GMC 305 V6 Rebuild with pics - The 1947 - Present Chevrolet & GMC Truck Message Board Network

*1LOW4X4* · 12-01-2010, 03:24 AM

First off, If you've done this...GIVE ME TIPS! I have several 350 rebuilds under my belt and the newer LS style ones too but I realize this is going to be harder (I assume) to find parts for and all that....I have another thread where a few guys gave me some good tips on helping it run better as far as changing the intake and carb setup...

Basically just a 305 V6 out of a 1964 GMC Suburban. It spun a bearing about 7 years ago, pulled it and set it on a pallet under a tarp up until today. Went and plucked it out of the woods.

I no longer have that '64 regrettably,

but I'm rebuilding this engine simply because one day I WILL have another 60-66 (hopefully GMC stepside) and I'll drop this motor in it. I dont want just another 350.

Lots of pics, I'll be updating as I go. Feel free to leave comments or advice

I had to put the LS1 I had on the stand on the ground and get this one on the stand, and then I pulled the pan plug. Immediately the pan started gushing water, for about probably a full minute. The engine was full of water all the way to the top. ALl over my garage floor and driveway. cleaned that all up, and started breaking her down. Didnt have much time tonight but heres what I got.

*1LOW4X4* · 12-01-2010, 03:26 AM

*1LOW4X4* · 12-01-2010, 03:31 AM

GMR-PERFORMANCE · 12-01-2010, 01:46 PM

My father and I bought a 409 engine complete for next to nothing. It was full of water as well. We drained it and filled it back up with kerosene or diesel not recall. But let it sit for about a week, and every day would put the breaker bar on the front pulley and rock the engine back and forth. After about 2 weeks of that the engine would roll over 360*. Sure was easier than trying to beat the pistons out of the bore. . BTW that engine is now in my dads 55 chevy belair... Rebuilt of course but goes to show a bit of time taking care can make the job go much smoother. You did not say if that engine is frozen or not. But even so doing this will also soften the sludge up. We did fill it to the top, if I recall you could see the diesel in the intake manifold. Yes a pan under the engine is a good idea, back then letting it drain on the ground was a normal deal.... WOW how things have changed.

jbgroby · 12-01-2010, 05:08 PM

1 low,

First, your need to keep the 3 grove lower pully, those are more rare than the engine, with tthat you can run P/S, A/C. IF you can locate a upper 3 groove that'd be super. Also you have a sime positive crankcase breather with teh filter try and salvage that fd you can those be rare too.

As you take the weight off the block no problem, but when you do the re-assembly, you might want to consider placeing a 4x4 under the front lip of the motor, these engine are HEAVY and I don't truck a regular engine stand.

Pop's C-10 · 12-01-2010, 05:22 PM

I love tha look of that motor

*1LOW4X4* · 12-01-2010, 05:36 PM

Quote:

Originally Posted by jbgroby

1 low,

First, your need to keep the 3 grove lower pully, those are more rare than the engine, with tthat you can run P/S, A/C. IF you can locate a upper 3 groove that'd be super. Also you have a sime positive crankcase breather with teh filter try and salvage that fd you can those be rare too.

As you take the weight off the block no problem, but when you do the re-assembly, you might want to consider placeing a 4x4 under the front lip of the motor, these engine are HEAVY and I don't truck a regular engine stand.

Thanks I was hoping you'd come in here. So thats what that little canister is on the back of the motor? I figured it was a crankcase filter of some sort...I'll hold on to that pulley....

This engine stand is supposed to be 2,000lb but I think you're right, this engine is super heavy.

Can you buy filters for that little canister? Also, hows the availability of parts for this thing? Such as gaskets, etc...

jbgroby · 12-01-2010, 06:49 PM

Yep, take the old one to any NAPA or Autozone you should be able to get one, if push comes to shove a fuel filter and or even med. course steel wool will work, Just cut out a cicrle of steel to drop in the bottom and drill some holes in it so the air can pass. The older style like I have, the draft across the bottom of the long tube draws the gasses out.

*1LOW4X4* · 12-01-2010, 08:50 PM

Nice. Do you by any chance know how to get that thing off the block? Does it screw off or....

