Clutch Problem with 4.6

[Robrover]

I have a 4.6 with Buick heads, Crane cam and Edelbrock 1404. It goes well, seems to pull strongly in all gears (LT77 box). But there is a problem launching off the line when I select first gear, rev it and dump the clutch. It appears to over rev as if the clutch may be slipping or not releasing quickly enough. Appears to be happening when I fast change into second also. It's a new 9.5 inch AP pressure and organic drive plate and is supposed to be for high performance road use. But I think I'm either overpowering the cover plate and it is not holding the torque, or I have a problem with the slave cylinder not returning quickly enough.

There's no hint of clutch slip when accelerating in any gear. I did the clutch slip test - car in 4th gear, handbrake on, let the clutch out - and it stalled, as it's supposed to if the clutch is not slipping.

Anyone experienced this before?

Rob

[bluetoon]

Hi Rob

Dont have the answer you are looking for, just thought i would welcome you to the forum and let you know that its 3am over here and it will be a while before someone can post a helpful reply to your question. Im at 'work' on nightshift at the moment having a casual surf LOL.

PS what you got the Rover V8 & Lt77 fitted into ?

Jim

[tonym]

Jim, i too have a sumo/granada/rover set up and will be looking for a new diff soon, what are your choices and why?

Cheers

[bluetoon]

Hi tony
When i checked my donor diff (2.0l Granada) i found it was 3.91:1 non LSD. After a little research through the forum and a conversation with Pilgrim it seems this Diff is too high for the Granada/RV8/LT77 setup. ie the engine will rev too high at cruising speeds and make 1st gear redundant.

Pilgrim's Diff of choice seems to be the Granada cosworth 3.64:1 LSD.

Another option is the Granda 2.5 diesel 3.36:1 non LSD for more relaxed cruising.

There are more options with sierra diffs, buts it gets a bit messy trying to find one with compatible drive shafts and flange sizes. There are other diff choices with the Bug eyed Granada, but i have had conflicting advise regarding compatability.

I have picked up a 3.64 granada cossie LSD from evil bay £80 delivered but will also keep a lookout for a diesel one and try that aswell.

i think the main dilema is between the higher ratio LSD 3.64 and the more relaxed 3.36 non LSD.

HTH
Jim

[wilf]

Robrover - are you sure this is not just down to wheelspin?

[Tigger]

Hi Jim
keep spotting your posts on site.I fitted 3.64 diff. to my sumo.It seems a good all round set up to me.If you want to give it a blast anytime just let me know.Am now going thro, learning curve with new GD jag 3.31 diff tremec tko600 set up.
Regards peter (tigger)