Kiggly flexplate crank bolt selection

[doesitonall4rs]

Im making this post in hopes to save somebody the headache in the future for Hardware selection for the kiggly flexplate to crank bolts.


Im in the process of swapping from a 5 speed AWD to auto. Been doing a lot of digging and a lot of different information out there. Hoping to clear it up for the next guy so they don't have to waste time modifying hardened hardware.

Some of the information I found out there suggests that modifying the 5 speed flywheel bolts in order to have enough "threads" on the bolts due to the thicker flexplate is the best practice. Before I started wasting my time hacking bolts I figured I'll pick up the factory auto bolts and see how big of a difference there really is.

Cliffs: It appears that the reach of a stock automatic bolt going threw the flexplate with the flexplate washer is exactly the same amount as a 5 speed bolt going threw the flywheel. (I counted 9 threads). Read on for the pictures if you don't believe me.



First notable difference the bolt heads on the auto crank bolts are smaller. (Auto bolt on the left, 5 speed bolt on the right)

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Next is a pic is showing how much longer the 5 speed bolt is (this is going threw the flexplate washer and kiggly flexplate). 13 threads sticking threw for the 5 speed bolt compared to 9 for the auto bolt. Also the 5 speed bolt is entirely too long and needs to be shortened so all said and done you may have 1-2 extra threads inside the crank if you spend time modifying the 5 speed bolts .

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Here is how much reach a 5speed bolt has into the crank with an OEM flywheel. (who woulda thunk it, 9 threads as well)

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Here is the part number of the the Auto crank bolts, Paid $12.30 for all 6 at extremepsi.

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Good luck and happy moding

 

[twicks69]

That is a 17.0mm flywheel bolt for reference. They are OEM 6-bolt automatic flexplate bolts.

 

[donniekak]

When I ran an auto with 2 flex plates I had to use cut manual bolts into the crank, and cut down gm flex plate bolts into the converter, both with loctite, or I had backing out issues. I also ruined a crank trying to torque a stock auto bolt with two flex plates, and a spacer plate.

On one occasion a backed out converter bolt almost ripped my oil pan off.

 

[doesitonall4rs]

Just torqued the auto bolts the other night to 105 ft/lbs on the kiggly plate and spacer washer (with loctite). Nothing out of the ordinary yet.

Ill report more once the car is running.

 

[Kapok6]

I just installed the kiggly plate this weekend, using 17mm crank bolts, the flexplate, and one washer. greased the heads, loctite on the threads, and torqued to 115ft lbs.

 

[Kapok6]

Also, I found that the 16mm long converter bolts were too long. I cut the bolts down to 12-14mm and used a lock washer. That seemed to work.