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Roller release bearing
Posted: Sat Sep 24, 2011 2:11 pm
by Hendy1201
Hi
I have read a bit about the roller release bearing for the Midget clutch. I have a midget engine and gearbox and it sounds like a good idea to use a better release bearing than the standard one. Was just wondering where I could get one from and what people think of them? Also is it the same item for the 1098 and 1275 clutch? Thanks.
Re: Roller release bearing
Posted: Sat Sep 24, 2011 5:44 pm
by Hendy1201
Also (think I'm getting paranoid now!), how easy should the engine turn over. It's had a rebore and re-grind and pretty much everything else is new. I can turn it over with both hands using the flywheel and just about move it with one hand. When torquing the flywheel bolts I had to old the wheel still while my dad tightened them up as it was turning. Does this sound ok.
I did check at every stage that everything turned freely but obviously as you add more parts it gets slightly stiffer. As I said, probably just getting paranoid!
Cheers
Re: Roller release bearing
Posted: Sat Sep 24, 2011 5:47 pm
by bmcecosse
If that's with plugs in then yes - should be ok. Be sure to fill with oil and run it up on the starter motor to circulate oil (plugs out and some oil down the bores) before even thinking of starting it.
Re: Roller release bearing
Posted: Sat Sep 24, 2011 5:51 pm
by Hendy1201
That was with plugs out!
Re: Roller release bearing
Posted: Sat Sep 24, 2011 7:12 pm
by mike.perry
The roller release bearing is well worth fitting to the midget diaphram clutch. Due to the extra load of the clutch, a carbon thrust bearing will wear quite rapidly, I know, I've tried it!
If you are using the Minor clutch linkage have you modified the relay shaft?
Birmingham MMC stock the thrust bearings, a bit pricey but when you set it against having to drop the box after a couple of thousand miles it is worth fitting.
Re: Roller release bearing
Posted: Sat Sep 24, 2011 7:19 pm
by bmcecosse
Well - as long as you can move it round on the starting handle with one hand........ When you were assembling it - was the crank spinning easily until you started fitting the pistons?
Re: Roller release bearing
Posted: Sat Sep 24, 2011 7:24 pm
by Hendy1201
It was fine without pistons, then a little stiffer with them, but still not too bad. I think the fact it has double valve springs (I know what you are going to say!) may be making it much tougher to move. I know I should remove the inner springs, but at the moment I just want to get the engine up and running so may leave them until I take the head off to do a few mods.
Re: Roller release bearing
Posted: Sat Sep 24, 2011 7:53 pm
by bmcecosse
Double valve springs........

Re: Roller release bearing
Posted: Sat Sep 24, 2011 8:07 pm
by Bazzalucas
Two items: a) I have the roller release bearing, and it's great. 2) What's wrong with double valve springs?
Re: Roller release bearing
Posted: Sat Sep 24, 2011 9:08 pm
by bmcecosse
Double springs = extra friction and wasted energy in the engine. It's never going to need to rev hard enough to justify them. The idea is to use springs that are 'just' strong enough for the max revs required. A 10098 should NEVER be taken beyond 6000 and a it's unwise to take a 1275 much beyond 6000 unless it has been lightened and balanced.
Re: Roller release bearing
Posted: Sat Sep 24, 2011 9:27 pm
by mike.perry
Valve bounce is a good way of stopping you over revving the engine

Re: Roller release bearing
Posted: Sat Sep 24, 2011 10:27 pm
by Hendy1201
Well it has all been balanced, but I don't intend on going over 6000 revs. I know that I will probably take them off in the future but at the moment i just need it running.
Going back to the first question, Who supplies the roller release bearing ?
Thanks
Re: Roller release bearing
Posted: Sat Sep 24, 2011 10:27 pm
by bmcecosse
Exactly the point!

Re: Roller release bearing
Posted: Sat Sep 24, 2011 10:44 pm
by Hendy1201
Sorry, have just seen Mike Perry's earlier post which says where to get one. Don't know how I missed that! Guess I need stronger glasses.

Re: Roller release bearing
Posted: Sat Sep 24, 2011 10:45 pm
by Hendy1201
Also, yes the clutch linkage has been altered as you have described in the past. Thanks.
Re: Roller release bearing
Posted: Sat Sep 24, 2011 10:50 pm
by bmcecosse
It must surely be possible to modify the relatively low cost Mini roller thrust for use here - I'll look into it!
Re: Roller release bearing
Posted: Sun Sep 25, 2011 1:19 pm
by Hendy1201
Got bored of writing my essay so had a look around for roller release bearings, I see Peter May (engineering) does one for the midget. A bit pricy but probably better than having to drop the box in a few thousand miles!
Re: Roller release bearing
Posted: Wed Sep 28, 2011 6:14 pm
by jaguar68
Define a few thousand miles

Re: Roller release bearing
Posted: Wed Sep 28, 2011 8:52 pm
by mike.perry
Depends on urban or motorway driving etc but I was not very chuffed at having to replace the carbon thrust which had worn down through the metal casing after what seemed a very short time. At the same time I modified the relay shaft.
The roller thrust is a straight swap for the 1098 carbon thrust