Flywheel remachining

[Mrs flatchat]

In case anyone needs to know

1st step - Set up in machine true to crankshaft bolt up face

2nd - A clean up pass - to uncover wear, damage, hot spotting and heat checking (cracks) etc --caused by worn / slipping clutch.

3rd - Machine until these marks disappear, usually about 1-1.5mm --any more than 5mm is probably time for a new FW.

4th - A cross hatch swirl pattern is applied to help the clutch bed in

5th - Deburr holes, retap threads, fit dowels if required and thoroughly clean.

Tips:- Wash Fly Wheel and clutch Pressure plate faces with a solvent to thoroughly remove any trace of oil, grease, wax or protective coatings.

Torque down clutch cover bolts evenly, paticularly on steel flywheels and use a smear of never seize on the bolt threads -as they have a habit of "firing" up (seizing) -especially if done up with a power wrench

[07cob]

Mr F

Looks like new! What did you use to get the crosshatch pattern?

Geof

[Mrs flatchat]

Trade secrets Geof --
better than new and finished with a 4" ceramic bonded sanding disc (skillfully applied of course)

[deano59]

ive been using a friends engine room to build my new race engine in nice sterile environment and I see him do about 4 or 5 flywheels a day . I like watching the crank grinding machine best of all . I think I could move in and live at his engine recon shop lol.

[Mrs flatchat]

Live in a machine shop - thats sick Deano -although most machine shops need someone to clean and polish the machines

Its imperative that the "hot spots" or surface hardening is completely removed -- the lathe is most efficient at this.
The planetary surface grinder is not the best for (performance) flywheels,
The process would take ages to grind out 1mm and using a magnetic chuck which stresses the surface out of shape also.

[PeterAllen]

Does resurfacing require removal of the crankshaft for rebalancing?

[Mrs flatchat]

Not usually -- some shops can do a premachine balance check of the FW, then an after machine balance validation of same
ie:- if it had an imbalance it would be brought back to the way it was presented