Used the temp gun tonight. Read hotter at the rear until the stat opened up. 190s on the thermostat housing, up to 208 on the surface of the back of the head. Seemed to regulate ok after that with low 200s on different points on the head. Not sure if that's unreasonably hot for the surface of the head. Does not want to restart when hot. Will probably end up rebuilding the carb.
Meaning... It doesn't crank? It cranks slowly, or "bucks" against the starter? It cranks fine, but just won't fire off?
6V systems rely on current flow as amp draw is 2x 12v. Ohm's law and all that. Wires need to be nice and thick, battery primaries should be o gauge at minimum. Rule of thumb for accessories, lights, heater, other similar loads 12 gauge, interior lights, or similar 12 gauge, light loads like ign 14 gauge. Good grounds are absolutely necessary for all items. I good ground strap feom body to engine or frame will usually make a large difference in how 6V stuff works. Dim lights, check the grounds, slow cranking clean and tight connections through the circuit. other lights 6v watts and 12v watts are the same so a proper 30 watt 6v bulb will be as bright as a 30 watt 12V assuming good circuits and connections. As far as needing a 12v starter to spin the engine rapidly to effect a good start, remember that these cars were only separated from cars that had hand crank starts but 10 years or so. So make your decision but a well maintained 6V system should perform is it was designed when these cars were daily and nightly drivers. Winter too.
Mopar L head 6 cylinder engines have a sheet metal tube in the main coolant passage in the block. Most people will assert that it is to feed coolant to the rear of the engine which it actually restricts as it is a tapered tube which lessens flow at the rear. It true purpose is to direct coolant out slots in the top of the tube toward the area of the valve seats. The taper of the tube follows the fluid dynamics design evidences by long run forced air ducts where the diameter of the tube gets smaller as it gets farther away from the heat source. and the size of the difusers alss gets smaller. The tube is the same, it tapers from front to back and the slots that force coolant upwards toward the valve area of the block go from large to small. Pretty advanced engineering for the times. Don't know if Nash was equipped the same. For your hot start problem, you are probably dealing with perculation. Under hood heat causes the fuel in the carb bowl to expand and overflow into the intake manifold. this may happen for several cycles until the residual pressure left in the line from the pump to the carb will no longer flow gas. So tow things cause the hot start issue. An intake manifold flooded with raw fuel, and a lack of fuel inthe line between the pump and the carb. Ethanol and current fuel mixes make it worse that gas in the 40's and 50's. The easiest way to deal with it is to set the float level lower so that there is less fuel in the float bowl and more room for it to expand before it overflows. I set mine about 3/32 different from factory spec. This has eleviateted my hot start issues. Also use a flooded engine procedure to restart your car after it sits for a while when its hot out. Slowly push the gas pedal to WOT then engage the starter, no pumping, just hold it open till it starts.
50/50 mix of coolant and water boils at apx. 220 degrees or more. So running at 180/190 still gives you a 30/40 degree cushion before boil over. Also your non pressurized system will seek it own level of coolant need. If you are refilling it because it puked some out after running, you are giving it more than it wants or needs. You need to have some expansion room in the tank. Typically as long as the cooling tubes are covered by a half inch or so you should be good to go. The 160 thermostat should be fully opened by 160 degrees, but that has not much to do with the final operating temp of the engine. These like to run a little hotter that what you may be used to especially if you are used to a pressurized system, as the pressure also raises the boiling point of the coolant mix.
Thanks for the info on operating temp. I felt much more comfortable last night after letting it run and equalize and checking everything with an IR thermometer. My only question now is how will I actually know if it IS overheating? Coolant boiling over? How hot is too hot? And when I say it doesn't want to restart when hot, it cranks just fine just won't light. Thanks guys. -MK
Have you pulled your plugs to see what they look like? Reading them can give you a lot of information about what is happening in your combustion chambers. coolant temp ranges of 170 to 190 are pretty typical.
Update: -Fiddled around with idle adjustment screw, still won't idle. Purchased a rebuild kit for the Carter WA-1 carb that's on there. -surface temps on the cylinder head are still around 200-210 at max when warmed up. Going to pull the radiator cap to verify coolant flow then see about sourcing a replacement water pump or rebuild kit
I agree with you on the motor oil issue. A factor that is missing is- cars of that era using factory recommended oil were lucky to see 50k miles without an engine overhaul, cars with todays multi weight detergent oil see 300k.
What is the temp of your thermostat? 200 - 210 does seem a little high. Could heat from the exhaust manifold be a factor? Did you check your rad? Cool spots could indicate poor coolant flow.
Thermostat is 160. Radiator was professionally flushed and checked by a shop familiar with old radiators. Temps are pretty consistent once the thermostat opens. Manifold is a log style bolted directly to the block, but I doubt it's a factor as I'm measuring directly on top of the head. Not much else it could be except water pump. -MK
Update: I think I found the issue. The rubber coupler that attaches the water pump drive shaft to the output shaft of the generator looked bad, so I cranked it over and watched and it was completely broken. The water pump drive shaft isn't turning at all. I bet the pump works a lot better when it's actually turning. New coupling and pump rebuild kit on the way. Also bought a rebuild kit for the Carter WA-1 carb on the car, so I pulled it tonight so I can rebuild it. SO CLOSE
God, I LOVE it when somebody actually diagnoses a problem and, in turn, is rewarded for their efforts! Now we're getting somewhere!
