Flexplate problems

[x-sinner]

My baby is a '72 Charger SE. Original 318 2bbl & 904 tranny. I replaced the flexplate a year ago, now it's tapping again. When I replaced it last time I heard a tapping but wasn't positive what it was because it had just been replaced by my best friend who I got the car from. This will be the 3rd flexplate in two years, anyone have any ideas what could be wrong? When I replaced the last one there was some play in the transmission mount so I replaced that. The torque converter is only about 4 years old. I really need to know what else to look for. I've been working on my own cars for quite a while now but I can't seem to figure this out. Please help.

[Dr. Righteous]

Originally Posted by x-sinner

My baby is a '72 Charger SE. Original 318 2bbl & 904 tranny. I replaced the flexplate a year ago, now it's tapping again. When I replaced it last time I heard a tapping but wasn't positive what it was because it had just been replaced by my best friend who I got the car from. This will be the 3rd flexplate in two years, anyone have any ideas what could be wrong? When I replaced the last one there was some play in the transmission mount so I replaced that. The torque converter is only about 4 years old. I really need to know what else to look for. I've been working on my own cars for quite a while now but I can't seem to figure this out. Please help.

Do yourself a favor and replace it with a B&M flexplate. The stock flexplate fine for a stock but they develop stress fractures over time and shatter.

[dwc43]

Also lock tight the bolts to make sure they are not backing out and causing it to break.

[John Kunkel]

Repeated flexplate cracking is the result of misalignment. Be sure the two engine block alignment dowels are present and extend far enough to properly index the trans case to the block.

The flexplate can be made more flexable by hacksawing through one of the spokes near the bolt holes at each of the four corners.

[Dr. Righteous]

Originally Posted by John Kunkel

Repeated flexplate cracking is the result of misalignment. Be sure the two engine block alignment dowels are present and extend far enough to properly index the trans case to the block.

True, Also I have seen a unbalance (no weights) converter shatter stock flexplates in matter of a couple hours running on a externally balanced engine. (400, 360) But the B&M lived through it.

[pishta]

line bored block will also make the crank centerline different than the trans centerline. Offset dowles can be had from Hamburgers as well as -1 undersized timing chains from RollMasters. I broke one too but it was becasue the bolts backed out. All four ears were cracked but had nowhere to go!

[x-sinner]

Thanks for all of the advice. I'm going to order a B&M flexplate tomorrow. I know that everything was lined up correctly. Right now I'm seriously thinking of putting in a big block. Thanks everyone.

[dave571]

Originally Posted by x-sinner

Thanks for all of the advice.... Right now I'm seriously thinking of putting in a big block. Thanks everyone.

NOW you're talking!