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 July 2nd, 2022, 03:29 PM
Prowbar Prowbar is offline
Senior Member
 
Join Date: Dec 2020
Location: Friesland, the Netherlands
Truck: 1965 GMC 1500, 305E, SM420
Posts: 187
Rep Power: 67
Prowbar will become famous soon enoughProwbar will become famous soon enough
Default Re: Got a 478...

Quote:
Originally Posted by FetchMeAPepsi View Post
Is Pete banned or something? Haven't seen him around in a while.
Just talked to him and he can't log on because his phone broke down and locked his info. He wants to get back on but hasn't taken the time to do so.

Last edited by Prowbar; July 2nd, 2022 at 04:00 PM.
Reply With Quote
  #12  
Old July 19th, 2022, 01:08 PM
Prowbar Prowbar is offline
Senior Member
 
Join Date: Dec 2020
Location: Friesland, the Netherlands
Truck: 1965 GMC 1500, 305E, SM420
Posts: 187
Rep Power: 67
Prowbar will become famous soon enoughProwbar will become famous soon enough
Default Re: Got a 478...

Took the time to get everything measured on the 478. The wear is a little more than I first anticipated, but most falls on the outer end of the spec. A loose engine is a happy engine...

Also discussed basically everything with BB V6 about these engines, thank you very much for that Pete.

There's wear in the cylinder bores but I'll just re-hone them and re-use the existing rings. The pistons look good.

As you can see I disassembled, then decked the heads and exhaust ports.
The heads and block are now at the machine shop for sleeving of a couple of worn valve guides, and having the block cleaned. Positive valve seats will be installed also.

I first wanted hardened seats on the intakes (exhausts have them from the factory), but there is little meat in the intake runners for a seat. While it will be run on propane, it will not have to work hard in my pickup, and combined with these engines' excellent cooling capacity it should not be needed really.

The block will only be washed at the machine shop. Got most of the parts in for the rebuild except for the rod bearings. Main bearings are still in spec, and good to use.

The exhaust manifolds are badly warped and the (previous) mechanics tightened the bolts way too much to try to get it to seal again. Almost every bolt 'ear' has a crack and will need to be brazed back together, milled, then painted in factory yellow.
Attached Images
File Type: jpg 20220715_165018.jpg (4.88 MB, Multiple views, 6 clicks)
Reply With Quote
  #13  
Old August 10th, 2022, 08:32 PM
Prowbar Prowbar is offline
Senior Member
 
Join Date: Dec 2020
Location: Friesland, the Netherlands
Truck: 1965 GMC 1500, 305E, SM420
Posts: 187
Rep Power: 67
Prowbar will become famous soon enoughProwbar will become famous soon enough
Default Re: Got a 478...

Got the clean block from the machine shop. The heads are still there.
Got all the parts in: rod bearings, core (freeze) and oil galley plugs, timing chain, etc. Also bought me a Buick V6 even fire HEI to convert and use. This should definitely help with a cleaner burn in these massive bores.

Build me a homemade heavy-duty engine stand from an old engine hoist which was scrap iron. Works really well.

Now all that left is a re-hone of the block and then I can start on the short block assembly. Can't wait to get this powerhouse in my truck!
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: [6066 GMC Truck] 478 gas vs. 478 diesel Archiver Previous Forum Posts 0 March 31st, 2004 02:37 AM
RE: [6066 GMC Truck] 478 gas vs. 478 diesel Archiver Previous Forum Posts 0 March 31st, 2004 12:46 AM
Re: [6066 GMC Truck] 478 gas vs. 478 diesel Archiver Previous Forum Posts 0 March 30th, 2004 12:23 AM
RE: [6066 GMC Truck] 478 gas vs. 478 diesel Archiver Previous Forum Posts 0 March 30th, 2004 12:21 AM
RE: [6066 GMC Truck] 478 gas vs. 478 diesel Archiver Previous Forum Posts 0 March 30th, 2004 12:08 AM


All times are GMT +1. The time now is 04:53 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2013, Jelsoft Enterprises Ltd 871660440834|1659282792|0
Feedback Buttons provided by Advanced Post Thanks / Like (Lite) - vBulletin Mods & Addons Copyright © 2022 DragonByte Technologies Ltd.