Small block rebuild - Hot Rod Forum : Hotrodders Bulletin Board
Hotrodders.com -- Hot Rod Forum



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

Reply
 
LinkBack Thread Tools
  #1 (permalink)  
Old 06-16-2014, 01:22 AM
Registered User
 
Join Date: Jun 2014
Posts: 2
Wiki Edits: 0

Thanks: 3
Thanked 0 Times in 0 Posts
Small block rebuild

Rebuilding a 327 out of a 1968 Chevy Camaro. The engine was dismantled without the pistons being numbered so it is unsure what cylinders they should be put back into. The blocked was honed the pistons were cleaned and have new rings. Can the pistons be put back in at random? If not what are the potential problems that can occur?

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 06-16-2014, 10:28 AM
1971BB427's Avatar
Registered User
 

Last journal entry: Latest changes
Join Date: Dec 2010
Location: Portland
Posts: 2,902
Wiki Edits: 0

Thanks: 132
Thanked 892 Times in 643 Posts
Not the best scenario, but it can be fixed. You'll need to be sure that whoever does the engine machine work will do a good job of sizing and balancing the rotating assembly. If it's all carefully sized and balanced, the location wont be a factor afterwards. I'd assume you'll also have the block bored and new pistons, as just honing and dropping them in at random locations may be your downfall.
Reply With Quote Quick reply to this message
The Following User Says Thank You to 1971BB427 For This Useful Post:
mmurray24 (06-16-2014)
  #3 (permalink)  
Old 06-16-2014, 11:11 AM
Registered User
 
Join Date: Apr 2007
Posts: 12,602
Wiki Edits: 0

Thanks: 220
Thanked 1,200 Times in 951 Posts
Quote:
Originally Posted by mmurray24 View Post
Rebuilding a 327 out of a 1968 Chevy Camaro. The engine was dismantled without the pistons being numbered so it is unsure what cylinders they should be put back into. The blocked was honed the pistons were cleaned and have new rings. Can the pistons be put back in at random? If not what are the potential problems that can occur?
Problem is more with rods than pistons though that isn't clean by any means but incorrectly placed rods will make a disaster on the crankshaft. There are several conditions that need to be satisfied at the same time.

1) Looking at the big end of the rods you will see a chamfer where the cheek and bearing bore meet, there will be a larger chamfer on one side than the other. This always faces to the outside of the rod journal so that the pair of rods has the small chamfers facing each other when assembled on their journal. Done backwards the rod will bind on the journal ends and with the crank become damaged.

2) The piston should have a notch or arrow that indicates facing forward toward the waterpump end of the block. This needs also to be correct to and with the rod installed correctly with the chamfers as outlined previously. The notch or arrow indicates the direction needed for the wrist pin offset. The pin is not centered in the piston but off set to keep the thrust side skirt pushed against the cylinder wall. If the piston is inserted backwards the offset will cause the piston skirt to snap over from the non thrust side to the thrust side with every revolution of the crank. It doesn't take much of this before skirts break off the pistons.

3) Not out of the woods yet. The rod caps are unique to each rod hopefully these aren't mixed up. For installation of the cap to the shank there is a relief for the tang of the bearing inset to mount into, not only must the tangs be in this relief but when cap is installed on the rod shank they must face each other. Then as the piston arrow and rod chamfer are correct so the insert tang relief needs to face out of the block toward you looking from the pan rail side.

So you've got three major things that have to come together at the same time for each and every rod/piston assembly. After that you can worry about getting the right piston back in the right cylinder if that is even possible given the unknowns and constraints.

Bogie
Reply With Quote Quick reply to this message
The Following User Says Thank You to BogiesAnnex1 For This Useful Post:
mmurray24 (06-16-2014)
 
  #4 (permalink)  
Old 06-16-2014, 01:15 PM
Registered User
 
Join Date: Jun 2014
Posts: 2
Wiki Edits: 0

Thanks: 3
Thanked 0 Times in 0 Posts
The rods and rod caps were kept together so there is no mix up there and yes the pistons are labeled indicating the side that is to face the front of the block. All precautions were taken to ensure proper instillation except for making sure that the pistons return to their original cylinders. Thanks for your quick and informative responses.
Reply With Quote Quick reply to this message

Tags
camaro, chevy, engine basics, pistons, rebuild

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:
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:
Insurance
Please select your insurance company (Optional)

Log-in



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
How much to rebuild a chevy small block? Evanniger Hotrodding Basics 9 03-04-2014 05:29 PM
first small block Chevy rebuild 1964 impala Hotrodding Basics 4 03-21-2012 09:18 PM
small block rebuild? DAVEY35 Hotrodding Basics 4 12-18-2011 11:52 AM
small block engine rebuild 74camaro Engine 2 04-06-2006 06:08 PM
small-block ford rebuild rickfishass Engine 1 12-09-2005 10:00 PM


All times are GMT -6. The time now is 04:45 AM.


Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.