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Is the 3/8 spacer they list actually an insulator block between the carb & manifold? If not, maybe one would help and if so, maybe one made out of modern insulating material would work better with the higher volatility gas.

Does anyone know if the higher octane gas resists vapor lock any better than the lower grades? I am currently using 87.

I don't know but I'm sure the vapor pressure and boiling point range is public data somewhere and shouldn't be too hard to find. I'd be surprised if there is much of a difference between 87 and 93 octane, but perhaps someone will dig out the numbers for some brand of gas and we can see.

For the temperatures and type of driving you were doing, your car seems to run warmer than a 47 Super Clipper that's local here and I'm somewhat familiar with. A couple of questions - do you have the correct fan belt and is it riding on the sides of the "V" and not bottoming out (bottom of the pulley grooves not shiney)? And what's the distance between your fan blade edges and the radiator?

I'm guessing you've already checked for retarded timing. How about running too lean on mixture? Since the 10% ethanol gas runs hotter and leaner, quite a few folks have rejetted their carburetors to a slightly larger main jet size - though I wouldn't think this would have an effect on temperatures at idle unless the problem on stopping at lights is just latent heat remaining from driving at road speeds with too-lean a mixture? Just rambling here - some thoughts I'm sure you've already considered.

O_D, thanks for your thoughts. The 185F coolant temp I mentioned was when it had been sitting and idling at a long red light. According to a new mechanical S-W gauge. Once it was moving again the temp dropped to around 170F. It has a 151F bellows type thermostat. It has the Packard five-blade fan and the proper John Ulrich fan belt. I believe the fan will need to be removed to replace the belt. The fan is about 3/4" from the radiator and the belt width is more than that. Any thoughts on adding diesel to the gas?

Howard, I'll need to check and see if it has the spacer between the carb and manifold. Thanks for the suggestion.

(o{I}o)

Don't know if there is any difference but if there were, I would expect the low octane to be more resistant.

The old low octane gas from the forties was.

Has anyone tried tractor gas or farm gas to cure vapor lock? it is 87 octane suitable for most cars that do not have high compression engines but formulated for carburetor use.

If farm gas fixes the problem, and we can find out how it differs from pump gas, that could lead to a cure.

JW, I've changed a number of those big FAT belts on 356 engines without removing the fan, but it's always struggle. Most recently on a 41 160 we couldn't get the fan belt past the vibration damper where it comes close to the lower radiator scupper. Ultimately we removed the fan and that gave us enough room to force the belt past the obstruction with the help of a little silicone grease, a long stick and a hammer. Problem no doubt resulted from a bit of sag in the motor mount.

If you do remove the fan, let me offer a suggestion. Find another bolt with the same thread as the fan bolts, cut the head off, and thread it loosely thru the pulley into the hub such that enough still protrudes after the fan is put back on to grab easily. This will locate the other holes for you and make it much easier to get the fan bolts back in. Make sure the stud threads in and out easily (clean the threads) because you'll only have your finger pressure to remove it when you go to start the 4th bolt.

Though I've had both my Packards in some very stressful, blistering hot situations I've never experienced vapor lock. But early on before I had developed my confidence, in anticipating a July 4th parade on a 100 degree day, I did add 1 gallon of diesel to a complete fill up (25 gallons total) on my 34 Eight. Car seemed to run OK but certainly did give a quite a bit of black smoke. No conclusion can be made from that event other than the old "might help, probably won't hurt". Prolonged use though may lead to carbon buildup on valve stems, rings, etc.

E Z temporary cure for sagging front motor mount when changing water pump or belt, put a block of wood and a jack under the oil pan

O_D,

I read with interest on the PAC site about the fan belt installation story. Neat solution to getting the belt on the vibration damper. These wide and thick belts are difficult to install on wide and deep pulleys. My belt is new so I do not expect to need to change it for quite some time. I agree with your recommendation to make some pilot studs to help locate and install the fan.

I have driven my 115C Convertible Coupe in a local July 4th parade in higher temps and much longer idle periods with no vapor lock problems. It does not have an electric pump and I use 87 grade gas.

I looked today and there is a thick spacer under the carburetor of the '47 Clipper.

I'll try a gallon of diesel on the next fill-up and see what happens.

Thanks.

(o{I}o)

May issue of Cadillac/Lasalle club magazine had and interesting article on the "vapor lock" syndrome. The writer told of numerous instances on his own cars and those on tour where the real problem was a crushed metal fuel line from the tank or a degraded rubber fuel pump inlet hose.

Fuel for thought

Fred, thanks for the reference to the C-LS club site. My fuel pump flex hose is new and the metal line from the tank to the pump is in good condition.

(o{I}o)

UPDATE:

I added one gallon of diesel fuel when I filled the tank yesterday (87 grade Chevron). This amounted to about a 5% diesel mixture with gas. Before that I removed the lower splash shield from the passenger side (the driver side one is missing). I did this thinking it may help to get rid of some of the hot air in the engine compartment. I then took if for a drive around the neighborhood (lots of stop signs and traffic signals). The car behaved beautifully, it never skipped a beat.

After coming home I advanced the timing from about 5 BTC to 10 BTC and readjusted the idle speed and mixture. There was no real reason for me doing this, except I wanted to do it.

During the drive I had a remote reading thermometer to measure the under hood temperature. The highest reading I saw was about 162F. Not has high as I thought it would get. Maybe the removal of the splash shield helped with this.

Today I went to help a friend, who lives about 10 miles away, install the radiator in his '58 Buick. After that we went for a ride in the Clipper which was a combination of freeway and city streets (again, lots of stop signs and traffic lights). This was much longer drive than yesterday. The car behaved beautifully. Not a sign of vapor lock.

It may be my imagination, but I think the engine runs smoother with the diesel than it did before I added the fuel. No smoke or odor evident from burning the diesel mixture.

Maybe, I have beaten this devil.

(o{I}o)