[j.adkins]

Hello, I'm new to the forum so thank you for having me.

What tolerance should there be on ring gear run out on a good SFI flexplate? I have called many different manufactures and gotten answers all over the board. From 0.005" to 0.050". Thanks in advance for any help received.

[RAIV55]

The stamped flexplates can be from pretty good (B&M, Hays and TCI) to pretty bad (Pioneer, CAT and other private labeled Chinese stuff). ATI, CSR, and JW are all excellent judging from my experiences. But to answer your question I'd consider .005 acceptable and much over .015 for radial runout too much.

BTW welcome to the forum. Hope you enjoy your time here.

[PONTIAC DUDE]

Have checked and run all our SFI and stock units on a lathe with a dial indicator.with up to .030 and no issues. As long as it's front to back and not end to end. then .015 is min.

[j.adkins]

Thanks for the info guys.

[bulitpruf]

I would be happy with .015 , 010 would be better. Starters with out nose supports will tolerate more, but they won't sound good. Starters with nose supports like a tighter number on the runout. The front to back should be corrected by the torque converter. The is more room for error here, .050 max.
Sfi should not be confused with quality. They spin them, check for cracks and test the tensile strength of the steel. There done.

[1FAST GTO]

My new "SFI" flexplate has some serious run out. I'm building a new engine and I was turning the crank slow, I hear this grinding noise from the starter area. GRRRRRRR
Mine has a CAT logo stamped into it!!!!!!! What a POS!

[j.adkins]

CAT says alot. Try PRW, B& M, TCI they are all good reliable pieces.