The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > 47 - Current classic GM Trucks > The 1967 - 1972 Chevrolet & GMC Pickups Message Board

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 08-30-2002, 12:26 PM   #1
bigblok
Registered User
 
Join Date: May 2001
Location: bangor,pa usa
Posts: 29
396/402bbc- internal/external balance ?

My beautiful machine is out again- rod bearing on #5keeps going.
Rebuilder replaced crank, bearings, rods twice. He said this motor is internally balanced, but others have told me it could be either, and others still have told me all bigblocks were external. rebuilder has no explanation for bearing wipeout. ANY INFO GREATLY APPRECIATED. I want my truck back!
__________________
72 C10 475HP 402BBC
Yes, it's fun, but gas ain't cheap!
bigblok is offline   Reply With Quote
Old 08-30-2002, 12:32 PM   #2
tom hand
CCRider
 
tom hand's Avatar
 
Join Date: Feb 2000
Location: Olive Branch,MS,USA
Posts: 2,232
I thought that 396/427 were internal and 454/502 were external
__________________
72 GMC Sierra SWB almost finished---- 84 Softail
Olive Branch MS
tom hand is offline   Reply With Quote
Old 08-30-2002, 01:09 PM   #3
Longhorn Man
its all about the +6 inches
 
Longhorn Man's Avatar
 
Join Date: Jan 2001
Location: Hilliard Ohio
Posts: 2,690
While i don' know about the 502, I have been told that the 454 is the only externial ballanced big block.
Might be time to find a new engine guy.
Longhorn Man is offline   Reply With Quote
Old 08-30-2002, 01:28 PM   #4
kxmotox247
Senior Member
 
kxmotox247's Avatar
 
Join Date: Jul 2002
Location: Champaign, IL
Posts: 1,397
Something is funny here...
Maybe the engine builder should be calibrating his equipment. Could it be a bent journal? How about debris in the oil passage blocking flow and starving it of oil?
That has to be frustrating.
I could be wrong but I thought 454's were the only externally balanced.
kxmotox247 is offline   Reply With Quote
Old 08-30-2002, 07:22 PM   #5
67 SS
Registered User
 
Join Date: Jun 2002
Location: NW ARKANSAS
Posts: 258
The smallblock 400 & big block 454 are externally balanced.Not sure about the 502.The crank should interchange between the 396,402,427and I think the 366.Has the block been linebored?(I think thats what they call it)Has the crank been checked for straightness?
67 SS is offline   Reply With Quote
Old 08-30-2002, 09:09 PM   #6
Chevyman69
Vortec 350's Suck
 
Join Date: Nov 2000
Location: Pickardville Alberta Canada
Posts: 544
The only externally balanced BB I know of of is the 454( I think the 502 might be as well, but I don't know). Sounds like a good engine guy to run away from. All the cranks will interchange(366,396,427) and even a 454's can be installed if the block is clearanced and you run the external balanced accessories. Sounds like an incorrectly measured journal or a bad crank, but at any rate find a engine guy that knows something.
__________________
69 Chev CST 10 reg cab lwb

Daily Driver: 92 Chev Reg Cab LWB Silverado 4x4, K.I.A 7:51 AM 04/22/03
Will be resurrected
Chevyman69 is offline   Reply With Quote
Old 08-30-2002, 10:52 PM   #7
Ratpowerd67
Registered User
 
Join Date: Aug 2002
Location: Trenton ,Texas
Posts: 328
the 454 is the only external motor. i should know, i have one in my 67.......rat
Ratpowerd67 is offline   Reply With Quote
Old 08-30-2002, 11:50 PM   #8
mikep
Used to have a truck
 
mikep's Avatar
 
Join Date: May 2002
Location: port orchard WA
Posts: 1,552
400 is

454 is

502 is


everything else isnt
__________________
No truck :-(
mikep is offline   Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not 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

Forum Jump


All times are GMT -4. The time now is 09:22 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright 1997-2022 67-72chevytrucks.com