Clutch cover not fitting RTS Clutch
Turbo Mini Forums

Hi I was about to fit my clutch cover but it will not fit there is a gap about 3mm. The release bearing is touching the clutch sleeve.
Has anyone had this problem?
one thing I can think of is to machine down the posts on the flywheel (MED ultra light flywheel) not sure how much by or possibly modify the clutch plunger.

https://flic.kr/p/2oZ5Yii

https://flic.kr/p/2oZ9Zk7

Is the friction plate definitely in there?

I had this problem with the first RTS I but using a turbo and uprated spring.
I had 6mm gap between the housing and the casing.
I machined material from the posts which made the spring sit flatter.
What angle is the spring currently?

Shane

I used the same flywheel from med and didnt have any issue..., so a few things to check.

Check the cover is not hitting the bolt heads of the spring plate, your washers look thick.
Also check the centre bolt/lock washer is sitting far enough in, looks further out than mine.

Has the C lock slipped when you assembled preventing things sitting home properly.

I certainly didnt need to machine the FW posts.. spacers I used were 10.8mm from memory. This got the fingers to sit flatter then yours I think.

Ps, I used a flange/ring laser cut instead of washers to hold the springs...
I made a few with slightly different ID's as this affect spring angle when bolted up.

I just had to dig out the notes I made when building mine.
I used the same flywheel as you, AP 180mm plate and an uprated and a turbo spring in the first instance.

I had to mill 1mm total off of the posts to get it to fit and function.
After hitting the same hurdle as you, when trial fitting I built the assembly with shims between the friction plate and flywheel face to gauge the amount needed to be removed off of the posts to get the cover on.

I then swapped out the new friction plate for an old one (shims still installed) to note the difference in spring position with wear as when the plate wears the fingers of the spring will be more pronounced (fingers toward release bearing).

What you don't want to happen is when your friction plate wears, the clamping to be reduced as your spring fingers are now contacting the release bearing (effectively releasing the clutch). I added/removed shims until I could fit the cover with a small amount of end float on the clutch plunger with a worn friction plate installed. The resulting shim thickness was what I machined off of the posts.

With the 1mm removed the spring sat flat compared to the angle previous, I recall comment about the spring sitting flat in one of the many posts covering RTS', but I cant find it with just searching quickly.

I had a conversation with Simon Hepburn a couple years ago about this and he made comment that he makes modifications to the "cover" when building his units but I cant remember the detail.

I tested my unit after building with a torque wrench and a primary gear with a bolt welded to it and it reliably and repeatably held over 200NM before slipping.
I later exchanged the turbo plate for a stock 998 used item to lighten the pedal and the only modifications I had to make was to the spacer heights to accommodate the thinner 998 spring.

Both units where tested on a hydraulic press with release pressures being less than my old pre verto with a grey diaphragm.

There may be an easer way to resolve the issue but the above worked for me and has been reliable.

Just as a side note I seem to recall a conversation with MED, there was a revision of that particular flywheel a few years ago. I do have two measurements noted for post heights to identify if the flywheel was current or previous.


Hope it helps.

Shane

Some pictures
https://flic.kr/p/2oZhFnt

The clutch sleeve is hitting the release bearing
https://flic.kr/p/2oZhGH7
https://flic.kr/p/2oZcb9f

The cover has about a 3mm gap.with the sleeve removed there is no gap

https://flic.kr/p/2oZhmSN

Put shims between a worn clutch plate and friction surface the flywheel (strips of sheet metal @ 12/3/6/9 o'clock positions) until the cover fits with minor end float on the plunger.
So if you put 1.5MM in to achieve the cover on with a little play on the plunger that's what you take off.
if you look at the flywheel, adding material via a shim between the flywheel face and clutch plate (for mock up only) you will have the same effect as machining the posts as you've falsely reduced the measurement between the flywheel face and the post without hacking the posts down, this allows trial and error, you don't to flatten/compress the spring so its then effectively concave.
Use a worn plate to simulate worse case of the spring finger movement toward the thrust bearing.
You must allow for clutch plate wear.

if you assemble your RTS with a new plate then a worn one you will see the affect this has on the spring finger position.

Shane

Edited by shane on 1st Sep, 2023.

I hope that makes some sense.

I have had a go trying different spaces with 1mm spacers added the cover fits with the release plunger having 1.5mm freeplay.
Would this be OK?
I have added up to 1.8mm the spring gets flatter then obviously more end float on the plunger.

That doesn't seem much free space when the plate wears?, you'd need to either fit a worn plate for comparison or remove the plate and substitute with shims the thickness of a worn item and work from there?
Shane

Ill see if I can dig out my knackered plate at some point this week to give you a datum measurement to work from.
From what I've read on here yes flat is a good thing.
Not necessarily less pressure as flat could be most loaded/highest pressure/ loading of the thrusts as the springs are under more compression.

Shane

Dont machine the posts on your flywheel, turn down the new spacers you made for your RTS assembly it will have the same effect. if you get it wrong they are easily replaced.

There is a performance gain to having the springs sitting flatter, you will get more clamping force and require less pedal effort to release the clutch. check out uTube there are some very good videos on the subject.

Own the day

Apologise for the delay on the measurements, new plate measured at 6.8mm and the old (down to the rivets) measured 4.9mm.
When looking at this issue I never gave thought to reducing the size of the spacers, without having an assembly in front of me to assess the affect its certainly something to try to see f it remedies your issue.

Shane

I have had the posts machined down on the flywheel and the assembly balanced. I had 1.5mm taken off the post's it's now all bolted together. The clutch cover fits and the plunger has reasonable free play should be enough for when the clutch wears. I could of took 2mm off the posts and the spring would of been completely flat. But because its the borge and beck pressure plate the springs do have slightly two angles to them where the AP pressure plate does not so a AP plate would be bette I did order AP but mini spares sent borge and beck.
But it's all together now and works.

Glad that you got a resolve.
out of curiosity did you experiment with the spacer lengths as Mr Joshua suggested prior to the posts being machined?

Shane.

Edited by jamesRs250 on 30th Sep, 2023.