I am going to convert my Fordomatic to a T85 OD.  I have a 10", or 10 1/2" ? flywheel and want to use a 11 1/2" clutch.  A 11'/12" flywheel is available for me to use as a template, and I have a machinist to drill the holes.  Is redrilling the flywheel a good idea/viable option?  Would the flywheel need to be re balanced?  The engine is all balanced, and not in my car yet.  I'm not sure about the exact clutch dimensions, and I don't want to go out in my garage to look it up in my shop manual tonight.  Should the whole flywheel/clutch assembly be balanced together?

Thanks,

Paul J. - '57 E Code

Paul:

Rebalancing is a good idea for a couple of reasons.  The original balance of the flywheel may not be perfect to start with, and the re-drilling operation could allow for a change in the location of the clutch in relation to the flywheel.  If the holes were offset just .001, the  heavy pressure plate could cause quite an imbalance.  My suggestion would be to balance the flywheel, then bolt the pressure plate on, mark it and the flywheel so that they are always installed in the same position, and balance the pressure plate.  Good luck with your changeover.

John - "The Hoosier Hurricane"

Thanks John,

I found that I have another flywheel that may be an 11".   The space between the bolt holes for the preasure plate are 3 1/2", my other one is 3".  The outside mounting holes are about 1/2" closer to the outside edge of the flywheel.  I can't find any part numbers on either one.

Paul J. - '57 E Code

Paul:

Is it a used flywheel?  If so, you can probably see the track the disc left on the wheel.  Measure that with your tape measure, you can quickly determine what diameter clutch it is.

John - "The Hoosier Hurricane"

I tried that John, but the surface is rusted, and I can't see the pattern very well.  I guess there would only be a small differance in the OD.  I'll look at it again.  I can see the pattern clearly on the 10" flywheel.  I think I may have access to an 11" flywheel to use for comparison, I'll pursue that too. 

Paul J. - '57 E Code

Paul:

I  measured  an 11"  flywheel.  The  center  of  the  pressure  plate  bolt  holes  are  1 1/4 " (scale measurement) from the OD of the ring gear teeth.  A 10" would theoretically be about 1 3/4".  Hope this helps.

John - "The Hoosier Hurricane"

Hey John;

After reading your last post, I measured a flywheel I just had resurfaced and it's for a 10" clutch. So, if I wanted to make it for an 11" clutch without having an 11" flywheel for a template, how could I do that? I know I'll need the 11" pressure plate, but how do I locate the holes to the center of the flywheel? Maybe I just need to buy one of Mummerts reconditioned 10-11" flywheels and be done with it.

Rono

  Ron Lane,  Meridian, ID

Rono:

The only one I ever did, I had an 11" wheel for a template.  I couldn't think of a way to locate the holes without one.

John - "The Hoosier Hurricane"

I cleaned the flywheels, but haven't had a chance to check the dimentions you suggested John.  The pattern on one flywheel measures 10" and the other 10 1/2".

Paul J. - '57 E Code

John, Thanks for the dimensions, that is exactly how my wider spaced flywheel measures.  So it is an 11" and it's out for resurfacing.  When I get the clutch attached, I'll have it balanced.

Paul J. - '57 E Code