Clutch fork movement ??

PostPost by: Hawksfield » Mon Apr 04, 2022 8:04 pm

friedy

The driven clutch plate that I removed at my recent change, it looks different to yours

DSC03846.JPG and
see text for fywheel side
John

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PostPost by: promotor » Mon Apr 04, 2022 8:43 pm

It looks like you've decided to get replacement clutch cover and drive plate which will hopefully solve your problem.

I did some checking with different thickness drive plates and found similar to what you've got with an 8.5mm thick drive plate - fingers facing slightly inwards.
However, when I fitted a drive plate of 7.25mm thick the fingers came outwards by approx 4mm (due to the leverage multiplication of the clutch fingers / pivot). That's also to say that as your clutch wears, the fingers come outwards more. 7.25mm is a worn plate, newer ones I have measure approx 8mm.

DSC01290.JPG and


I did rectify the problem of fitting a 9mm thick drive plate a long time ago by spacing the clutch cover away from the flywheel by approx 1.5mm. This was on an 110bhp engine and probably did 20,000 miles without any clutch problems or any feeling of the flywheel being out of balance. Not that I'm advocating for anyone else to do it and I'm sure not many people would opt for that, but it did work. The spacers were made of a set of three large and three small spacers that fitted under the clutch where the 6 x bolt holes are. Each set were identical in size and weight so probably cancelled any effect on the flywheel out! You can just make them out in the photo below (one small one is missing though). For reference the drive plate in the photo is not a Lotus one, it is a 8.5" diameter pinto plate for use with a type 9 on lotus clutch and flywheel.

DSC01299.JPG and


Just thought I'd post my findings in case it's useful to anyone even if it's not going to help you specifically as you're buying new. The Lotus clutches (4 speed) with the thrust pad are the same as the 5 speed clutch without the pad. I know this as I used a Lotus clutch cover with the thrust pad, but cut it off for my use. Measuring this one against a brand new one without the pad shows they are they same.

HTH
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PostPost by: friedy » Tue Apr 05, 2022 5:16 pm

I've measured the distance from the pressure plate to the flywheel and it's 4mm, I will measure the same on the new cover when I get it.
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PostPost by: promotor » Tue Apr 05, 2022 7:00 pm

friedy wrote:I've measured the distance from the pressure plate to the flywheel and it's 4mm, I will measure the same on the new cover when I get it.


I'm not quite sure what you are measuring there?
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PostPost by: Larry C » Wed Sep 13, 2023 5:47 pm

I am starting this up again as it is precisely the problem I am having, but the specifics are a bit different. I have the same clutch fork movement. Even when near the edge of the bell housing, I cannot engage a gear.

I had the engine out, and just reinstalled three days ago. I am using the same clutch cover (pressure plate) and release bearing. I did install a new disc. The clutch was fine before removing the engine. I even tried pulling the fork back with a turnbuckle so it would stay in its maximum release position while I started the engine. That way, any issues with the hydraulics would not be involved. I started the engine ( rather loud as I have one half of the exhaust header off to access the slave and fork), and I still could not engage a gear.

With the engine off, I can easily engage and disengage the gear lever simply by rocking the car a bit fore and aft.

Any suggestion would be much appreciated. Oh, the car is my '73 Elan Sprint.
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