Electric Fuel Pump SU v Hardi

[geoberni]

Due to some recent facebook posts about Carbs flooding after fitting a Hardi Pump, I thought I'd look at some Specifications.
Retailers are always plugging the Hardi as a 'like-for-like replacement, but I wondered what the evidence was. Did the facts support that???

SU Electric Fuel Pump Max Pressure as per their website: https://sucarb.co.uk/technical/technica ... mps-single

LP Pumps are max 1.5psi -------- ( Edit to add that this equates to just 0.103421 Bar)
(The HP 'Pusher Pump' e.g. Classic Mini is 2 - 3.8 psi, depending on model presumably)

Hardi Pumps as per their company data sheets : https://www.hardi-automotive.com/en/pro ... mps-1224v/

Part No
112-5 ... 0,13-0,20 Bar This is the one recommended as the SU LP Replacement
13312 ... 0,13-0,20 Bar
13312V... 0,18-0,26 Bar
3310-0 ... 0,13-0,20 Bar

All the above pumps are almost double the maximum pressure of the SU LP Pump
The rest of the Hardi Range are much greater pressure.

it's no wonder people get Carb Float Chamber leaks.... Certainly food for thought regarding Hardi Pumps.

[svenedin]

Very interesting! I too saw the Facebook posts about problems with Hardi pumps. It is absolutely typical that people fit a part that isn’t the original but is cheaper and then wonder why the wrong part causes problems. We all know SU fuel pumps can be rebuilt with a bit of effort and that’s cheaper than a new Hardi pump! I’ve given up saying fit the proper SU pump. Then the endless fitting alternators, alloy wheels, the wrong seats etc. Grrr.

On the bright side, second hand Lucas C40 dynamos are cheap and if people keep ditching SU fuel pumps there should be a good supply to rebuild!

Weirdly though some second hand parts are very expensive. Lucas DR3a wiper motors for instance. I assume the originals were ditched for newer design motors too long ago for there to be a ready supply of the originals

Stephen

[Peted7202]

Would it be useful to do a survey on here of those who have fitted Hardi's and their experiences. A limited number of posts on FB is not much of a scientific approach with some facts and a smattering of assumption and guesswork.

[svenedin]

Agree it isn’t very scientific. It’s the lowest tier of evidence, “case reports”.

[Chief]

I couldn't say if it was the original, wouldn't surprise me though.

So I could guess that the SU pump in my car worked for probably about 40 years before giving up.
It was replaced with an SU pump, that was around about 20 years ago now.

No known issues, so while that's of no use in the experiences of Hardi users, it does say something about SU pumps

[Owlsman]

In the interests of the scientific research path down which this thread seems to be going .........all I can say, is that I fitted a Hardi pump over 4 years ago and it's been fine ever since. I've no idea what output capacity is supposed to be - as far as I recall, I just bought it and fitted it, believing it to be a direct replacement for the standard SU pump.

Two MGBs I owned over 20 years ago also had Hardi fuel pumps and never game me any problems. The GT actually became my wife's everyday car for about 3 years and did about 7,000 miles a year during that time.

Not very scientific I know but I have no personal evidence at all to knock Hardi pumps. Incidentally, I didn't chose the current one on my Moggy for economic reasons - in fact, I'm sure it was more expensive than a standard SU one at the time.

[geoberni]

Some people seem to be misunderstanding my intent in posting this and taking it along the lines of a 'Which is Better?' discussion.

I'm just advising that the Hardi is not a direct replacement for 'Fit, Form and Function'.
It delivers almost twice the pressure of the SU, so the Carb float has more work to do in shutting off the fuel flow.

Look on it more like replacing the 803cc engine in a Series II Minor with a 1098cc, without considering what effect it will have on the Gearbox and Differential.
It'll work, but at max power it's going to result in some damage eventually.

[Peted7202]

viewtopic.php?t=77224

[svenedin]

My hypothesis is, the SU fuel pump is worn out and gives up so they go for a nasty cheap non-original replacement. Then the worn out needle valve gives out. It just about tolerated the aged pump and they got elderly together. I find those Hardi pumps vile. They are completely wrong like alternators or negative earth!

[Chief]

They are completely wrong like alternators or negative earth!

