Re: 51 fuel pump

Posted by Carl Madsen On 2009/5/31 14:23:45

Check out BigKev's article above, it has all the details you need to give yourself the confidence to tackle the project. The kit was around 60 dollars but to send your carb to them and have them professionally do it is only 125. 65 dollars is equivalent to three cases of beer, two tanks of gas, or one trip to the movies. (UP is a great movie BTW).

I haven't started rebuilding it yet, but the kit is here.

We discussed this for a while, and here's that thread:packardinfo.com/xoops/html/modules/newbb ... orum=2&post_id=27743#forumpost27743

(BigKev you may want to have an expert proof this and put it in the frequently asked questions.)

Here's a response to someone else who had similar problems:

I have similar symptoms of vapor lock. The problem could be the new fuel is more susceptible to heat than the original stuff 50 years ago. There are several possible cures:

1. The heat shield goes above the fuel pump and below the exhaust manifold and helps direct air from the fan onto the fuel pump. This was removed by mechanics because they were unnecessary. They sell them at Kanter, I believe, but a friend of the packard website sold one to me for a lot less. Different types for different years.

2. An auxiliary electric fuel pump can be added near the fuel tank with a bypass and check valve, powered using a switch on the dash (you can get 6V or 12V, some allow fuel to pass through while not operating, and most have a fuel filter inline before the electric pump). Pumping extra cool fuel helps get past the vapor lock, but if your mechanical fuel pump looses an internal diaphragm, you could pump fuel into the motor directly and ruin the motor. It's best to either use the electric temporarily (momentary switch) or totally bypass the mechanical.

3. A return fuel line goes from a T fitting near the carb with a restrictor to the fuel tank, thus using the extra pressure to return the hot fuel to the cool tank and keeping the entire fuel system cooler. The trick is the correct size restrictor, or the return fuel line will be the path of least resistance and your carb will not get
the proper pressure.

(Drawing below is from Tom - thanks Tom!)

4. Moving the fuel line away from the exhaust manifold.

5. Insulating the fuel line.

I'm no expert, this is what I learned in the last year from this wonderful website. I'm putting 1, 2, and 3 into action on my vehicle, plus I'm rebuilding the mechanical fuel pump. I found insulation on one of the websites, I believe it was summitracing, but I'm not sure and I'm going to try it without insulation.

(I found something that may work:store.summitracing.com/partdetail.asp?autofilter=1&part=EAR-731006ERL&N=700+115&autoview=sku

)

Then and Now is where I got the fuel pump rebuild kit - call and ask for Tom 781-335-8860 - he'll want a lot of details from your fuel pump - there's a number stamped on the side and he'll want to know if the steel pull rod inside the pump has a square hole in it. Mine did. Reference BigKev's rebuild article on the packardinfo.com website.

Then and Now also sold me a restrictor for 17.50 and a bypass kit for 19.50, which includes all the necessary t-fittings hoses clamps and check valve to bypass an electric pump.maritimedragracing.com/antique_auto_parts_cellar.htm

orthen-now.com

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