My Willys 3A and 3B Community

3A, 3B, DJ Technical Knowledge Base => "Original"-- Technical Questions, Answers, Observations => Topic started by: garage gnome on March 06, 2013, 09:29:24 PM

Title: Which fuel pump is correct for my Willys?
Post by: garage gnome on March 06, 2013, 09:29:24 PM: This question comes up from time to time, what fuel pump DO I need??? Some will say glass bowl is correct and others will say metal tops are correct. Personally, I think the assembly line workers used whatever was in stock that day!!! This is a real in depth discussion about it - Are glass bowl fuel pumps OE? (http://www.thecj2apage.com/forums/glass-bowl-fuel-pump-oe-or-not_topic5482_page1.html)

Well, this is a rather hard answer to come up with. From what I've seen, Willys used four, yes 4 different types durning 3A production, two single actions and 2 double actions, with some assumptions. The single actions were used on engines with the 2A style front engine plate, where the driver's side engine mount foot is pointing to the back. These can be found on jeeps up to a '49 3A where 2A parts were still being used. The factory had a brass adaptor to fit the engines to the 3A frames. The double actions don't fit this style. On the later style engine plates where both engine mount feet point toward the grille, there is a rectangular cut-out in the plate to make room for the double action pump.

The brass adaptor used on some '49 3As.

(http://i748.photobucket.com/albums/xx125/willyscjmj/1949%203A/24867117.jpg)

The bottom one came off an early 3B, so I suspect it can be found on late 3As. The next one up is the original off my '53. The next one is off a 2A, but these metal top single actions can be found on '49 3As too and the top one is the original off my '49. These are all ACs.

(http://i748.photobucket.com/albums/xx125/willyscjmj/fuel%20pumps/IMG_1249.jpg)

The one off the 3B had a factory 1/8" spacer behind it.

(http://i748.photobucket.com/albums/xx125/willyscjmj/fuel%20pumps/IMG_1255.jpg)

Not the locations of the vacuum pump ports between the two double actions. The ones on my 53's original pump are in totally different locations and are 1/8 NPT (left side of picture) where as the 3Bs uses barb fittings. Note the drain petcock (right side).

(http://i748.photobucket.com/albums/xx125/willyscjmj/fuel%20pumps/IMG_1253.jpg)

(http://i748.photobucket.com/albums/xx125/willyscjmj/fuel%20pumps/IMG_1252.jpg)

When the tops are remove from the two glass bowl pump and the single action metal top, you'll notice all three have a very fine brass screen filter.

(http://i748.photobucket.com/albums/xx125/willyscjmj/fuel%20pumps/IMG_1257.jpg)

(http://i748.photobucket.com/albums/xx125/willyscjmj/fuel%20pumps/IMG_1256.jpg)

The fourth though probably has the best built in filter, a very deep sediment bowl along with a fine screen.

(http://i748.photobucket.com/albums/xx125/willyscjmj/fuel%20pumps/IMG_1258.jpg)

(http://i748.photobucket.com/albums/xx125/willyscjmj/fuel%20pumps/IMG_1259.jpg)
Title: Re: Which fuel pump is correct for my Willys?
Post by: johnrb3b on March 07, 2013, 09:23:37 AM: Is that a dead bug in the last picture? ;D
Title: Re: Which fuel pump is correct for my Willys?
Post by: garage gnome on March 08, 2013, 06:55:02 AM: No, it is a clump of nasty hair or fur. I didn't investigate it too far. ;D
Title: Re: Which fuel pump is correct for my Willys?
Post by: gmcjr on March 20, 2013, 08:14:01 PM: Good Job GG! Lots of good info! One thing I can add, if the original double action fuel pump had a 1/8" spacer between it and the block, and it doesn't get reinstalled, you will have insanely high fuel pressure (I had 10-12 psi, if I remember right. Not good, especially with a solex carb.) and not to mention extra stress on the pump diaphragms. I learned this the hard way.......sometimes p/o's are not very nice
Title: Re: Which fuel pump is correct for my Willys?
Post by: maximushuntermus on March 20, 2013, 09:36:01 PM: Is there any significance to the 1/8" plate? Does it being there or not change the pump rate?
Title: Re: Which fuel pump is correct for my Willys?
Post by: maximushuntermus on March 20, 2013, 09:37:09 PM: Oooops never mind I just missed reading the previous post, Duh !!!!
Title: Re: Which fuel pump is correct for my Willys?
Post by: Kenny_Kustom on April 01, 2013, 08:52:17 AM: The PO put an electric pump on my 3A.
I ordered a glass bowl pump, no Vac.
I also got a spacer for it. Do I need to put the spacer on?
Title: Re: Which fuel pump is correct for my Willys?
Post by: garage gnome on April 01, 2013, 08:58:03 AM: You only need it if you are running a solex carb. It will work with the carter though. As stated above, the spacer saves on wear and tear on the diaphragm.
Title: Re: Which fuel pump is correct for my Willys?
Post by: gmcjr on April 02, 2013, 11:47:07 AM: Quote
The PO put an electric pump on my 3A.
I ordered a glass bowl pump, no Vac.
I also got a spacer for it. Do I need to put the spacer on?

