fuel pump rod stuck

[Ton76]

After running my rebuild 2.0 CU engine for 12000km on an electrical pump I've decided to place an original mechanical pump after the electrical one broke last summer.

Now it seems the fuel pump rod gets stuck in the engine case. I have to push it quite firmly to get it in and I need a pair of pliers to get it out. Because of this the fuel pump obviously doesn't work.

The rod is perfectly straight. Not wanting to mess with the engine cases I've sanded it down a bit with a pillar drill and some sandpaper. Hower it seems to help a bit it doesn't do the trick completely.

My guess is there's some sludge build up, because of the absence of the mechanical pump, or scars left over from the engine rebuild obstructing the rod tube.

What would be a proper way to clean the rod tube in the engine case without causing damage to the case or engine?

Thanks.

[desertrefugee]

Are you sure the rod is perfectly straight? I've seen them bind and/or make lots of noise in Chevrolet V8s when they were seemingly straight ... but were not.
_________________
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- a bunch of vintage motorcycles
- Numerous telescopes of various size and function

"For I have loved the stars too fondly to be fearful of the night." - Sarah Williams

[Ton76]

Hi,

Yes, it's perfectly straight. I checked it with a straight edge. You know, the special tool used to check cylinder heads etc.

[MarkWard]

Ton76, we did not get any T2.5 or T3's in North America with carbs. Are you asking about an aircooled 2.0 engine or a WBX delivered with a carb stock? There is probably a reason someone deleted the stock pump at some point. On the Type 2s that were carbed I came across more than one bus that would quit after running for a while. It ended up that the fuel pump shaft was worn and did not provide enough lift.

For mechanical fuel pump advice, you might be better off asking in the "bus" section. Also a picture might help. For example on the Type 1, the fuel pump rod sat in a bakalite peice to center it. You might have something similar. I think it is unlikely the steel pushrod is riding in a small aluminum bore. Also for grins, chuck the pump shaft up in a drill and spin it. That will give you a visually of the shaft. I do the same with valves.

My choice would be to run a mechanical pump for a few reasons. Hopefully you get it resolved.

[Ton76]

Thanks!

Yes, it's got dual carbs. We didn't get much fuel injected busses in Europe. Even most of the later WBX engines still had a single Solex carb.

The original pump on my van was deleted because it was leaking. It was replaced with an electrical pump which I've never been too fond of. When it died last summer I went on the lookout for a mechanical one.

I could check the length of the shaft since I've pulled it, together with a broken fuel pump, from an old 2 liter type 4 engine. The end tips look a bit worn and the shaft could indeed be worn off.

I did actually put the pump shaft in a pillar drill. I did that to sand it off a bit with sandpaper. It is perfectly straight. I've also checked it with a straight edge as I mentioned before.

[MarkWard]

Still not clear, is this a WBX engine or an AirCooled 2.0? Does the pump attach at the top of the case or the bottom r/s of the case? Sounds like the part the shaft slips into just needs to be cleaned. Probably caked in oil/carbon from not having a rod moving in it for some time and being capped off. I am trying to explaing this part. It is a fuel pump spacer.

[Ton76]

Sorry, is a type 4 aircooled 2 liter CU engine.
The pump is attached to the bottom r/h side of the engine. It has the bakelite spacer without the tube.

My guess was that it was caked in sludge.
In the mean time I've found out that the shaft should be 139,8 mm in length. I'll measure the old one and I'll buy a reamer to clean the hole the shaft sits in.

[Wildthings]

[Ton76]

I know. But spraying cleaner in the engine doesn't sound like a good idea either.

[MarkWard]

If you are into guns at all, a gun cleaning kit comes with an assortment of bore brushes. I use them when I overhaul an engine. That plus some sort of solvent like laquer thinner or acetone. Yes too loose is not good either.

[Ton76]

A copper gun cleaning brush wetted with some carb cleaner sounds pretty good actually.

[Ton76]

Problem fixed.

The original push rod was pretty worn out. It was 3mm shorter than it should be.
I turned the old rod into a reamer and used it to clean out the rod tube.

[MarkWard]

A result. Thanks for posting back an update.

[Ton76]