6066 (1960-1966) GMC Truck Club Bitcoin now accepted here! 
Pay Dues
Pay Dues or become a Site Supporter
 



Go Back   6066 (1960-1966) GMC Truck Club > 6066 GMC Truck Club Forum > GMC V6 and V12 Engines


GMC V6 and V12 Engines Engine repair and rebuilding

Reply
 
Thread Tools
  #11  
Old January 6th, 2017, 10:08 PM
David R Leifheit's Avatar
David R Leifheit David R Leifheit is offline
Senior Member
 
Join Date: Jan 2013
Location: Dallas, Oregon
Truck: 1960-1966 1000-4000 series
Age: 56
Posts: 275
Rep Power: 125
David R Leifheit is a jewel in the roughDavid R Leifheit is a jewel in the roughDavid R Leifheit is a jewel in the rough
Default Re: Replacement 305 for a 1961

Quote:
Originally Posted by bobdylan View Post
I would think that a knock that went away after it warmed up, could not be to serious. If it was a rod bearing I think it would get worse. How is your oil pressure? You will see a drop in pressure if you have a bad bearing. Have you checked compression? I would not pull to investigate until I knew what was going on.
I wouldn't take the chance (now).
I had a small knock. Didn't sound too bad so I let it go. Besides, I had been told the engine had been "rebuilt" fairly recently. The knock got a little louder over time, but never had a power issue and didn't seem to affect the vehicle at all. One day, at 55mph, the knock quit. So did the engine. The rod cap had finally fallen off and the connecting rod no longer was "U" shaped where it went around the crankshaft, it was almost a "T" shape. And the valves/inside of the head was embossed on the top of the piston. Never did get that one out of the engine before scrapping it (wish I hadn't, the block was still good).
A small tapping can be -anything- so if you have the opportunity to go through the engine to find it, do so. Even if that noise is the sole "excuse" for getting another one and learning about these engines.
__________________
--
- David R Leifheit
in Dallas, Oregon
mailto:
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

(2) 1961 1500
1962 1000
1963 2500
1963 4000
1964 2500
Reply With Quote
  #12  
Old January 7th, 2017, 02:57 AM
Jmclendon's Avatar
Jmclendon Jmclendon is offline
-= Site Supporter =-
 
Join Date: Sep 2016
Location: Brisbane, QLD
Truck: 1961 1500 Stepside
Age: 34
Posts: 174
Rep Power: 88
Jmclendon is just really niceJmclendon is just really niceJmclendon is just really niceJmclendon is just really nice
Default Re: Replacement 305 for a 1961

Quote:
Originally Posted by bobdylan View Post
I would think that a knock that went away after it warmed up, could not be to serious. If it was a rod bearing I think it would get worse. How is your oil pressure? You will see a drop in pressure if you have a bad bearing. Have you checked compression? I would not pull to investigate until I knew what was going on.
Once it warms up the only thing you hear is the valves happily tapping away. Oil pressure looks fine. It holds nice and steady.

I haven't done a compression test on it yet. I guess in part because other than the pre-warm up knocking it runs great. Over Christmas I was hauling about 1000 lbs (if you include my wife and the fat driver LOL) down the highway with no dramas at all. I did have to drop down to second once (I'm running a 3 spd manual), but that was on a rather steep incline off a scenic route.

I guess it's just one of those things where I know the sound can't be good news. So, I figure if I can find a quality replacement engine then the old man gets to stay on the road while I work out what's going on. If I can't find one, then I'll likely have to take it to someone for a rebuild, simply because I don't want him to sit around for ages while I learn what I'm doing and track down parts etc....

I really want to learn as much as I can, but I don't want to let the old boy fo fallow while I'm doing it. I'm greedy I guess LOL
Reply With Quote
  #13  
Old January 8th, 2017, 03:18 PM
6066gmcguy's Avatar
6066gmcguy 6066gmcguy is offline
-= Site Supporter =-
 
Join Date: Jan 2013
Location: Honeyville, Utah
Truck: 1965 3500 Rescue Squad
Age: 57
Posts: 613
Rep Power: 186
6066gmcguy is on a distinguished road
Default Re: Replacement 305 for a 1961

As for a bolt in swap, any year 305, 351 or 401 would drop in place of the 305.
Finding one downunder mite be a bite harder then here in the states.
__________________
Links to Other Places:

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
on FacePage.

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
.
the
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
on FacePage.
Owner of:
1965 GMC 3500 Custom Rescue Squad {Black Built Bodies}
1968 Ford Galaxie 500 Convertible
2006 Yamaha Rhino 450
2008 GMC HHR Panel.
Reply With Quote
  #14  
Old January 8th, 2017, 10:18 PM
Jmclendon's Avatar
Jmclendon Jmclendon is offline
-= Site Supporter =-
 
Join Date: Sep 2016
Location: Brisbane, QLD
Truck: 1961 1500 Stepside
Age: 34
Posts: 174
Rep Power: 88
Jmclendon is just really niceJmclendon is just really niceJmclendon is just really niceJmclendon is just really nice
Default Re: Replacement 305 for a 1961

My reason for concern.... Might have to turn the sound up. Sorry about the file size.



