Concentric clutch release bearing

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bash
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Concentric clutch release bearing

Post by bash »

This bit of kit is designed to be used on the Lotus gearbox but is intended for a Ford engine and is marketed by rwd motorsport, but its the gearbox end thats important and it will fit the Lotus assembly. The reason for going down this route relates to my Rover V8 conversion for which I had cast up a bellhousing to match the Lotus ( Toyota ) gearbox. I had used a combination of Lotus related bits amongst others and it worked fine for about 3000 miles, until I got a nasty rattle. It turned out that my bellhousing was slightly too long and the splines on the gearbox input shaft were wearing the friction plate centre, hence the rattle. a slight machining job later and I got the bellhousing correct. But, and this is the important bit, this conversion can be fitted by all of you with the Lotus engine.

So what do you get for your money. A concentric bearing, 5 countersunk cap head screws, a machined aluminium plate and some alloy spacers for the screws.
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The kits pictured here with the nose housing from my gearbox. the main modification requires this nose to be shortened. I was surprised at the robustness of this nose piece because it dosnt do owt ! the cast part has an oil seal ( which I replaced ) but there are no bearings in this component at all.
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Anyway, I took a hacksaw to it leaving a short stubby nose.
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heres a top view of the loose assembly.
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And another view
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This is it in the bellhousing before I describe the complicated bit.

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This isnt a bolt up bit of kit, it does need some adjustments etc. When the assembly is bolted to the gearbox, and before any hydraulics are connected some measuring and adjusting will be required. The concentric has to be fully compressed and the distance to the bellhousing to engine interface measured and then 3mm is taken off this measurement. This is to allow for future clutch wear as the fingers on the pressure plate will move out as the frictionplate wears. This has to equal the distance from the bellhousing interface on the engine to to clutch fingers. If it sound simple, it isnt, they are both a pain to get right so has to be done many times to ensure accuracy. The adjustments are made to the spacers, either by adding washers or machining them shorter.
The hydraulics then need to be addressed. Fortunately the Lotus master cylinder is the correct diameter for the job at 5/8". This and a bleed is then fed thro. There is only a single pipe into the concentric and a Y piece is added to a second pipe with the bleed attached, its easier to look at the photo. Bleeed this before putting the engine back in, it has to be done very carefully and needs someone working the concentric and another working the pedal while its bled.

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Make sure that the hydraulic pipes are well clear of the clutch cover when its assembled.

Any issues ? No. The pedal is extremely light and even the lightest rest of the foot on the pedal will promote slippage. Could you make one yourself, yes if you are called Pete Boole, to us lesser mortals probably not.

Bash
On a mission to find the airspeed velocity of a european swallow.

Pete Boole
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Re: Concentric clutch release bearing

Post by Pete Boole »

Great write-up Bash 8). Do they offer a kit for the LT77 as well?

Pete

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bash
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Joined: Thu Nov 03, 2005 15:34
Model: Se, V8
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Year: 1986
Location: Doncaster
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Re: Concentric clutch release bearing

Post by bash »

Not as far as I know cos they are Ford specialist really, but I think you could make one. The concentric is just a standard bit and the alloy plate is just summat to mount that on and connect to the gearbox so with an accurate centrepoint and suitable machine tools its not difficult.

Bash
On a mission to find the airspeed velocity of a european swallow.

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