Black Widow Build (1960 1/2 ton)

[60ShortStpeGMC]

I bought this truck in March, 2013. It ran and was mostly all there but the right-front wheel bearings were missing. If I remember correctly, the purchase price was under $900 - which left me room for trailering and the expensive wheel bearings.

I've done lots of small things to this truck since purchased. I'll list 'em here, adding photos where I have them. Eventually bring the build up to date. It still has the 305v6 in it.

I call it the black widow because after two days in my garage there were 3 or 4 fresh webs and associated, fat black widows roosting between it and the floor. The truck was built in Oakland, still resides in California. Lots of rust from the Bay Area, something I didn't really understand at the time.

Attached photo is straight out of the CL ad I found the truck in. After cleaning up all the spiders, I found the 4 original hub caps under the seat. :thumbsup:

[60ShortStpeGMC]

This is a list of the various and sundry items I changed on the truck during the first year :
April

- installed inner & outer wheel bearings, front passenger side - added missing lug nuts - replaced air filter & housing (in hind-sight, I shoulda just modified the housing to accommodate a standard filter) - added 8-ball gear shift knob (father-in-law extracted from his attic and drilled it out for me) - added turn signal controller to fuse box - wired turn signals to fuse box - fixed broken lug, driver side rear - wired cigarette lighter to fuse box - removed old floor coverings - removed "tow hitch" wiring - added driver side exterior rear view mirror
May

- changed oil & filter - adjusted exhaust pipe and muffler - removed bed rails, pinned down plywood bed (everything rattled like heck)
June
- added reflective foil to front turn signal housings - removed old speedometer cable
August
- replaced steering wheel w/one from '62 C10 (had a shmarmy 80's style steering wheel, good riddance) - added V-6 emblems to hood ($10 for the pair at local swap meet, couldn't help myself even if they're not factory corrrect) - trimmed plywood bed and re-pinned it down - replaced rear springs w/used springs from '62 C10 (old springs had been "heat treated") - replaced speedometer cable (used 68" length, can use 62 length") - rewired rheostat on old fuel sending unit (this didn't really help things though) - replaced fuel sending unit gasket and mounting hardware - removed seat, spray painted interior floor and sill plates - patched upper door sills (under drip rail the whole section was gone, both sides. Cut and bent some thin sheet metal, riveted in place and "sealed" with black poly-euro seal) - eliminated steering wheel wobble - removed exhaust pipe from muffler rearward (tried to cut it, but entire thing came off in my hand)


September

- cut exhaust pipe and added short piece behind muffler - cut and installed dash panel patch cover (got into the free pieces bin at the local plexiglass place) - cut and installed front turn signal covers (that free bin again)
- refurbished stock turn signal switch at base of steering column (not currently using it, but had fun learning. Practiced on a '62 column first.)
October

- refurbished front turn/parking light assemblies (grounding issues fixed)
- intalled new yellow bulbs in front turn signals - installed used gas pedal
November

- replaced both brake/turn signal assemblies with new ones ($7.50 ea at Pep Boys, yep went cheap but they look fine. Spent a minute spray painting the insides for a touch of class) - replaced screws that hold fuse box to firewall - restored brake/turn/running light harness connector December

- replaced positive terminal battery cable - replaced battery
- replaced locking gas cap - added battery hold down assembly
- added two seat belts (after the kids slid across the seat during an average left turn this addition became a little more important) - added exterior peep mirror, removed temporary exterior mirror.

[6066gmcguy]

Great Truck, would love to see more pics.

[FetchMeAPepsi]

Lotta work already! I second the need for more pics. Every time you post a pic of a GMC an angel gets it wings. :thumbsup:

[60ShortStpeGMC]

A couple other pics of the truck.

