1966 GMC 305 V6 Service

[Rufton]

Originally Posted by MusicMan70

That's awesome Ruf; need more pics ya'know.

Thanks.
I'll post a few more pics.
Took a low res video but couldn't sneak it in as an attachment.

[Rufton]

Some things I did for kicks:
Took some lift measurements for reference.
Used 2 stroke fuel as starting fluid.
Put 5 gal 50:1 ratio 2 stoke fuel in tank.

[Rufton]

When I went to hook up tach I noticed coil +/- hooked up opposite than I think it should be.
Coil polarity wrong for decades I guess; ran fine though.
I connected coil "-" to distributor.

Capacitor wire broke off; maybe something to do w/ radio interference.
Don't know if cap difficult to find.

[Rufton]

Complete GMC 305E V6 solid lifter

[jbgroby]

Rufton,

I did not read through every post, but IF you have not made the following modification I would suggest it.

Add the petronix ignition and get rid of the points and stuff. It will be the best $75.00 you spend, installs in less than 10 minutes.
I did it and not regretted it.

Jake

[Rufton]

Originally Posted by jbgroby

Rufton,

I did not read through every post, but IF you have not made the following modification I would suggest it.

Add the petronix ignition and get rid of the points and stuff. It will be the best $75.00 you spend, installs in less than 10 minutes.
I did it and not regretted it.

Jake

Thanks Jake.
I've experimented w/ Pertronix.
It is a fine ignition that allows you to keep OEM distributor cap
I found no increase in mpg and couldn't detect smoother operation.
One advantage of points is you can cheaply keep a spare in glove box.
One advantage of Petronix is it maintains accuracy over 5000 rpm.
My rule of thumb is to keep points in sub 5000 rpm and sub 5000 miles per year.

[Rufton]

Dropped the first run oil and I'm happy.
Have to look close to see any trash on element.
I didn't find any large glitter.
Couldn't feel any metal on rare earth magnet inside pan.
Little trash inside canister unfiltered side but not bad at all .

That 1/4" dot on bottom of canister is where I punched drain hole in effort to avoid mess. Ended up making a mess anyway

[Rufton]

Driving around I noticed I don't have to hold teeth just right to avoid clutch chatter. Both driver side mounts were loose before rebuild which explains chatter. The driver side trans mount dropped bolt which would have been an easy fix had I noticed. The engine mount rubber separated from metal which isn't obvious. The passenger mount was attached but loose.

I've weened 2 cycle oil to 100:1 ratio in fuel.

Break in tip: Squirt valve train w/ oil during first few minutes; can't hurt but may help.

[raylube]

This picture reminds me of your rebuild

[Rufton]

Originally Posted by raylube

This picture reminds me of your rebuild

Wow!
Thanks for that pic.
It made my day!

[TommyDuncan]

I know it's kinda early but I am really curious what kind of mileage you are getting.
Are they really as bad as they say?
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[Rufton]

Originally Posted by TommyDuncan

I know it's kinda early but I am really curious what kind of mileage you are getting.
Are they really as bad as they say?
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I'm very curious about the mileage also. I log mileage every fill. I put smaller main jets in worn out 305E last year and improved hwy mileage from 10 mpg to 12 mpg. The compression was so low and oil consumption so high I was surprised it didn't foul plugs. I hope the fresh 305E will do better. My gear oil in rear and trans may be too heavy for mpg; I'm thinking of switching to lighter gear oil.
I expect initial readings to be low because not fully broken in.

Guess I should road trip to get mpg data faster

[TommyDuncan]

Originally Posted by Rufton

I'm very curious about the mileage also. I log mileage every fill. I put smaller main jets in worn out 305E last year and improved hwy mileage from 10 mpg to 12 mpg. The compression was so low and oil consumption so high I was surprised it didn't foul plugs. I hope the fresh 305E will do better. My gear oil in rear and trans may be too heavy for mpg; I'm thinking of switching to lighter gear oil.
I expect initial readings to be low because not fully broken in.

Guess I should road trip to get mpg data faster

thanks for the reply. What rear end gears are you running?

