The Stovebolt Site Forums The Shop Area Engine Shop Starting a truck w/o a temperature gauge

Hi All,

Well, I'm just about to give the '51 GMC another try (yeah, I'm the guy who went done the driveway backwards with no brakes - see Gallery/1951). Got all the brakes completely redone - master cylinder, wheel cylinders, flex hoses, brake lines. Everything that was on the truck was rusted into junk. Lines looked good on the outside, but when I bent them they broke - rusted on the inside. Lesson there, for sure. Got functional emergency brakes. Final bleed and I'm good to go. Recored radiator is waiting on a support to arrive from Mother Trucker - then back together the front end goes.

Here's the problem - I don't have a functional temp gauge in this truck. I've flushed the block and replaced the thermostat with a new 180 (yeah, I drilled the 1/8" hole - thanks to oldgmctrucks.com). Still, I won't have any good way of knowing how hot the engine is running once I crank it up. Any advice out there on this?

Another thing -

http://chevy.oldcarmanualproject.com/

GREAT site. Tons of shop manuals online for free. Don't know if this is common knowledge, but it should be.

David Bush

Get one of the infra-red temp gauges that registers when you point it at something and pull the trigger. We used those things to check tire temps on the race cars after a hot lap, and they're very accurate. Just point & click at any surface, and you get an instant reading. The coolant outlet neck above the termostat, the radiator tank, or even the coolant in the top tank with the cap removed would be a pretty good source of reference. The tool isn't that expensive, unless you need some outrageously high temp capability.

Jerry

Great advice from Hot Rod Lincoln. Those things have come way down in price and can spot cold cylinders that aren't firing as well as the uses he suggested and more.

i used a kitchen thermometer in the filler neck. but i don't have a significant other to complain. ron

you can get a replacement sending unit from jim carter. part # reme926

Hotrod Lincoln, what brand of IR temp gauge would you recomend?

I've got one from Harbor Freight (the one with the laser pointer built in) and found it to be accurate to with 4 degrees of the really expensive calibrated thermometer I compared it to.

i use a fluke 65. will be pricier than HF but then its that much more durable and better quality. what you need to know about them is that the duller the the target the more accuarate any IR is. it has to do with emissivity and reflectivity settings inherit to the device.

I bought a $10 temp gauge and sending unit and mounted under the dash.
I like to see what is happening from the inside of the cab.

Thanks for all the tips. Anybody have any experience with the repro gauges from Jim Carter (Ashton51)? Looks like they run about $50. Lots of places offer them, but I'm guessing they're all sourcing them from the same place. My gauge is stuck at 220. Think I'll try the IF heat gauge for now, depending on how cheaply I can but one.

David B

i got one from jim for my 40 and it works and it just happened to be in stock. should you decide to go that way you will need to send the bulb and the temp unit from the instrument panel and send that back to them after you put in your new one.

heat guns are fine for spot checking but when im in the office i want to be able to see the temp and the oil pressure at all times.

Cheap-o aftermarket gauge to get by with, then buy a good replacement when you get funds! Joe

That's what I've done for now - $15.99 Sun mechanical gauge from Pep Boys was a straight bolt in - didn't even have to change the fitting in the head. Tested it and it works, but reads about 10 degrees cold (water boiling at 202). Thanks for all the tips.

David B

Hi All,

Fired her up today! Yee Haw! Ran for about 30 seconds and died as if I'd cut the switch. Had gas, figured it was electrical. 1st guess, the points had closed up on me. Pulled the cap and that was it - still got the old points in, got to swap them out. Regapped them and tightened - she fired right off. Let her run up to temp, until thermostat opened. Cheapo temp gauge worked just fine.

Looking pretty good - no blue smoke, really rough idle, but plugs and points will help (already got new cap & rotor). Drain plug on side of block behind gas pedal linkage is leaking. It's the one that looks like a radiator draincock. I'm guessing that's a standard NAPA part - anyone know? Service brakes and emergency brakes working. going to run a block flush through tomorrow. Drain system, add the stuff, fill with water, run 10 minutes, let cool, drain. Supposed to help clean out the water jacket on engine. Any body used this stuff?

I've used products like the radiator flush you have in mind with little visible success. I recently got a Mustang running for my pastor that hadn't been started in 20 years. I ran the cooling system flush through, old style agressive stuff, then the neutralizer, the coolant was still very brown and rusty. I flushed it twice more with straight water and it was still pretty brown. I'll be flushing it again at every oil change until it is no longer rusty.

Devin

Interesting thing about points. I replaced the points in a small fleet of Chevrolet C-60s and decided they didn't need lube on the distributor cam. Not really being cheap, just stupid.

They started quitting within a week. I had to replace them all again, and I did lube them this time. No more problems.

The point is that distributor cam lube turns into something else after sitting for 20 years. I think a lot of people could avoid problems by lubricating the distributor cam before trying to start the engine.

auto zone carries a radiator cap with a built in thermometer for my 54/235. i had issues with the gages and did this as a back up. ron

oster: WE b OLD
Subject: Re: Starting a truck w/o a temperature gauge

auto zone carries a radiator cap with a built in thermometer for my 54/235. i had issues with the gages and did this as a back up. ron

Thanks, but $15.99 Sun gauge seems to be working fine. Got in new points, condenser and plugs tonight. Curious to see what the difference is tomorrow in the way she runs. Old plugs were Champions and the electrode had to be bent way down to get the gap set properly. Replaced with Delco R43s.

