Idle speed drops when clutch depressed.

[Dean]

strange thing, my boss was talking about bearings at work, as we needed one for a machine, he was saying he really goes back to the machine supplier as all bearings have a code and you can just go to you local bearing supplier and pick one up. and sometimes at a cheaper cost.

it was new to me. my local ones are hastings, brighton and godstone.

this is for me turned into a very interesting topic. and be good to see how its solved.

i have nothing bad about MED,i bought there roller tip rockers,( not yet run them)
but i also have a friend who also noticed that the locating washer and crank bolt were much thicker, he did have clutch problems and for him its was his primary gear, it chewed the bush up, maybe due to the engine sitting for a while after rebuilding and not being run so might of run a bit dry.
he also went back to a standard size washer and bolt.

[ianh1968]

Top Tip:

To check the clearance between the bolt head and the back of the
thrust plate:
1) Stick some plasticine to the head of the bolt.
2) Re-build the rest of the clutch assembly.
3) Operate the clutch.
4) Observe the results.

If the plasticine completely crushed, that will be your answer...
The answer here will be either "Yes" or "No"!

Ian

[ianh1968]

Any news?

Ian

[Lakeland997]

Thanks for asking Ian.

The problem is the primary gear binding on the crank. The images show this pretty clearly.
The prize goes to GraemeC who was the first to suggest this as a possible cause.
The thrust washers are in the right way round Spider (phew) and the crank end float is 0.006"

It looks to me like the primary gear rear bush is tapered and tight on the inner edge. I've sent it back to be checked.
Bear in mind when looking at these that the engine has run for less than 30 minutes and the clutch depressed maybe only 20 times.

IMG_2600.JPG

IMG_2609.JPG

[mk1coopers]

Good that you have found the problem,

[GraemeC]

Do I get a prize?!

It was the front bush that I had problems with. Glad you've found it though, its tantalisingly close now.....

[Spider]

I'm happy that that's all that it turned out to be.

I've notice mainly of late that the 'top hat' section of the Rear Bush does close up more when hot, due to the flange on it, so I give them a light taper at that point, not that your's got would have gotten a chance to get hot.

Also, it does appear fairly 'dry' in there, respects too that you've likely cleaned all the lube off before snapping off those pics. I'm not sure how you lube them for use, but I find the Hot Oil Soak over about 6 hours works a treat.

[Lakeland997]

I have to admit Spider to not lubricating this end as much for fear of it getting on the clutch but I'll apply your soaking advice when reassembling.
I'm going to re-check the cam timing and a few other things before putting it all back in the car.

Graeme, I'll sort out the prize for next time you visit

[wantafaster1]

What sort of clearance should there be here, I have a brand new crank and new drop gears.

[Lakeland997]

I've been told 3 thou.