Check crank with plastic guage help!!!! - Hot Rod Forum : Hotrodders Bulletin Board
Hotrodders.com -- Hot Rod Forum



Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Engine
User Name
Password
lost password?   |   register now

Reply
 
LinkBack Thread Tools
  #1 (permalink)  
Old 07-22-2007, 05:19 PM
Registered User
 
Last photo:
Join Date: Mar 2006
Location: Ohio
Posts: 232
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Check crank with plastic guage help!!!!

Folks, I can't find information on this anywhere. I bought plastic guage strips to check my crankshaft bearing mains on my 350 small block chevy but I can't find instructions on how to use it and what I am looking for. Does anyone out there have the information I need? I am installing a new 400 crank in my freah 350 block and want to make sure things are right!

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 07-22-2007, 05:35 PM
Registered User
 
Join Date: Jun 2007
Location: west. Colo
Age: 57
Posts: 26
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
you need to start with a dry and clean crank and mains( caps and block). with NO lube or anything else. lay a small strip of plastigage on the journal going across the radii of the journal. torque the cap to specs. and using the sleeve the plastigage came in, reading the inch side match up the thickness of the flattened plasigage to the gauge on the sleeve. that is the oil clearance that the bearing has. now do the same to all the rod bearings also. after you have done that, clean the bearings and journals off with brake clean or equiv.have fun
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 07-22-2007, 06:17 PM
King of my Man-cave.
 
Last photo:
Join Date: Nov 2003
Location: Michigan
Age: 55
Posts: 2,899
Wiki Edits: 0

Thanks: 3
Thanked 15 Times in 12 Posts
Quote:
Originally Posted by 31choptop
you need to start with a dry and clean crank and mains( caps and block). with NO lube or anything else. lay a small strip of plastigage on the journal going across the radii of the journal. torque the cap to specs. and using the sleeve the plastigage came in, reading the inch side match up the thickness of the flattened plasigage to the gauge on the sleeve. that is the oil clearance that the bearing has. now do the same to all the rod bearings also. after you have done that, clean the bearings and journals off with brake clean or equiv.have fun
Actually, plastigauge was designed to be used on cranks that are in service, so they are supposed to be lubricated. That's why the directions say to wipe off the oil where the plastigauge is to be applied.

tom

Last edited by machine shop tom; 07-22-2007 at 07:10 PM. Reason: atroshus spelin
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 07-22-2007, 07:07 PM
Member
 

Last journal entry: frame build
Last photo:
Join Date: Apr 2005
Location: sioux falls, sd
Age: 68
Posts: 601
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Don't just rip off a piece of it. That will distort the reading because stretching it makes the diameter smaller. Cut it with a sharp knife or razor blade or scissors. use a piece as long as the bearing is wide. Don't remove it from whatever it sticks to before measuring.
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 07-23-2007, 04:54 PM
Registered User
 
Last photo:
Join Date: Mar 2006
Location: Ohio
Posts: 232
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Thanks

I knew you folks would come through. Does anyone know what measurements I am looking for? The plastic guage cover has a measurement range on it. How do I find out what the min and max is for my crank?
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 07-23-2007, 05:36 PM
383silverado's Avatar
Registered User
 
Last photo:
Join Date: May 2007
Location: tucson az
Age: 35
Posts: 389
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by camaro freak
Folks, I can't find information on this anywhere. I bought plastic guage strips to check my crankshaft bearing mains on my 350 small block chevy but I can't find instructions on how to use it and what I am looking for. Does anyone out there have the information I need? I am installing a new 400 crank in my freah 350 block and want to make sure things are right!
are you a building a 383 or 377 ?

4.030 bore 3.75 stroke= 383
4.0 bore 3.75 stroke=376.99

i think the mains have to be turned down in order to use the 400 crank in a 350 block.

http://www.chevymania.com/tech/383.htm
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 07-23-2007, 07:50 PM
techinspector1's Avatar
Senior Curmudgeon
 
Last wiki edit: DynoSim combinations Last photo:
Join Date: Oct 2005
Location: Hemet, California, USA
Age: 72
Posts: 12,947
Wiki Edits: 326

Thanks: 760
Thanked 1,013 Times in 849 Posts
I think what you're looking for is the suggested bearing clearances. For a street motor, 0.0020" (two thousandths) on the rods and #1 through #4 mains with 0.0030" (three thousandths) on the #5 main. A little less will be ok, a little more will make the crank and rods rattle a little with thin oil and will contribute to low oil pressure. On a high-perf motor with a premium oiling system, you would want to open the clearances up another 0.0005" (half a thousandth), also called (five tenths) or (five ten-thousandths).

Side clearance for each rod pair on the big end, 0.014" to 0.020" (fourteen thousandths to twenty thousandths).

Crankshaft end play, 0.003" to 0.008" (three thousandths to eight thousandths).

Each builder has his favorite clearances and we'll probably hear from some others on this subject.
Reply With Quote Quick reply to this message
  #8 (permalink)  
Old 07-24-2007, 09:11 AM
Registered User
 
Last photo:
Join Date: Mar 2006
Location: Ohio
Posts: 232
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
techinspector1

techinspector1, thank you that was what I was looking for! Great help all!
Reply With Quote Quick reply to this message

Recent Engine posts with photos

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

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


Similar Threads
Thread Thread Starter Forum Replies Last Post
bought a stroker crank... or did i??? 280zxWith305 Engine 6 02-18-2005 06:40 PM
383 Crank Hits Pistons 68NovaSS Engine 17 08-09-2004 02:33 AM
crank problem Zartan Engine 17 05-11-2004 02:39 PM
400 Crank sb72elcamino350 Engine 3 04-15-2004 02:42 PM
crank / block combo's toddtheodd Engine 5 03-17-2004 10:38 PM


All times are GMT -6. The time now is 02:19 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.