Weren't later models factory fitted with alternators making them right?
(also if you want to have a towbar fitted as far as I'm aware the only option is negative earth due to current UK law (which includes backdating to older vehicles like the Minor) requiring the use of those towing electric relays.

without considering what effect it will have on the Gearbox and Differential.

Anyone would think you were expecting a reply mentioning those things if you hadn't got in with that first

[geoberni]

without considering what effect it will have on the Gearbox and Differential.

Anyone would think you were expecting a reply mentioning those things if you hadn't got in with that first

Just trying to give a comparable example of how the extra pressure has to be considered, because not everyone can grasp the relative differences.
Mind you, some people still might not ....

[Bill_qaz]

They are completely wrong like alternators or negative earth!

Weren't later models factory fitted with alternators making them right?
(also if you want to have a towbar fitted as far as I'm aware the only option is negative earth due to current UK law (which includes backdating to older vehicles like the Minor) requiring the use of those towing electric relays.

without considering what effect it will have on the Gearbox and Differential.

Anyone would think you were expecting a reply mentioning those things if you hadn't got in with that first

I hate dynamos and positive earth

[firedrake1942]

The Hardi is, in my experience, much noisier than the SU and has a tendency to overheat and fail. Nor is it particularly cheap.

[svenedin]

They are completely wrong like alternators or negative earth!

Weren't later models factory fitted with alternators making them right?
(also if you want to have a towbar fitted as far as I'm aware the only option is negative earth due to current UK law (which includes backdating to older vehicles like the Minor) requiring the use of those towing electric relays.

without considering what effect it will have on the Gearbox and Differential.

Anyone would think you were expecting a reply mentioning those things if you hadn't got in with that first

I hate dynamos and positive earth

Don’t have a Morris Minor then. I believe there were some police vehicles fitted with the “alternator” but still positive earth. The. Alternator and negative earth is never correct in a civilian vehicle.

[Bill_qaz]

Stephen I think you have lost your sense of humour,it was in jest

Just because you don,t like something doesn't make it wrong, you have lots of mods on your minor(from your posts) an alternator is just another mod.
I bought my minor with many existing mods, including alternator and negative earth, disc brakes, servo, seatbelts and more, all of which I think are improvements. If I wanted or cared about originality I would of bought one unmodified but I bought it as a toy to enjoy and use.

[myoldjalopy]

Stephen I think you have lost your sense of humour,it was in jest

Just because you don,t like something doesn't make it wrong, you have lots of mods on your minor(from your posts) an alternator is just another mod.
I bought my minor with many existing mods, including alternator and negative earth, disc brakes, servo, seatbelts and more, all of which I think are improvements. If I wanted or cared about originality I would of bought one unmodified but I bought it as a toy to enjoy and use.

If you can find one! It seems especially the early 1000's have suffered all sorts of modifications, some subtle and some not so subtle.

[Bill_qaz]

Stephen I think you have lost your sense of humour,it was in jest

Just because you don,t like something doesn't make it wrong, you have lots of mods on your minor(from your posts) an alternator is just another mod.
I bought my minor with many existing mods, including alternator and negative earth, disc brakes, servo, seatbelts and more, all of which I think are improvements. If I wanted or cared about originality I would of bought one unmodified but I bought it as a toy to enjoy and use.

If you can find one! It seems especially the early 1000's have suffered all sorts of modifications, some subtle and some not so subtle.

But that was my point, I personally didn't want standard and would of carried out many of the mods already on my purchase, a deciding factor of buying it, and I am still doing things that I want. The cars are as Individual as the owners. It's no reason to state a modification is wrong!(as Stephens post) it just means you don't want it on your car as its not your taste.Not many 60 year+ cars are original even if unmodified many replacement parts are copies.
Sorry to go so far off the original topic
viewtopic.php?t=76113

[geoberni]

Back On Topic Time

I'm just advising that the Hardi is not a direct replacement for 'Fit, Form and Function'.
It delivers almost twice the pressure of the SU, so the Carb float has more work to do in shutting off the fuel flow.

I'm just pointing out that fitting a Hardi may reveal other issues due to the increase in pressure.
Many people, including myself until this week, are unaware that the Hardi is almost 100% more pressure than the SU.

[philthehill]

Even with a standard SU carb the fuel delivery system can benefit from the installation of a fuel pressure regulator.
https://www.ebay.co.uk/itm/304972778989 ... R5qn387AYw