Downsizing Clutch Diameter

[Ken Crans]

I think im going to downsize from the 11 inch clutch in the truck,3 Speed Light Duty,when i got the motor that clutch came with it. I have a real nice pedal, but a little stiff,well my legs get a little tired, so i was thinking a 10 inch clutch. I have both discs on the bench( 10,11) not much difference... but the pressure plate springs are much bigger on the 11 P Plate in a half ton truck? but my question is even though it calls out for a 10 it seems small. do they make a 10 1/2? No problem on the machining of the flywheel for the new location of the bolts.

[Straightpipes]

Ken, most of the half tons were 10 inch. Theres no need for the larger clutch.

[Bored&Stroked]

With a light duty truck like you have, go with the 10 inch and enjoy it! It will have more than enough holding power and should make driving the truck even easier. There is just no need for that 11 inch beast of a clutch in a light weight truck.

[estout81]

I'm running a 10 inch B&B clutch in my '48 with 276ci engine with no problems. Also, I've put about 12K miles on it and don't spare the throttle.

[richard crow]

if you down size to a 10 you will have to drill the fly wheel or get an other fly wheel plus buy the 10 clutch & most are made in china good luck with that. if you don,t have a two piece oil pan you will have to remove the oil pan. take your 11 & send it to fort wayne clutch ask them to reduce spring pressure so it feels like a 10. much less work less money & you get a very good unit. bob,s your uncle

[Ken Crans]

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I like that idea, i'll have to call them for a quote..Lot less work and money for me and my 11 inch clutch assembly is new. Thanks

[Ross F-1]

Originally Posted by richard crow

...if you don,t have a two piece oil pan you will have to remove the oil pan. ...

Not on an 8BA/8RT

[AnthonyG]

Ken, might I inquiry how you plan to drill flywheel for the smaller pp & clutch plate? The reason I ask is I had a pp attached to a flywheel originally meant for an 11" pp. someone redrilled for 10" which mine was & I installed not realizing this as I didn't notice the extra holes on the larger circle. Finished the job and drove the car, thought engine had a miss, then thought timing out engine ran rough, then thought crank was bent where connected to FW. After months pulled FW & pp out and saw that the 10" holes were redrilled & tapped. I checked the 11" hole pattern and they were concentric within .010" then checked the redrilled holes that my 10" was bolted to and they were .090" out of concentrcity and what was causing all the vibration I had been frustrated trying to find.

[flatheadmurre]

Originally Posted by Ken Crans

I like that idea, i'll have to call them for a quote..Lot less work and money for me and my 11 inch clutch assembly is new. Thanks

Lighter versions use just 2 of the 3 spring positions on the pressureplate.
Might just cut out 3 springs and give it a try....

[Ken Crans]

I'm a machinist by trade so drilling new holes would be easy, even .010 out of concentricity will make it vibrate.

[AnthonyG]

Mine probably is closer in concentricity than.010 as there is no vibration now. Probably was the loose nut behind the controls handling the equipment poorly, lol