[starnest]

Originally Posted by bsa_bob

The flex plate was tightened down ...off center. not completely flat[fitted]on the crank. before the tightening down sequence began.therefore it just broke out at the shown point hth No other reason to me.

This makes sense to me, I wouldn't have thought of it because when I assemble stuff I always check fitment before and during tightening of the bolts.

I would think that some of the other alignment issues discussed are possible, but not something I've experienced.

Since you had this failure of the flexplate, I would check to be sure your flexplate, trans, etc fits correctly before putting it back in the car.

[tjoy427]

Kevinmack.
Not a lot of people have extra money laying around. I replaced a dozen or more flywheels that looked exactly like the one you pulled out, and they were hammering so loud it would've fooled almost anyone into thinking the motor was blown. It would be prudent to pull the oil filter and cut it open. You don't need any fancy tools. Examine the filter media for the presence of any metal particles. If there is no metal, I would install a new filter and change the oil. Since the motor has been setting for a while, a pre-oiling is mandatory. The pro-form tool is not terribly expensive and does a decent job, but if you have any old distributors available, a nut welded on the top and spun with an air ratchet works very nicely, and they don't heat up. Of course if metal is obvious you will have to make a decision as to the best use of your hard-earned money. Stay away from the cheap crate motors as most are assembled with questionable parts and sometimes questionable labor. If you do choose to go that route, stay with a reputable company that will stand behind their product. Assuming there is no metal, remove the spark plugs and squirt a bit of motor oil into each cylinder. After you have achieved oil pressure, have a friend turn the motor over with a ratchet as you continue to pre-oil. Just a couple revolutions is adequate... you don't want to damage the camshaft. The only other thing that you may want to consider, while the motor is out, is a new set of valve seals. Easy to do with the motor on the stand and very inexpensive.

[farna]

I just remembered something... part of the problem may be the quality of the flexplate IF it's a recent (in the past 10 years) purchase. My brother works on a few of the local farmers and friends vehicles. He recently put a reman engine in a 2002 or so Chevy truck and bought a new flexplate. The flexplate cracked in the center after just a couple months (and over 2500 miles... truck used by a siding company). He'd bought a NAPA "made in China" flexplate. The replacement was purchased from GM, but low and behold it was "made in China" too! Probably the same flexplate, just reboxed by GM and cost $20 more. We figure the one that cracked probably wasn't properly heat treated (hardened). That will happen occasionally even with US manfuactured items -- everybody makes a lemon now and then, though it does seem to occur a little more often for some...