FF Flywheel

[eastfizzrp16]

I recently purchased a FF 1600 flywheel machined for a 7.25" clutch. After cleaning off some slight surface rust, it appears the raised "step" is .090". In the book, How to Build and Maintain Competitive Formula Ford 1600 Engines, the recommended step height is .097 to .100". Tilton also recommends a similar measurement (.098" - .100"). My clutch disk (used) surface measures .098", within the minimum of .074". The "stepped" portion of the flywheel face shows no wear and is in great shape, as is the rest of the flywheel.

Do I need to machine another .007" to .010" off the flywheel to increase the step height, or is the .090" step enough?

Best regards,

Lowell

[Steve Demeter]

How did you measure the step. It is easy to pick up .010 inch error if trying to measure it with he depth stick part of a pair of calipers. Had someone ready to machine my flywheel based on my measurement and fortunately he checked the step first. My measurement was off by .015. I now use depth micrometers.

[eastfizzrp16]

Thanks for responding. I first measured the same as you initially did. I then double-checked the measurement using a straight edge and stacked, individual elements of feeler gauges. I supposed I could have introduced an error in both cases. Will drop by a machine shop tomorrow and have someone measure the step with a true depth mic.

Will report back on what I find. I'll also give Tilton a call and see what they have to say.

Best regards,

Lowell

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[eastfizzrp16]

For what it is worth, I finally dropped by a machine shop this morning to have the step in the flywheel measured with a depth-micrometer. Four measurements were taken around the step, each being 0.089". So my initial measure was close. Didn't call Tilton as it seems like the step really does need to be re-machined. The flywheel needs to be lightened anyway, so it will not be much more work to correct the step.

Best regards,

Lowell