I've decided to fill the motor up with diesel for a few days, It wont turn over freely and I dont wanna have to fight it to disassemble. I might take the heads off though while I'm waiting. Or maybe just remove the spark plugs and pour diesel through the holes onto the pistons, maybe they will help loosen the rings up

*1LOW4X4* · 12-01-2010, 11:27 PM

I have a lot more pics, but My iphone took a crap so I'm upgrading tomorrow to the new one.

I filled the engine up completely with diesel, and took one of the heads off. All three cylinders were full of water but no rust. Filled them up with trans fluid (its good for seeping past those rings).....The head gasket still has "GMC" stamped in it, so that tells me its never been apart. Its very cool, I'll be hanging it on the wall lol

**Bugeyev8** · 12-02-2010, 01:20 AM

wow...you must really want that 305E...looks like a whole lot of work to me, there are two runners in the wreckers here, too bad you were not closer

jbgroby · 12-02-2010, 01:40 AM

Quote:

Originally Posted by 1LOW4X4

Nice. Do you by any chance know how to get that thing off the block? Does it screw off or....

I've decided to fill the motor up with diesel for a few days, It wont turn over freely and I dont wanna have to fight it to disassemble. I might take the heads off though while I'm waiting. Or maybe just remove the spark plugs and pour diesel through the holes onto the pistons, maybe they will help loosen the rings up

Spray PB Blaster or Kroll oil on it a few time a day and gently tap it with a rubber hammer on each side, they are pressed in the block, they come out, that one has prob. not moved since it was put in.

*1LOW4X4* · 12-02-2010, 02:00 AM

Quote:

Originally Posted by Bugeyev8

wow...you must really want that 305E...looks like a whole lot of work to me, there are two runners in the wreckers here, too bad you were not closer

I enjoy working on old stuff. Its not that I want it that bad as much as its something to do. Its mostly about taking something that doesnt work and making it sing again.

**Bugeyev8** · 12-02-2010, 02:04 AM

Quote:

Originally Posted by 1LOW4X4

I enjoy working on old stuff. Its not that I want it that bad as much as its something to do. Its mostly about taking something that doesnt work and making it sing again.

Check out the GMC V12 build thread on here "Blauar"

**Bugeyev8** · 12-02-2010, 02:07 AM

here is the link, its a great thread to read

http://67-72chevytrucks.com/vboard/s...d.php?t=254111

*1LOW4X4* · 12-02-2010, 03:06 PM

Ok, I got the heads off and one cylinder really worries me, it's full of rust and it almost looks like the cylinder wall may be pitted....can you bore these ok or.....I'll know more when I get it cleaned up good later with my steam pressure washer
Posted via Mobile Device

jbgroby · 12-02-2010, 04:51 PM

Yes, if its not too bad, you can go up to .60 Over size, thay have pistons for theat at Kanter or Egg. IF you need to bore, You might want to start with a fresher balco like one of the other memebrs have. Get her boiled or baked out to see what you got. Gefore spending any cash.

*C-10 simplex* · 12-02-2010, 05:33 PM

i can't help, sorry. But, i can hinder and go off on tangents.

With that train of thought, when dealing with "unusual" engines----in other words anything NOT small or big block chevy or small block ford, how does a machine shop, or anyone for that matter, know what dimensions are stock and what further dimensions are permissible---how much it's safe to overbore?

How do they know what tolerances are acceptable and desirable in regards to align-boring, decking etc. etc.

jbgroby · 12-02-2010, 07:46 PM

C-10,

It's not the the engine is unusual, but rather overly built. The stock pistons were nicknamed Coffee Cans for a reason.

http://inlinethumb50.webshots.com/45...500x500Q85.jpg

MY son when 16 and we were taking the first engine down.

The stock bore was 4.25" and the pistons you can get from Kanter or Egg . and come 4.25 + .20, .40. & .60 over size. Remember these are 4 ring pistons 3 compression and 1 oiler.

The skin on these piston shafts are something like 1/4 thick or more and the way the engine is cast is that 90% of the sleeve is exposed to the water jacket, that why she ran so cool.