Sent from my E6653 using Tapatalk
Reply With Quote
  #15  
Old January 9th, 2017, 01:18 PM
turbobill turbobill is offline
Member
 
Join Date: Feb 2013
Location: northern NY
Truck: A few engines plus a Toro-Flow
Posts: 84
Rep Power: 52
turbobill is on a distinguished road
Default Re: Replacement 305 for a 1961

Maybe the "knock" is a valve a bit looser than the rest. Once the engine warms up, the clearance is reduced enough that it clatters no louder than any of the others.
Reply With Quote
  #16  
Old January 9th, 2017, 03:24 PM
bobdylan bobdylan is offline
Senior Member
 
Join Date: Mar 2015
Location: mclouth kansas
Truck: 64 Gmc suburbann 305e, 4speed. v12 truck engine, v12 irrigation,2-305e,305a,305d
Age: 61
Posts: 365
Rep Power: 111
bobdylan is on a distinguished road
Default Re: Replacement 305 for a 1961

Take a long rod , hold it to your ear, and against the engine in different places., see if it is the upper end or lower end.
Reply With Quote
  #17  
Old January 9th, 2017, 08:09 PM
TJ's GMC's Avatar
TJ's GMC TJ's GMC is offline
Senior Member
 
Join Date: Mar 2015
Location: Cave Junction, Oregon
Truck: 1964 GMC 1500 LWB Wideside 305E V6.
Posts: 1,257
Rep Power: 333
TJ's GMC is on a distinguished road
Default Re: Replacement 305 for a 1961

Quote:
Originally Posted by bobdylan View Post
Take a long rod , hold it to your ear, and against the engine in different places., see if it is the upper end or lower end.
x2 to that notion
__________________
"Excuse the rust I use my truck"
1964 GMC 1500 305E/sm420 4 barrel intake mod and dual exhaust.
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

1964 Chevy C20 292/SM420
1966 Chevy C10 292 hotrod 6/TKO600
1977 Chevy C20 572 BBC/TH400
1984 Chevy C30 292/SM465

My youtube channel aka Military Chevy:
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
Reply With Quote
  #18  
Old January 9th, 2017, 10:51 PM
snazzypig snazzypig is offline
-= Dues Paid =-
 
Join Date: Dec 2013
Location: Colorado Springs CO
Truck: 1962 1500 Wideside, 1961 1000 Wideside
Posts: 43
Rep Power: 62
snazzypig is a jewel in the roughsnazzypig is a jewel in the roughsnazzypig is a jewel in the rough
Default Re: Replacement 305 for a 1961

I agree that it could be a loose valve. The erratic tapping seems to point to something in the valve train.
Hopefully your stethoscope stick will find the source!
Reply With Quote
  #19  
Old January 29th, 2017, 08:33 PM
bluestreak1854 bluestreak1854 is online now
Junior Member
 
Join Date: Apr 2016
Location: Clarendon Texas
Truck: 1966 GMC 4000
Age: 63
Posts: 17
Rep Power: 15
bluestreak1854 is on a distinguished road
Default Re: Replacement 305 for a 1961

I have a 305e v6 that i would sell-- it would probably need work-- I completely rebuilt it several years ago -bored new 4 ring pistons- cam lifters etc. but it has been a few miles since then-- I took it out because it just quit one day and I haven't taken it apart to see what happened-- suspect timing chain or blown head gasket although it never got hot-- i also have a 478M out of an 8500 coe truck that has a allison automatic behind it -- it is a good running engine and tranny with only 8696 miles on it-- i have the radiator,shifter , and mounting if you are interested
Reply With Quote
Reply

Bookmarks

Thread Tools

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


Similar Threads
Thread Thread Starter Forum Replies Last Post
Replacement parking brake cable for 1961 Paul in Nola Wheels, Tires, Suspension and Brakes 0 April 18th, 2013 07:34 PM
Re: 305 v6 rear seal replacement Archiver Previous Forum Posts 0 May 21st, 2010 02:53 AM
Re: 305 v6 rear seal replacement Archiver Previous Forum Posts 0 May 20th, 2010 11:14 AM
Re: 305 v6 rear seal replacement Archiver Previous Forum Posts 0 May 20th, 2010 02:06 AM
305 v6 rear seal replacement Archiver Previous Forum Posts 0 May 19th, 2010 02:00 AM


All times are GMT +1. The time now is 06:11 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2013, Jelsoft Enterprises Ltd 106|0
Feedback Buttons provided by Advanced Post Thanks / Like (Lite) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.