RTS slips at 10psi
Turbo Mini Forums

BTW, The pillars aren't flat - they slope down towards the centre.

On standard flywheels the inner edge is 0.1 mm lower than the outer. On an aftermarket steel one I measured 0.2 mm (maybe the manufacturer's attempt to increase clamping force)

I didn't let that stop me cutting the posts down on mine, just a heads-up for when you take your measurements and cuts.

Edited by PhilR on 2nd Apr, 2016.

Make smaller spacers !

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

I thought we'd established the spacers are the right size...

Now that is a much better explanation.

That also explains how the pillar holes and alignment dowels all appeared to be drilled slightly off radius; and therefore why the flywheel was 0.5mm off-centre and off-balance (balanced perfectly once the dowels corrected)

Yeah, that distortion dosent surprise me. Especially on the lightweight flywheels, I guess this is why med changed their design from the earlier lighter version

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

I think all my problems here are caused by the ap rally clutch being only 7.1 mm thick whereas this other clutch plate i have here is more like 7.9mm thick and clamps up correctly.
I want to use the Ap plate though.
I did a search on clutch plate thicknesses and stevieturbo said they usually are 5/16 thick which is almost 8mm so that corresponds with my findings.

sounds reasonable, Ive used the 190mm plate which iirc was nearly 8mm, so thats at least .75mm thatr can come off the lugs

From memory the spacers I've had made in the past were all around 10.9 to 11mm tall and about the same in diameter.

Also worth mentioning that i think you have used a re manufactured cluth in there somewhere which might mean that the friction face on the pressure plate will have been refaced a little. Could it be that they have replaced the wire rings with something a little thicker also? Check your spacer length.

So i have had 50 thou removed from the flywheel pillars so now with a new AP rally clutch when clamped up the springs are almost flat. Tested it with my pillar drill and confirmed it releases ok
Fitted new clutch arm and clevis pins and plunger and release bearing. Primary gear endfloat is 4 thou. Throw out stop set at 6.5mm
Starts her up and the point where the car moves is an inch from the top of the clutch pedal. The point when the drop gears go silent is half a pedal down. So far so good
Goes for a ten minute drive and now getting slight crunching when trying to engage gears while at a standstill. Drop gears are now not stopping even with the clutch on the floor. Can confirm the throwout stop is touching the clutch housing with the clutch pedal on the floor so hydraulics are all ok.
Tried again when car had cooled and was ok until it had warmed up again.
Any ideas please?

Edited by dazibee on 12th Apr, 2016.

Oh i also changed the c washer on the primary gear for a tighter fitting one, wonder if the flywheel is touching it and making my primary gear go tight?

I had a similar problem with my first one. Basically it wouldn't disengage fully.

Turned out the pressure plate was fouling on (what would be on yours) the head of the bolts where the rivets would normally be. These should really be countersunk.

Give the throwout some more travel to see if it resolves it.

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

* edit to correct spring ratio*

I always check now for displacement at full throw out.

Acording to the text book, there should be at least 2mm displacement at full throwout.

We know tge AP type clutch to have roughly a *2.41:1 ratio on the spring, so, not acounting for deflection, 6.5/2.41=2.7mm......... the 2mm displacement kind of looks like a good place to start.

I assemble the clutch on the bench, then use 2 dti gauges and a flywheel puller to check pressure plate displacement at 6.5mm throwout. I found the newer clutches to be a problem as they have relocated all the fixing holes in the backing plate to eliminate the differences to an injection clutch, BUT, they left the clearancing for the rivets/bolts in the backplate where they were. Other times ive found the pressure plates are a different thickness in this critical area. Its easy fixed by running the pressure plate in a lathe, or, as slater suggested, as i have also done, is use counter sunk screws instead. Half a dozen of one six of another......

Edited by Sprocket on 11th Apr, 2016.

I opened up the throwout to prob 8mm. Same thing. Works as expected until it warms up then dragging. Im thinking primary gear getting tight? This med light flywheel i already know is crap, wouldnt suprise me now that i have put a different c washer on the crank it is snaggng?

Confirmed the clutch works perfectly ok until engine is hot. Took it apart again, primary gear is not seized but there are some marks on the outer bush that im not sure about and dont think they were there when i assembled it last week.
Crank taper is nice and smooth and so is inner bush on primary gear. I can feel slight roughness on the outer primary bush where the marks are. I will try to get some better pictures

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Edited by dazibee on 12th Apr, 2016.

What causes these marks, just debris contamination. Do i need a new primary gear?

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I had similar with an MED crank. The crank was hardened, and the tail was a dull grey, but smooth. It scuffed the primary gear bush in a similar manor. I had the tail polished and fitted a floating bush in a different gear and the problem went away.

One thing to check is the backlash between the idler and primary gear, this needs to be done with the transfer case fitted, so the only room you have to measure is where the seal would normally fit

Also, I always use some wheel bearing grease on the gear bushes on assembly.

crank is a med one oddly enough. But its been ok for 1700 miles, only went wrong when i closed the endfloat up a bit to 4thou and reassembled it the other day. The taper is nice and smooth. I will put a new primary gear on and some grease. The marks are not too bad but i can feel them with my fingers so that is probably what is stopping the primary spinning when it gets hot

And i will put the original c clip back on so its got 6 thou clearance again

Ok now not getting any clutch slip so that is something. I have changed the primary gear for a new one. Five thou endfloat, five thou running clearence for the rear bush. Cant get at the crank taper to measure where the front bush sits, but not expecting it to be far out. New primary has a floating front bush. Have boiled this one in oil and it has a lot of lube on it.
Clutch works perfect when cold, but dragging slightly when warmed up still. It is only noticeable when stationary and with the clutch on the floor can still hear the drops spinning. Engaging a gear stops the drops. Getting a bit of clutch judder which i expect will go away after a few miles just as my first clutch plate did.