Fuel Pumps

[TomJ]

Hi all:

Trying to do a rebuild with a mixed bag of parts that I bought as a "1951 CJ3A" but it turns out that apparently the engine is a gear driven MB motor so here's where I am. �I'm trying to stay as close to period correct as I can but there is such a mixed bag of stuff here that I'm gonna have to make some compromises. This is the fuel pump that was on the engine, from my reading I gather that it is a dual action pump that also supplied vacuum to run the wipers. Do I have that right? So my next question would be that I was going to use electric wipers (trying to balance functionality with nostalgia) so would I be alright to use a new single action pump (glass bowl variety) instead? I figured I would rather just get a new one rather than take the time to try to re-build this one.
Idea's....opinions?

Tom

[Bob W]

You are correct. Just be sure to use the correct spacer, or none, depending on the fuel pump you choose. Most of the single action type do not require any spacer. That CJ-3A type in the photo requires a thin spacer and it looks like it is still stuck on the pump mounting flange.

[TomJ]

Bob...how do you tell what spacer you need?  The instructions you get with the pump?  Or do you watch the cam lobe with the pump bolted on?
Finding out that it's actually an MB block kinda threw me, I feel like I have to watch everything I order to make sure it will fit.
Tom

[Bob W]

Use the original application of the pump.

For a CJ-2A single action - no spacer.
CJ-3A double - thin spacer.
M-38 double - thick spacer.

Unfortunately many modern listings just say all the pumps fit any engine with no mention about shims, thereby complicating things. You are probably safe with a single action pump and no spacer.

[calvinhunt]

Bob,

  Would you take this one step further?  Please provide the thickness of the thin and thick spacers.  
  
  By the way, thanks for sharing your expertise over the past several years.  Most of us rely on your knowledge and experience.  

[Bob W]

I don't have the exact thickness handy but the thin spacer is about 1/8" and the thick spacer is about 1/2".

Thanks  

[Comanche_County]

Good stuff to know, Ive been wondering about the difference in fuel pumps.  My 51' has the larger double action and my 50' has the smaller single action pump.

[TomJ]

Jay....I know what you mean, I have a '49 sitting out back I'm going to get to next, but I stumbled across a (what I thought was a '51) that a guy had gotten tired of and just wanted to get rid of, so I bought it.  I'm trying to get that one running but every stage seems to hold a new suprise.  When I got the engine back from the shop I realized it didn't have a CJ3 engine stamp but appeared to be an MB block, even though it had the dual action fuel pump, gear drive timing, etc.  So now I'm not sure about ordering parts, what accessories to put on it.  Since I was thinking about using electric wipers I thought I'd just use a single action pump (like the '49 in the barn has).  It can get a bit confusing.

Tom

[calvinhunt]

Tom,
Unless you were planning to make an original restoration, go ahead and use the single action fuel pump and the electric wipers. �Even with the dual action fuel pump the wipers are not as effective as I would like (However, they are just for looks.  I don't even have a top for my Jeep and will never be driving it in the rain).  Maybe it's just my pump.  Even though it's new there is no guarantee that it is working like a NOS did.  I've been disappointed with nearly every reproduction part I ended up having to install during my restoration.  As I've said on this site before, "If I had to do it over again, I wouldn't do what I did and make it as original as practicably possible.  In the stead I would make the Jeep I wanted, with the spare tire on the back, electric wipers, 12 volt electrical, Saginaw steering, etc. So, I would suggest that you don't be too troubled about the proper fuel pump, electric wipers, etc.  Just my thought, for what it's worth.  

[TomJ]

Hey Calvin:
Yeah I know what you mean.  I bought a basket case, suppost to be a "51 but the frame had been altered and it turns out to have an MB motor converted to gear drive so my thinking was to keep it as close to original as possible but go ahead and upgrade a few things as it isn't going to be a showpiece anyway.  As I go along I'm looking more and more at little things I can do to make a practical daily driver as well as close to original. (like upgrading the oil filter to protect it) Anyway I think it will turn out OK, just a little frustrating a times.
By the way looked at your's in the pictures you've posted and I'm kinda hoping for something along the lines of what you seem to have.  A nice little dependable runner to drive and enjoy.  Mine may not end up as nice as yours, but I'm tryin!!
Tom

[calvinhunt]

Tom,
  Sounds like you have the right attitude as you get into this project. There were some frustrating times as I was restoring my Jeep, but for the most part, it was really enjoyable and rewarding.  Even now, as I drive it around either in town or out on the trail I marvel that so many parts, manufactured and assembled over 60 years ago, still operate and perform just as they were designed to do so long ago.  Yes, they have been disassembled and overhauled, but the crank, the rods, the cam, the accessories, the tranny, the xfer case, the rear ends, etc., all function perfectly.  I did use as much as possible, New Old Stock parts (Not because I am a purist, but because I so dislike the JUNK that is sold as serviceable Jeep parts.  Yet, when there are no NOS parts, I'm glad to have repros.  They are better than nothing.
  Enjoy the rebuild, and then enjoy your finished product.  
  Thanks for sharing you project...your frustrations and your progress.