[RAIV55]

Originally Posted by blown 68

the face of the thrust bearing? my engine is being gone through right now, and i want to know how you can check the trueness/squareness of the number 4 main cap.

i had a very irregular wear pattern on my forward thrust bearing that gave out on the dyno,(no tranny load..) it looks as if the cap is leaning torwards the front a bit, causing wear on the bottom half of the shell only. there is next to no contact on the upper/block forward half, but the lower/cap half is worn down over .002 or more. the endplay was at .008 at the rebuild, and was over .012 at teardown. the backside of the lower/cap half has almost no contact either......

anyway, he is going over the engine now, but i want to know how others check the squareness, so i have some comparison of knowledge when we talk about it. also, if the cap is leaning, do you cut it and reline hone? i am not well versed in machining, so thanks for the patience......

any info or help on this issue would be greatly appreciated, i really want this to be the last time i deal with this engine not cooperating.....

thanks folks!!!!


davey

Davey, there are several ways to check it out. The fastest way is to measure endplay with the cap off and then install the cap with beaing. After centering the thrust recheck the endplay. If it changes the thrust surfaces aren't aligned. Usually you can get by if the difference is mimimal (.0015 or less). Prusian blue on the thrust bearing will reveal the high spots.

There are many times machinists overlook this when line boring/honing mains. Often when the sides of the thrust cap is ground they aren't perpendicular with the parting line hence the cap is crooked on the block. If that the case you need to determine how far out the runout is on the thrust flange and angle cut the cap to correct. The block will have to be realign honed.

If you need further information on set up and checking proceedures, I'd be glad to pass on some info.