What is the distance from block to flywheel clutch face for the 3 1/2?
What minimum flywheel thickness will work, and what are the measurement points?
When I last did the clutch on my Mark V, the refaced flywheel moved the clutch engagement closer to the block, which changes the pedal linkage geometry slightly. While it works fine now, I wonder how far down the flywheel could be ground and still work fine. Also, I wonder if that ever became a problem if anyone has put a spacer shim between the crank and flywheel to overcome this question.
My particulars have the engine pistons now at 70 thousandths oversize, so the horsepower and torque are only about 4% percent above the standard 125 HP-rated engine.
All measurements are inches.
Block rear face without C348 rear plate and gasket to rear face of crankshaft = 1.562"
Flywheel clutch face to inner face contacting crankshaft = 0.938"
C348 rear plate thickness = 0.156"
It seems to me like a pretty thick flywheel, and refacings usually don’t take off more than 0.010"-0.015", so there may not be cause for concern there.
For a refacing you should remove the pressure plate locating pins so they can do the whole face. A mill collet works nice for this, or a drill press chuck and a prybar. Or there may already be holes drilled through to the back side so you can use a punch.
There has been some discussion on the XK forum about various thicknesses on the clutch release throwout bearing from different sources, so that should be carefully measured. Also the release fork locating pin has been known to break.
I wouldn’t recommend a spacer between crank and flywheel as it is spigotted on and not by a great amount.
If you use a diaphram clutch, which seems to be what is offered these days and is cheaper. you will need to use a carbon thrust with a different offset to compensate. A Rob says, the pins are prone tobreaking, both the carbon thrust carrier one and the one on the outside of the bell housing. It’s a GOOd THING to put a dab of MIG on each while it’s apart to stop any movement building up.
The flywheel face should be ground in a swirl pattern.
I have just taken the gearbox ofF a 3.5 litre Mk 1V motor & the distance from the back of the block to the clutch plate side of the flywheel measures 62mm.