dramas than anyone would want, but knowing you, the right solution will be found.

Reading your comments re proper grade of oil and cooling for the elan gear box, if one was to run the elan in a Targa style tarmac rally event, or perhaps like you, compete in historic events.

What would be the best type of gear oil that should be used in the elan gear box?

As mentioned above, I run an 80 grade gear oil, with a Nulon anti friction additive, it seems to work well as there has been no gearbox issues over the past thirty years.
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Many race cars are fitted with oil coolers for the gearbox and also the diff, wouldn't that be an over kill for normal competition in an elan.

The Ford gearbox must be made tough like the old MG TC gear box, as they both seem to cope with engine power outputs way in excess of what they were ever designed for.
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PostPost by: rgh0 » Thu Apr 18, 2019 2:29 pm

I would think unless your into endurance racing in hot climates a gearbox or diff cooler are overkill especially if using modern polyolester synthetic oils like Redline which are very heat tolerant.

I prefer Redline MTL 75W/80 GL4 oil in the gear box as it is formulated specifically for the friction characteristics needed for syncro gearboxs and gives a very smooth and quick gear change. i have never seen a need to use heavier oils in the gear box.

I prefer Redline 75W/90 GL5 oil in the diff as again it is specifically formulated for hypoid style diffs.

Redline was the first company to start making these style of oils for the auto market based on the base oil technology that was developed for improving lubrication in gas turbine engines. There are other companies that have followed suit and now make similar products

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PostPost by: rgh0 » Tue Jun 04, 2019 11:05 am

Went to place an order with TTR for the Quaiffe helical gear set today but the feedback was they cannot supply currently due to "quality problems" that need resolution, so not currently taking orders. Hopefully my current Elan gear box lasts until they resolve it. I wonder if it relates to the change to a much thicker 140 gear oil specification as discussed above

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