Crank Spun Out - 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> Hotrodding Basics
User Name
Password
lost password?   |   register now

Reply
 
LinkBack Thread Tools
  #1 (permalink)  
Old 03-09-2012, 07:43 AM
Registered User
 
Join Date: Mar 2012
Posts: 139
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Crank Spun Out

I have another 350 that a guy gave to me and he said the crank is spun out. What does this mean? I can turn the engine over and the crank is all in one peice.

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 03-09-2012, 08:41 AM
68NovaSS's Avatar
Hotrodders.com Moderator
 
Last wiki edit: Working with chromed bolts
Last journal entry: New to me T-Bucket
Last photo:
Join Date: Sep 2002
Location: Nine Mile Falls, Washington
Posts: 5,215
Wiki Edits: 9

Thanks: 99
Thanked 130 Times in 121 Posts
Being local jargon, hard telling. I'd think it spun a main bearing. Are any chewed up?
__________________
Boost adds dignity to what would otherwise be a vulgar brawl...

Midnight Sun Street Rod Association
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 03-09-2012, 08:50 AM
Registered User
 
Join Date: Mar 2012
Posts: 139
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
I guess Ill unbolt the crank and if it looks good then ill use it and get new bearings
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 03-09-2012, 09:13 AM
F-BIRD'88's Avatar
Yada Yada Yada
 
Last photo:
Join Date: Oct 2005
Location: Ontario, Canada
Posts: 9,524
Wiki Edits: 0

Thanks: 2
Thanked 330 Times in 327 Posts
Your local engine rebuilder shop can regrind that crank.
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 03-09-2012, 09:25 AM
Registered User
 
Join Date: Mar 2012
Posts: 139
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
I guess what I would need to know is how would I tell if the crank is bad? I took it out and it looks fine. Its not craked or anything.
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 03-09-2012, 09:32 AM
F-BIRD'88's Avatar
Yada Yada Yada
 
Last photo:
Join Date: Oct 2005
Location: Ontario, Canada
Posts: 9,524
Wiki Edits: 0

Thanks: 2
Thanked 330 Times in 327 Posts
Quote:
Originally Posted by allansmith859
I guess what I would need to know is how would I tell if the crank is bad? I took it out and it looks fine. Its not craked or anything.
I trust you did not hit your head when you fell off the turnip truck

Take the crank and connecting rods and the block to your local engine rebuilder.
He will inspect and advie and estimate machine work cost.

The block will need to be bored and honed. The main saddles need to be checked and may need align honing. May need decking.

A stroker crank will need block clearanceing. May need connecting rod to cam lobe clearancing.

The stock 350 connecting rods will need to be resized.
The crank will need to be reground 10-10 or 20-20.

This is obviously your first build.
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 03-09-2012, 09:45 AM
Registered User
 
Join Date: Mar 2012
Posts: 139
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
I have took alot of engines apart and put back together but yes this is my first build where I am looking for a power engine. Im looking for advise not for someone to pretty much say Im an idiot.
Reply With Quote Quick reply to this message
  #8 (permalink)  
Old 03-09-2012, 09:56 AM
68NovaSS's Avatar
Hotrodders.com Moderator
 
Last wiki edit: Working with chromed bolts
Last journal entry: New to me T-Bucket
Last photo:
Join Date: Sep 2002
Location: Nine Mile Falls, Washington
Posts: 5,215
Wiki Edits: 9

Thanks: 99
Thanked 130 Times in 121 Posts
Quote:
Originally Posted by allansmith859
I have took alot of engines apart and put back together but yes this is my first build where I am looking for a power engine. Im looking for advise not for someone to pretty much say Im an idiot.
Nobody is calling you an idiot, but when you post that a crank might have a spun bearing, then plan to simply put new bearings on it...someone has to wake you up, you should at least know what a spun bearing's journal would look like. All but one shiny and smooth, one scored badly...what's wrong with that picture? If there's no scoring, ask the guy what he means.
__________________
Boost adds dignity to what would otherwise be a vulgar brawl...

