SU Fuel pumps

[johngosnell]

I need to replace on of the fuel pumps , so which one, the original or an electronic version AZX1308 or A ZX 1308EN ?

regards John

1B1257BW

[Glyn Ruck]

You want to get away from mechanical points at all costs. So the electronic version or go for a good reliable non polarity sensitive Hardy pumps as Porsche used to use pre fuel injection. I have used two Hardy pumps for reliabilty sake. Make the same noise. Identical mounting. Can't be seen. Well priced. No modification of pipework needed. Same fittings.

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[NigelW]

In light of the possibility of the UK getting E10 fuel in the not to distant future would these pumps be compatable with said fuel? If anyone has any ideas on how to cope with the raised levels of ethanol they would be welcome.

[Glyn Ruck]

The Hardy pumps are compatible with all alcohol fuels. One thing I checked on as in SA's Highveld area we have 12% Sasol heavy alcohol in our fuel which wiped out my correct look nylon fuel piping in a couple of weeks so I went to black alcohol compatible flexible piping.

Early SU pumps were not alcohol compatible. Burlen says their new pumps can tolerate alcohol.

Huco pumps also gave diaphragm trouble with alcohols. They have fixed the problem. A friend with an S Type that was fitted with Huco pumps had them replaced FOC by Huco after the diaphragms disintegrated.

Jaguar nylon fuel hose after 2 weeks exposure to SA alcohol laced fuel below. All elastomers, nylons, plastics in the system need to be alcohol compatible. The alcohol containing fuel needs to be kept dry to prevent phase separation & corrosion issues. Alloys in fuel system components need to be free of even small amounts of yellow metals (e.g. Copper) or this catalyses corrosion. Terne coat plated steel fuel tanks can give trouble.

Hydrous alcohols such as Brazil sells require carburettors etc. to be manufactured out of pure Zinc or they corrode badly. Especially below the venturi where very low temperatures are experienced. I have seen Pierburg carbs corrode so badly on VW's in Brazil that they fell off the manifold. When they moved to fuel injection they were rigorous with compatibility testing.

Been down this road for our oilco. The good news news is that old Jags in SA have not displayed much trouble with 12% alcohol fuel other than some flexible pipe issues & some corrosion on the mesh strainer in the top of the fuel filter.

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[John Quilter]

I've been running five old British cars, MGTD, two Morris Minors, Austin 1300, and my 3.8S all with SU fuel pumps and SU carbs on unleaded 10% ethanol gasoline here in Oregon and California for the last 20 plus years and have not suffered any fuel pump, fuel line, or carburetor issues as a result. While not a fan of 10% ethanol, I think the concerns are way over blown, just my personal experience.

[NigelW]

Wow thanks for that Glyn, looks like we've got a bit of work to do over here. CMC the restoration specialist has advertised they can sort out your Jaguar to run on the fuel but at a cost of nearly one thousand pounds, I wonder what they do for that.

[NigelW]

Interesting John, they have put the frighteners on us here about the fuel and it is out to consultation with the government and interested parties at the moment. Of course the classic movement are dead against.

[John Quilter]

And 40 years ago the introduction of unleaded gasoline was going to be the end of our engines as well. Been using that since 1975 and not had any issues either. Maybe because I don't drive my cars "like the hammers of hell" all the time.

[Glyn Ruck]

The unleaded fuel issue is quite a different matter to alcohols in fuel. Valve seat recession with unleaded fuel was only really an issue with cast iron cylinder heads with no separate seats but the valves seating straight on the cast iron. Standard Jag valve seats are more than sufficiently hard & durable for unleaded fuels. Only constant use at high RPM could require the lubricating value of lead or other additives on some engine's valve seats.

The oil industry has experienced plenty of trouble with alcohol laced fuel in older vehicles. Many newer vehicles are happy on E85. Fortunately the UK & USA only use anhydrous alcohol & at relatively low doses. Just keep water out of your fuel tank. While the industry does a far better job these days of keeping service station tank bottoms dry. I would still be careful not to fill up your older car just after a tanker discharge that stirs up the tank bottom.

It is also dependent on the type of alcohol.

But there are many scare stories out the like ZDDP content of modern engine oils.

[Glyn Ruck]

Wow thanks for that Glyn, looks like we've got a bit of work to do over here. CMC the restoration specialist has advertised they can sort out your Jaguar to run on the fuel but at a cost of nearly one thousand pounds, I wonder what they do for that.

It would be very interesting to know what CMC intend doing. They are probably going the whole hog of removing all brass parts from carbs etc like spindles & needle & seats & replacing them with Stainless Steel etc. as they can catalyse corrosion.