VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1937-1945 1938 General

I finally took the car on a short trip, 80 miles round trip. There are a couple of things that I'm not sure are correct or not.

On a test drive the night before the temp reached 212 but when I stuck a thermometer in the radiator the temperature was only 195 F. The next day was warm, 70 going, 90 coming back. The engine was in the 190 F range going but stayed at 212 F all the way back. I did notice that there was some minor steam venting around the lower hose connection to the radiator after my return, almost no loss of fluid though. Is this an indication that the thermostat is bad? How could it build up pressure enough to get past the hose clamp when hot but not cold and only in that location?

The car rides a little bouncy. It still has the original tires and I think the toe-in is set a about twice what it should be. I never had the shocks rebuilt but they had enough fluid to cover the spring valve mechanism. Do I have to have them rebuilt or is this just the way the car is going to drive?

The generator does not put out enough juice to power the head lights, radio and feed back to the battery. Is this normal?

The engine is not very smooth. It seems to be reall rough, sort of like a lawn mower engine. Is that normal?

The problem is I never really rode in a car 70 years old so I'm not sure if maybe my expectations were a little to high.

Brian

Have you had the radiator back-flushed or flow checked ??

I'd think you'd have boil over if the thermostat was stuck closed, but I suppose it's possible it wasn't opening all the way. Easy to check - just remove it and put it in a pan of water on the stove (suspended a bit above the bottom) and bring the water to a boil while you watch the thermostat's operation. If in doubt, replace it. I always check any new thermostat BEFORE installing it, just in case.

For reference, my '37 runs about 180°F or a little less, in 60°F ambient and under 190°F in 95°F ambient.

You can also try it without the thermostat to see if the car runs cooler.

No, a rough running engine is not normal. You should give it a tune-up and then see if that helps the problem. If not, the roughness could be caused by any number of things. The 1937 and 1938's drive real nice and your car should drive nice too.

With both the radio and headlights on, your generator will probably not have enough output to support all of the equipment. :( :( :(

What temperature thermostat are you running?I run 160's in my cars but in summer weather they will run in the 180 range on the hi-way.At 90 deggrees will run higher depending on speed and wind direction.At 90 degrees with a fresh engine could run a bit more than that.Correct way to check the reading of your temp gauge is by using a non-contact thermoter with a laser beam.Shoud be checked in the head area where the temp. gauge is connected.This is the hot spot of the engine.Most dahs gauges indiacte a lower temp.-seldom higher if inaccurate.

Rough engine???idle rough-miss???valves adjusted too tight??vacuum leak??

If the car is a Master with leaf front springs the ride is bouncy-they were not smooth riding cars.Also the steering can be rather ubcertain-to say the least.Fill the front and rear shocks with hydralic jack oil and try again.

My '39,which has the same generator and voltage control as a '38 will charge to + with the lights,radio and heater on.....at speeds oner 20-25 MPH....over 60 will taper off and drop down ,which is normal with a 3 brush generator.I would suspect that your third brush setting is off.

I tested the radiator before I put it back in and the venting looked like it was from the hose to radiator connection. Can I put pressure on the radiator to locat the leak and not do to much damage to the cooling system? The radiator fluid looks clean but if I have to I'll clean and flush. Can you normally see the flow through the radiator with the cap off?

I forgot that I had never brought the engine up to temperature before setting all the clearances. It was warm the last time I did it but had always intended to go back and recheck. The engine idles smooth, but when I press the gas it almost seems unbalanced. It's loud too.

I'll go through the tune up this week after I set the clearances. I did notice that when I hit the gas I lost my vacuum (the wipers stopped), does that seem right for this engine/wiper system?

I'll reset the generator. It's been in the car so long, waiting for me to finish all the other items, I don't remember if it was set right.

I still have plenty of jack oil. I'm shooting for another Friday cruise night. If I get the rest done I'll refill and see how it rides.

Thanks for the ideas,

Brian

To put pressure into the cooling system on a 1938 it would be necessary to block the over flow tube as it is located on the top of the radiator top tank.I wouldn't put too much pressure on an old core....perhaps only a few pounds.

