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I'd like to put an auxiliary fuel pump on my 400 so that the battery doesn't get a severe workout after it sits a week or two. I believe it would be prudent to bypass the mechanical pump so that gasoline wouldn't be pumped into the crankcase if the mechanical pump poops out.

Question - Is that the preferred installation? What electric pump is being used? Approximate cost?

Thanks,
Bernardi

Bernardi Quote:

I have an electric auxiliary pump on my 55 Pat. I located it right below the driver's door on the frame by cutting the existing fuel line. I've had it there for 10 years. I bought it at NAPA. It's a pulse-type pump which means if it fails or is off, fuel will still be drawn through by the mechanical pump. I wired the on/off switch through the package tray fan switch on the dash. "High" is full on and "Low" is reduced speed which I never use.

Price? I forget, but it was inexpensive as those things go.

I wouldn't worry about pumping gas into the engine through a broken fuel pump. I've never inspected the fuel pump to see if there is a route where pushed through gas can get into the crankcase. I suppose it's possible, that's pretty rare from my experience.

For priming the carb after sitting or dealing with vapor lock, the electric pump can't be beat.

Craig

Bernardi,

This is a commonly considered question, including here on packardinfo.com.

I am a firm believer in the parallel fuel pump installation over the series method. Here is why: in the series method, if the diaphragm of the mechanical fuel pump leaks and you try to use the series electric pump to get home, it fill pump gas into the crankcase and through the vent on the pump on the ground but also very near the hot manifold.

Here is a link to one of the discussions on this site. Note: it links to a great explanation on the packardclub.org site:

https://packardinfo.com/xoops/html/modules/newbb/viewtopic.php?viewmode=flat&type=&topic_id=12850&forum=4

Regarding the cost, I'd say it'll added about $15 to my installation, which I did myself. Can send photos if you like.

I hope this helps,
Pat

39SixSedanMan Quote:

A "belt and suspenders" solution, but I can't really argue with it if you want to go that route.

I have installed hundreds of electric serial pusher pump installations on Pontiacs back in the day (1970s) and NEVER had a failure where the mechanical fuel pump failed in such a way that it filled the crankcase with gasoline or blew gas out all over the road. The Pontiac mechanical fuel pump is very similar to the Packard one. The Pontiac installations were on blow-thru Turbos where the fuel pressure goes up to maybe 20psi. No failures.

So, take this advice for what it's worth.

Craig

Craig wrote:

Quote:
Fuel pump diaphragms can and do fail - and leak.

You might wanna take a look at the illustrated fuel pump overhaul procedure in the 55-56 shop manual. If the diaphragm leaks within the perimeter defined by the two halves of the pump body, fuel will be pushed up into the upper body. Although there's a seal for the push rod of the diaphragm assembly, it can also leak. As a result, fuel gets pushed around the diaphragm rod, out through the opening for the rocker arm in the upper body, and into the engine timing cover, which leads right back to the oil pan.

That condition is not at all uncommon in any brand/model of vehicles with a mechanical fuel pump that are driven off the camshaft. As part of checking the engine dipstick for oil level, one should always give a sniff for the smell of raw fuel. Else, you could end up with a bevvy of engine problems a lot sooner than you might expect.

External leaks, of course, are more obvious - typically washing gunk off the adjacent are of the engine. (Found some nice original ivory engine paint on my former 55 Patrician, tha way.) Yet, if you don't consider a hot exhaust manifold to be a problem, what do you think a stray arc from a cracked plug wire might do in such case?

Mind you, that's nothing compared to the ruptured steel fuel feed line that I recently experienced with my tired old, high-pressure, fuel-injected, POS GM daily driver.

I may not agree with 39SixSedanMan's specific solution, but his concerns certainly are valid.

If someone simply installed an electric fuel pump, in-line as a pusher, for a bona fide case of vapor lock and they mistake low fuel pressure from a leaking mechanical pump diaphragm for another vapor lock event, the electric pump is gonna push fuel somewhere that it shouldn't - with potentially harmful results.

Thank you, one and all. Winter has arrived in Pittsburgh, so it may be spring before I crawl under to install an electric helper pump. You offered some excellent advice. If it were not for PackardInfo I probably would not own any Packard, much less three.

Bernardi

The question is are you going to use it as a "primer" or vapor lock helper, or as a backup in the event the mechanical fails.

If as primer/vapor lock helper, then the "series method" is perfectly valid, as you are not running the motor off of the electric full time, just occasionally in those situations.

I use mine to "prime" the system when the car has been sitting for a few weeks, and that makes the car start much faster. Once the car starts, I turn it off the electric pump.

On mine, when I turn on the pump with the car not running, I can hear the pump come on, and the sound it makes (tone) changes as the line pressurises. If that tone doesn't change, then that means I am either out of full (not pumping at all), or that fuel is being pumped unrestricted to somewhere. Which should never be the case with the car not running, unless you have a blown mechanical diaphragm.

My intent is only for priming. I've never had a V8 Packard suffer vapor lock. In some of the reading I did recently, one writer used a push button switch. That would assure that the pump was not inadvertently left running.

Thanks for your thoughts.

Bernardi

Bernardi, several folks I know use what sometimes is called a "dead man" switch, meaning you have to keep your finger on it to keep the pump actuated. I guess you meant the same thing by a pushbutton switch. I think it's a very good way of doing it.