12 replies to this topic

[jime17]

Morning... to those of you sufficiently near the Greenwich meridian. Other times of day are available.

It has occurred to me that the diaphragm in my mechanical fuel pump might be leaking. Everything smells of fuel including me so it's hard to judge properly but I think the oil seems a bit ready to drip off the dipstick seeing as I put it in only recently. 20w50 obviously.

So questions...

1. Is there a way of checking in situ that doesn't rely on oil smell

2. It looks like my pump is of the type that has the screws in the cap so I'd hazard that I could change the diaphragm. It seems the kit is of similar cost to the minispares own version pump. Is the su version of sufficiently better quality to make changing the diaphragm a better bet or are the pattern ones just as good so fit and forget?

Your experiences would be most gratefully received...

[Spider]

Greetings from Australian Eastern Daylight Saving time zone.

 

You can usually see the Oil Level rise when the Diaphragm fails, though if the leakage is slight, the petrol will get drawn off by the Crankcase Breather. Another way is to have the Oil tested, but you'd be better off just overhauling or replacing the pump rather than paying for a test.

 

I've not seen it occur - yet - however I have been reading more and more similar cases in recent weeks. The newer fuels, only recently changed I believe, dry out the rubbers used in many pumps, even fairly new ones, and cause them to go hard and crack.

 

I am told that SU are on to it and their new kits & pumps have suitable rubber in them, however, I would ask the question just in case they try moving old stock.

[jime17]

Ha ha. Good evening Mr spider. I trust you are well. I thought you'd given up answering my questions after had you trawling ancient microfiche records for engine number deciding!

It might be my imagination that the oil seems thinner. It smells but not strongly. It may be blowby gasses.

Do you have any opinion on the minispares pumps? They are similar price as a diaphragm kit it seems.

Alternatively I think an electrical one might cost in roughly the same too. Are they worth the hassle of wiring them in?

[nicklouse]

reasons for an electric pump.

 

for me the main reason is to be able to reroute the fuel lines away from the exhaust down pipes when it has been changed from original.

 

otherwise there is not much need for them on a road car.

 

as to your question re the pump or diaphragm kit. in the past I would always just change the pump BUT most of the pumps I see now seem to have the inlet and outlets pointing this way and that and would need repositioning so changing the diaphragm is about the same work and you know the ports are in the correct orientation.

[Retroman]

Probably same on lancashire time

 

Burlen do list various diaphrams but as above you need to know it will take modern fuel and fit your older mechanical pump.

 

http://burlen.co.uk/...=pump diaphragm

[panky]

This happened to me, not on the Mini but on the Commer. First thing I knew about it was when the oil light came on because the oil was so thinned out with petrol, all down to a tiny pin hole in the diaphragm

[Cooperman]

I'm with Nick on electric pumps.

 

The advantages of fitting a pair of FACET pumps in parallel are the increased reliability, the removal of the risk that diaphragm failure will pump petrol into the sump, the pumps have individual fuel filters before the pumps and the fact that the carb(s) float chambers will be filled immediately the ignition is switched.

 

FACET standard pumps are not expensive, it is easy to fit them under the rear seat base panel inside the sub-frame, there is not a lot of piping involved and all you need is a power feed and an earth connection. For best reliability fit two pumps, in parallel, with separate power feeds and earths

 

The original pump position can be blanked off.

[jime17]

Probably same on lancashire time

Burlen do list various diaphrams but as above you need to know it will take modern fuel and fit your older mechanical pump.

http://burlen.co.uk/...=pump diaphragm

I hope so as were in the same county.

Thanks everyone. Looks like I have a decision to make.

Do the facet pumps draw enough current to warrant a relay or do i just pick up a switched live from the fuse box?

[Cooperman]

With twin electric (FACET) pumps, you simply take one live feed from the ignition switch 'AUX' feed, run it via an 8 amp fuse to one of the pumps. Take a second live feed and run it via a separate switch and fuse to the other pump. Use different earth points for each pump.

 

Alternatively, have two live feeds to two fuses, two (hidden) switches and you have another security device.

 

Twin pumps need to be piped in parallel, which is easy.  All you need ate two T-pieces and a length of proper fuel pipe with some pipe clips.

[mikal]

Speaking of facet pumps, I have one fitted to my car, on the bulkhead next to the wiper motor. I have read in several places that the pump is designed to push rather than suck and should be mounted below the tank on the rear subframe. Having said that, it's been in that location for years and never given me a problem including during the Melb-Bali road trip. Should I move the pump or leave it where it is using the "if it ain't broke, don't fix it" theory?

[Spider]

According to the paperwork from Facet, the pumps that most sellers offer will only 'lift' 300 mm and have a pressure of 5.0 PSI.

 

They will lift higher than that when new and really, once the system is primed, it will 'lift' many tens of feet.

 

SUs do seem to usually cope with the higher pressure , they 'like; only 2 -3 PSI, so if rough roads are encountered, a regulator couple be required to keep the Carbs from flooding.

 

Facet do list a pump that suits SU Carbs, but as demand is low, it's not one anyone keeps.

 

I did look in to and try a few Facet pumps, and personally, I came away not particularly liking them. I ended up settling on the SU German copy (Hardi) that Mini Spares offer and have been very happy with them, to the point where I feel they are better than the SU pump.

[jime17]

Well thanks everyone. Food for thought.

[mikal]

Hi Moke, I'm running a 45 Weber and the pump is probably 600? mm above the bottom of the tank. I'm going back to Oz in a few weeks after 6 months so hopefully the pump primes. A bit of test I suppose. I'm thinking of doing another road trip to Bali, if so I'll take a spare pump just in case...