Lolita's new 388 incher is going together. The crank thrust bearing clearance is only about 2.5-3 thousandths of an inch instead of the 4-8 it should be. Any ideas from you other engine builders ? I've never had this happen before..?
Nothing some 600 grit on a piece of glass or a surface plate couldn't solve... that would work out to about .0005-.001" per side. I'd recommend checking your work with an outside mic to prevent uneveness. Personally, I'd be inclined to just Scotchbrite the thrusts and run it as is....is this a manual trans car?
Are you sure you're getting an accurate reading from your dial indicator....? I usually use my .0001" universal (.015" per revolution) indicating on the crank hub at the rear of the engine and use a screwdriver to move the crank... if using a plunger-style indicator, be sure the plunger is parallel to the crank CL...
Thanks, guys. Yeah, Pat, dial indicator at the crank snout, parallel to the crank axis. I'm tearing it back down today to do some more stuff I thought of ( radius oil drainback holes, etc.) and I'll address the crank thrust clearance while I'm at it. C4, by the way..
Remembered something when I woke up this morning...amazing huh? *G*
Did you set the thrust by bonking the crank back and forth with a dead-blow mallet? Sometimes that helps get a more accurate reading...
Also, while you're doing your checking, you could bolt the C4 bellhousing on and check for runout of the crank to the pump register. I usually also dummy up the trans with at least the front pump and check the converter for proper clearance to the flexplate. A lot easier to fix now then when everything is together.
Yeah, I've always used the mallet method. The screwdriver method asserts an
off-axis thrust, and I don't think it gives accurate results.
The cool thing about the other checks is that I bought a spare trans a few weeks ago to build while the car is still running with the old engine. The other checks become easier yet under those circumstances !