weird problem not chevy - Team Camaro Tech
Troubleshooting Diagnosing problems done here.

LinkBack Thread Tools Display Modes
post #1 of 6 (permalink) Old Aug 20th, 02, 10:52 AM Thread Starter
Gold Lifetime Member
Join Date: Mar 2002
Location: New Jersey
Posts: 1,456
ok, i know this isnt about a chevy but we need some help, my friend has a 68 amc amx with a 390 ci engine,when he got the car the engine ran but had a rod knock, so we took the engine out, we had the crank cut .010 on the mains and .020 on the rods, had the rods resized with new bolts and the block was bored .040 over.ok bare with me! on the amc engine the thrust bearing is on the center cap or the #3 cap, when we torqe that cap down to 100 ft lb the crank will not turn. loosen up on the cap and it spins fine. checked the bearings to make sure they were .010 and they are,it only gets tight when we torqe the thrust bearing all others are fine? so we plasti gauged it, all bearings were ok around .0015 the thrust one was .001 or smaller? our next thing was to have the block line bored, we figured that would solve our problem, but it didn't same thing happened. we bought the crank back to the machine shop and they said it was fine and measured out fine. anyone ever have a problem like this, what could be the problem is it posible that the bearing could be defective. oh and its not tight on the thrust part either? help.

jcdubs is offline  
Sponsored Links
post #2 of 6 (permalink) Old Aug 20th, 02, 11:03 AM
Senior Tech
ZZ_430's Avatar
Join Date: May 2001
Location: Houston, Texas
Posts: 4,491
Sounds like the crank is bent.

Don~ ZZ430DropTop
70 RS
67 RS/SS Convertible, 70 RS
ZZ_430 is offline  
post #3 of 6 (permalink) Old Aug 20th, 02, 02:47 PM
Senior Tech
Join Date: Feb 2002
Location: Williamstown,PA
Posts: 500
Could be a side clearance issue on the thrust bearing.

'69 RS Camaro
355 5-speed 4.11
1 2RUN is offline  
post #4 of 6 (permalink) Old Aug 20th, 02, 04:43 PM
David Pozzi
davidpozzi's Avatar
Join Date: Nov 1999
Location: Central California, USA
Posts: 10,074
Check the edges of the bearings. If the crank was turned and the crank throw radius is a larger radius than before, the edges of the bearings will have to be narrowed to fit.

Check my web page for First Gen Camaro suspension info:
David's Motorsports page
First Gen Suspension Page
67 RS 327 original owner. 69 Camaro Vintage Racer, 65 Lola T-70 Chev SB Can-Am Vintage Racer
davidpozzi is offline  
post #5 of 6 (permalink) Old Aug 21st, 02, 12:54 AM
Super Moderator
Bess-68's rule
Everett#2390's Avatar
Join Date: Sep 2000
Location: Va Beach VA
Posts: 31,626
Before putting block assy back together, be sure to use the long skinny rifle barrel brushes to clean out the oil passages, with soap and hot water, to remove metal shavings and other stuff. It would be a pity to assemble and crank it up only to have the bearings go bad due to trash being pumped through them. Where else is the stuff going to go?

Another technique you might do is to clean all the journals & bearings. Coat the journals with Machinist's Bluing. Make sure there is no foreign mat'l between the bearing and its saddle in the block. Place the crank into position in the block. Tighten the bolts. Remove the crank. Check for bluing on the bearing shells, this is where its touching (binding). As David suggested, it may be the journal radii too big. Clean the machinist's bluing from parts using alcohol and a lint-free rag.

Put crank on V-blocks and dial indicator on center bearing journal and rotate crank to check for run-out. Should be no run-out.

A '68 AMX, nice ride. Been looking for a '69 to fix.

Everett 68/350/PG/11.90/115mph
Everett#2390 is offline  
post #6 of 6 (permalink) Old Aug 21st, 02, 10:50 AM Thread Starter
Gold Lifetime Member
Join Date: Mar 2002
Location: New Jersey
Posts: 1,456
thanks guys, i'm gonna go over this with a fine tooth comb and try to figure it out, i told him to stick with chevy lol. also we put the crank in another 390 block and it would spin, but kind of tight for my liking, i think dave might be on to something i'm gonna check the edges on those bearings thanx.

jcdubs is offline  
Sponsored Links

Quick Reply

Register Now

In order to be able to post messages on the Team Camaro Tech forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.


Confirm Password:
Email Address
Please enter a valid email address.
NOTE we receive a lot of registrations with bad email addresses. IF you do not receive your confirmation email you will not be able to post. contact support and we will try and help.
Be sure you enter a valid email address and check your spam folder as well.

Email Address:


Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

For the best viewing experience please update your browser to Google Chrome