MED engine detune and overhaul

[Hans Efde]

Last weekend I removed the engine. Today I removed the release bearing housing and diaphragm spring cover. I found that the spring was an orange one, so it seems there must be an assembly error that has cause the excessive play on my crankshaft. I also found that the thrust plate was discolored and had a damaged inner edge. The release bearing has about a 1.5mm radial play.
Here are a few pics of what I found:

engine out, becomes routine.

engine out.jpg (131.04 KiB) Viewed 7336 times

clutch release bearing with about 1.5mm radial play

clutch release bearing.jpg (104.19 KiB) Viewed 7336 times

orange spring

diaphragm spring.jpg (82.01 KiB) Viewed 7336 times

thrustplate

thrustplate.jpg (99.16 KiB) Viewed 7336 times

flywheel

flywheel.jpg (110.58 KiB) Viewed 7336 times

I have a few questions i hope you can answer:
- may the release bearing have radial play?
- is this normal for the thrust plate to look like this?
- what kind of bolts goes into the flywheel for the puller, metric ones or imperial size? I tried M10 bolts but they did not fit. Or should I try M10 with UNF thread?
I am also looking at buying a flywheel puller. I've seen one made of a thick plate of steel, but also severalones with slots in them and thinned out. Like this:
http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... K:MEWAX:IT
Are these any good or should I avoid them?

[manifold]

Hi Hans,

Here you go, based on my experience. The flywheel puller for that should be imperial. I have a feeling its 3/8 UNF.

Those thrust washers do get cut into now and again. Why not turn it over? Or if not, just replace it off a second hand cover.

You might want to check the thrusts inside your engine..between cylinders 2 and 3. Should be within tolerance or when you push clutch on you will be grinding it down and that will cause major oil starvation problems when the frags block the oil pickup and go through the pump. Been there done it. If they are out of spec you would notice the engine speed down a bit (or stall) when you press the clutch and the bottom pulley would move on the water pump side when engine is running.

If you have some play in release bearing, replace it. Its only a few quid. Save having to take the WOK cover off later, which although not difficult, is an annoying pain on a Mk3.

[Hans Efde]

Hi David,
Yes the engine will be stripped down completely because of the excessive play in the crankshaft. I was really surprised that it was just an orange diapraghm spring causing this. But because the clutch felt heavy (and the Mini specialist thought it was a grey clutch spring) I am sure it was an adjustment problem (having reread Des Hamill's book on a-serie tuning) causing the clutch to bottom out and hence giving the crankshaft a large push. Another lesson learned!

[manifold]

could be an adjustment problem hans.

i dont have the big nut on mine (throw out stop) release bearing plunger....i let it find its own level and keep my eye on the little return stop an ensure their is a few thou gap. havent had a problem on either engine since. also make sure that the flywheel/pressure plate is in spec if its been lightened. Looks like yours is an light weight one....those spacers have to be spot on that space off the flywheel straps....otherwise you are in trouble.

[Hans Efde]

It looks like the there is a gap between the straps and the diaphragm cover as well. The previous owner spend thousands of pounds on this engine and parts but he put it together like Lego.

[manifold]

Not sure what you mean there Hans.

Do you mean there are spacers directly between the clutchcover diaphragm and the straps?

I'm pretty sure there shouldnt be.....It would cause the clutch to either slip too much.....or for the diaphragm to not bend over centre and release on the cone.....which actually could be the cause of the heavy clutch feel. The ring cone (or whatever you want to call it under the cover) goes so far then releases under pressure once its back is broken. If it doesnt, it will continue to push sideways....and then the crank thrusts will burn out. I only have spacers directly above the flywheel under the straps (x2....not x3) to make up for the amount of meat that has been removed from standard dimensions.

I hope that makes sense.

[Hans Efde]

No there are no spacers. The straps were directly bolted to the pressure plate bosses. The previous owner complained about continuous breaking clutch cables and then resorted to a hydraulic system. It seems he went for the solution by solving the problem at the wrong end. Because he assembled the clutch according to the standard build up procedure and not taking into account the special parts he used -like the lightened flywheel- he introduced a number of problems like the heavy clutch and accelerated wear of the crank shaft.
He did this before with the ignition setting. He bought a 2000 pound MED engine (that's for a bare engine ) with lowered compression, but put the ignition on the standard Haynes setting of 5degr BTDC. This caused misfires which he solved by dialling in 9% CO. So he never got to the full power of this engine. When I discovered this, I put the ignition at its lowest setting (beyond the scale, about 20degr BTDC) and put the CO back to 1.5%. This turned the engine in the little rocket on the video.
This engine is becoming a Pandora box. The more I open it, the more sh*t I find. to be continued.

[manifold]

Hans,

If its an orange cover, thats about right for the spec of engine you had. Maybe a bit overkill for a standardish engine though.

If you have a hydraulic system what clutch arm do you use. I hope its the long one like mine......if its the short arm with that flywheel you will have issues. It should be a long clutch arm. I recommend the MED one. Its night on bullet proof.

It maybe that the orange cover needed breaking in....so to speak. They ease off after they age a bit....but the damage may have been done early on.

[Hans Efde]

I have checked internet and can find only 2 versions, a very short one and a sleek longer one. Mine looks like the longer version, it measures 15,5 cm from pivot point to clevis pin hole. Is this a good one or do longer ones exist?

[manifold]

sounds like the right one to me. verto hydraulic/cable one is much shorter.

im assuming the little stop was set right too. thats the 1/4" or so bolt that screws in the wok cover to stop the arm.if theres no gap between it and arm at rest it means clutch is pushing against crank all the time. Not good. Leave a small gap. About as thick as a cigarette packet card thickness.