[60ShortStpeGMC]

January
- replaced tail gate chains - purchased front hubs from 69 c10
- installed lock set (ignition, door locks, glove box) - rebuilt master cylinder - drilled holes for middle seat belt - purchased master cylinder & power brake booster from '71 Suburban (failed with this effort) - replaced all screws holding window actuator in the door panel on driver side, replaced most of them on passenger side (rust issues)

February
- installed new valve-cover gaskets - sent stick shift to blacksmith for bending - finished rebuild of '69 front drums/spindles (these were farm fresh to begin with) - installed new water temperature sending unit - installed new shift lever boot - purchased Captain Fab's bracket/clutch m/c kit
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March
- remade battery cable ends - tested alternator, works fine

April
- removed stock master cylinder - installed Captain Fab's bracket on firewall - added clutch master cylinder - added brake power boost master cylinder (87 chevy s-10, had all manner of issues finding a coupling for brakeline to m/c) - replaced all clutch tubing - replaced all brake tubing for rear brakes (reused tubing for front brakes, hand bent some and used prebent) - clutch pedal and brake pedal linkage customized - replaced front and rear brake hoses
3918
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June
- replaced heater faceplate/control unit with used one

July
- replaced fuel pump and fuel lines (the truck came with an electric pump, so I continued with that. Bent my own lines.) - replaced fuel sending unit

August
- replaced chevy horn button with gmc horn button

December
- rebuilt orignial heater faceplate/control unit and reinstalled (the rivets holding the rear bracket to the faceplate were shot. I finally got enough nerve to drill into the rear of the faceplate and thread some screws)

[60ShortStpeGMC]

Hold tight, this'll bring us up to date here in 2015.

February
- replaced front hubs/drums with hubs/drums from 1969 c10 (yes, this match up really did work. Now my bearings cost $30, or whatever, not $100. Plus, a modernization benefit.)

April
- rebuilt wood bed using original plywood that was laid over everything - replaced tires (with used tires....{sigh} budgetary restrictions)
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May
- won "diamond in the rough" at local car show :signthankspin:
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- at the car show with me are two out of the three reasons my truck budget is so low (father-in-laws red POS just beyond the nose there) - drove the heck out of the truck -

June
- drove the heck out of the truck part two (nothing better than a running/driving old truck!)

July
- replaced alternator (went with same as 75 chevy nova:63 amp, 3 o'clock pin location) - replaced starter solenoid - rebuilt Rochester 2g carb (new carb for about $45)

August
- replaced holley 1904 carb (single barrel) with Rochester 2g (because it was free..er..$45) - bought a hinky $15 two-to-one adapter (but, I mean, what the hey) - replaced original throttle linkage with cable - removed choke cable (just a temporary clean-up procedure) - installed "glow skull" in dash (yep, gimmick. but, pull the lights on and it glows: a decent "lights on" reminder. Monkey wired some inline fuses to dim the blinding glow-skull powers.)

September
$ all spent - reduced to toying with carb return springs and etc - clutch went out in between runs up and down the block (fortunately while in the garage)

October
truck fund still empty - pulled transmission (father-in-law said "oh sure, just lower it with your hands and rest it on your chest".)
:ahhhh:
- for the casual reader, be advised that the SM420 weighs about 135 lbs. (my father-in-law later said "well I never'd done one of those!". and to this date he still hasn't :teehee:) - removed clutch assembly
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November
- purchased clutch set (shout out to FetchMeAPepsi for the parts #s) - $ all spent - tried and tried and tried and tried to nudge them flywheel bolts free

December
- paid reg - $ all spent - applied liberal amount of penetrating oil to flywheel bolts, waited designated time and... pulled flywheel (finally!)
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[TJ's GMC]

Good looking truck! In for the build.

[6066gmcguy]

when I hear "Black Widow" I think of the old Southern Pacific paint job called the "Black Widow", here are some of my fleet of SP N-scale locos from one of my other hobbies.

[60ShortStpeGMC]

I like it.
In fact, a set of red side-wall tires might be in order.

[60ShortStpeGMC]

Ed - I like the "work truck gone bad" on the tailgate. The door panel webs are cool too. Heck of a truck.

[60ShortStpeGMC]

Cool beans, got the fly wheel resurfaced today. Finished with clutch reassembly this evening.

