hey guys my friend is swapping motors in his camaro, and i saw something i'm not sure is supposed to be he has an 88 camaro and he's putting in a pre-86 motor meaning the 2 piece seal and the crank flange does not look straight when looked at from the side, could it be bent? also anyone know what size the flexplate bolts are for the 2 piece seal flexplate? the 1 piece ones are too long

 

doubt it's bend. put an indicator on the flange and check the run out. if you know the bolts are too long measure the part of the bolt sticking out and buy new bolts that length. i'd guess all the bolts are the same length and you have some other problem.

 

The flange should be absoltuely flat and straight, perpendicular to the crank axis. I've never seen a car crank bent in such a way that the flange could be significantly off, but the crank could still turn.

If the bolts you have are too long, then most likely they're flywheel bolts, not flex plate bolts. They're exactly the same except different. But they're special bolts; just go to your local speed shop and get some flex plate bolts in Mr Gasket or ARP or something, they're pretty cheap and not worth risking your legs or your life over.

The 2-piece cranks (except 400) are internally balanced. That is, they contain all the counterweight that the crank requires, on the crankshaft. The 1-piece ones are too, except that the last little bit that needs to be on the very rear of the crank to help counterweight the rearmost rod journal, can't be there because the crank flange has to be perfectly round; so there's a small weight welded to the flex plate or cast into the flywheel, to duplicate the portion of the counterweighting that was created on the flange of the 2-piece motors. It's very small though, and the motor is still classified as "internally balanced". But a 2-piece flex plate (except 400, and 454) is completely neutral balanced and can go on the crank in any orientation.

Here's a pic of a 2-piece flange; this one is a 400 though, so it has the dowel pin to positively orient the flywheel to the crank.

 

ok this one does not look straight with the rear of the block and i dont trust this motor at all supposedly its rebuilt, it has new pistons but i dont trust it.