All the information you ever WANT to know is here.

http://www.6066gmcguy.org/gmcv6a.htm

*1LOW4X4* · 12-02-2010, 09:51 PM

Some pics of when I tore it down. I am worried about one particular cylinder which was full of dry rust. It looks as if the wall coulf be pitted, which would mean it needs to be bored. No big deal for now.

I have other pics of it clean, and 'll get them up as soon as they upload. I used my steam pressure washer on it and it did it some good

All the cylinders had goo but that orange one worries me....

*1LOW4X4* · 12-02-2010, 09:58 PM

Head gasket, thought this was pretty cool. Stamped GMC.

*1LOW4X4* · 12-02-2010, 10:06 PM

Now that its clean I'm eager to tear the bottom end apart and see what was knocking in there, I didnt find any metal chunks in the pan only sludge....

First thing in the AM I'll be pulling it apart

*1LOW4X4* · 12-03-2010, 12:32 AM

Well went ahead and pulled one rod cap. What do you see.

Shaky · 12-03-2010, 09:11 AM

This is pure awesomeness. I love non-mainstream engines (although the wildest I've gone is my 292).

*1LOW4X4* · 12-03-2010, 04:45 PM

I have heard they are. I'm having a bear of a time trying to get the crank out, I've got 4 pistons off the crank and 3 mains but one main is stuck and the crank still wont turn to get to the other rod caps.....

I called my machinist and he got pretty excited when I spoke of the engine. He's usually a pretty serious guy and only talks when he needs to, but he was like "I havent seen one of them in 15 years"! lol

I'm going to bring him the block and crank next week.

12-01-2010, 03:24 AM	#1
1LOW4X4 Account Suspended Join Date: Jul 2010 Location: Southeast Texas Posts: 189	GMC 305 V6 Rebuild with pics First off, If you've done this...GIVE ME TIPS! I have several 350 rebuilds under my belt and the newer LS style ones too but I realize this is going to be harder (I assume) to find parts for and all that....I have another thread where a few guys gave me some good tips on helping it run better as far as changing the intake and carb setup... Basically just a 305 V6 out of a 1964 GMC Suburban. It spun a bearing about 7 years ago, pulled it and set it on a pallet under a tarp up until today. Went and plucked it out of the woods. I no longer have that '64 regrettably, but I'm rebuilding this engine simply because one day I WILL have another 60-66 (hopefully GMC stepside) and I'll drop this motor in it. I dont want just another 350. Lots of pics, I'll be updating as I go. Feel free to leave comments or advice I had to put the LS1 I had on the stand on the ground and get this one on the stand, and then I pulled the pan plug. Immediately the pan started gushing water, for about probably a full minute. The engine was full of water all the way to the top. ALl over my garage floor and driveway. cleaned that all up, and started breaking her down. Didnt have much time tonight but heres what I got.

12-01-2010, 03:26 AM	#2
1LOW4X4 Account Suspended Join Date: Jul 2010 Location: Southeast Texas Posts: 189	Re: GMC 305 V6 Rebuild with pics

12-01-2010, 03:31 AM	#3
1LOW4X4 Account Suspended Join Date: Jul 2010 Location: Southeast Texas Posts: 189	Re: GMC 305 V6 Rebuild with pics

12-01-2010, 01:46 PM	#4
GMR-PERFORMANCE Registered User Join Date: Aug 2010 Location: Keller TX Posts: 836	Re: GMC 305 V6 Rebuild with pics My father and I bought a 409 engine complete for next to nothing. It was full of water as well. We drained it and filled it back up with kerosene or diesel not recall. But let it sit for about a week, and every day would put the breaker bar on the front pulley and rock the engine back and forth. After about 2 weeks of that the engine would roll over 360*. Sure was easier than trying to beat the pistons out of the bore. . BTW that engine is now in my dads 55 chevy belair... Rebuilt of course but goes to show a bit of time taking care can make the job go much smoother. You did not say if that engine is frozen or not. But even so doing this will also soften the sludge up. We did fill it to the top, if I recall you could see the diesel in the intake manifold. Yes a pan under the engine is a good idea, back then letting it drain on the ground was a normal deal.... WOW how things have changed.