Flywheel before:
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Flywheel after:
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Clutch assembly installed and the throw-out bearing and fork.
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Next up, install the tranny. :upyes:

[60ShortStpeGMC]

Gettin' close...

3993

[GMCNUT]

All Solid Black 1955 through 1960 GMC trucks came from the factory with the wheels painted Aspen Green if you can believe it - almost none exist today that way, but that's how they came originally when new. Aspen is a green color about as loud as the green color of Pistachio ice cream - almost like glow in the dark green. I am not sure I can bring myself to do it to my own Black 1960 GMC when it gets a repaint (mine is known as the "Black Phantom" on this board) but I definitely dare you to consider adding that GMC-only oddity to yours and see what people say when you tell them it is supposed to be painted that way....LOL

[60ShortStpeGMC]

LOL

I saw a late 60's Ford, all black with an Aspen green grill today. Kinda made me flinch. I'll pass on painting my rims that color. :teehee:

[60ShortStpeGMC]

I have had a difficult time getting the transmission to mate with the bell housing. I can get it within the last half-inch only to be stopped cold. :banghead:

I went searching around the webs to find out what else I could do besides rent a transmission jack. It just so happens that I found the answer on another truck forum. Somebody said that they buy longer bolts than stock, cut the heads off and use them as guides.

Long story short, that solved my problem. I didn't buy bolts, however, I bought threaded studs instead. Same difference but saved myself some time and effort.

Now to figure out why the clutch doesn't engage.... :ahhhh:

[60ShortStpeGMC]

Hm, newly installed clutch doesn't disengage. :banghead:

Based on some reading, I checked the following:

Master cylinder: new, works good, plenty of fluid.

Slave cylinder: old, no leaks, visibly works good, plenty of fluid.

Throw out bearing: new, in throw out fork, clutch pedal readily moves bearing, looks like bearing engages pressure plate springs, though at the end of the clutch pedal stroke.

Throw out fork: original, operational (e.g. not bent or broken), mounted correctly, clutch pedal readily moves fork.

99% sure that the clutch plate is not installed backwards. It simply wouldn't fit if I did - at least I think so.

Only thing I can see is that the clutch plate appears to be pinned between the flywheel and the pressure plate. Odd. I thought it was supposed to float between the two? :helpsign:

4073

[David R Leifheit]

Hm, newly installed clutch doesn't disengage. :banghead:

Based on some reading, I checked the following:

Master cylinder: new, works good, plenty of fluid.

Slave cylinder: old, no leaks, visibly works good, plenty of fluid.

Throw out bearing: new, in throw out fork, clutch pedal readily moves bearing, looks like bearing engages pressure plate springs, though at the end of the clutch pedal stroke.

Throw out fork: original, operational (e.g. not bent or broken), mounted correctly, clutch pedal readily moves fork.

99% sure that the clutch plate is not installed backwards. It simply wouldn't fit if I did - at least I think so.

Only thing I can see is that the clutch plate appears to be pinned between the flywheel and the pressure plate. Odd. I thought it was supposed to float between the two? :helpsign:

4073

Does this bearing look like the old one?
There are two throwout bearings for these trucks. A long (or tall) and a short. I suspect you need the long one, I also suspect that the bearing when the pedal isn't pushed down sits loose and doesn't contact the fingers on the pressure plate at all.

Either that or there needs to be some adjustment made on the pushrod to snug the system up.

The disc *should* be pressed against the flywheel and pressure plate when the clutch -isn't- depressed. I've never looked to see how much space is created when the pedal is depressed, but it likely isn't much.

While I should have throw outs of both types in my trucks, I am not pulling the transmissions so I can take pictures (and the ground is swampy so crawling under is a nasty proposition) as most (if not all) of my trucks have that same, or similar, very "light" transmission.

-If- the throwout is fine, and the pushrod length is fine... then _gremlins_.

[60ShortStpeGMC]

Does this bearing look like the old one?
There are two throwout bearings for these trucks. A long (or tall) and a short. I suspect you need the long one, I also suspect that the bearing when the pedal isn't pushed down sits loose and doesn't contact the fingers on the pressure plate at all.

