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Thu Nov 05, 2009 12:05 pm

I was looking at a parts place and noticed that there are all sorts of fuel pumps... I saw a fuel pump that was for a late model engine with an alternator. I was not aware that there was such a specific fuel pump...anyway that is the fuel pump that was on my 1970 SP. It ran ok but I have recently picked up the correct pump but have my engine torn down and haven't had a chance to test it out.

I am sure it makes a difference, but what kind of difference should it make if I have the correct one.

I am just curious. Thanks

Thu Nov 05, 2009 12:09 pm

The original fuel pump for a 1970 1600 SP is not a rounded-top pump, and not slanted either. Note that the slanted types require a 4.0 inch steel pushrod and the non-slanted ones take a 4.25 inch pushrod. The plastic flange is the same (leave it in place). Make sure to get the fuel pump inlet and outlet lines ariented correctly.

Thu Nov 05, 2009 12:11 pm

None at all.

The two main fuel pumps (dome-top & square-top) deliver the same pressure, and interchange between early and late engines. The real difference between the two is that the early one didn't have a check valve (it was a retrofit item, p/n 113 127 405) and the later one had a check valve incorporated into the top of the pump.

Thu Nov 05, 2009 1:36 pm

So YB, here's a weird request:

Not just a pump that will fit or work with a 1972 AE engine, but the one that CAME on that engine.

I've only seen line drawing diagrams of it from the VWoA User's Repair and Maintenance Manual. It has a round dome top (not a sloped top) with a screw in the middle of the top. There is a wide conical filter screen in it.

The same diagram showed the input and output sides connected by some kind of check valve.

Ever seen this character? (It can barely be made out in this picture below:)

Thu Nov 05, 2009 1:41 pm

webwalker wrote: Ever seen this character? (It can barely be made out in this picture below:)

Yes. And if you'll kindly buy me the stamping machine to make new top sections, and the press to press the two halves together, I'll be only too happy to rebuild it for you... :wink:

:D

Thu Nov 05, 2009 2:12 pm

I know that later versions of this unit were a once piece unit that was permanently stamped together.

This is a previous version that had a screw on top to hold the metal cap on, so that you could replace the wide conical filter. The filters were designed be replaceable. I think these were the last replaceable filter units made before the one piece units that were to simply be replaced when they wore out.

Thu Nov 05, 2009 2:13 pm

webwalker wrote: I know that later versions of this unit were a once piece unit that was permanently stamped together.

This is a previous version that had a screw on top to hold the metal cap on, so that you could replace the wide conical filter. The filters were designed be replaceable. I think these were the last replaceable filter units made before the one piece units that were to simply be replaced when they wore out.

Check. I think I've got one in a box of cores if you want it.

Thu Nov 05, 2009 2:39 pm

I'll dig out my User's Maintenance and Repair Guide tonight and post the relevant diagrams. That pump, complete and in good condition, would really be the topper for my restoration. I'm running a cad plated Brazilian pump now (with the short pushrod) but when I switched the engine back over to a generator from the alternator that had been added, I didn't bother to do the fuel pump until I could get the right one.

M

Thu Nov 05, 2009 5:24 pm

Here's the diagram from page 60 of the User's Repair and Maintenance Guide for the 1972 Model year.

Thu Nov 05, 2009 5:33 pm

webwalker wrote: Here's the diagram from page 60 of the User's Repair and Maintenance Guide for the 1972 Model year.

I still need the machinery to be able to rebuild it. Have that here next week for me, okay?

:lol:

Thu Nov 05, 2009 5:43 pm

Excuse my ignorance :oops: but other than the gaskets and o ring (which I could imagine could be impossible to source) what are the other things you usually to the shop a pump? Rebush the pivot? Again, pardon my lack of knowledge in this work.

M

Thu Nov 05, 2009 6:31 pm

The original pump on my 71 looked like the above and failed because the pump diaphragm failed. No way to fix that unless you have the heavy equipment mentioned. On the early rebuildable pumps, the diaphragm was replaceable and included in the kit.

Fri Nov 06, 2009 5:11 am

webwalker wrote: Excuse my ignorance :oops:
I'm not pokin' fun. I've tried to help those pumps, but as bnam mentioned, I'm woefully underequipped.
webwalker wrote: but other than the gaskets and o ring (which I could imagine could be impossible to source) what are the other things you usually to the shop a pump?

That pump would require a diaphragm which is not available. It was never designed to be rebuildable like the earlier pumps were, just field-serviceable.

Fri Nov 06, 2009 7:27 am

Ok. That explains it perfectly.

In that case I plan to fall back on the Pierburg 1600. I noted that the early dometop Pierburgs that you sell have the checkvalve. Was there a check valve integrated in the later Pierburg 1600s? Or did it simply become unnecessary for some other reason?

M

Fri Nov 06, 2009 7:33 am

webwalker wrote: Ok. That explains it perfectly.

In that case I plan to fall back on the Pierburg 1600. I noted that the early dometop Pierburgs that you sell have the checkvalve.
They have the check valve. If you pay for it. :wink:
I sell them as I can find them. I sold a pump to a fella a few weeks ago, and put a check valve on it. Later on, I needed a check valve to take a reference picture of. Found out the hard way that I'd sent out the last one I had in my stash! Don't even have one for myself. :cry: They're not all that rare, but being a non-serviceable part, not just every one I get is useable.
webwalker wrote: Was there a check valve integrated in the later Pierburg 1600s? Or did it simply become unnecessary for some other reason?
The 'square-top' pumps have the valve integrated into the pump. It lives beneath the square cover.