Lotus Elan

Clutch Recommendations

PostPost by: jkolb » Sat Jul 16, 2005 12:29 am

I have a very well built 1600 TC that is a hot street engine (165 hp). It has been built like a race engine with the exception of cams and compression (10.5). Steel crank, rods, and caps. The engine was fully balanced with an older clutch and I want to replace it. It was balanced with the crank and flywheel, but was balanced last and I assume it is in balance and was not used to bring anything else into balance. In any event I want to replace the clutch and driven plate with a high performance assembly, but not a competition unit that will require constant replacement of the disk. Any suggestions? Trans is 4spd close ratio and rearend is 4.10 LSD. Car weighs 1350 lbs.

Thanx

Jerry
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PostPost by: rgh0 » Sat Jul 16, 2005 3:54 am

Jerry

Not quite sure why you want to replace the standard 8 inch clutch as it should be good for more than your engine.

The 5 speed plus 2's and S4 sevens made in seventies used a 8 1/2 inch clutch plate (out of an MGB of the same period I believe) which is a bit stronger than the original 8 inch clutch plate. It fits straight into the standard Elan pressure plate assembly. The later pressure plate assembly out of the plus 2's also had a stronger diaphram spring than the original Elan assembly but requires a different throwout bearing.

There are 2 types of these 8 1/2 inch clutch plates around one with 4 springs in the hub and one with 6. The 4 spring type seems to suffer from fatigue cracks around the hub springs so get the six spring type if go down this route if you can. You can also get competition clutch plates with no hub springs at all, stronger again but puts more shock load on the drive train, I have never tried them nd dont really see the need in an Elan.


You can use a solid bonded clutch plate instead of the normal riveted variety with a spring plate in the middle between the friction faces. This is a little more tolerant of abuse but at the expense of a clutch that is not as easy to smoothly engage. This however is not a problem with 5000rpm standing starts.

Small diameter multiplate racing clutches from people like Tilton will aid in reducing rotating mass when combined with a lightweight flywheel but this combination is not really road usable and has limited life with racing starts requiring regular renewal.

I use a standard 8 inch clutch and pressure plate assembly with a lightened steel flywheel in my historic racing elan without any problems.

regards
Rohan

PS Without high lift cams (0.410 inch plus lift), big valves (1.625 Inlet and 1.4 Exhaust) , big carbs (36 mm chokes) and cam timing for peak power at at least 7500rpm to use the rev capability of steel crank, rods and forged pistons properly (say 290 to 300 degrees with rapid ramps) and a very good porting and exhaust job to get all the rest working properly you will not have 165hp out of a 10.5 compression 1600TC.
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PostPost by: elans3 » Sat Jul 16, 2005 3:04 pm

Hi Jerry, I would entirely agree with Rohan, no need for a race clutch at all in a road car with mods as you describe, you'll just give yourself poor driveability and grief with frequent clutch replacement.
Much better to stick with a good quality std replacement 8".
Been there , made those mistakes in my younger days. Also would rate your engine with the mods you describe as 135bhp, you need the cams, valves and big chokes in the carbs to give 165. With twincams its easy to get 135bhp without going all steel, but much more costly to get another 30 brake, as you need the extra revs and the breathing capability.
Regds
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PostPost by: jkolb » Sat Jul 16, 2005 6:04 pm

The engine does have high lift cams, big valves and 45s with big chokes, etc. I wanted a robust engine, but can't use a 13.5:1 fire breather that won't run below 5000 rpm. I also don't want a racing clutch for all of the reasons that you have cited. an I am just a little uncertain of the clutch that I have, cover included, and would like a recommendation for a well made heavy duty alternative to the stock clutch. The particular concern is that it be well balanced out of the box, as I do not want to have to tear the engine apart again to balance the lower end. Do you have any experience with quality and balance of aftermarket clutches? AP looks good, but I have not talked with anyone who uses their HD product.

Thanx

Jerry
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PostPost by: elans3 » Sat Jul 16, 2005 10:29 pm

Hi again Jerry. Now we see ! Your first posting made it sound as if you had an all steel balanced bottom end, but with a standard (ish) top end.
AP are pretty good, I used to rally an Escort TC with a balanced bottom end, and changed the clutch about every 6 events for a new AP HD one, never had any problems with balance, always felt the same.
Although later I rallied a GP 2 170bhp Opel Kadette GTE RWD, and used Fichtel and Sachs HD (Alloy Cover) Commodore unit and HD disc, which seemed to last forever, and the first one did 18 events before I changed it as a precaution, it was only half worn. They're now just Sachs, and I'm not sure of their range any more, as I'm talking mid 80's, but it would be worth a try on their website. Extremely high quality gear, and much less than the race clutch prices.
Hope that helps,
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PostPost by: rgh0 » Sun Jul 17, 2005 12:27 am

Hi Jerry

It sounds like your concern is about maintaining the engine balance with the new clutch. If the bottom end was balanced well in the first place with the crank and flywheel being balanced separately and then checked together and match marked, then the flywheel itself should be in good balance by itself.

You should then be able to remove the flywheel and have it balanced with the new clutch pressure plate assembly. The main cause of imbalance of the flywheel and pressure plate assembly is usually a slight eccentricity of the pressure plate mounting dowels versus the flywheel mounting hub on to the crank. No matter how wheel balanced the pressure plate is by itself it needs to be checked and if necessary rebalanced and match marked on the flywheel.

regards
Rohan
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PostPost by: paros » Thu Jul 21, 2005 4:58 pm

Hi

As to clutches, I have an engine very similar in spec and for reasons I won't go into but relate to living in Greece an no good engine balancing I too neded a cluch change.
I replaced the normal flyweel and clutch with a twin plate, but organic clutch from Super Clutch in Southam, Warwick, 0044 1926 812136 I think. Tony Tewson is the MD and knows his stuff, and if you talk with hiim feel free to say it was Richard from Greece who suggested you contact him.
I use the car for racing and for shopping and the clutch is every bit as soft as a normal Elan cluch BUT is great when the lights go from red! Clutch wear is reasonable but having to reverse onto ferries here and drive around Pireus would wear anyones clutch and nerves!
You will also need to ament the realease arm and bearing - a packer behind the bearing basically which Tony supplies. Drawback - very heavy cltutch pedal even with the normal .625 master cylinder.
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