Lotus Elan and Lotus Elan Plus 2 Forums

Hi,

I have a BDP (200ish hp) powered S4.

I have the engine out and as a precaution, I'm considering replacing the clutch.

The car is new to me, so I dont know the history of the clutch. Although I know that the whole thing only has 7200 miles on it.

The flywheel is an aluminum one with a steel friction surface.

The clutch cover is a Borg & Beck that, the best I can tell, is stamped Type 8-8 1/2. It has white or light grey paint on the fingers. It appears to be in good condition.

The disc is also a Borg & Beck. It has 51580 stamped on one side and 53131 on the other. The friction material has no slots in it, and is .278" thick. It appears to have some metallic content.

I'm looking for input on if I should change it, and if so, what should I replace it with.

I've spoke to Dave Bean and they have an AP cover and a disc that they source locally. They didn't have any specs on the disc.

Thanks for your help!
-Kyle

I have a Tilton twin disk clutch with light weight flywheel in nearly new condition which I want to sell.
It will easily handle 200HP.
Eric
64 S1

Hi Eric,

Race clutches are wonderful things, but this is a street car.

Thank you for the offer.

Kyle

When I bailed on my Tilton and race flywheel i went to a AP set up i got from burtons - try there.

The Burton AP clutch is good for road use. You need to know the maximum torque and RPM of your engine to help determine clutch suitability. 200HP doesn't mean much in terms of selection criteria.

disquek wrote:Hi Eric,

Race clutches are wonderful things, but this is a street car.

Thank you for the offer.

Kyle

for a very high torque supercapacity engine requiring a high friction clutch, a multiplate mechanism may be more compliant to use than a very stiff mono plate one (more durable as well)...

Max torque on this motor is 160 ft/lbs at 5500RPM.

I'm not up for a multi plate clutch. I've owned many of them in race cars and still have one. They're not usable on the street.

Bean had a pressure plate that they rated at 170 ft/lbs. But they no longer have it and cant get them.

I'm wondering if the torque capacity of these clutches is partially based on the weight of the car, and if these ratings are based on the weight of a Cortina, not an Elan. But this is pure theory.

The Burton AP clutch is rated at 140 ft/lbs. I think what's in the car is a Borg&Beck version of that 140 ft/lb clutch. I think this because it has white paint on the spring fingers, and that's what's on the AP also. The old clutch didn't slip, so it might be fine to just replace it with this unit. But I was hoping to find something that's rated to take the output of this motor.

-Kyle

disquek wrote:Max torque on this motor is 160 ft/lbs at 5500RPM.

my street elan has an Helix heavy duty monoplate clutch (purchased from QED, no affiliation) given to 179 foot.pound torque - it's the 5 speed version with bearing (concentric slave in my case), but I would think there is also a standard version.

disclaimer: it is a bit binary, I'm used to it but when friends get to try my car, even if they are used to race cars (multi plate clutches for those E-type lovers...) they tend to stall at first...
I also tend to get left calf cramps when driving back home in traffic jams after a long strenuous week-end (should mention I had an injury a long time ago but still), and I counter that by going into neutral in anticipation and leaving a lot of room in front of me.

You might be able to cheat a bit by playing on the hydraulic leverage (e.g. smaller diameter master cylinder if you find one), but you'd have to make sure sufficient travel is still there.

ps: I understand the clutch torque capacity is solely depending on the clutch material (friction coefficient ...) and mechanism (pressure ...), nothing to do with the rest of the car - then for a given car (weight/interia) and engine (power/torque but also tires/gearing etc) you may be able to pass all the engine torque to the wheels at all times or have the clutch burning prematurely if it spins (not strong enough for your setup)

The other reason for using a small diameter clutch is that it won?t blow up and take your legs apart if you over Rev the engine. It?s also faster and way more fun to shift. You can learn to control it on the street.

Eric