12-01-2010, 05:08 PM	#5
jbgroby Registered User Join Date: Nov 2008 Location: Lacombe, LA Posts: 2,770	Re: GMC 305 V6 Rebuild with pics 1 low, First, your need to keep the 3 grove lower pully, those are more rare than the engine, with tthat you can run P/S, A/C. IF you can locate a upper 3 groove that'd be super. Also you have a sime positive crankcase breather with teh filter try and salvage that fd you can those be rare too. As you take the weight off the block no problem, but when you do the re-assembly, you might want to consider placeing a 4x4 under the front lip of the motor, these engine are HEAVY and I don't truck a regular engine stand. Attached Images __________________ http://s1299.photobucket.com/user/jb...23904108567829

12-01-2010, 05:22 PM	#6
Pop's C-10 Registered User Join Date: Jul 2010 Location: memphis Posts: 2,537	Re: GMC 305 V6 Rebuild with pics I love tha look of that motor

12-01-2010, 06:49 PM	#8
jbgroby Registered User Join Date: Nov 2008 Location: Lacombe, LA Posts: 2,770	Re: GMC 305 V6 Rebuild with pics Yep, take the old one to any NAPA or Autozone you should be able to get one, if push comes to shove a fuel filter and or even med. course steel wool will work, Just cut out a cicrle of steel to drop in the bottom and drill some holes in it so the air can pass. The older style like I have, the draft across the bottom of the long tube draws the gasses out. Attached Images __________________ http://s1299.photobucket.com/user/jb...23904108567829

12-01-2010, 08:50 PM	#9
1LOW4X4 Account Suspended Join Date: Jul 2010 Location: Southeast Texas Posts: 189	Re: GMC 305 V6 Rebuild with pics Nice. Do you by any chance know how to get that thing off the block? Does it screw off or.... I've decided to fill the motor up with diesel for a few days, It wont turn over freely and I dont wanna have to fight it to disassemble. I might take the heads off though while I'm waiting. Or maybe just remove the spark plugs and pour diesel through the holes onto the pistons, maybe they will help loosen the rings up

12-01-2010, 11:27 PM	#10
1LOW4X4 Account Suspended Join Date: Jul 2010 Location: Southeast Texas Posts: 189	Re: GMC 305 V6 Rebuild with pics I have a lot more pics, but My iphone took a crap so I'm upgrading tomorrow to the new one. I filled the engine up completely with diesel, and took one of the heads off. All three cylinders were full of water but no rust. Filled them up with trans fluid (its good for seeping past those rings).....The head gasket still has "GMC" stamped in it, so that tells me its never been apart. Its very cool, I'll be hanging it on the wall lol

12-02-2010, 01:20 AM	#11
Bugeyev8 Senior Member Join Date: Aug 2009 Location: San Leandro, Ca 94577 Posts: 854	Re: GMC 305 V6 Rebuild with pics wow...you must really want that 305E...looks like a whole lot of work to me, there are two runners in the wreckers here, too bad you were not closer

12-02-2010, 02:07 AM	#15
Bugeyev8 Senior Member Join Date: Aug 2009 Location: San Leandro, Ca 94577 Posts: 854	Re: GMC 305 V6 Rebuild with pics here is the link, its a great thread to read http://67-72chevytrucks.com/vboard/s...d.php?t=254111

12-02-2010, 03:06 PM	#16
1LOW4X4 Account Suspended Join Date: Jul 2010 Location: Southeast Texas Posts: 189	Re: GMC 305 V6 Rebuild with pics Ok, I got the heads off and one cylinder really worries me, it's full of rust and it almost looks like the cylinder wall may be pitted....can you bore these ok or.....I'll know more when I get it cleaned up good later with my steam pressure washer Posted via Mobile Device

12-02-2010, 04:51 PM	#17
jbgroby Registered User Join Date: Nov 2008 Location: Lacombe, LA Posts: 2,770	Re: GMC 305 V6 Rebuild with pics Yes, if its not too bad, you can go up to .60 Over size, thay have pistons for theat at Kanter or Egg. IF you need to bore, You might want to start with a fresher balco like one of the other memebrs have. Get her boiled or baked out to see what you got. Gefore spending any cash. __________________ http://s1299.photobucket.com/user/jb...23904108567829

12-02-2010, 05:33 PM	#18
C-10 simplex Account Suspended Join Date: Dec 2008 Location: indisclosed Posts: 1,515	Re: GMC 305 V6 Rebuild with pics i can't help, sorry. But, i can hinder and go off on tangents. With that train of thought, when dealing with "unusual" engines----in other words anything NOT small or big block chevy or small block ford, how does a machine shop, or anyone for that matter, know what dimensions are stock and what further dimensions are permissible---how much it's safe to overbore? How do they know what tolerances are acceptable and desirable in regards to align-boring, decking etc. etc.

