Crank main thrust bearing question
 

Whats the trick with checking thrust bearing fore and aft clearance. Something like tapping the crank fwd with light hammer or something.....?

You put a dial indicator on the end of the crankshaft, balancer or flywheel, then gently pry the crankshaft forward then back and measure the movement.

Ck it first without the rear main cap in place. Then ck again after installing the cap. If it gives same measurement it will verify that the cap/block align and that both halves are taking the thrust load.

JIM

is this an assembled, installed engine or are you building it?

Careful manipulation of a long screwdriver should work vice a hammer.

383 rebuild with new bearings. Havent done this for 5 years so need to study up on all the tricks again. Thanks guys. :thumbs:

While I'm at it do you guys know the normal allowance on the clearance?

Agree with above advice! Was your block "baked", if so, needs to be line honed (any competent machine shop knows this, things can and do shift from the high heat)? Besides checking each journal to verify radius, your crank needs to be placed in a cradle and rotated with a dial indicator on each main journal to check for run out (bent crank) might not look bent, but let's say it has 3 or 4 thousands run out, not good! Yes, you definitely should be using assembly lube, you definitely don't want any between the back side of your bearings and the block or caps. Verify again caps are in proper order and direction! When you do figure what is "pinching" your crankshaft, I would get new bearings, I would not use those again. Also, you need to take that same dial indicator and check your thrust bearing clearance (crankshaft movement front to back), this is very important, a little too loose or a little too tight and you'll be pulling your engine back out in no time! I would take the block, caps, bolts and crankshaft along with new bearings back to your machine shop, figure out the issue, remedy that and bolt it together/set it up right there with their guidance, if they're stand up guys and you've paid them for all of the machine work, they should have no problem helping you get this part right, wouldn't take long at all!!!! Good luck 👍

Damn related threads, the above post was meant for the 383 bearing problem post in the C4 performance section! How can you "copy" everything you've typed and get it on the right thread!? I've done this a number of times, don't know how it scrolls past and I reply to an old thread, very frustrating!🤬

This should help you out.

https://www.enginelabs.com/engine-te...shaft-endplay/

Left click on the text and highlight it all in blue, then move your mouse curser within the blue area and right click....a menu will pop up and hit copy. To put the text where you want it, click your mouse curser where you want the text to start, then right click for the menu, and click paste.

Hope that helps

Thank you👍

:iagree: Those 'related threads' are a royal PITA. I hope whoever hosts this forum will finally realize their mistake and eliminate them.

I think there is a user defined setting where you can turn off "related threads". :)

Really?!! Please tell me how! Those things are making me insane.

Open Top right drop down menu (next to your user name)
Select "User Control Panel"
Look for "Edit Options" on the menu on the left
scroll down to "Thread Display Options"
Select "Disable Related Threads"

Hope that works. :)

It did. :rock:

Thank you, Thank You, Thank You!! :hurray:

Those instructions should be in a sticky! I know I'm not the only one.