6 replies to this topic

[jpsmini]

Hi all,


I have recently rebuilt my 1275 with verto clutch. The clutch / flyweheel assembly is a ST2 MED Ultra Lightweight assembly with an AP racing plate (so quite a lot of clamping force).

I must admit my idle isn't the smoothest in the world, even with an SW5 cam... perhaps a little more advance would smooth things, although with just a standard Lucas unit and an M45 charger, I can only dial in so much advance before things get dangerous! However, on pressing the clutch the revs drop around 200rpm, enough to start stalling the engine from its previous 750rpm idle.

As part of the rebuild thrust bearings were all replaced and end float fully assessed, so no concerns there. I can happily change gears with only 1/3 of the total clutch travel, so I can only assume I simply don't need as much travel as the clutch arm is providing. To remedy this I had planned to move the throwout stop further up to hit the wok at much less travel, however even when the clutch is fully depressed there isn't enough thread to allow the stop nut to hit the wok.

Should the nut travel far enough up to limit travel? If not, any suggestions how I can reduce the total amount of clutch travel, or should I perhaps ensure I have a perfect idle before I try any further?

Cheers.

Edited by jpsmini, 21 August 2018 - 05:09 PM.

[GraemeC]

My first instinct is that this is a release bearing problem. Maybe not fully seated on the plunger?

[nicklouse]

sounds more like worn parts. should only need setting to 6mm and that is it.

[Dusky]

Reading this I think he has too much travel. Easy to fix this, some big washers that slip over the plunger between the nut and wok.

[jpsmini]

Reading this I think he has too much travel. Easy to fix this, some big washers that slip over the plunger between the nut and wok.

Yes, too much travel. This certainly seems like the most simple way to resolve. Graeme raises a good point about the release bearing perhaps not being fully seated, but as there is no noise from the bearing or judder, I'm inclined to try the extra washer approach first before taking the wok off.

Edited by jpsmini, 22 August 2018 - 07:03 AM.

[nicklouse]

The thing is the release bearing just fits and if it dies not you can not get the O ring on.

You could have wear on the top hat and on the fingers but it still works.

[jpsmini]

I'm pleased to report this was solved, and easily too. Timing light showed over 40 degrees of advance at idle, which also explained another issue I was experiencing... slow cranking on the starter. Quite staggered there was no audible detonation, but with a CR of 8.2:1, 98 RON fuel and octane booster, this must be sufficient to prevent detonation even under boost.

With the advance now set to approximately 8 degrees at idle, with total advance approaching 28 degrees at 4000rpm, the idle is significantly smoother and pressing the clutch lowers the revs only very slightly.

I will leave the throwout stop exactly where it is!

Edited by jpsmini, 25 August 2018 - 10:57 AM.