4 1/4" stroker

flatjack9

flatjack9

Well-known member
I'm building a 4 1/4" stroker for a customer. I have an Eagle crank and 3 5/16" Ross pistons with the metric ring pack. I was going to use 21A rods with full floaters, but the fillet on the rod journal is not like the Ford crank. The floaters hang up on the fillet. Has anyone run this combination or should I get the Scat rods? If so, what bearing do I use?
 
What you're trying to do do can be done, but you have to start measuring things. The crank jurels are sized for the Buick bearings and the after market "H" beam rods. When I do something like this I get the assembly from Gary in NY. He provides a quality product that drops right in. I have some doubts in the reliably of the 21A rods. Might have gone with the 29A ones. I say this, but the 296 engines that were common back in the 50's and 60's ran very well. I have one that has over 50K miles and still runs good. Buy the rods, and get it balanced.
 
If you check the pictures in my book you will see how I machined the FF bearings to accommodate the fillet.
 
Check Jwl's book on how to machine the bearings.
21A rods can be made very reliable but it will take some work.
They need to be shot peened and then reconditioned.
This will still be cheaper than H beam rods.
 
Ol' Ron said:
What you're trying to do do can be done, but you have to start measuring things. The crank jurels are sized for the Buick bearings and the after market "H" beam rods. When I do something like this I get the assembly from Gary in NY. He provides a quality product that drops right in. I have some doubts in the reliably of the 21A rods. Might have gone with the 29A ones. I say this, but the 296 engines that were common back in the 50's and 60's ran very well. I have one that has over 50K miles and still runs good. Buy the rods, and get it balanced.
Click to expand...

Right, the journals are 2.000 where as the Ford's are 1.999.
 
JWL said:
If you check the pictures in my book you will see how I machined the FF bearings to accommodate the fillet.
Click to expand...
Did you make an allowance for the larger diameter journal? I wish I had some slightly used bearings laying around.
 
Pete said:
Check Jwl's book on how to machine the bearings.
21A rods can be made very reliable but it will take some work.
They need to be shot peened and then reconditioned.
This will still be cheaper than H beam rods.
Click to expand...
I have a set of reconditioned rods, but they have not been shot peened. This is going to be a light duty application. The owner just wants bragging rights I think. He originally wanted to go to 304, but I recommended he stay with a 3 5/16 bore and lie about the size. The reason I decided to go with the Ford rods is that I remembered reading JWL's book and he was using them in a 304" engine. As good a recommendation as you can have.
 
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I found an old set of rod bearings that are .108 thick. With a 2.220 rod ID, 2.000 rod journal and .216 (.108 x 2) bearing thickness, I'm left with a total clearance of .004 or .002 per side. With the proper radius I should be in fine shape. Thanks for the input.
 
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