305E torque specs crankcase Vent & timing question

[GMCNUT]

So I have taken the 64 2500 series to the mechanic shop to do a full re-gasketing of the entire 305E - the whole thing gasket-wise is getting redone. Does not need rebuilt - just stopping the leaks. So I need to know what the head bolt torque sequence and specs are (maybe in a manual I already have?) and I know one of you already told me this, but I have lost where I wrote down the timing for it.

Appreciate your help - Thanks!

PS - this mechanic shop does all types of work on old 50's and 60's vehicles, but they see so few GMC V6's they said I should probably ask the group to throw out any known "gatchas" related to working on or re-assembling a 305E - they do not understand where the crankcase ventilation occurs for example - they said they think some of the oil leaks were caused by ineffective crank case ventilation? curious to hear what any of you might have to say....thanks

[bigblockv6]

Your V6 has two PCV valve threaded directly to the intake port on the cylinder head(one for each head). Once the valve cover are off you'll see them, make sure to replace them with new ones or else you'll be blowing gaskets and seal again in a short time. There are two types that NAPA carries and both will work, NAPA\Echlin# 2-9254 or #2058. If you could find one from GM it would be an AC CV623C.

[FetchMeAPepsi]

BigBlockV6, does that work for a 305D too? I have a road draft tube and I thought that handled the ventilation
If not I might need to get dirty on that project too soon.
<sorry for hijacking GMCNut!>

[bigblockv6]

The 305D is a completely different setup and has one external PCV valve.

[aphaynes]

Originally Posted by GMCNUT

they do not understand where the crankcase ventilation occurs for example - they said they think some of the oil leaks were caused by ineffective crank case ventilation? curious to hear what any of you might have to say....thanks

I had a lot of oil leaks due to the clogged crankcase ventilation filter mounted on the block behind the driver side valve cover. It is press fit in the engine, and since there is little room where it is sandwiched between the valve cover and firewall, I could never get it out. I used someones advice and simply kept flushing it with engine cleaner until the brash mesh in there was looking very clean. Then I obviously had to change the oil. With the brass mesh clean and new filter installed in the canister, I replaced the PCV valves under the valve covers, valve cover gaskets, valley pan gasket and added a gasket to the distributor that was missing. I have not leaked a drop since.

I would have never even known there was brass mesh in there if Barry had not enlightened me.

Some pics from my build thread...





Dicussion of this beast starts here on my build thread...

http://6066gmcclub.com/forum/showthr...t=48103&page=5

[AZKen]

I just "rebuilt" my crankcase vent canister. Took out the screen and the copper plug and cleaned. Sandblasted can and cover and repaint. I just discovered that when chasing the intake threaded holes, you run into the push rods?Bent 3 before I caught on. V6 newby dummy.
Why do you have to replace PCV on 305E, aren't they totally metal check valves? Can't they be cleaned and reused. What is in them that degrades?

[GMCNUT]

Wow - am I ever glad I asked these questions. This 64 is the only running driving GMC V6 I ever had out of all the ones I own or have owned, so despite being a member of this 6066 crowd for quite a while now, this is my first time to have to pay attention and really focus on what everyone's been talking about for years....so first time to do anything mechanical to a V6 in other words. I will enjoy this experience and so appreciate all the VERY useful info above from you guys - thanks so much!

[GMCNUT]

So last questions are 1) what is the timing on a 305E? and 2) what are the head torque specs?

[BarryGMC]

7-1/2 degrees. But I usually push it a bit. Say 8-9. I time to ear as far as it will go without pinging. Head bolt torque 65-72 foot lbs.

[GMCNUT]

Originally Posted by BarryGMC

7-1/2 degrees. But I usually push it a bit. Say 8-9. I time to ear as far as it will go without pinging. Head bolt torque 65-72 foot lbs.

Thank you Barry - so is there a diagram that shows the head bolt sequence? I am sure you are supposed to tighten them in some kind of proper order - this shop is not too familiar with the things that make working on a V6 different from what you would do on a Chevrolet V8, so I need to tell them or show them - I have all the shop manuals etc if its in one of them - maybe that orange and green shop manual for 60's GMCs?