Lotus Elan

Back in the saddle again....

PostPost by: Davidb » Fri Aug 14, 2009 5:15 pm

I finally have acquired a racing Elan again-25 years after racing 26-R5 and 15 years after selling my last racing Elan in pieces. The car I have bought is interesting in that it was the Pacific North West 'C' Improved Production Championship winner in 1967 and '68. The car is a '65 S2 number 4844.
It has a four bolt steel crank, BRM cams, Heim jointed rear suspension, rear sway bar, close ratio gears, splined drive shafts and a Detroit Locker (Groan...). I am sure I will find other things as I strip it.

I have a couple of questions for you experts:
Can the original close ratio gears be made reliable? My last gearbox of this type would last maybe three races before it became difficult to shift.

Are 125E connecting rods suitable for racing? I have not seen the rods in this engine yet but the original owner tells me that is what they are-they have been 'prepped'.

The block has been bored and sleeved to 85mm....

I am the fourth owner of the car-the guy I bought it from had owned it for 25 years and slalomed it a few times.
'65 S2 4844
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PostPost by: rgh0 » Sat Aug 15, 2009 12:45 am

David
Welcome back to the joys of Elans in competition.

I see no reason why an original close ratio box can not sustain racing. A good modern synthetic gear oil such as Redline will certainly help. Ultimately second or third gear will fail due to fatigue if the can is raced for long enough and hard enough but the replacement quaiffe close ration straight cut gear set will last forever.

125E rods can be prepped with ARB bolts,shot peening and polishing and weight reduction but in the end they will fail somewhere around 7500 rpm and make an expensive mess of the rest of your engine. As long as you stick to a rev limit around that your OK but then your wasting the capabilties of the rest of the engine to go happilly to over 8000 rpm if you have a steel crank and suitable cams

cheers
Rohan
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PostPost by: batfish » Sat Aug 15, 2009 5:59 pm

David

I second Rohans comments on the rods. I destroyed an engine when a rod let go, left a big hole in the side of the engine block, standard rods and bolts are only good to 7500 rpm.
If using higher revs you must use race rods and big end bolts.

regards

andy
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PostPost by: Dag-Henning » Mon Aug 17, 2009 1:04 pm

David, the gears of the original box are ok, but be prepare to service the box after the season, - 4-5 hours of racing. The syncrorings will need your attention. ( - if you race, that is... ) I do not know where you race, but in Europe, some of us race under the rigorous FIA rules, and are getting trouble with the straight cut gears from quaiffe. Reason is that the number of coggs do not correspond to the numbers in the homologation papers, although the ratios are the same...... :shock: How crazy can it get........As Rohan says, these gears are stronger than the original helical ones, that are really getting hard to find, so take care.....If you can use the quaiffe gears, do it! I have heard that someone in Finland are starting to reproduce the helical gears from the 2.5/1 box, but have not seen them yet. Hopefully, they will be available some day....

Dag
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PostPost by: cabc26b » Mon Aug 17, 2009 2:35 pm

David,

If you can, go ahead and get a quaife gear set , they last a long time and give no trouble. The Stock box is likely to run ok for only a short amount of time after a rebuild. As dag says there are some people/companies out there that have reproduced the OEM parts in an improved spec but in some cases these parts ,added to the stock gear sets will be very close to the cost of a quaife dog kit- It sounds like you are on pacific time so , FIA rules/stipulation do not apply, CSRG are the strictest group, out west , I know they don't like Dry sumping the motor, but I don't recall them caring about the gearbox, but check with them first if that's who you want to run with. Central and eastern time zone groups don't care about running the quaife gear sets.

Quaife and Salisbury LSD's are available if/when you decide to archive the Detroit locker..

George
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PostPost by: msd1107 » Mon Aug 17, 2009 4:55 pm

RE: Gearbox reliability concerns.

You can finish the gears and diff with the REM process (http://www.remchem.com/ or one of its licensees). See Race Engine Technology Issue 016, pp 36-41.

This decreases friction losses, cuts down on oil temperature, gives a small increase to ultimate strength, and increases reliability substantially. It is also relatively affordable.

A goodly percentage of the top end teams use this process as a base, with other friction reducing and/or DLC type coatings added.

Look at how small F1 gears are for 800+ hp, compared to our gears for 200 hp.

David
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PostPost by: Davidb » Tue Aug 18, 2009 12:41 am

Thanks to all for the responses!
My present thought is to use the existing gears for the first season anyway-and probably have them treated as suggested-I will certainly have the diff treated.

I will get a set of proper race rods-why risk it? I had Carrillo rods (and that is the correct spelling-I looked it up!) in 26R5 with a Hart 416B head and Mahle pistons. I am looking for a 416B head now-anybody know of one for sale? I doubt I will use Mahle pistons.

What is the generally accepted rev limit for these steel 4 bolt, rope seal cranks?
'65 S2 4844
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PostPost by: cabc26b » Tue Aug 18, 2009 1:21 am

David -

I would need to know more about the crank before I would venture a guess on how fast you could spin it - On the other hand I ran a steel fully counter weighted lip seal crank ( 12 bolt flywheel flange) with carrillo rods in my last race car - I set the rev limit at 9000 RPM and would typically shift when the tach needle left the dial. No issues.

On the Hart416B - I think talking to John McCoy would be your best bet. Have him CNC your head and then fit the 416 B Fuel Injection set up he has for sale to it. I am also confident that John can hook you up with the right piston to get you close on the head/valve/cam cleaance.

Just don't knock me from my place in his queue, i have been waiting long enough....

George
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