Re: ...knock...knock! Cracked Flywheel
Re: ...knock...knock! Cracked Flywheel
No difference when using a bowtie block vs a stock block. The application differences in which flex plate will work will be whether you run a one piece or a two piece seal crank. The other difference will be whether you are running an internally or enternally balanced crank. This assumes a 168 tooth flexplate is use in all these cases. You can also get the several applications in a 153 tooth flexplate. The 153 tooth flex plate is smaller and lighter but does require a different starter. Also the 153 tooth plate will not work with the larger dia TC sizes. John
Thanks much John! 1-piece rear main seal, engine internally balanced to 8,500, 9/11 TC, has a 168 tooth GM flex plate balanced (holes machined into face in 4 places), smaller/lighter (less heat-soak prone) high-torque starter new/GM 6495N used on 95-05 GMC/Chev 4.3L trucks. So with that I believe the TCI SFI 399273 with 168 teeth, Internally Balanced, GM Trans, All Engine sizes is one to chose from for this engine setup?
Looking at where the cracks are in your broken flexplate pics, it seems as if the flexplate was doing a lot of forward and back movement at the edges vs the center. Possibly more than normal. Always make sure that there is the correct amount of gap between the TC and the trans pump when installing a different TC or flexplate. And always use the correct torque spec when tighting the crank bolts as well as the flex plate bolts. Uneven bolt torque around the pattern will cause areas to stress differently which will lead to early material fatigue
It is also a good thing to check your driveshaft length when lowering your vehicles with lowering blocks. Lowering with lowering blocks can cuase the rear alxe to set forward farther and may cause problems throughout the drivetrain.
John
Many great points, see if my memory will retain all that. I believe the measured distance to ensure TC is fully engaged onto the front pump should leave a space of about 1/16" to 1/8" from TC to Flywheel/Flexplate, that true with these trucks too? Torque TC bolts in sequence if you want to play it real safe so as to not bind the TC on the pump bushing, never had one that snug to not just move easily so might be overkill. If there is a vibration, unbolt and rotate TC one bolt hole and retest, did have this once and cured it with this trick on a 3.1L motor, though I don't like the concept of it happening in the first place.
I like the easy idea for others to test theirs by unbolting the TC from FP and lightly rap the FP to listen for a bit of a ring, or not :tdown:
Got a great compilation of data here, should be pretty helpful for future reference.
Jeff M
