1966 GMC 305 V6 Service

[Rufton]

Mark cap address before removing from worn engine.
Easy to verify connecting rod clearance w/ inside and outside micrometer.
Don't forget to make sure cap is on it's mate in original orientation.
Crank main bearings over 3" and crank pins over 2.8" which is hefty.

[Rufton]

Lightly polished crank.
crank end play.
Cleaned all oil passages.

[Rufton]

Used newfangeled rear main seal RTV, pipe cleaner thingy, and H2O to initiate cure.
OEM rear main side seal style more difficult to install and was phased out of my gasket kit.

[timmytimm3]

Excellent write up so far! With that much meat between the cylinders I bet it could hold a lot of boost with the right head gasket setup and a forged bottom end. How large can they be bored out to?

[Rufton]

Didn't forget the hidden galley plug

[Rufton]

Originally Posted by 1963c-10

Very well done thread. Now how about some pics of the truck

Maybe, if this freshened engine behaves.
Truck is camera shy.
Lil rough around the edges

[Rufton]

Originally Posted by timmytimm3

Excellent write up so far! With that much meat between the cylinders I bet it could hold a lot of boost with the right head gasket setup and a forged bottom end. How large can they be bored out to?

Mine is 40 over.
Some versions came w/ advanced metallurgy crank.
All cranks are over designed and super heavy.
You could improve power a bit for kicks just check pockets first.

[TommyDuncan]

With that hefty bottom end and the low end torque these engines make I can only imagine one with a supercharger!
Is there a good source for parts for these? Are most wear items readily available?
I have always liked the "unique" engines. I had a Jeep with an odd fire V6 and although it was sometimes frustrating, it was a fun engine to work on and it had a sound all it's own.
Your build thread really has me thinking...
Posted via Mobile Device

[Rufton]

Originally Posted by TommyDuncan

With that hefty bottom end and the low end torque these engines make I can only imagine one with a supercharger!
Is there a good source for parts for these? Are most wear items readily available?
I have always liked the "unique" engines. I had a Jeep with an odd fire V6 and although it was sometimes frustrating, it was a fun engine to work on and it had a sound all it's own.
Your build thread really has me thinking...
Posted via Mobile Device

Can't just buy every part at wally world but I was able to source everything pretty quick and easy; maybe I got lucky just this one time. There were some parts on ebay that came and went. I had all new parts sourced but didn't buy because I found a built short block.

Executive summary: The easy way is Chevy 350.

[Rufton]

Before pulling tired 305E I took pics of coil, alternator, etc.

[Rufton]

Siphoned coolant to avoid mess and for possible reuse.
Knocked out front seal.

[Rufton]

Punched out dip stick tube w/ drill bit.
Tagged push rods.
Crank pulley.
Trans bleed.

[Rufton]

I went ahead and stripped short block in truck; not typical.
Just got started and couldn't stop.
Everything so easy to access.
Ran into zero frustration which is nice.

[Rufton]

Not every day you see someone remove the engine and trans and leave the bell.

[Rufton]

Sludge not bad for a few decades.
I didn't touch inside pan; just propped it up over night.
Only possible sludge issue I saw was rocker arm shaft which can easily be serviced after removing valve covers.
In the future I will verify rocker arm flow every time I adjust lifters.
In the past only adjusted lifters about once per decade or two.

[Rufton]

Timing chain play may be one of the factors of worn 305E's personality.
Ran fine for me but took new driver a while to operate smoothly.
New chain gets bath.
No energy wasted stamping timing marks.

[Rufton]

Fuel pump cam.

[Rufton]

Oil filter housing mystery.
By-pass valve can't open if filter gets clogged.
Pretty sure it was that way in 72 when truck purchased.
Musicman70's by-pass is installed other way.

[Rufton]

My 305E solid lifter first start plan; comments welcome.

More advance maybe more engine heat.
Less advance maybe more header heat.
Mark dist #1 TDC before pulling worn engine.
Measure solid lifter cold lash on worn engine.
Valvoline 10W-30 VR-1 conven racing; API=SL, Zn/Phos = 1400/1300 ppm (6-8-2011).
Select filter w/ anti drain-back valve.
Rare earth magnet in pan and on filter.
Prime oil pump and verify flow to rockers.
Set static timing.
Adjust solid lifter cold lash on the loose side.
Install engine.
Verify transmission fluid.
Little 2 stroke oil in gas tank.
Top off coolant then install T-Stat.
Ready box fans and water spray for cooling radiator fins.
Ready oil psi gauge; IR gun and timing light.
Top carb bowl or use minimal starting fluid.
Run 305E solid lifter 1000 rpm for 10 mins.
Verify rocker oil flow and 20psi oil.
Set timing w/ light.
Mild revs not to exceed 2000 rpm.
Keep between 160 to195F.
Top coolant and install cap after T-stat opens.
Shut down at 10 mins.
Torque heads and intake.
Run at 2000 rpm 10+ minutes w/ mild revs.
Torque heads and intake.
Inspect oil filter element and drained oil..
New oil/filter.
Drive easy for 25ish miles avoiding steady rpm.
Check solid lifter lash.
Drop oil and inspect oil and filter element.
Run conventional oil for 500 miles.
Torque heads and intake.
Set solid lifter hot lash.
Inspect filter element and drained oil.
Run slightly used oil through coffee filter and donate to beater car.

[Rufton]

So happens the threads for my steering wheel puller fit and was long enough to draw damper into position. Otherwise a long bolt w/ proper threads and some spacers would work.

[Rufton]

Cleaned one head w/ roloc and other the old fashioned way.

[Rufton]

Thought I'd give Permatex Copper Spray-A-Gasket a try.

[Rufton]

New solid lifters.
New push rods.
New oil pump drive shaft.
Prepping rocker arms for inspection.

[Rufton]

Spent one rotation cleaning cylinders w/ WD40. May squirt a shot of WD40 in plug holes before installing plugs.

[Rufton]

Short block coming together.