Which fuel pump?

I need to replace the old pump (some aftermarket electronic thing). It works and hasn’t let me down but it’s just wrong so I’m replacing it.

I seem to recall, but couldn’t find, complaints about some of the new but old style SU pumps. Can anyone advise on which of the old style, but new, pumps to get?

Btw, I see three types on the SNG site…original and then two types of old style electronic.

Checked the archives but couldn’t readily find the answer.

The key difference between the two is the older style has points and the new style doesn’t. They’re both SU and look the same. I bought an electronic model from SNG, installed it, and it didn’t work. It went “thump” and quit. Took it out and hooked it directly to a battery. Went “thump, thump” and quit. Disconnected and reconnected it several times and it started thumping along happily … but I still put the old one back in, with a new diaphragm and cleaned up points. The electronic one I keep in the boot.

I rebuilt my fuel pump with points 20 years ago and am thinking to rebuild it next year although there are no problems with it.

I bought the one with the points, a non-electronic original. The reason these things usually die is related to the points and if a good bash with a piece of wood or a rock doesn’t get it going I stand a chance of cleaning the points. Can’t do that with electronics.

I installed the electronic version of the SU then rebuilt the original points pump and carry it as a spare.

Hasn’t has a problem in 6 years and 30,000+ miles.

Just in case, I also carry a quick-to-fit inline electric pump to get me to the evening’s motel destination:

I wonder if that could plumbed into the line ahead of time and just switched on if the SU dies.

That is exactly how I installed it just prior to the 2016 CCOL. It was okay in most driving but I found if I really got on it on steady incline I could out-run the fuel supply. The unpowered inline pump simply had too much restriction to supply enough fuel for maximum demand.

Now I have the spare in the boot with a pair of threaded fittings on each end that splice it in just below the fuel tee at the carbs. The hot wire is already in place with one end of an in-line fuse holder. The other half of the fuse holder is on the power feed for the pump for a quick hook-up. From the test period:

Having done all that I suppose it guarantees I will never need it.

I have the pump with the points and rebuilt it with new points about 3 times. Plus I have a new one
that I’ve been carrying around in the boot for lets say 35 years. A few months ago the pump was acting up so I replaced it with the new one. I should of bench tested it first because it didn’t work.I took it out and saw that the points had a coating; after cleaning , filing the points it worked fine. So I rebuilt the old one again by putting new points in.So far it’s working fine, the next time I rebuild it I will also change the diaphragm. I am happy to stay with the original point setup.

A very good friend who was a British car mechanic mostly Jags, regaled to me the time a friend was returning from West Virginia in his AH 3000 when the fuel pump started going out. Called my buddy who told him he could get him a replacement by bus the next day. Didn’t hear back. Next day the fellow shows up at his garage. He had taken the knockoff hammer and hung it by the pump. Ran a string to the cockpit and started driving. Every time the pump started to go out he yanked on the string to bring the hammer against the pump without having to stop. Made it all the way back. If he wasn’t a Virginian you could say that was some Yankee ingenuity

2 Likes

Years ago only on hot days my original would start clicking very loud and stop delivering fuel. I assumed I was suffering with a vapor lock type problem. I spliced one of the aftermarket electronic type pumps into the system and mounted it down lower closer to the level of the tank. It have not had trouble with this since.

My original still is in place in the car sort of as a spare since back then it would work fine most of the time. Anyone know if my problem on hot days just means I could re-build the original pump to solve that problem ?

David
68 E-type FHC

Hi Les…I monitor the UK E type forum on a regular basis…i have not seen any common issues raised re SU style fuel pumps recently…Just for info you can convert a standard pump with a small Cct from Marek both have mechanical pionts…its what gives the characteristic ticking sound when tbe pump is operating…in the standard unit quite a high current is switched through the points…on older units the points pit and dont give as good a contact hence the old cure bang it with a hammer…on the Marek conversion electronic unit the same points switch a much lower current…this then operates a power transistor that switches the higher current needed for the pump…so the main advantage is no points wear…One thing to consider whatever you use is a dedicated fuse for your pump…the standard E type setup dosnt have one…The Burlan SU electronic version has no points…the unit does have the characteristic tick sound caused by a small moveing magnet…Steve

I have the standard SU pump but converted it to electronic with some switching transistors about 25 years ago - works great.

Thanks Steve,
They appeared here - XK Tranistorized Fuel Pump
If you look back at another thread from a bit earlier, you’ll see why I made the pcb - other listers were simply soldering a rat’s nest of components onto the end of their fuel pumps and that seemed like a pretty dumb idea to me so I just designed something better.
kind regards
Marek

Hey Steve,
On the SNG site they offer three pumps…one is stated as “OE” …another is stated as “standard”…the third is stated as “uprated”…any ideas what the differences are?

I tried the electronic SU years ago when they came out. After a few month one of the electronic ends burned up… maybe they were not designed to run 12 hours non stop :). I ve used Holley low pressure ever since. Good flow but a little loud.

Jegs has a low pressure quiet pump which I may try.

I used the SNG in-tank modern one… worked perfectly.

Hi Les…sorry not sure why 3 are shown…you would need to contact SNGB…However Burlan who make the pumps show two 1308 models… http://sucarb.co.uk/su-fuel-pumps-spares/single-hp-pumps-kits.html Just for info the fixing bolt for pump to bracket is an unusual size…5/16 bsf i think…all the best…Steve

Steve,

Both of those pumps on the Burlen site state they are high pressure. We require low pressure pumps at around only 2 - 3lbs right?

Hi Les…although they say high pressure(2.7-3.8 lb/in2) it is compared to the L low pressure pump…full spec here http://sucarb.co.uk/technical-electrical-fuel-pumps-single

Hey Steve,
Thanks for the Burlen/SU link, most informative. I did note that they say the “electronic” pumps do NOT have points…did I read that correctly and if so, I wonder where the “click” comes from?