We had blue smoke and a maiden voyage yesday! First time this truck has gone around the block under its own power since 1976.

I took Aston51's block draining tip from oldgmctrucks.com and I'm really glad I did. I had already drained and flushed the system (or thought I did), but the block drain behind the exhaust manifold was just seeping some nasty looking crap, not really flowing. I completely pulled the drain valve off - still almost no flow. Got a piece of heavy wire like he suggested and started working that sucker around in there. A big blob of some particulary nasty crap cleared and then you should have seen the rusty water run out. Lots of solid, sandy looking crap in there - amazing that the engine wasn't overheating (who knows, maybe it was in '76). OldCarKook suggested that it's the leftover casting sand from original assembly. Kept refilling the radiator after replacing the drain, then pull the drain and work with the wire some more. Finally got a consistant clear stream of water. Then I used 2 bottles of Prestone Fast Flush, filled the rest of the way with water.

Cranked her up - almost ready to go. I've got new points, plugs, rotor, dist cap and condenser in, but the truck idles roughly. Wires were replaced a long while back (10 years?), but look good. I went to each plug in turn and pulled the wire. I could hear the engine roughen slightly as the plug didn't fire. Didn't find any dead cylinders. Accelerator pump is gone in the carb, so you've got to do a bit of gas pedal jiggling to keep it going as you give it gas. Not sure what's causing the rough idle.

Now, time to tackle the dreaded driveway. We taped the whole process this time and, if I can figure how to do it, I'll post it. Brakes seemed a bit grabby, but working fine to go down the steep drive. No exhaust system, just a short exhaust stack stuck on at the manifold, so it's LOUD. Steering remarkably tight (makes me believe the 24,998 miles on the odometer). Synchros in the trans feel good, but shifting is a bit stiff. All gears working with no weird noises, no jumping out of gear.

Pulled a few hills in 2nd and the truck pulled great. I expected the rough idle to translate to missing and skipping under load, but it just didn't happen. She pulls like a Trojan when you give her some gas. Anybody got any ideas about this missing at idle? Got a Zenith carb rebuild kit on the way since I know it's needed, but wondering if it might help with this problem. Maybe valve adjustment? Any opinions welcome.

Got back home and couldn't back her up the steep drive because the truck was so light in the rear (all the wood's rotted away). Spun tires and played hell for three tries before I gave up and came up front first. Let her cool completely and then pulled the block drain. Another load of rusty looking crap came out. Flush, fill, flush, fill until water is clean.

Well the plan was to go around the block under power before Christmas - got her done with 10 days to spare. Merry Christmas to me.

David B

Congratulations! Nothing like that first ride!

Devin

Thanks, Devin. Any ideas about that rough idle? Carb? Valve adjustment? Timing? Guess I'd better check all three. Can't figure why it would idle so rough and then not break down at all under a load.

David B

David,

The carburetor idle circuit is different than the mid/high speed circuit. You can have trouble in one, and not the other. When the engine is actually idling, any problem would be more apparent as it's just loping along.

Stuart

The short stub pipe might be part if the miss, or at least magnifying the problem. Rebuild the carb before getting worked up about it. A miss like that can show up at anytime!

Good job on the first drive, its pretty cool to finally get it out on the road!

Joe

Thanks, Joe. I actually wondered about whether the short exhaust stack might be causing some problems (no back pressure), but wasn't sure. Got to pay to get the exhaust done, though, and that'll have to wait until after Christmas. Meanwhile, carb rebuild kit is on the way from Jim Carter for my Zenith. I'll keep you posted.

David B

If you want to do a really aggressive cooling system cleaning, use muriatic acid- - - - -the same stuff that cleans bricks, or goes into a swimming pool to adjust the Ph. Put about 6 or 8 ounces into the radiator after filling it with clear water, run the engine up to operating temp, drain and refill with water. Add two boxes of baking soda to neutralize the acid and run for 5 minutes. Drain, flush with clear water, and refill with a 50/50 antifreeze/water mix. I used that method on a bunch of concrete mixer trucks I used to maintain that were clogged up with limestone dust in the cooling system. Works like a champ!
Jerry

That casting sand reminds me of my favorite Russian Tank story. After one of the mid-east conflicts the Israelis gave the US one of the T-64s that they had found idling with no crew in it. Curious US personnel at Boatwright found more than 2 pounds of casting sand in the oil system. Those are tough engines but almost always put out as much oil smoke as Diesel smoke.

You should be brought up on charges for doing that to that beauty.

I broke in my engine without a temp gauge. A professor of mine told me humans can only withstand temps of around 140-150F on the hand. My radiator didn't get much hotter than I could touch (on the metal), so the water wasn't much hotter than my thermostat rating (165 or so). You could do it that way, but make sure you're circulation system is flowing ok. Also, don't be afraid of a little smoke and fumes right after it warms up if you're dealing with a freshly panted/assembled engine. Just make sure they die down after about half an hour.

My 52 GMC 100 was painted the same original color. Nice truck, and good luck with your project.