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
  #1  
Old April 10th, 2016, 07:34 PM
ilvracn's Avatar
ilvracn ilvracn is offline
-= Dues Paid =-
 
Join Date: Nov 2013
Location: atlantic iowa
Truck: 1966 gmc 1500
Age: 59
Posts: 215
Rep Power: 123
ilvracn is on a distinguished road
Default v-12 project begins

FINALLY GETTING STARTED ON V-12 PROJECT.
FIRST I NEEDED A STAND FOR THIS MONSTER, SO I BUILT ONE[ATTACH][ATTACH]V-12 008.JPG[/ATTACH][/ATTACH]
Attached Images
File Type: jpg V-12 006.JPG (830.1 KB, Multiple views, 19 clicks)
File Type: jpg V-12 007.JPG (822.8 KB, Multiple views, 12 clicks)
Reply With Quote
  #2  
Old April 10th, 2016, 07:37 PM
ilvracn's Avatar
ilvracn ilvracn is offline
-= Dues Paid =-
 
Join Date: Nov 2013
Location: atlantic iowa
Truck: 1966 gmc 1500
Age: 59
Posts: 215
Rep Power: 123
ilvracn is on a distinguished road
Default Re: v-12 project begins

Mounting engineV-12 013.JPG

V-12 011.JPG

V-12 019.JPG

[a
ttach]4401[/attach]
Attached Images
File Type: jpg V-12 017.JPG (876.9 KB, Multiple views, 18 clicks)
Reply With Quote
  #3  
Old April 10th, 2016, 08:02 PM
ilvracn's Avatar
ilvracn ilvracn is offline
-= Dues Paid =-
 
Join Date: Nov 2013
Location: atlantic iowa
Truck: 1966 gmc 1500
Age: 59
Posts: 215
Rep Power: 123
ilvracn is on a distinguished road
Default Re: v-12 project begins

The stand is made of 1/4" thick tubing. It is plenty strong, better to be overbuilt than too light. The upright is set back 10 degrees, that is too much. When the block goes to the machine shop, i will cut a notch in the upright and make it about 4 degrees. The cam and crank are perfect, standard no wear. 11 out 12 cylinders no wear will go back standard. #9 piston burned pretty badly, .020 deep spot about 1 inch long at top of cylinder. I think i'll put a sleeve in that hole and keep everything standard. Has anybody put a sleeve in one of these?

My pistons have small dish. I've seen pistons with a small dome, does anyone know what compression the small dome makes? I'm looking for about 9.5 to 10 to one.

Mom was not happy about orange shirt. It was new, oopsV-12 023.JPG

V-12 025.JPG

V-12 021.JPG
Reply With Quote
  #4  
Old April 11th, 2016, 01:56 AM
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: 68
Posts: 373
Rep Power: 152
bobdylan is on a distinguished road
Default Re: v-12 project begins

Looks like fun. I got one of mine running yesterday. I lucked out, I bought a couple of V12's about a month ago, when I got home I used a bore scope, and found they had been rebuilt years ago and had never been run, had 20 over pistons fresh valves. I rebuilt some old v12 truck carbs, bendix stromberg ww2. still have some fine tuning to do. Let me know if I can help, I learned a lot thru the process. I also have a lot of parts. Bob
Reply With Quote
  #5  
Old April 11th, 2016, 01:41 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: 68
Posts: 373
Rep Power: 152
bobdylan is on a distinguished road
Default Re: v-12 project begins

Awsome place to work. I stopped at some machine shops that did a lot of v12's, and they sleeved a lot of these engines, should not be a problem. Did you have any trouble finding a shop in you area to do that big of block? A lot of the high compression pistons had a raised oval shape, I have several blocks that have them. they are. .030 and .040 over. have not tried getting any out, they are stuck.
Reply With Quote
  #6  
Old April 11th, 2016, 03:33 PM
ilvracn's Avatar
ilvracn ilvracn is offline
-= Dues Paid =-
 
Join Date: Nov 2013
Location: atlantic iowa
Truck: 1966 gmc 1500
Age: 59
Posts: 215
Rep Power: 123
ilvracn is on a distinguished road
Default Re: v-12 project begins

i need to ask a favor, can you take a caliper and measure the dome height of those pistons. length and width would be good to know also. can you send pic showing shape of dome? this will help me figure out compression ratio.

any idea where to get rod and main bearings? thunder v-12 has cam bearings listed.

does anybody make a neoprene rear main seal, i found a rope seal kit

thanks, rick
Reply With Quote
  #7  
Old April 11th, 2016, 04:20 PM
bigblockv6 bigblockv6 is offline
Senior Member
 
Join Date: Jan 2013
Location: Rohnert Park, ca.
Truck: 1968 KM2500
Posts: 1,325
Rep Power: 415
bigblockv6 will become famous soon enoughbigblockv6 will become famous soon enough
Default Re: v-12 project begins

I've seen rod and main bearings listed on ebay but of course you'll need 2 V6 sets for the V12. FelPro makes a neoprene main seal.
Reply With Quote
  #8  
Old April 11th, 2016, 07:59 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: 68
Posts: 373
Rep Power: 152
bobdylan is on a distinguished road
Default Re: v-12 project begins

On ebay there is a v12 listed from Canada, If you scroll down he has a picture of a high compression piston setting next to a standard dish piston. Also some specs. My pistons look just like those. Bob
Reply With Quote
  #9  
Old April 11th, 2016, 11:16 PM
ilvracn's Avatar
ilvracn ilvracn is offline
-= Dues Paid =-
 
Join Date: Nov 2013
Location: atlantic iowa
Truck: 1966 gmc 1500
Age: 59
Posts: 215
Rep Power: 123
ilvracn is on a distinguished road
Default Re: v-12 project begins

the only rear main seal i can find is fel pro part # BS 40048, it is a rope seal.
Reply With Quote
  #10  
Old April 11th, 2016, 11:34 PM
bigblockv6 bigblockv6 is offline
Senior Member
 
Join Date: Jan 2013
Location: Rohnert Park, ca.
Truck: 1968 KM2500
Posts: 1,325
Rep Power: 415
bigblockv6 will become famous soon enoughbigblockv6 will become famous soon enough
Default Re: v-12 project begins

Where have you been looking for a main seal? When I built my 478M the FelPro gasket set came with a neoprene main seal. I think Oreilly Auto parts did have them as well.
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
Re: Project: 702 V-12 GMC Crewcab Archiver Previous Forum Posts 0 September 3rd, 2007 02:16 AM
Project: 702 V-12 GMC Crewcab Archiver Previous Forum Posts 0 August 22nd, 2007 01:49 AM
Project: 702 V-12 GMC Crewcab Archiver Previous Forum Posts 0 August 19th, 2007 04:12 AM
Re: Project: 702 V-12 GMC Crewcab Archiver Previous Forum Posts 0 August 16th, 2007 01:29 AM
Project: 702 V-12 GMC Crewcab Archiver Previous Forum Posts 0 August 15th, 2007 02:01 AM


All times are GMT +1. The time now is 05:24 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2013, Jelsoft Enterprises Ltd 681711554703|1710433473|0