VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1929-1932 Vaporlock

Took the 31 Phaeton out for a long run yesterday. It has a new Fillingstation honeycomb radiator, no leaks, good water pump, baffle in place, and runs well generally (Rebuilt engine 4,000 miles ago [in 1983] using cast iron pistons). Car has always had a tendency to run hot if going 40 MPH. When entering long uphill climbs requiring downshifting to seconds, we travel SLOW to keep RPMs down, it will boil over hard after approx 2 miles. The uphill is just steep enough that 3rd gear will not make it. We stop and let the car cool down before slowly replacing lost antifreeze. This has always worked pretty well, but it will eventually boil again. But this time after resuming the uphill trip, the engine seemed as it lost power' It labored much more that usually (in 2nd gear). Air temperature was about 74 degrees F on this trip. On previous trips in hotter weather, we have not had the 'loss of power' issue. Could this have been a result of vapor lock on this trip?. Car seemed to recover later in the day after a long picnic lunch break and rest. The trip is an 'annual' drive from Manassas, VA through Sperryville up to Skyline drive with the Big Meadows visitor center as goal, and thence back home to Manassas. Have any of you had a similar problem? BTW, the new honeycomb core does not appear to give my car any better cooling than the original one that has small leaks.VCCA #18184

Hey 31Phaeton!

So let’s start with a question. Do you have a thermostat installed in the car? You said your running antifreeze....which will foam from what I understand without a thermostat in the engine. During the touring season I always try to remove the antifreeze and use just water with a water pump lube, it has better cooling properties and will not kill your paint.

Bruce

I have had some minor overheating problems in the past and was advised to nix the antifreeze in the "non freezing" months.I was told that the engine will run much cooler on pure water with w/p lube and have found that to be quite true.....Good luck!!

Vapor lock occurs when the gas in the fuel pump boils or the line leading to the fuel pump boils and turns to vapor. It will give the same results as running out of gas. A loss in power may indicate a different problem....timing comes to mind first. Also in my experiance I found that keeping the car speed up (better air flow) or at least engine speed for better water flow.
I disagree that clear water will cool better than a 50/50 mix.The difference will be so lttle that the average person could not tell the difference. Same for the thermostat. The advantage of the 50/50 mix is that it will raise the boiling point by several degrees.
Seeing the problem has gotten worse I would say there is a problem arising.
Ever try a four blade fan?

i went over my cooling system soup to nuts in my 30 coach.
new rad core. new sealed water pump, new baffel plate, 160 t stat, block and head rodded out. timing at 12. four bladed fan. running alittle less than 50/50 antifrezze. meaning more water than antifrezze
my car will run at 160 all day long unless its gets over 90 air temp and then it start to over 170 but as long as keep the car moving the temp will come back down to 160. chev nut is right. vapor lock as to do with fuel not cooling water.

Thank you for feedback. So vapor lock acts as totally out of gas, not 'dirt in the carb? I did change my modern paper-based 'hidden' fuel filter before this trip, and it is still 'almost' clean after the trip. I do not have thermostat in either my 31 Phaeton nor the Special sedan since i seldom drive the cars in cold weather. My antifreeze does not 'foam' when boiling or otherwise. I do have a four blade fan. The phaeton originally had a two blade fan when i bought it in Norway 1965. Air temperature over there seldom reaches 80F. As you indicated I suspect timing may be 'retarded' or late, will check later. Also I do have a couple of noisy valves, seems hard to keep them adjusted. Valves, guides, and rocker arm/bushings are almost brand new, compression is even on all 6 cyls, couple of the pushrods did bend years ago on first start up after 7 years of storage, but appears to be straight enough for good valve action. I do have a noise at the front of the camshaft-did replace the fiber gear with NOS. How fast do you folks drive in second gear on long uphills? Don't want to up the RPMs too high. Thank you again for your interest in my 'heat issue'18184

Another issue that could cause the gas to vapor lock and to have a loss of power would be gasoline with Ethanol.

There are several potential causes of your problem. First I down shift both my '28 four banger and my '31 at between 20-25 mph. Try not to exceed 25 by too much. That keeps the air flowing through the radiator and also much higher HP and torque. Lugging the engine will only hasten the over heating/boiling when climbing a long grade.

My hit list of potential causes is 1. Points, 2. Condenser, 3. Coil overheating. Does not take much corrosion or burning on point contacts to reduce spark. Heat can also increase resistance between grounded point arm and also ground of condenser case. Both need good ground to work effectively. If condenser is bad replace it. Coils can over heat. Have had the one on my '28 do that several times on long slow upgrades. Pour a little cool water on the coil and off we go. It is a known problem with modern replacement coils. Though not as common on 1931 (much more on the late 4 cyl.) the ignition switch can also over heat. Be sure to gap the spark plugs at 0.040 and advance timing to 16-18 deg BTDC.

If the engine coughs as it quits then fuel is more likely than ignition. Try pouring the cool water on the fuel pump. Look for any bubbles in the glass bowl when engine is running. A little water can plug the paper filter (if you use one) and not be seen.

Air in the cooling system will cause the antifreeze mixture to foam. No air no foam. All switching to water does is reduce the tendency to foam. Does NOT solve the reduced heat transfer inside the engine. Air bubbles are a prime cause of cracked heads. So my advise is to use antifreeze (I do!) and keep it from foaming by keeping the air out! It can be considered a safety factor or early warning system before things get to the point that the head cracks. Restrictions between the engine and radiator will reduce gas bubble size and loss of coolant but are just another means to treat the symptom and not the actual problem.

Chipper, thank you for your list of potential culprits. I'll check the ignition components as you suggest. I did tighten the waterpump packing earlier so there is no air being sucked in as far as I can determine (no water leaks or drips at the packing. I pretty much stick to your suggested speeds by gear by listening to the engine. Our gasoline here in VA contains 10% Ethanol, but in a pinch, the oldtimers ran those Chevies on Kerosine and during the war using wood gas. Performance did suffer though, I was told. I guess ethanol is a bit too strong for these engines? Erling Storstrom from Norway had an article about ethanol in the G&D some time ago. Again thanks for the suggestions, I'll try those items first. BTW, I have in the past replaced both manifolds, carburetor, fuelpump, coil, condenser, and spark plugs- non of these remedies made any changes to the performance. As a side note, when starting the Phaeton, it always require using the choke in addition to some accelerator pump use to keep engine alive until it warms up a little. My Special sedan starts much easier; careful with the choke, just a little, otherwise it floods, and it settles down nicely almost immediately. The two cars are like night and day when it comes to start-up. I would think they should be fairly identical... I am using Champion D16 plugs, have since 1965 since the car came equipped with those when I got it. I assume Champions are just as good as the AC Delco plugs? #18184

31Phaeton - you mention the new radiator, etc but you didn't mention flushing the block and/or head. If the block is plugged up you're missing some valuable heat transfer capability. Just a thought prompted by Buggymangp's comment. Good luck !

I have used Delco and Autolite plugs in my '31 & '32 Chevys. Have Champions in one of my '28s. All seem to do well. If the ignition systems are identical then the carburetor is the next suspect. Some engines are more cold blooded than others. I would suggest switching the carburetors to see if the problems switch or are the same. That will tell if it is a carburetor difference of just a cranky engine.