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

The gas gauge in my '49 Custom 8 is inoperative (it was the float) and so I have to go by the trip meter to estimate when to get gas. So far, on two occasions, I've run out of gas at almost exactly 182 miles. That's only 9 mpg! I just bought the car about a month ago and it seemed more sluggish than I thought it should be, but I attributed it to overdrive and brake issues which I've since fixed. My '50 Ford, which has a higher power loading (30 lbs per hp compared to the Packard's 26 lbs per hp), performs like a Porsche compared to the Packard. Both cars have the same Borg-Warner overdrive and the Packard even has a higher rear end ratio (4.07 compared to 3.73 to 1). I'm worried that there is something seriously wrong with the engine. It only has 43,000 original miles. Now the pervious owner claimed he hadn't been able to drive it much due to illness, but I think he still ran it at least once a month. The car runs smooth and cruises nicely at about 65 mph on the freeway, but it accelerates very poorly. I checked the timing and it's appears to be correct. Any ideas out there?

Ron

Most probably your defective float( repair of float thread) is allowing way too much fuel into the engine. I would also check your brake drums after a short trip and if they are hot then your brakes are incorrectly adjusted. it would also pay to conduct a compression test to check if your engine has the potential to produce reasonable power, may have a Low comp head on. There are lots of possibles and it is just a matter of sorting out the ones that matter. PT

First of all, 9 MPG isn't that bad, but with a stick and overdrive you should be able to do a few MPG better, especially if you keep a steady speed and don't tax the engine.

You're going to need to play detective here, but that also means getting to use some fun diagnostic tools!

My first step would be to do a major tune-up on the engine if you haven't done one recently. The major tune-up includes almost all of the investigative work you'd do for a gas mileage complaint, and it has the added benefit of turning known unknowns into known knowns, so to speak.

Take a look at the Engine Diagnosis and Tune-Up Training Manual for further detail.

It's impossible to isolate a cause without doing some investigation, and with a new (to you) car, it could well be multiple small things adding up. Some of these would also result in other symptoms, so that could help pinpoint the issue.

Some causes:
-Faulty carburetion
-Incorrect initial ignition timing
-Low compression
-Faulty distributor mechanical advance
-Restricted air cleaner
-Faulty/leaking vacuum advance

I would pay particular attention to the timing. Even a few degrees retarded on those engines make the performance drop like a stone. They run quite well with 6,7 or even 8 degrees initial advance. Be sure to set that while idling very slowly and with the vac advance tube disconnected.

It is easy to make a quick check of both advances by observing the timing marks as you rev the engine. Take it up to oh 2500 or so whilst watching the marks. By this time they will have marched quite beyond the pointer. Snap the throttle closed and the marks should immediately jump well back as the vac advance is shut off, then the marks should return more slowly to the initial setting as the revs fall to idle.

A Custom 8 should be a snappy performer. They were not slow cars.

Poor low speed performance with good high speed performance is symptomatic of retarded valve timing. Although the car is low mileage there may have been work done on it during the past 67 years.

A vacuum gauge will indicate this problem, and a compression test should be done as well. A dwell meter can be used to check the distributor condition. It should remain fairly stable with increasing rpm. If it increases more than two degrees the distributor needs to be repaired.

If the motor is running rich the plugs will be black as will be the case with poor ignition.

The Custom 8 should get around 15 mpg with good carburetion, but those carburetors are old which reduces that figure. Low compression is a big culprit for poor fuel mileage.

There is nothing I know of that "wears out" in a carburetor that can't be made brand new with a good rebuild. An engine with good compression, new timing chain and sprockets to insure correct valve timing and a fully rebuilt carb should perform as new.

Rather than discuss aspects of erosion, let me relate a story from the old days.

There was an outfit called "Tire Trading" in New Jersey that was the authorized Stromberg distributor. The owner was an eccentric and wasn't forthcoming about his stock of parts. However, someone managed to acquire a brand new old stock Stromberg EE-23 carburetor from the place.

They put the unit onto a 34 Super 8 and the difference in performance was so dramatic the old carburetor was considered junk.

Anybody who has worked on carbureted cars during the 60's and later will tell you that a new carburetor will perform than a rebuilt. The old brass units will hold up better but cheap pot metal zinc castings age.

The new EE 23 might very well have made the car perform much better but it does not logically follow that the old one was "junk". Most probably the old one was assembled incorrectly, had wrong or missing gaskets, worn or incorrect jets etc etc.

I've put brand new carburetors on old cars and some perform poorly. Dried out gaskets, missing lead plugs, dried out accelerator pump etc. That did not meant the new carb was "junk", it just needed a minor repair.

I've never seen an "eroded" carb and we have 25,000 in stock and not one of them brass. Brass carbs went by the wayside about 1930, our '30 Packard has one.

Nobody today knows how those cars are supposed to perform because they weren't alive when the cars were sold.

I suppose you could build a time machine and go back to, say, 1972. You could then buy a rebuilt carburetor for your Chevrolet from NAPA and a brand new carburetor from the dealer. You could even buy an AC Delco rebuilt from the dealer. We sold different levels of repairs. If the customer wanted top notch performance we recommended a brand new carburetor. When we rebuilt motors we put on a brand new carburetor. We also installed over the counter carburetor kits. We also sent carburetors out to hot shot rebuilders. Sure I put a little carburetor kit on my 1961 Ford and it was okay. It passed all the state emissions tests as well. I put a rebuilt carburetor on my 1979 Dodge to pass a 3 gas emissions test. It was $57 while a brand new unit was $156. The original lasted 128,000 miles, but the rebuilt held up for, I think, three years. So I bought a car with a computer controlled carburetor which adjusted itself for wear.

Those old cars with their grasshopper strainer air cleaners suck in all sorts of abrasives at high velocity. Another item is corrosion. Flex fuel vehicles are built with corrosion resistant metals because E85 will erode fuel lines and injectors at a higher rate than conventional gasoline.

Carburetors are a compromise the same way as rebabbitting connecting rods. The old manuals all state that Babbitt bearing rods should be replaced when worn out. But you can't go to a dealer so you have to make compromises.

I guess it sums up like this: A rebuilder can replace the serviceable parts that wear out - jets, idle screws, float needles and seats, power valves, accelerator pumps, etc, etc. He can put the thing on a flow meter and measure the air to fuel ratio as well. But if a brass jet wears out then what about the cheap non-serviceable pot metal body?

As I said about the pot metal body, of all the carbs we've handled we've never seen an eroded body. The air filter removes most of the abrasive material.

We can get a pretty good idea of how a carburetor performs today vs how it did 75 years ago. Mileage and performance data can easily be compared. Likewise a brand new old stock venturi can be visually and dimensionally compared.

The biggest erosion, in my experience, is in the jets. We replace them as needed when rebuilding.