What's cool is that this is the issue that originally put the car out of commision years back when my wife's grandfather was still alive. It's the reason the cars been sitting in someone's garage or barn for the past 5 years. And now I can resurrect it, get it back on the road, and start makin' memories! -MK
You are a lucky man, LOVE that ride. Welcome to the mysterious world of old cars... Listen to the advices you got here, swap all old rubber hoses etc and you'll soon be on the road with that baby. D More pics, please PS did you find out what that thing on the fire wall is?
The thing on the firewall is a vacuum motor for the wipers apparently, although I haven't tried to use them yet. None of the gauges work, and the lights aren't working correctly so I have a lot of rewiring and electrical work ahead of me.
I used to hate 6 volt till I got my present truck, always starts and everything works, sometimes when its hot it lags but always keeps turning, and when you think ah battery is dead no way it fires...keep it 6 unless your wiring is falling apart
Very Kool car ! A classic saved and w/ family history, can' t get any better than that. Sounds like you are making good progress and love reading the advice on repairs, as my wife chose a 51 Buick Roadmaster as her ride, (restored stock) and try to fix mechanical issues myself.
Well I rebuilt the carburetor (Carter WA-1 1-barrel) in my kitchen last night. Let the parts soak in carb cleaning solution in the garage, and they came really clean. I snapped the head off of one of the tiny brass screws that attaches the throttle plate to the throttle shaft, so with the aid of the machinist at work today, I'll get that drilled out. Lots of gunk and debris in the bowl, so it should run a TON better now that everything's all clean. Got the rebuild kit from Mike's Carburetor Parts, which is a great resource for vintage carb parts. Kit had a new accelerator pump, gaskets, springs, check balls, and needle and seat. So I'll reinstall the throttle shaft tonight, and probably put the carb back on the car. Then as soon as the water pump shaft coupler shows up, I can throw that on and hopefully the car will run, idle, and NOT overheat. Stay tuned... -MK
I have a 1937 Buick Special that is still a 6-volt system, and it works beautifully. I have made 1 change to the electrical system on the car, and that was to replace the generator and regulator with an internally regulated Delcotron 10SI alternator that I converted to 6-volt. Simple to do, all you need is one of these: http://store.alternatorparts.com/partnod10se61.aspx It all depends on how original you want to keep the car. I was more concerned with driveability. I keep a spare regulator module in the glovebox, so if I do have an alternator failure, I can always pick up a 10SI intended for use on a 1973 Chevy Nova from virtually any parts store in the country, install the 6-volt regulator, and be on my way. EDIT: Mine is 6-volt negative ground. You can also get all the diodes, etc that you need to convert one to 6-volt positive ground.
Errrrrrrrgghhghh... There is hardly ever any reason to remove a throttle plate from the throttle shaft, unless you're replacing or rebushing the shaft. They only require cleaning and don't need any adjustment... unless they've been removed from the shaft. Which it has been, now. This is why they are assembled with tiny brass screws that are usually swaged over on the end to discourage removal. When reassembling, make sure you've got the plate right side up and that it's not rotated 180 degrees from its original position. Back out the idle speed screw so the throttle can close fully. And take some extra time aligning the throttle plate in the shaft so that it fully seals, all the way around, when the throttle is closed. Make sure the throttle operates smoothly through its entire range of travel, especially at wide open. You don't want to find out later that the throttle binds and wants to stick open when you lift off the pedal.
The brass screws are swaged over so they don't work loose and get sucked between a valve and piston top. Might want to make sure you do the same to prevent this.
I used loctite to prevent them from backing back out. Long story short, the rebuild was a huge success! After waking it up the car runs and idles beautifully. As soon as I get the coupler installed tomorrow and verify the cooling system works, I'm going for a ride!
Water pump not turning, ha ha ha no wonder it heats up. While you are replacing the (rubber?) universal joint have a look at all the rubber parts under the hood like rad hoses, heater hoses, vacuum hoses, fan belt etc. You may want to replace them if they are softened by oil, cracked, or mummified. It takes a few hours to replace everything but can avoid a breakdown later, and it only has to be done every 25 years.
Gary's more right than I am about the screws. But sometimes "over-rebuilding" a carb can lead to more frustration and hair-pulling than you bargained for. Glad it's gone back together smoothly for you so far.
All of the other rubber components under the hood look good. Rad hoses are in great shape and must've been replaced recently. I put a new belt on it when I had the fan off to service the radiator. While I had it running last night I put it in gear and let it roll forward and reverse a little bit to make sure the trans and clutch worked. Brakes pedal went almost all the way to the floor, so that's probably my next project along with reviving the lights. They said they went through the brakes a few years ago, so I'll probably pop the drums off and inspect the system. Mabye it just needs re-bled. Regardless, I'm hopefully hours away from a short test drive...
If the brakes work but pedal is low most likely they need adjusting, no self adjusters back then! When brakes get badly out of adjustment you need to adjust them up, they will wear down quickly but if you adjust them again after a few weeks they will hold their adjustment for a long time (several years in a car that is not used a lot). Inspecting the brakes, filling the system with fresh fluid and bleeding out the old fluid is a good idea, this should be done every 2 years on old cars.
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