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AC Delco Fuel Pump


Colin
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Folks:- just to ask a question and also give you an idea of what was lurking inside my AC Delco fuel pump (and before I seriously think about electric alternatives).

Question:- top pic shows the inside of the pump body. See the fibrous crud( I think was bits of cigar) drawn up into the pump, and which was packed in the dark recess pictured. 

DOES that dark recess have any channelling, drilled or otherwise? 

'Cos if it does, despite cleaning crud out with the smallest of watchmaker's srewdrivers and swishing with meths after (the pump, not me), it may still be blocked somewhere . . . hence my fuel drawing problem(???). 

Second shot shows the valves in situ. According to the w/shop manual, these are supposed to be accessed by a 2 screw covering plate; NOT in my case!

So, are they interference fits and is there a method to remove and replace with the spare, new valves that came in the AC repair kit, without mullering the pump case??

I didn't perform a diaphragm centering action prior to tightening body screws. Problem?? 

More thoughts, please. 😊

IMG-20200716-WA0003.jpg

IMG-20200716-WA0005.jpg

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Thanks to all. I'm glad not to have blocked up any invisible jets or anything of the ilk. Sounds like replacing the valves - even if I could work out what 'normal' resistance is supposed to equate to, could be fraught with damage risk?!? 

I'm beginninv to become more and more perplexed, I admit . . . 😐 

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Would just like to thank everybody for all their help and suggestions in my whole fuel system renovation. Some great ideas and help, there.

I should just like to invite you all now to give me the good kicking I deserve . . . 

Re the fuel pump, although it was many moons ago when I last had it apart to clean etc.. prolly ten years or so) and back then had no problem with it working well afterwards, this time round I have finally discovered, I simply hadn’t reassembled it correctly!! 😅

As soon as it was properly reassembled (diaphragm properly engaged), of course there was sucking/blowing at the valves . . . !!

refit, quick carb chamber fill with fuel and she started, first pull 😁!

 However . . . I am still puzzling the reason for it ‘failing’ those months ago, which led me to undertake this whole system renewal process but in actual fact, better     I found the tank drain tube to be dodgy and additionally the flexible lines brittle and perished whilst she was in my garage and not whilst out on the road  somewhere . . . . !

Given the finding of fibrous material in the pump chamber and what appeared to be a cigar butt in the tank along the way, I guess that must have been swilling around in the pump originally and caused its lack of enthusiasm to start. And, by the time I’d finished faffing with decisions about the way to renovate the tank and renew all the lines, it’d dried out . . . . and then I undertook to install the new pump and diaphragm with just a hint my own attendant trademark stupidity!

I sure hope you have all enjoyed my ridiculousness!!

Cheers all!

C.

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Glad you seem to have got it sorted Colin, I have been on the same journey and had some very interesting conversations with 3 of our suppliers who seem genuinly unaware that the 204893 pump replacements they are selling are not suitable. My workaround of fitting a pressure regulator didnt last long as the pump didnt like the back pressure and fell apart. The attached photo is of 204893 pumps for Herald 1360 from two different suppliers, anyone spot the issue with one ? I have also been told I need a spacer ( which I dont) and that it should work fine at 8lbs/in (which it wont). I have reverted back to my old pump using only external filters and like yourself have changed ALL my rubber for ethanol proof. We will see.

20200724_131629.jpg

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luckily I wasnt on the road. it went while I was turning the engine over in the garage to measure the fuel pressure. The casting has completely separated from itself. Not a great advert.  I wont bore you with all the details but all I wanted to do was change out a 40 year old italian made pump which has very small filters in it which block easily, I found I did have some suspect old rubber and even some badged as R9 which appeared to be "melting" and blocking the pump. Ive now got nothing but ethanol proof and copper piping and the old pump with the small filter removed and large external filters fitted. I spoke to 3 of our largest suppliers and they seemed unaware that the pump they sell 208502 is too strong for the Herald but at least one has said they will talk to their suppliers ( I suspect they all come from the same source). One suggested that the 208502 was fitted to the 1300 Mk4 spitfire and may have needed a spacer but I couldnt test that as the studs arent long enough to fit one, if any Spitty people know if it wasnt just the 1500 that had a spacer that might explain something. And to make you feel better Colin, I managed to assemble my pump internals the wrong way round and couldnt figure out for a while why no fuel. 

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Wow! I feel for you!! That's a worse pump scenario than my own.

Although my elementary mistakes were rectified (albeit I drove to a fuel pump specialist in Reading with attendant costs for the pleasure), I think I may have sourced a 'correct' replacement, should I ever need one, now, hav8ng bought a Quiton Hazell unit advertised. I'd already refitted and run the car on the old AC Delco, so wasn't going to faff to see if it truly is a good'un. But I did what I could to compare to the pics of the AC I took when it was off and being compared to the unit I bought from the 'R' supplier and it looked a better match (lever arm and flange/gasket correctly shaped). I may never know . .  . !! But well done for being so tenacious with your efforts with replacements. BTW, my invoice from 'R' said no spacer required. And, the specialist, Reading, would have completely rebuilt my old AC Delco lock stock and barrel for £65 if he'd not discovered I had simply been a Wally! 

Best. C. 

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I would have thought it should be possible to test the pump pressure without fitting to the engine. The pressure is determined by the spring, so it will be the same after a few hand pumps as it would be in normal use. The maximum flow rate, of course, is a different matter.

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2 hours ago, NonMember said:

The pressure is determined by the spring, so it will be the same after a few hand pumps as it would be in normal use. 

There are actually two positions of the actuating lever; light pressure will move the lever to what appears to be the full extent and it will spring back after, so it gives you a false impression that the pump is not pumping. Press harder and it will then go all the way in, and you'll hear the valves begin to suck or blow quite audibly. 

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