CJ fuel pump id

4x4M38 · Post by **4x4M38** » Tue Aug 19, 2014 7:58 am

How do I tell if the CJ glass bowl pump I have has the vacuum capability?

It looks like my PCV valve connection on the left side of the block is plugged off. That really can't be a good deal. Figure I might as well get that plumbed back in as well.

I have a CJ carb.

Suggestions?
Thanks,
Brian

RICKG · Post by **RICKG** » Tue Aug 19, 2014 8:36 am

http://willysmjeeps.com/v2/modules.php? ... it&lid=109

Go here to id your pump.

Post by **wesk** » Tue Aug 19, 2014 9:31 am

A single diaphragm fuel pump on a Willys engine is only half the size of a dual diaphragm fuel pump (one diaphragm section for the fuel and one for the vacuum)

Dual diaphragm military fuel/vacuum pump.

Civvy dual diaphragm fuel/vacuum pump.

Note in both of the above photos the pumps have an upper fuel pump diaphragm section with two ports and a lower vacuum pump diaphragm section with two ports.

Single action/diaphragm fuel pump.

4x4M38 · Post by **4x4M38** » Tue Aug 19, 2014 10:22 am

Thank you Wes.

It looks like I have a single action glass bowl pump.
The dual job will have to go on the next phase on the project list.

In the meantime, I'm not sure this looks right.
First it appears the cover has been bolted back on upside down.
This vent is now next to the cowl.
Second, I wonder if this thing being unplugged has anything to do with all of the oil and gunk on the back left of the engine, bellhousing, and things aft.....

I should at least plumb this into the manifold, right?

The more I look the more silly things I find.

At least it runs and idles smoothly, and doesn't smoke.

Brian

Post by **wesk** » Tue Aug 19, 2014 10:40 am

Early Willys engines used a road draft pipe connected to that fitting and crankcase fumes and splash were directed down and under the jeep. In the 50's the move came to use engine manifold vacuum to discard the fumes back into the engine. This gives you four choices.
1-Live with what you have and the mess.
2-Add the road draft tube
3-Plumb it ala CJ2A to the intake using a PCV valve in the plumbing.
4-Install M38 PCV/Fording valve assembly and plumb it correctly for your jeep.

Had you researched the archives, photo albums and the manuals you may have reached this same conclusion.

From my L134 photo sub-album:

Early road draft pipe set-up.

CJ2A plumbing

M38 plumbing

4x4M38 · Post by **4x4M38** » Tue Aug 19, 2014 10:41 am

By the way,
I am not really dense, and am learning.

I have just recently found that using the Search Articles window on the left side of the page usually results in very little information.

The only way to get multiple results with the search function is to use the Search button above with the hourglass in the icon. It functions as I expect.

Thanks,
Brian

Post by **wesk** » Tue Aug 19, 2014 10:42 am

Actually the best results is to use Google.

4x4M38 · Post by **4x4M38** » Tue Aug 19, 2014 10:50 am

Thanks Wes.

I usually try not to go into the CJ stuff because there is so much M-series data to absorb. Weeding through just the M stuff eats up a lot of time. Unfortunately I guess I have no choice because of the Frankenjeep I have has so much civvy stuff on it. Deciding which is which is daunting at times.

I do try and research the archives as much as possible. In fact sometimes I think the wife wonders if I have a new online friend.

I appreciate you and others providing not only the info but the links to the data as well. It will help research down the road.

In the meantime I do apologize for seeming to fire without looking first.

In any case it appears whether the CJ or M version I need to flip that cover which is held on with two bolts. Any advice whether I can do that, get the old gasket off and the metal cleaned, and everything put back together without removing the header?

Take care,
Brian

Post by **wesk** » Tue Aug 19, 2014 11:01 am

If your crankcase vent fitting is the one in that little photo it is already correctly installed. You may need to loosen the bolt to rotate it so your new plumbing will fit correctly except being aft of the carb which means just mirror fabricate the plumbing from that side. To move it the side valve cover will have to come off. The vent fitting uses a composite/paper gasket which is easy to cut from gasket stock. The bolts use a small copper crush ring type gasket which is a hardware/auto store item. Try to avoid disturbing that side valve cover. If it comes off the gasket usually tears and then the decision to remove the manifolds will usually result in broken studs when you try to break them loose with brute force instead of heat and penetrating fluid.

New plumbing is fairly simple to get. The PCV is sold by many of the vendors and the tube and fittings are standard hardware items. A close study of the parts books both military and civvy will get the tube sizes and fitting industry numbers.

4x4M38 · Post by **4x4M38** » Tue Aug 19, 2014 1:46 pm

It really is maddening. As you pointed out, the fitting is oriented correctly in the valve cover, and if Bubba deployed just a little recon he could have put the thing back on correctly.