Packard Forum Index » Post-War (1946-54)

Out driving the 51 today in 100 degree temp to test the new radiator. It works fine, but the bugger bear vapor lock popped up. The car runs fine as long as I don't give it too much fuel. Got home, put it in the garage, then the neighbor wanted a photo of it. Tried to start, but the fuel was boiling - it has a glass type fuel filter in line, in front of the carb. I have the factory issue heat shield over the fuel pump. The line coming out of the fuel pump is steel instead of the old rubber type. The line goes up parallel with the radiator, then curves back close (2" +/-) over the exhaust manifold. I bent the tube away from the manifold, but without much sucess.
Here's what I'm thinking of doing.
1. replace the steel line from the fuel pump with a rubber line.
2. insulate the steel line with an asbestos substitute.
3. route the lines as far away from the exhaust manifold as possible.
4. Get some of Fred Kanter's clothespins.....
Any suggestions?

There are a few suggestions in this thread which might be worth trying also.packardinfo.com/xoops/html/modules/newbb/viewtopic.php?post_id=57609&

I'll check the carb in the morning. I bet I left the insulation spacer off. I know the fiber insulation around the fuel pump bolts is missing. Any suggestions as to a subsitute if I can't find them in the parts bin? The heat riser valve is working nicely. I may also try moving the fuel filter to the vertical part of the line vice the horizontal part, which is over the exhaust manifold. thanks

I'm wondering about the diesel. Believe there was another thread after someone tried it and reported good results.

You can buy various ranges of phenolic rod or higher temp rated Garolitemcmaster.com/#phenolic-rods/=df8q31 orusplastic.com/catalog/item.aspx?itemid=23765&catid=679 and cut & drill your own insulators. Getting the exact OD size needed with standard sizes available is probably not going to happen so may need a bit of lathe or sanding work.

I believe the original type of line between the pump and the carb is a regular steel line. The factory service manual shows this as well. Any rubber line I think would had been something done by a previous owner IMHO.

For reference this shows the placement and position of the steel line in relation to the manifolds:

Check the carb BOWL vent. Gas cap vent too.

Clothes pins on sale this week, 15 cents each, 5 for a dollar. Get 'em while they're hot!!

I recently encountered an owner of a much earlier model Packard than yours who claimed to have endured chronic vapor lock over a 10 year period and had now found an effective solution.

He fitted a large vent to the float bowl above the fuel level. His car has a very small hole in the float chamber cover to allow the fuel to flow but he claimed this was not large enough when vapor lock occurred and his vent line was about 3/16" to 1/4" diameter piped down to below the engine.

Now I am a skeptic on this subject having heard of just about every solution you can think of from owners who swear the vapor lock is cured only to find that it is still there on the first really hot day.

This owner was very credible and I pass on his solution for what it is worth, I have trouble understanding why it would work but will try it on my 1920's Packard.

Until now the best solution I have found is to add kerosene however in very adverse conditions, which we sometimes experience here in Australia, it needs lots, I have used up to 20%, it makes no discernable difference to power but is very inconvenient getting it in such quantities.

Electric pusher fuel pump is the answer. It worked on my 55 Pat in 115F heat in Vegas.

Today's gas has ethanol mixed into it which has a lower Reid vapor pressure than gasoline, hence the old fixes are not as effective.

Craig