Spridget aluminum flywheel - use and ID ?

J

Joel McGinley

Well-known member
I have a pretty nicely-made aluminum flywheel with an embedded steel friction surface that looks like it will fit my 948cc street Bugeye engine. But it seems an odd mix of dimensions- It has the 4-bolt pattern without dowels like the 948 does for the crank. The friction surface is only 6 1/2 inches diameter, which seems to suggest that it only fits the early 948 clutch such as the "6-spring or 9-spring" versions where the disc is 6 1/4 inch diameter. (After this, the 1098 and 1275 clutch seem to use 7 1/4 inch discs.)
However, the flywheel has the bolt pattern for the clutch cover like a 1275- three closely-spaced pairs of bolts with a dowel in the middle of each pair. A 9-spring clutch does not fit to it, as it has 6 bolts equally-spaced and two dowels that are 180 degrees apart.
The flywheel has an engraved mark that looks like "mf" - I don't know who this maker is. Any help? I would like to figure if I could get the right disc and clutch cover to put in my Bugeye as a "Sunday to the park driver" Joel
 
The MF is probably Mueller Fabrications. Lee made a lot of early Alum. flywheels, although I'm not sure he used the friction insert on early ones, that's something I first saw from Tilton.

As to fitting stuff... What you describe sounds close to what we used to do...ran the 1275 pressure plate/disk on the 948. I started with a nine spring, then up graded to a stock 1275 on my H car, in the 70's. Had to "move/add" 3 of the holes and dowel pins, 3 vs 2.... It would seem that if a 1275 pressure plate is fitted, then you could use a disk for the smaller surface/dia... ie. use the stock bugeye driven plate if matches to your wear plate...just give up some friction area. If not acceptable, then probably could get by with the "overlap" for the 1275 driven plate...,just not what you wanted, but doubt that you'd notice difference once done...

As I recall, I used a 1275 pressure plate and disk on the bugeye.. The bugeye and 1275 had same dia. driven plates, where the 1100 was much bigger, but I may be wrong... For the 948 we made our own alum. flywheel, first running on the alum surface, then later digging out a section and flame spraying back a Stoody alloy (hard facing...think it was #6) into the alum. for friction surface...raced it for years...(Tilton wasn't on my list of things I could afford...and don't believe they had heat shield stuff early for bugeyes...)

Also, there is an outfit in Ca., Clutch.net , I believe...that can make what you need for a driven plate... had them make 2 for the F car in 09....one organic the other w/metal pucks... good price/parts...however the center hubs were too long, had to trim to keep out of T/O washer backside on pressure plate, so do a check before throwing into the car... Of course you'll have to play with front cover pivot heights, and throwout forks and brgs, to get stackup need to work right.

Anyway, the MF logo sounds like what I have on the early G Spit stuff I got from Lawrence...

Bob L.
 
Your flywheel appears to be the same as one I purchased for my 948 engine. This flywheel had the clutch cover 6-bolt pattern, and three dowels, for a 1275 clutch.

If you use this flywheel and clutch combination, also use the clutch release bearing for a 1275 (different offset).

Charlie Tolman
H/P 40 (Retired)
 
Thanks again! I memember Lee as an top National SCCA racer, since I grew up in Southern California. The flywheel I refer to was given to me in an accidental exchange of parts from a previous engine builder- instead of my actual item. But I think I can make it work if I have it surfaced and use the 1275 pressure plate. Should help "perk up" my 948 engine as we leave a traffic light !! joel
 
Joel, using the 948 flywheel with the 1275 clutch is old deal with the 948 racers, we even had Fidanza make a run of aluminum flywheels this way for the 1098s, they are long gone these days, but it does make for a better clutch than the stock 948.
 
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