If I remember, the spacer only applied originally to the double action pumps. As GG said, you can put one on the glass bowl pump to reduce fuel pressure if needed, but it can reduce fuel pump volume as well.
Title: Re: Which fuel pump is correct for my Willys?
Post by: Kenny_Kustom on April 02, 2013, 01:03:10 PM: Hmmm... So.... Without any vac. Should i use it or not ? I have a weber carb..
Title: Re: Which fuel pump is correct for my Willys?
Post by: gmcjr on April 02, 2013, 02:57:57 PM: Quote
Hmmm... So.... Without any vac. Should i use it or not ? I have a weber carb..

The factory specs for fuel pressure are 2 1/2 to 3 3/4 psi, and enough volume to pump a half pint within 20 strokes of the pump.
I would try with the spacer first (just to err on the side of caution), and see how close it comes to the factory specs. If it doesn't work, remove the spacer. Then if its too much pressure for the carb, you might need a regulator.
You don't want to be climbing a steep grade and have the carb run dry halfway to the top ï¿½ ;)

I 'm 90% sure the single action glass bowl pumps didn't use the spacer, but I could be wrong too. Hopefully, somebody else will chime in......
Title: Re: Which fuel pump is correct for my Willys?
Post by: garage gnome on April 02, 2013, 06:52:38 PM: The original one on my '49 didn't use one, nor did I put one in. The only one I found it on what the double action glass bowl pump from the 3B Fhead. The original double action on my '53 didn't have one. Bob, should there have been one on my '53?
Title: Re: Which fuel pump is correct for my Willys?
Post by: Bob W on April 03, 2013, 06:27:26 AM: The CJ-3A 647911 Fuel and Vacuum Pump is designed to be mounted using two 638737 Gaskets and one 647669 Spacer.
Title: Re: Which fuel pump is correct for my Willys?
Post by: garage gnome on April 03, 2013, 07:35:53 AM: Thanks Bob. Mine didn't have the spacer, so someone had it off one time or another.
Title: Re: Which fuel pump is correct for my Willys?
Post by: Kenny_Kustom on April 03, 2013, 08:18:30 AM: Quote
The CJ-3A 647911 Fuel and Vacuum Pump is designed to be mounted using two 638737 Gaskets and one 647669 Spacer.

So, with fuel pump alone ( no vac) you don't use the spacer?
Title: Re: Which fuel pump is correct for my Willys?
Post by: garage gnome on April 03, 2013, 08:51:19 AM: Correct, unless you need decreased fuel pressure.
Title: Re: Which fuel pump is correct for my Willys?
Post by: athawk11 on April 11, 2013, 02:29:32 PM: In a different thread, Nate asked for some photos of this fuel pump. ï¿½I don't want to cloud up what is right or wrong in a 3A. ï¿½I want to emphasize that, to my knowledge this is [size=14]NOT[/size] an original fuel pump in a 3A. ï¿½This is just another style you might find in yours. ï¿½This is a single action flat top fuel pump that was found in a early '49 3A. ï¿½Additionally, the engine is a 3A, but the front engine mount plate is a 2A. ï¿½

Tim

(http://i1195.photobucket.com/albums/aa397/athawk11/athawk11%20Willys%20White/20130323002_zpsab39f2fa.jpg) (http://s1195.photobucket.com/user/athawk11/media/athawk11%20Willys%20White/20130323002_zpsab39f2fa.jpg.html)

(http://i1195.photobucket.com/albums/aa397/athawk11/athawk11%20Willys%20White/20130323003_zps451bcc6e.jpg) (http://s1195.photobucket.com/user/athawk11/media/athawk11%20Willys%20White/20130323003_zps451bcc6e.jpg.html)

(http://i1195.photobucket.com/albums/aa397/athawk11/athawk11%20Willys%20White/20130404002_zps5b884837.jpg) (http://s1195.photobucket.com/user/athawk11/media/athawk11%20Willys%20White/20130404002_zps5b884837.jpg.html)
Title: Re: Which fuel pump is correct for my Willys?
Post by: garage gnome on April 11, 2013, 02:54:33 PM: I think that is a replacement from an auto parts store. Just good info to have in this thread so if the question does come up, we have the answer.