A friend of mine had one of these and swears he got 7mpg no matter what. He also said it was geared to low for much hwy use. After looking at their low rpm torque curve I wonder if it is necessary to gear them that low?
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[Rufton]

Originally Posted by TommyDuncan

thanks for the reply. What rear end gears are you running?

A friend of mine had one of these and swears he got 7mpg no matter what. He also said it was geared to low for much hwy use. After looking at their low rpm torque curve I wonder if it is necessary to gear them that low?
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Pre 2012:
305E loves 70+ mph cruise
3.07 dana 44
P235/75R 15 28.9"
Stromberg WW 280 CFM 2bbl
Main jets 0.055", 0.054"
Poor compression
high oil consumption
2" single exhaust pipe
quiet muffler
mix 8-9 mpg
70mph hwy 9-10mpg

2012 changes:
Main jets 0.050", .050"
70mph hwy 11-12 mpg


2013 changes:
Main jets 0.050", .050"
305E rebuilt
Good compression
Low oil consumption
mpg to be determined

[TommyDuncan]

Originally Posted by Rufton

Pre 2012:
305E loves 70+ mph cruise
3.07 dana 44
P235/75R 15 28.9"
Stromberg WW 280 CFM 2bbl
Main jets 0.055", 0.054"
Poor compression
high oil consumption
2" single exhaust pipe
quiet muffler
mix 8-9 mpg
70mph hwy 9-10mpg

2012 changes:
Main jets 0.050", .050"
70mph hwy 11-12 mpg


2013 changes:
Main jets 0.050", .050"
305E rebuilt
Good compression
Low oil consumption
mpg to be determined

thank you again!

There is a really clean long bed knee knocker that has been sitting for at least 5 years that I am slowly convincing the owner to sell to me. I wanna like the V6, I really do...
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[Rufton]

Originally Posted by TommyDuncan

thank you again!

There is a really clean long bed knee knocker that has been sitting for at least 5 years that I am slowly convincing the owner to sell to me. I wanna like the V6, I really do...
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You don't have to like the V6; I have a place to store it

[raylube]

Guess I should road trip to get mpg data faster

here is a suggestion

[Rufton]

That truck used to have an "It's a Doozy" camper top that looked like that.
Functional but looks only a mother could love

[TommyDuncan]

I just reread this whole thing(again)...

...any updates? How's the mileage doing?
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[Rufton]

Running great.
Only put 250 miles so far.
Only getting 9 to 12 mpg.
Has steering vib above 60 mph.
Plan to address vib next.
Then tune distributor.
Maybe AFR and vacuum gauge in future.
Maybe dual exhaust in the future.

[TommyDuncan]

Thanks again for taking the time to do this write up. It has been a big factor in finally buying the truck I mentioned earlier.
It is a 62 with a 4 speed Hydramatic auto and it's pretty heavily optioned and complete down to the hubcaps and radio... the way it was parked and the fact that I was on his land for work made it hard to get an up close look. Stay tuned for a build thread starting in the fall.

I might be in the market for engine parts soon also if you have any leftovers?
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[Rufton]

Your truck looks good; looks straight and solid from here.
Have spare short block but you probably don't need it.
I was tempted to hoard some ebay and Rockauto parts but didn't.
Wouldn't hurt to check hot lash, compression, plug color, head temp, etc.
I glued gasket to vc and it's still leak free even though it's been removed a few times.

[TommyDuncan]

Originally Posted by Rufton

Your truck looks good; looks straight and solid from here.
Have spare short block but you probably don't need it.
I was tempted to hoard some ebay and Rockauto parts but didn't.
Wouldn't hurt to check hot lash, compression, plug color, head temp, etc.
I glued gasket to vc and it's still leak free even though it's been removed a few times.

The owner before last used a barrel nut and some all thread to convert it to a modern air filter. The barrel nut rattled loose and went into one of the cylinders while it was running and I guess it made some noise before he shut it off. He thinks it was brass but couldn't remember for sure. I have no idea what damage that could've done?
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[1963c-10]

Rufton....engine came out great

[Rufton]

Thanks.

Unlike modern engines, 305E head remove/install is kinda fun (for gear head). I wouldn't run it a second before pulling head or using an inspection scope camera to have a look see. If very lucky you may retrieve through plug hole; then buy lotto