torque converter bolt clearance

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pwadventurer
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torque converter bolt clearance

Post by pwadventurer »

I have a 440 cast crank motor with a with a 727 auto trans. I installed a Hughes HUP24-25 HD converter along with a B and M 10237 flex plate to keep converter balanced. The bolt heads I used to secure converter are factory, .250" thick .500" long, and only give .008 to .011" clearance to engine block, ( crank thrust bearing play). Seems a little close!!

Is this acceptable or does someone make a shim to go between crank and flex plate to push converter rearward or thin headed bolts.

Rick

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MadMC63
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Re: torque converter bolt clearance

Post by MadMC63 »

I'm not sure of the correct answer but I do know the clearance has always been close. Loose bolts hit the block and it shaves the heads off or worse. When your first putting them in and rotating the assembly you have to get them in completely or you cant rotate to the next one.
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Re: torque converter bolt clearance

Post by marklein »

How far from the flex plate is the converter before bolting it up? If you push the converter back toward the trans with no bolts in it, measure that clearance. You can buy a shim for a standard flywheel that is .080" thick. That will give adequate clearance as long as you have good clearance between the flex plate and converter. They have always been relatively tight.

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Re: torque converter bolt clearance

Post by pwadventurer »

With the converter pushed back, the clearance is 2/32" (.0625"). I probably need that to protect pump. I was looking at the ARP bolts, but they didn't spec thickness. I guess the problem stems from the new converter that uses 7/16-20 bolts, same as crank to plate bolts, verses the 5/16" bolt that are with factory TC. Maybe grinding the block where the bolt heads circle around a few thousand" will be ok, or maybe just take a few off the bolt heads would be easier.

Rick

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Re: torque converter bolt clearance

Post by dodgeboykim »

I would polish a little block clearance.
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Re: torque converter bolt clearance

Post by pwadventurer »

OK so I went with shaving .050" off the head of bolt because the transmission is in place and the rear cam bearing forging would have to be trimmed as well. It sits flush with bell. I have .060" clearance and feel better now. The 7/16" bolt heads are 3/4", so there's still a lot of meat left.

Thanks to all for your help!! Now I am ready to fire it up.

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