Valves should be set with everything up to full operating temp...if set during warm up will be too tight when hot and idle will be "rough".I set mine at .007" and .014" and have never burnt a valve.

Is engine noise air induction noise??what type of air cleaner are you running??The truck air cleaners have no noise reduction and will be noisey under throttle opening.

Some of the noise may be from the intake of air but the engine is not smooth. What I mean is that when you hit the gas it's not a smooth ramp up in speed. It's more like the engine is having to overcome some sort of resistance to get up to speed. When I hit the gas on my new car it seems to leap up to speed, like that's where it should be running. Once at speed on the 38 there seems to be a lot of vibration. It could still be that I have all the valves a tad to tight.

I should have time Wednesday to warm it up and set the valves. I'll take out the thermostat first and do a bench test of the opening temperature, then during warmup I'll leave the cap off and a thermometer in the radiator to see when the flow begins. Once up to temp I'll finish off with the valves.

Brian

You can not compare the power delivery to a modern car - but it should be smooth.Is the timing betwwen 0 and 8 deg. advanced?

Try it with out a thermostat...really not necessary in the summer.Will just take a bit longer to warm-up...put it back in in fall.

Checking the Delco instructions the third brush is set in the max. charge position when the air cooled generator is used with a voltage controll.Then it will produce 26-30 amps when needed.

Is the distributor vacumn advance unit working correctly ? Timing error can result in a poorly running engine and also can cause high engine temps.

Brian, Sounds like you recently got this vehicle. Here is a list of things I do even if the car is running OK so I have a baseline.

1. Change oil, trans and rear. Grease the car well. Do not over oil the starter or generator.

2. Drain old gas/clean tank if needed, new fuel lines, my car ran ok but the fuel line was packed with rust. An inline filter before the fuel pump may save you big headaches down the road.

3.I pull the radiator have it cleaned, new hoses and thermostat. Is the water pump OK?

4. Bleed brake system and pull wheels to check for leaks.

5. Check wiring system and mend any frays.

6. If the vaccum advance is not working the car may not run right. You can buy these nos or have yours rebulit.

7. If you don't have knee action shocks, the shocks on your car are easy to remove and clean. If the shocks leak around the shaft I took some plumbers string, coated it with RTV and wrapped it tightly around the the shaft and it stopped/slowed the leaks on my car.

8. Check voltage at the Generator, regulator and battery.

9. The carbs are easy to rebuild. I have this done so they are bench tested.

10. How are the motor mounts and trans. mount?

Hope this helps.

It functions in that it holds vacuum. I never tested it in any other way. Is there a way to check if it is moving the advance the correct distance?

Brian

MacHB

See the comment about the vacuum advance.

Most of those items in your list have been done. I will check the thermostate again and recheck the valve gaps. I never really checked the third brush position. When I rebuilt the generator I put it back the way it was. I was just happy it worked. However, when I did the rebuild I cleaned the commutator gaps and put in new brushes. I don't know if that could throw things off or not.

I have an old AC inline filter for the gas.

Engine mounts are good.

Brian

I took out the thermostat and tested it and it opened at 180 as written. I left the thermostat out and refilled the fluid then started the engine. I could see flow but could not tell if all the tubes were open. I ran the car at fast idle for 20 minutes and the temperature caused the fluid to expand so I put the cap back on. The radiator overflowed a little and the temperature on the dash registered 212 F. The car was just sitting in the garage but it should be able to stay cool at 80 F ambient. What else can I do?

I checked all the spark plugs. One through five all had varying degrees of brown to gray deposits, six was all brown. The oil had a dark tint but that may be due to the red assemble oil.

The vacuum was dead on 20 when I started and the timing was steady. I checked all the gaps and they were all slightly wide, I was expecting to find them all narrow. The engine sounds better with all the gaps closer to the correct value however I get an intermittent squeak somewhere in the engine. Under acceleration it does sound more like a smooth engine and the exhaust smells better.

The vacuum now runs steady at 19 and I had to adjust the timing slightly. I checked the function of the vacuum advance and the distributor does advance under acceleration.