Midnight Sun Street Rod Association
Reply With Quote Quick reply to this message
  #9 (permalink)  
Old 03-09-2012, 10:04 AM
Registered User
 
Join Date: Mar 2012
Posts: 139
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Thats was the plan. To replace the bearings and use the crank
Reply With Quote Quick reply to this message
  #10 (permalink)  
Old 03-09-2012, 01:52 PM
willys36@aol.com's Avatar
Hotrodders.com Moderator
 
Last wiki edit: How to rebuild a Rochester Quadrajet 4MV carbureto...
Last journal entry: How to change auto shift timing on 200R4
Last photo:
Join Date: May 2002
Location: Bakersfield
Posts: 8,384
Wiki Edits: 21

Thanks: 1
Thanked 4 Times in 4 Posts
Welp, sounds like that there krank is spun out fer sure, by gum!! Back in '42 I knew a feller . . . . .
Reply With Quote Quick reply to this message
  #11 (permalink)  
Old 03-09-2012, 03:55 PM
Blazin72's Avatar
You got a leaky spark tube...
 
Last wiki edit: Rearend removal
Last journal entry: General Lee
Last photo:
Join Date: Jul 2005
Location: Union, WA
Age: 32
Posts: 2,868
Wiki Edits: 19

Thanks: 0
Thanked 2 Times in 2 Posts
Quote:
Originally Posted by allansmith859
Thats was the plan. To replace the bearings and use the crank
What they are telling you to do is take that crank to a machine shop. Unless you have an outside micrometer you will not be able to tell if the main journals are in spec. You won't know if it's cracked or not by looking at it. It would need to be magnafluxed if there was any suspiscion of cracks. The same goes for the block. Unless you have precision measuring tools you won't know if the cylinders or the mains are in spec. You could fairly easily check the deck flatness but it isn't as easy to determine the deck height. If you have the engine disassembled then it needs to go to the machine shop and let them check everything.

The same applies to the heads if you plan on reusing them.

If you put it back together with new bearings and rings and without having the necessary machine work done don't complain because you have low oil pressure, a knocking noise or it's burning oil.

What did the bearings look like when you pulled them out?
Reply With Quote Quick reply to this message
  #12 (permalink)  
Old 03-09-2012, 04:06 PM
starnest's Avatar
elkyholic
 

Last journal entry: Center Link Installed
Last photo:
Join Date: Apr 2007
Location: Virginia Beach
Age: 60
Posts: 327
Wiki Edits: 0

Thanks: 4
Thanked 5 Times in 4 Posts
I've never heard of "crank is spun out".

I have heard of a spun bearing, generally this means the bearing has spun in the cap and saddle (either a rod or main bearing). This happens when the friction of the bearing to the crank journal exceeds the holding force of the bearing's back side to the cap and saddle (and/or the holding tabs have sheared).

In general you can tell more by inspection of the bearings than you can the crank journals. Any time the batting on the bearing surface is damaged (front or back) you need to take the block, crank, rods w/pistons to a machinist to have them checked and/or repaired. (In other words, what Fbird said).

There are instances when everything looks okay and you put it all together and find out soon after that the crank (and/or the other parts) needed to be serviced.

Now, everybody play nice.
Things aren't always what they seem.
You can't know what you don't know.
And all insults are provided with good intent, Really!
Reply With Quote Quick reply to this message

Recent Hotrodding Basics 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
Spun bearing on 406, but why? Pre-Tuner Engine 48 05-25-2011 02:26 PM
spun rod bearing cause seandiddy Engine 2 09-11-2010 02:11 PM
spun rod bearing astrops Engine 1 04-20-2004 09:27 AM
402BB Spun Bearing Rod/Crank? bbc45473 Engine 3 02-29-2004 05:41 PM
Spun a bearing-350..Why? Ted655 Engine 17 10-17-2002 11:56 AM


All times are GMT -6. The time now is 10:18 AM.


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.