MTFCA Forum

We are replacing my speedster flywheel thanks to cracks from the triple-pin holes to the centre bore.

The current flywheel had been lightened somewhat (not in the area that cracked) and I plan to do similar to the replacement.

Very interested to hear others' opinions/suggestions/experience about where one can remove a fair bit of mass without compromising integrity.

I'm not worried about the flywheel being TOO light and thus affecting smoothness — the magnets add substantial mass and the whole setup will be balanced.

I have taken about 4 pounds off of them with magnets and about 7 pounds when using an accessory ignition with no issues. Sure does make them rev up quicker.

Hank

I would definitly balance flywheel after doing removal of material and the magnets... We knife balance them

Back in the mid to late eighties, there was an article printed in the Vintage Ford with a diagram on how to lighten the flywheel by a Canadian machinist, if I recall correctly. Prior to my learning lathe machine work, my machinist friend followed the instructions and I recall him removing 10 or 11 pounds - that flywheel is in my Racer w/full length A crank & BB RAJO and as Hank stated - she revs up real quick !

Definitely rebalance.

It’s been a while so the the numbers are a bit fuzzy... but seems to me the stock flywheel weighs 30 lbs bare. I turned 15 of these pounds off, and have been abusing the remaining flywheel for the last 10 years or so... not sure I recommend going this far, but sure makes for a snappy motor!

If you are leaving the magnets on... I’m not sure that you could remove enough weight to make a difference. Might not be worth the effort for just a few pounds, especially with the resistance of the magnets acting like pump impeller veins.

Had my crank & lightened flywheel spun balanced up to 4 K r.p.m. prior to final engine assembly - Zoom-Zoom !

Thanks to all for your comments. Much appreciated.

Chris I have a cut down fly wheel in the barn. I will try and get some photos and measurement and post them later today.
Fitz

Here are two photo of my cut down flywheel. The diameter of the flywheel is about 10".
Fitz

I LIKE IT!!!

But... do you have pics of the cut down magneto to go with it???

Kevin this all got when I bought my speedster.
Fitz

Thanks for those pics Ralph. That is quite the flywheel — gonna be tough to mount my magnets though...