Chevrolet Repair: Flex Plate, thrust bearings, having trouble finding information

Question
QUESTION: 1989 GMC S-15 pickup 2.5 engine changed from 5 speed manual transmision to 700R with after market lockup .The swap was made about 6 months ago ,It keeps breaking the flex plates around the bolt holes,I have installed three flex plates and am in the process of installing the fourth .I am having trouble finding information on the bushing for the crankshaft to convertor ,had a regular straight drive pilot bushing reamed out on the last install and it lasted 3 or 4 months ,checked with Chevrolet and ordered a bushing that is suppose to work in the 2.5 but had to have machine shop to turn it down to proper outside diameter with less than one thousand run out .This bushing is longer than the straight drive bushing .Hope you can give me something to check on I am almost ready to give up .The run out was not checked on the straight drive bushing .

ANSWER: Hey,

 Lets start fresh.

 When you pull the converter towards the flex plate are you able to bring them together or do you have to pull it in with the bolts.  The converter should come right up to the flex plate without any pressure at all. Before you start at all you should be checking deflection of the crank in the motor for worn thrust bearings.

Wayne Howie



---------- FOLLOW-UP ----------

QUESTION: Thanks, yes the convertor pulls aginst the flex plate snug as it should and there seems to be no thrust play in the bearings

Answer
snug.....  I assume you mean it can be pulled by hand against the converter and will turn a bit to line up the holes.  IF there is any pressure required to pull them together thats why it is cracking the flex plate.
 I would suggest looking into that pilot bushing issue.  If the converter is not centric it could be causing the vibrations that is taking out the flex plate.  


w