Either that or there needs to be some adjustment made on the pushrod to snug the system up.

The disc *should* be pressed against the flywheel and pressure plate when the clutch -isn't- depressed. I've never looked to see how much space is created when the pedal is depressed, but it likely isn't much.

While I should have throw outs of both types in my trucks, I am not pulling the transmissions so I can take pictures (and the ground is swampy so crawling under is a nasty proposition) as most (if not all) of my trucks have that same, or similar, very "light" transmission.

-If- the throwout is fine, and the pushrod length is fine... then _gremlins_.

Aha! You make a couple of very interesting points. :thumbsup:

I'll take your word about the clutch plate and scratch it off the list for now. And the slave cylinder push rod is almost maxed out. I even placed it on the outer end of the fork for additional travel/leverage.

The new throw out bearing was pretty close to the old one, but, if memory serves, not as tall. Also, I'm pretty sure the throw out bearing is not pressing against the fingers of the pressure plate when the clutch is not engaged.

Thinking about your feedback, it would seem that my problem could be solved if I had more travel in my clutch pedal or slave cylinder push rod. So you're probably spot on - the extra travel could be absorbed with a taller throw out bearing.

Thanks, that gives me something to go on. :teehee:

[60ShortStpeGMC]

Getting the correct throw out bearing solved the problem. In this photo you can see the difference in height (or width in spec-speak).
4212

The installed bearing is identically sized to the original. I had to adjust the slave cylinder push rod, but that was it. Running driving truck now.
:upyes:

[60ShortStpeGMC]

Although my last entry said "running driving truck", that's not quite right. Before the clutch went out I was tuning a Rochester 2jet, trying to get it to run on my single barrel manifold.

I was using a jinky adapter. I say jinky because it was a $14 item that, well, looked like it was produced as an after thought.
4424

Too its credit, the adapter did it's job. But I was experiencing hesitation during acceleration from a stop. Which, my research said, was probably a vacuum leak. Sure enough, the vacuum can on my distributor was shot. Replaced it.

Adjusted the points. Adjusted engine timing. Still hesitation during acceleration from a stop. Good 'ol hose-to-the-ear-trick revealed a vacuum leak at the base of the adapter.
Well, bummer, but not too surprising. The gasket there was very thin. In fact I had a second gasket on there that I'd cut out of thin cardboard.

Figured the ultimate test was to replace the gaskets with a gasket sealer. Yep, I did that. Very carefully. And only as a test - wanted to know if that would cure the leak. But, alas. Still sucking air - less than before, but still a leak. Still hesitating on acceleration. Uh-oh, looks like more than a vacuum leak...

Started thinking that maybe the adapter isn't a good match with the intake manifold. Figured I'd need a new gasket, a good one, and maybe clean each surface real good. Possibly check the base of the adapter, make sure it was "level" or flat or whatever.

That means removing the intake manifold.

Dang, I only wanted to remove the intake in order to replace it with the new-to-me 2 barrel manifold I picked up a while back. But, that manifold doesn't directly fit my 2jet either. Bummer. But heck, gaskets are cheap, right? Keep the two-barrel on hold a while, clean and adjust the surfaces. Fix the vacuum leak, then proceed to checking the carb.

But that means removing the intake manifold.

Browsing around the net I found some quality adapters that might actually work with my 2jet and two-barrel manifold. After much reading, the manifold fits a "small Rochester" carb as-is. Good to know. But my 2jet is the "large" variety. After more reading, turns out that Dashman (<br><font color='red'>To view some links or images in this forum your post count must be 1 or greater. You currently have 0 posts. Maybe you should introduce yourself with a new topic?</font><br>) sells an adapter for a "small Rochester" manifold to a "large Rochester" carb. Nice stuff too.

