Flexplate bolts clearances

[Schurkey]

Why does that flexplate have a shadow of being mounted against a hub on the side we can see?

Valid concern, and one that I completely missed. Is the flywheel installed backwards? Which direction do the torque converter bolt pads face?

So if thats the crank hub your mounting to with that flexplate and those are original bolts, don't you think the problem is your sockets ? I know some of my half drive sockets have heavier walls than my three eighth drive sockets in same bolt size. Maybe?

No, the photo shows the original, GM bolts. The problem is with the aftermarket bolts he got at O'Reillys, that have a huger head/wrenching surface intended for two-piece rear main seal cranks. Those cranks have a bigger bolt circle, which puts the bolts farther from the crankshaft register in the middle of the flexplate--more room for bigger bolt heads.

 

[Billys44s]

Why does that flexplate have a shadow of being mounted against a hub on the side we can see? So if thats the crank hub your mounting to with that flexplate and those are original bolts, don't you think the problem is your sockets ? I know some of my half drive sockets have heavier walls than my three eighth drive sockets in same bolt size. Maybe?

My factory bolts worked fine it was just the aftermarket bolts i had a problem with, it didn’t matter if i use a cheapy socket or a name brand it stick hit with the 11/16 head even with a open wrench the head of the bolt didnt clear but i ended up reusing all the factory bolts and put it back together and its been so far so good

 

[GoToGuy]

Did the supplier provide wrong bolts? Did they provide Flywheel rather than Flexplate bolts? Some partspersons and or parts suppliers don't do the " required due diligence " when researching make model fit part application. I often have the " what were they thinking? " moments during repairs.

 

[Billys44s]

Did the supplier provide wrong bolts? Did they provide Flywheel rather than Flexplate bolts? Some partspersons and or parts suppliers don't do the " required due diligence " when researching make model fit part application. I often have the " what were they thinking? " moments during repairs.

There weren’t the wrong bolts they sold me i tried both flexplate and flywheel bolts and they were still rubbing the crank, ive change a few flexplates and flywheel in the past and i never ran into this problem besides on this truck, my only theory is its was built in canada and ship to the us and maybe there motor where built a little different but im not sure if thats it, i have a truck that was 1 year older i did a trans swap in and i used the same bolts from oreillys and they worked fine i even swapped that one from auto to stick and still never had a flywheel bolt isssue

 

[Schurkey]

The problem traces back to GM's decision to reduce the bolt circle on the Small-Block (and 90-degree V-6) engines when they transitioned to one-piece rear main seals in '86.

Those bolts fit the two-piece rear main cranks just fine. They're tight on the newer cranks because the bolt circle is a half-inch smaller, moving each bolt 1/4" closer to the crank hub.

GM did NOT reduce the bolt circle on the big-block engines when they went to one-piece seals.

 

[Billys44s]

The problem traces back to GM's decision to reduce the bolt circle on the Small-Block (and 90-degree V-6) engines when they transitioned to one-piece rear main seals in '86.

Those bolts fit the two-piece rear main cranks just fine. They're tight on the newer cranks because the bolt circle is a half-inch smaller, moving each bolt 1/4" closer to the crank hub.

GM did NOT reduce the bolt circle on the big-block engines when they went to one-piece seals.

I actually didnt know that, id figure if i ran it like that it would rub and id be back at square one,i ended up using my originals because they seemed less of a headache for me to deal with but thats good to know for the next time i have to do one of these