Any thought on the heat problem?

Thanks,

Brian

Also, can I adjust the third brush on the generator while it's in the car? Any hints would be helpful.

Thanks.

Brian

The cooling passages in the block could be restricted, the gauge may be off a bit and the overflow may be due to having the radiator too full. You could check the coolant in the radiator while the car is running (use caution) with a thermometer and see if the dash gauge is close, make sure you dont have the radiator too full, I leave mine an inch or so above the top seam. Mac

I put a thermometer in and ran the thing up to temperature. The dash gauge is accurate and the temperature of the fluid is 212. When the temperature goes over 200 F, the squeaking starts. So what's the solution, new core?

What is the dwell angle for this car?

Thanks,

Brian

What squeaking? The water pump? It is hard to tell about the radiator, as I stated in my first reply I always have the radiator cleaned/re-cored on my cars. Removing the radiator on this car is a pretty good task (the hood needs to be removed) while it is apart you may consider a new water pump. NAPA may be able to find you one or have yours re-built. Are you using anti-freeze or just water? Your car may not be boiling over, you may have the radiator too full (expansion). When it "boils over" can you hear bubbling/rumbling in the block or the radiator?

Forgot to mention, you may want to clean the ground from the battery to the trans.. This may help with the electrical problem.

The third brush is easily adjusted on the car. Unlatch the band at the rear of the generator, loosen the small screw on the back of the generator and move the third brush toward the engine block to reduce the amperage or away from the block to increase. Set it up so it charges slightly at cruise RPM with all electical loads on.

Tighten the third brush screw before running the engine each time you adjust the third brush.

George

On the 1938-39 passenger car generator adjust the 3rd brush all the way over for maximum charge-the voltage controll will take over from there.

You can do a "home test" on the radiator...Force water into the upper hose pipe of the radiator (with garden hose)-water should expell from the lower hose pipe with force is the core is "clean"-reverse proceedure-should do the same.

With the points set at the recommended gap (.018"-.023") the dwell should be from 28 to 33 degrees....if not in that range the distributor cam is worn.Dwell only measures the time (in degrees) that the points are closed-not the gap....gap is more important.Changing the gap will also change the timing so rechecking timing will be necessary.

Hey bigbth,

When I first got my 40 Coupe, she was overheating. I did a back flush and all kinds of crud spilled out and it helped the over heating problem. I know there are a lot of other things that create overheating, but what worked for me might work for you. I hope you solve your temperature problem quickly. Let us know.

I gapped the points to 0.018 and the dwell changed from 25 to 30. I can see the dwell better than I can gap the points so I thought that would be a better test than me trying to confirm the rotor is in the right position while I'm checking the gap. Thanks for the info Chevgene.

Squeaking-I don't know what is squeaking. It could be the water pump, generator, one of the rocker arms, I can't seem to find it. It doesn't happen when the car is cool but is definitly there when it reaches temperature.

Speaking of temperature, it may be my imagination but I would swear that the car is getting hotter faster everytime I start it. I'll try flushing the radiator. I would rather not take it out of the car but if it has to go it has to go. I called and the local radiator place and they said it would be about $300 for a new core, does that sound about right? Is there anything that I would need to tell the radiator guy about this core that he would not know otherwise? Is there a clean in place method for these radiators?

I'll check the generator again to make sure the brush is over where it should be. If the battery is fully charged and the car is running, will the charge indicator go to "0"?

I will run the car on a short test this weekend to see if the engine adjustments have helped the ride.

Thanks to everyone,
Brian

The charge will drop back to 0 when battery is fully charged....will be just slightly to the + side.Takes a lot of driving to get a 6 volt battery fully charged.

Brian, Do you have a fax number? I have a copy of a tune-up cheat sheet from "38" if you would like a copy. I would refrain from driving the car if it is running hot. Try spraying wd-40 near the base of the generator and behind the water pump pulley and see if that quiets the squeaking temporarly. $300.00 is about right and consider the water pump. No other way to work on the rad. Mac