Fuel pump flow and pressure.

[Dave H]

Getting ready to fire the motor after rebuild, thought it best to do a flow test first ,expected to get the 1 litre  per 15 seconds at the injection pump outlet NRV ( non return valve ) But got nothing, the fuel pump will not create enough pressure ( 0.8 bar I believe) to lift  the NRV of its seat . The NRV is the no hole type to go with the T piece vapour mod at the fuel pump. Tried to get flow at the CSV but got a mere 0.5 litre in 15 seconds, All sounds familiar yes.
All lines,  hoses , filters tank etc are new , even the hole in the bottom of the flower pots been checked .
I’m thinking it’s got to be the fuel pump yes.. removed pump and before stripping I thought I’d Jerry rig it up to measure flow at the pump itself to get a baseline. The pump on its own will deliver 1.5 Litres ( of water ) per 15 seconds, as soon as I put the NRV in the line it dead heads the pump.
Many of you guys must of Rebuilt these pumps, what problems do you encounter ?
Is it likely to be brushes, dirty commutator or something else entirely?

[Dave H]

Think I may of found the culprit , the commutator has one hell of a step in it, I’m sure it’s not supposed to be like this ☹️

[Dave H]

If anybody has one of these armatures to sell in better condition than mine please PM me.
Regards
Dave

[BaronYoungman]

I hope I was helpful you should find a local guy that works on small electric engines to rewind and restore your armature.  Bob

[Dave H]

Many thanks for pointing me in the right direction Bob, your a real good guy .

[getsmart]

Hi Dave,

I rebuilt my tall pump and I only replaced the brushes and the bearings. When I went to test it the pump did not work. I then primed the pump (ie poured petrol/kero into manually) after that it fired up and tested as per specs.

Hope this helps,

Rgds, Joe

ps . I bought the pump kit from George Des from this forum.

[Dave H]

Hi Joe
My commutators beyond repair as can be seen. Yours doesn’t look too bad for now.
Bob Youngman put me onto the right track ,the armatures now getting rewound and a new commutator fitted.
When I fit new brushes and seals and it should be like new again.
Hope to have it back within the week and will post pictures.
Cheers
Dave

[BaronYoungman]

If it works for you that is great. I just caution you that the glue that is holding all those wires together is probably 30 plus years old and unfortunately with today's ethanol gasoline if it eats away at it.  What will happen if the wires will become loose those very thin wires and start touching each other and then it will deaden out some of the pickups so your pump will have dead spots in it or it could cause a complete failure if a wire came loose and shorted out a whole section at a time. If you have a local gentleman who works on small electric motors he should be able to rewind your pump armature reasonably ( under $160). Just my two cents because of your going through all the trouble to rebuild your pump I strongly suggest rewinding the Armature prevents future problems. Bob

[Dave H]

100% agree with you Bob.

[getsmart]

Fair enough approach guys. Though if you get fuel into your armature you might have bigger problems than dead spots    , ie, the electrics being sealed from the pump assembly. I was amazed how good condition mine was in. Armature windings tested fine though having said that I think its a good idea to keep a spare pump so one day when I get my car back on the road I'll try and get a spare that perhaps has shorted its windings and repair it. These are not cheap!!!!! And I am not rich!!!! 

Whilst we're on fuel I was surprised to see that the inside of my 55 year old fuel tank looked like new!!!! Fuel is pretty good here in Australia and most of the main petrol stations don't add ethanol to my knowledge.

[mbzse]

.../...if you get fuel into your armature you might have bigger problems than dead spots.../...

True for the early, bigger fuel feed pump.
The later, smaller type was introduced in 1969, and it has its armature running immersed in fuel 

[getsmart]

Haha- very true Hans!!! I wonder if one style is better than the other? Must be a discussion post on here somewhere on the pros and cons !!! 

[Dave H]

A quick update on the armature rewind and new commutator. As I’m in the UK I sent the rotor complete with upper housing to B&T rewinds of Birmingham UK, cost was £168 uk pounds including postage. Anybody in the USA I would suggest contacting Bob Youngman who has much experience in these pumps.
Rotor was returned within the week.
As I’m waiting on new seals From Germany I thought I’d assemble the pump with old seals and test in water as before, difference is night and day.
It now pumps at 1.2 bar and lifts the injection pump Outlet check valve set at 0.8 bar. Delivery through the check valve is over 1ltr in 15 seconds so very pleased with the results. Just stripped the pump again to dry out the water and await the new seals for final assembly.
Looking forward to firing up the engine next week for the first time in 10 years.
Doubtless It won’t go as smoothly as I hope so I expect to be back picking your brains next week 🤗 cheers guys.
Dave