12-02-2010, 07:46 PM	#19
jbgroby Registered User Join Date: Nov 2008 Location: Lacombe, LA Posts: 2,770	Re: GMC 305 V6 Rebuild with pics C-10, It's not the the engine is unusual, but rather overly built. The stock pistons were nicknamed Coffee Cans for a reason. http://inlinethumb50.webshots.com/45...500x500Q85.jpg MY son when 16 and we were taking the first engine down. The stock bore was 4.25" and the pistons you can get from Kanter or Egg . and come 4.25 + .20, .40. & .60 over size. Remember these are 4 ring pistons 3 compression and 1 oiler. The skin on these piston shafts are something like 1/4 thick or more and the way the engine is cast is that 90% of the sleeve is exposed to the water jacket, that why she ran so cool. All the information you ever WANT to know is here. http://www.6066gmcguy.org/gmcv6a.htm Attached Images __________________ http://s1299.photobucket.com/user/jb...23904108567829



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12-02-2010, 09:51 PM	#20
1LOW4X4 Account Suspended Join Date: Jul 2010 Location: Southeast Texas Posts: 189	Re: GMC 305 V6 Rebuild with pics Some pics of when I tore it down. I am worried about one particular cylinder which was full of dry rust. It looks as if the wall coulf be pitted, which would mean it needs to be bored. No big deal for now. I have other pics of it clean, and 'll get them up as soon as they upload. I used my steam pressure washer on it and it did it some good All the cylinders had goo but that orange one worries me....

12-02-2010, 09:58 PM	#21
1LOW4X4 Account Suspended Join Date: Jul 2010 Location: Southeast Texas Posts: 189	Re: GMC 305 V6 Rebuild with pics Head gasket, thought this was pretty cool. Stamped GMC.

12-02-2010, 10:06 PM	#22
1LOW4X4 Account Suspended Join Date: Jul 2010 Location: Southeast Texas Posts: 189	Re: GMC 305 V6 Rebuild with pics Now that its clean I'm eager to tear the bottom end apart and see what was knocking in there, I didnt find any metal chunks in the pan only sludge.... First thing in the AM I'll be pulling it apart

12-03-2010, 12:32 AM	#23
1LOW4X4 Account Suspended Join Date: Jul 2010 Location: Southeast Texas Posts: 189	Re: GMC 305 V6 Rebuild with pics Well went ahead and pulled one rod cap. What do you see.

12-03-2010, 09:11 AM	#24
Shaky Six in a row makes it go... Join Date: Mar 2009 Location: Vacationland: Maine Posts: 1,346	Re: GMC 305 V6 Rebuild with pics This is pure awesomeness. I love non-mainstream engines (although the wildest I've gone is my 292). __________________ 67 C20 long step resto: http://67-72chevytrucks.com/vboard/s...d.php?t=342086 66 C10 long step build: http://67-72chevytrucks.com/vboard/s...=1#post3814790 CT to Alaska in a 67 C10: http://67-72chevytrucks.com/vboard/s...d.php?t=399224 “The height of sophistication is simplicity." - Clare Boothe Luce

12-03-2010, 04:45 PM	#25
1LOW4X4 Account Suspended Join Date: Jul 2010 Location: Southeast Texas Posts: 189	Re: GMC 305 V6 Rebuild with pics I have heard they are. I'm having a bear of a time trying to get the crank out, I've got 4 pistons off the crank and 3 mains but one main is stuck and the crank still wont turn to get to the other rod caps..... I called my machinist and he got pretty excited when I spoke of the engine. He's usually a pretty serious guy and only talks when he needs to, but he was like "I havent seen one of them in 15 years"! lol I'm going to bring him the block and crank next week.

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