Luckily, I had the money. Bought a Dashman's adapter and ... the two barrel manifold is in action.
4425

:thumbsup:

Man, I had to fight my way through 40-odd years of gunk!
4426

Still, hope I'm not shaving a yak here. Even if the new adapter/manifold swap cures the vacuum leak, the hesitation on acceleration hasn't been totally addressed. Likely something with the carb. Since I rebuilt it, I wouldn't be surprised something's amiss. I guess it's time to break open the 2jet again.

[60ShortStpeGMC]

First thing I did was adjust the float.

Second thing, it seems like the original vacuum pump spring was a li'l bit softer than the new one. Very good condition still so I swapped 'em out. The neck of the new one seemed to hang up on the linkage it attaches to whereas the old one swiveled smoothly.
After all is said I done, I suspect this was unnecessary.

Third, I shortened the throttle rod.

Put it back together and stuck it on the engine.
4428

Had to play with the idle a lot. Ended up lengthening the throttle rod a tad. After that, I managed to get a decent idle and air/fuel mixture.

And no hesitation during acceleration. :ahhhh:
I did a happy dance right there in the garage.

Had to fart around with the throttle return spring. Actually might have an issue with the throttle body blades. They seem to want to stick open that last 1/16" of an inch instead of returning to the proper idle speed. Changed the bracket location and changed the springs and the issue is almost gone. I'm letting that issue sit a while. After a few more miles I'll do more about it. Yes, that's the wait-and-see technique.

Meanwhile, a running driving truck. woot!

[60ShortStpeGMC]

So the hesitation during acceleration showed up again. Dadgum. :pullinghairout:

Decided to gasket-ize the new adapter. Right in the middle of the two adapter pieces. Just in case. While I had the carb off I inspected the throttle blades. They were sticky before I rebuilt it. Certainly not sticky. Double guessing myself is all. But, found that the throttle cam moved a wee bit before the accelerator pump moved.

Hmm.

Sure enough, the throttle blades would open about 1/16th before the accelerator pump would engage. "Gee" I said, all by myself in the garage. "Wouldn't that mess with the air/fuel mixture?" I'm sure the old-timers reading this are saying 'saw it right off'.

Long story short, adjusted the "throttle rod" to remove all play in the throttle cam. Hesitation at acceleration gone. :thumbsup:

[azlamm65GMC]

Nice

[60ShortStpeGMC]

Ran through the old posts. Dang! Got rid of that big-base rochester a long while back. The aluminum adapter was really very nice but didn't work out. Yes, carb icing is a real thing.

Have a small-base rochester on there now. Hey, no adapter! New tires. She's running good.
7049

Recently had a notion to get rid of the points. Bought an ignition module, cap, rotor, wires and plugs. Everything worked great. Couldn't spin the distributor enough to get it tuned, vacuum advance pot hit the coil bracket.
:upyes:


Time for a new bracket. I guess.
7050


Got timing between 5 and 10. Seems right. Runs well. Drove well. Quickly developed fuel leak during test run. :banghead:
Must be a rochester thing.

The original coil bracket, if you're curious, can be seen here.
7051

[60ShortStpeGMC]

Fuel leak wasn't a Rochester thing after all. Turns out that I replaced the needle, seat, and float - leak went away. :thumbsup:


Hesitation at acceleration came back. Messed with the accelerator pump rod more. Upped the curb idle speed. A fast idle, but almost no hesitation. Test drive was ok but engine would "diesel".


Took another look at the timing. Dialed it in, again and adjusted curb idle speed to 800 rpm. I think that's right. Sounded good, better than before. And no "dieseling".



Test drive was good. Even had accelerator response. I probably need to adjust air/fuel mixture. But, until then, time to drive it a while.

[60ShortStpeGMC]

So after poking around this site, I found that the idle speed is spec'd at 400-450 rpm. My 800 rpm was pretty far off. :teehee:



Turned down the curb idle speed, but just couldn't reach 400-450 rpm. Even with a touch up on the timing. Settled at 600 rpm.


So, it drove well still. No hesitation and no leaking. Can't be all bad, right? I'll be convinced after I try a cold start tomorrow.


Learning to love my nerd kit...
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