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Clutch Problems On New Build (4 replies)

BGT
1 year ago
BGT 1 year ago

I have just installed a completely rebuilt engine and gearbox in a '69 MK2. The engine block is from a 1275 GT, gas-flowed head, SW5 camshaft, moderately lightened flywheel and all balanced etc. The gearbox is standard helical gears with 3.44 X-pin diff, S driveshafts and discs.

The engine started fine and it ran the 20 minute camshaft run-in without any problems. When I pushed the clutch down to drive the car forward the engine stopped dead. It did that three times before we pushed the car back in the garage. This was about 2 months ago. Since then have been checking and re-adjusting the operating clutch arm (non-verto) and the throw-out stop. All to no avail. Have had the flywheel off and checked all the clutch assembly etc., no problems found. Bled the hydraulics. All the time testing the car which drives OK when cold, but as soon as it warms up the problems re-appear.

The most recent test results are; 

Engine cold;

  •  Push clutch to floor, no significant effect on engine speed

  • Push pedal 1/3 down – feels like the clutch thrust race is just making contact, engine note changes slightly

  • Carry on pushing, no difference in engine note.

Engine warm by now;

  • H/brake on, engage first & lift clutch about 1/3 way, engine begins to slow.

  • In neutral, engine ticking over, clutch about 1/2 way down, engine slows down more than when 1/3 way down when cold (above), pedal fully down, engine does not change from when 1/2 way down.

  • Into reverse and back up the slightly inclined drive, push clutch down, but the car does not run down the drive until it is put into neutral.

  • Put in first, with clutch down & foot off the brake car does not run down the drive.

  • Car is very hard to get in and out of gear, in fact easiest to engage is reverse.  Car does not stall though.

Has anyone experienced this sort of thing before and do they have a solution please?

BGT
1 year ago
BGT 1 year ago

Sorry, that did not format very well and there is no facility to edit it on this site.

ROLI
1 year ago
ROLI 1 year ago

Sorry to be the provider of bad news but your problems seem to be the crankshaft centre thrusts. You may have put a pair the wrong way. Whatever you do, dont keep on trying it ! It will ruin your crank very quickly. Take the engine out, split it and just take off the centre main and carefully check the thrusts. Good luck! R

BGT
1 year ago
BGT 1 year ago

I am sure that is not the case ROLI and it does not explain why the problem occurs when the engine is warm.

ROLI
1 year ago
ROLI 1 year ago

Thats because as the engine warks up and expands there is a steel to steel contact that has no oil grooves. Good luck!

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