[Redark1]

Wanted to get some info or understanding on the availability of a flex plate for a Ford small block conversion using a E4OD or 4R100. seeing the discussions so far and my reading I guess there isn't a flex plate available as far as aftermarket. I wanted to make sure of this and if its true then I guess I'm going to figure out where to go from here because the old system with the wave ring and flex plate avail the price and availability is slim and cost prohibitive.

I'm a Machinist by trade and have the ability to produce one if needed. I'm really looking for input here from the community on this. any help or input is welcome.

and to add I just found a factory Cummins adapter for the small block and this is the direction I'm going for now unless things change.

Thanks

 

[char1355]

OK, you can use the stock Cummins flex plate that came with the GM adapter plate. And yes, those parts are expensive, You have to add one hole in the adapter plate to access the bolts for the converter as none of the small block Ford vans were automatic. Might check this guy out. This flex plate looks like a very high quality piece. Need to contact him to get all the particulars. CUMMINS TO FORD AUTOMATIC ADAPTER FLEXPLATE, USA MADE! 4BT 6BT 12V 24V CR 6.7 | eBay

 

[Redark1]

Ok didn't know the gm flex plate would work so thanks. ill look into that. as for the one on eBay I already contacted him and its too large to fit in the small block adapter. its probably for a 7.3 / big block ford.

so had a thought at dinner after reading your comment and I think I can replace the wave ring with a solid ring to take the extra power that's going to go thru this. that's about the simplest way to do this, anyone have a dimension of the thickness of the wave ring from the face of the flex plate.

 

[char1355]

Member RubeBonet makes a replacement for the wave ring assembly that is light years stronger than the OEM piece. Here's his web site. Custom Fabrication - Rob Bonney Fabrication Don't think he's any cheaper than the Cummins part. Member Oldroofer is using one on his Chevy. Here's his build. Look at post #43. 53 chevy 5-window, faux 3800 The Ford and Chevy torque converts have the same bolt pattern. Not sure how that could ever happen. LOL. Just have to use the 6 bolt heavy duty Ford converter like came on the 4R100 7.3 diesel. You'd want to measure to be sure everything fits,

 

[Redark1]

so i looked at the link you provided and its not listed. guess I would have to contact to see. i did find a pic of the unit he made and it looks good and strong. anyway looking around last night someone else made a piece to replace the wave ring back in 2007-2008 and i found it on here.

members name is Amwise and he posted pics of an aluminum ring he made. hope its ok to share. also put a pic of the one Rubebonnet makes here.

anyway I've already come up with a start on a drawing and i will make my own to save the cost. but thanks for the info and i hope it helps anyone else looking to do this or looking at a replacement going forward.

 

[char1355]

Yes, I saw that early design. That guy was making some nice parts for Chevy swaps but haven't seen anything from him in a long time. He built that for his own use. Not a bad design but not sure I'd make it out of aluminum. And it would take one heck of a chunk of steel to make it that way. That big piece of billet aluminum wouldn't be cheap either. The big thing is knowing exactly how thick to make it so all parts work. Here's the original thread where he built that part. This was 14 years ago. Stronger wave ring

 

[Redark1]

just to comment the aluminum would be plenty strong and the cost wouldn't be to bad with some of the scrap metal yards. steel is so cheap and getting a piece would be pretty easy as well. many places carry drops and remnants it makes things easier to deal with.

 

[Redark1]

Wanted to ask if anyone has the outer diameter measurement of the Cummins 3918957 flex plate for the 4bt please.

Thanks

 

[Redark1]

To ask another question, is there any other flywheel 3913056 that cross matches the manual transmission flywheel for the Chevy / Ford setup.

 

[char1355]

Ford and Chevy Cummins flywheels are the same diameter but not the same thickness or pilot bearing. The Ford flywheel assembly is part 3920709 which consists of flywheel 3906613 and ring gear 3905909. This flywheel is 1.312" thick. The Chevy flywheel assembly is part 3913056 which consists of flywheel 3913055 and ring gear 3905909. This flywheel is 1.830" thick. Both flywheels are listed as 13.5" diameter. Not sure if that includes the ring gear.

 

[Redark1]

Just to put the dimension in here for the ring gear with a 146 tooth count, its 14.98 / 15.00

thanks for the info.

 

[char1355]

OK, then that means the flywheel is 15" with the gear on it. The flex plate should be the exact same diameter since the same block adapter and starter are used for both. You might contact Cummins and their engineering department would have exact drawings of the part. Don't see how it could be any different than the flywheel.