Hi All,
I need to change my mechanical fuel pump on my 1978 Sprint. Is there a make and supplier that you have used
and you can recommend their pump as being the best quality and reliable. It seems a bit of a minefield out there
as most seem to be non original types.
Cheers Guys Phil
Mechanical Fuel Pump Advice
Re: Mechanical Fuel Pump Advice
I have a 1300 dolly, and the pump on started playing up this time last year (sucking air).
To cut a very long story short I tried three different new pumps, two from 'reputable' suppliers and one from a cheap eBay seller. They all caused the float chamber to overflow. I bought a pressure gauge and it confirmed that the pumps were all producing around 10 psi (the requirement is 2.5!)
One of the triumph manuals suggest that thick gaskets added to the pump can be used to reduce a slight over pressure, but I found doing this only reduced it by about 1-2 PSI.
In the end I added a cheap pressure regulator set to 2 PSI, and it's been fine since. I gather too that even the regulators are frought with problems too, but it seems I was lucky with mine (so far!)
The sprint pump has a different shaped operating lever to the ohv pumps, but the main casting looks very similar, so I suspect there may be a potential issue with overpressure of these too...
To cut a very long story short I tried three different new pumps, two from 'reputable' suppliers and one from a cheap eBay seller. They all caused the float chamber to overflow. I bought a pressure gauge and it confirmed that the pumps were all producing around 10 psi (the requirement is 2.5!)
One of the triumph manuals suggest that thick gaskets added to the pump can be used to reduce a slight over pressure, but I found doing this only reduced it by about 1-2 PSI.
In the end I added a cheap pressure regulator set to 2 PSI, and it's been fine since. I gather too that even the regulators are frought with problems too, but it seems I was lucky with mine (so far!)
The sprint pump has a different shaped operating lever to the ohv pumps, but the main casting looks very similar, so I suspect there may be a potential issue with overpressure of these too...
Re: Mechanical Fuel Pump Advice
The pressure is predominately controlled by the spring, the stroke controls the volume or flow.
Seemingly, as with so many classic car repro parts, they can't get the spring rate correct - witness the ongoing issues with the oil pressure relief valve spring in the County oil pump on the slant 4 and stag V8 engines, that has been ongoing since 2009 (may be before but that is when I had a problem with over 100 psi oil pressure on a County new pump I fitted to my Stag).
The Standard Motor Club had exactly this issue on petrol pumps they were selling for the SC engine (fitted to the Standard 8's and 10's, Heralds and your 1300 Dolomite)., The solution is simple - as with oil pumps - use the spring from your old petrol pump. (Only possible on pumps that can be serviced - they can be identified as they have a circle of 5 or six screws holding the top halve onto the main body.
Even better just refurb your old pump if the arm is not worn. That way you know it has the correct arm and will pump at the correct pressure. Easy to do.
Seemingly, as with so many classic car repro parts, they can't get the spring rate correct - witness the ongoing issues with the oil pressure relief valve spring in the County oil pump on the slant 4 and stag V8 engines, that has been ongoing since 2009 (may be before but that is when I had a problem with over 100 psi oil pressure on a County new pump I fitted to my Stag).
The Standard Motor Club had exactly this issue on petrol pumps they were selling for the SC engine (fitted to the Standard 8's and 10's, Heralds and your 1300 Dolomite)., The solution is simple - as with oil pumps - use the spring from your old petrol pump. (Only possible on pumps that can be serviced - they can be identified as they have a circle of 5 or six screws holding the top halve onto the main body.
Even better just refurb your old pump if the arm is not worn. That way you know it has the correct arm and will pump at the correct pressure. Easy to do.
1975 Sprint Man O/D in Honeysuckle Yellow
1971 Stag Auto White
Too many cars, too little time!
1971 Stag Auto White
Too many cars, too little time!
Re: Mechanical Fuel Pump Advice
Unfortunately my old pump was not serviceable. It was an AC made one but peened together so not easily dissected. I did cannibilise it and tried to use the spring (it was a different diameter) in one of the new pumps, but the pressure it produced was less then 1 PSI so I gave up that idea.marshman wrote: ↑Wed Apr 16, 2025 9:41 am
... your 1300 Dolomite)., The solution is simple - as with oil pumps - use the spring from your old petrol pump. (Only possible on pumps that can be serviced - they can be identified as they have a circle of 5 or six screws holding the top halve onto the main body.
Even better just refurb your old pump if the arm is not worn.
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Re: Mechanical Fuel Pump Advice
I fitted a 'modern' Quinton Hazell pump to my Sprint in late 2023 and have had no issues with it since, though it didn't do that many miles last year.
Being the tight fellow that I am, I bought three pumps at the same time as that was the maximum I could have within the same standard (but in my opinion extortionate!) postage rate, so have two identical pumps here on the shelf (I have more than one Sprint before you consider me a fool easily parted from my cash!). Happy to let you have one of them at cost...plus postage
Being the tight fellow that I am, I bought three pumps at the same time as that was the maximum I could have within the same standard (but in my opinion extortionate!) postage rate, so have two identical pumps here on the shelf (I have more than one Sprint before you consider me a fool easily parted from my cash!). Happy to let you have one of them at cost...plus postage