Flexplate bolts clearances

[Billys44s]

Hey guys.

I’ve been having an issue for the last few weeks on mounting my flexplate on my 92 chevy 1500, the bolt i had bought the flexplate bolt kit from oreillys and it had a 11/16 head and a 7/16 thread and the problem i had was that it was the right thread but the bolt head was hitting the crank and the only one thats will clear are the factory bolts but i cant find the a bolt thats close to factory head to save my life has anyone else had this issue before?

 

[GoToGuy]

What wrench head size should it be? Fine or coarse thread? 7/16 shaft diameter?

 

[GoToGuy]

So when installing , it threads in till it hits crank hub and stops turning? Smallblock are same thread and head, diff' length for flywheel or flexplate. Have not seen or heard of reduced diameter head for flex or flywheel instalation. Where are original to compare to?

 

[Billys44s]

Yes, Threads in until it hits the crank it doesn’t have even enough clearance to get a socket on it without hitting the crank i can barely fit a opened end wrench in there without hitting but the factory bolt i have will go in just fine which i have installed below but if i use the newer 11/16 head bolt it rubs

 

[tpass]

are the bolts you are buying specifically flex-plate bolts or are you buying something else, like flywheel bolts?(flywheel for a manual transmission)

I ordered new flexplate bolts from rockauto when i bought a new flex-plate and they were fine.

 

[evilunclegrimace]

Yes, Threads in until it hits the crank it doesn’t have even enough clearance to get a socket on it without hitting the crank i can barely fit a opened end wrench in there without hitting but the factory bolt i have will go in just fine which i have installed below but if i use the newer 11/16 head bolt it rubs

What is the matter with the bolts in the pic?

 

[Billys44s]

The bolts in the picture work fine i found the rest of the factory blots to put back in but i used them as reference of how much clearance i had, i think those are a 14mm head but the kits i got all came with a 11/16 head type of bolt and as far as im aware i bought the flexplate bolt kit but who knows if that was even the right kit because my oreillys has alot of people who dont know what there even doing half of the time

 

[TechNova]

try some punctuation, it will be easier to read.
If I am reading it right, the bolt heads were too close to the crank register to get a socket on.
If you have cheap sockets, the walls are thicker. Snap On, Mac, Matco etc have thinner walls and will fit.
You will run into some other examples of this. I have a set of 35+ yr old Craftsman (when they were well made) comb. wrenches that are to big for the RWD GM car U joint bolts. I have a MAC wrench with a thinner wall that fits.

 

[Schurkey]

ARP and Moroso sell bolts with a 3/4" wrenching surface, and they say they're not for use with 1-piece seal crankshafts (the bolt circle diameter is smaller on 1-piece seal cranks.)

Mr Gasket, Spectre, and others have flexplate bolts with 11/16 wrenching surface.

Looks like Pioneer, Hughes, and ATP have the bolts you need. The Summit description doesn't mention head size, but the photo looks like OEM-style bolts, and the description for ATP mentions 1-piece seal cranks. Verify length needed before ordering.
www.summitracing.com/parts/pio-859029/make/chevrolet

www.summitracing.com/parts/hup-hp8988/make/chevrolet

www.summitracing.com/parts/atp-zx-2036/make/chevrolet

CHEVROLET Pioneer Automotive 859029 Pioneer Flexplate Bolts | Summit Racing

Free Shipping - Pioneer Flexplate Bolts with qualifying orders of $109. Shop Flexplate Fasteners at Summit Racing.

www.summitracing.com

Hughes Performance HP8988 Hughes Performance Flexplate Bolts | Summit Racing

Free Shipping - Hughes Performance Flexplate Bolts with qualifying orders of $109. Shop Flexplate Fasteners at Summit Racing.

www.summitracing.com

CHEVROLET ATP Automotive ZX-2036 ATP Flexplate Bolts | Summit Racing

Free Shipping - ATP Flexplate Bolts with qualifying orders of $109. Shop Flexplate Fasteners at Summit Racing.

www.summitracing.com

 

[GoToGuy]

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?