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MG MGB Technical - SU Fuel Pump - Mech vs Elect

Parts suppliers like Victoria British have the old style SU fuel pumps (mechanical points, @$115) and the new electronic version (no points, @$140). These two versions are externally identical. Does anyone know if one can convert an old mechanical style pump to the electronic version? When an old style SU pump stops working, most times all one needs to do is clean or replace the points. I've been repairing my own pumps in this way going on 35 years. But, I'm getting older and anything that I can do to save myself from crawling under one of my B's would be a plus.

























Steve Buchina

Steve - Any SU fuel pump can be converted to all electronic with the kit that Burlen fuel provides. It is an easy conversion, but rather expensive. If you have been successfully replacing points and keeping the pumps running, you should have no problem installing the conversion. The all electronic version of the pumps does away with the points and thus the problem of burned points or the problem of the points filming over if the pump is not run for several months. The draw back to the conversion, is that it will not operate properly if the internal swamping resistor is burned out as can happen if there is clog on the inlet side of the pump, causing the pump to stall in a current on condition.

I will send you a write up of my SU fuel pump services and my approach to converting the pumps to solid state, which is somewhat less expensive and is not affected by the swamping resistor being burned out. Cheers - Dave
David DuBois

78B- Electric fuel pump starting to go down hill. Looking to replace with new electric. Both Moss and VB sell fuel pumps nut label them as replacements for SU.

I have a Weber carb. Will the catalog SU Fuel Pump work with the Weber?

thanks

Shook
Shook

Shook - I can restore your SU fuel pump and convert it to solid state for less than a new pump. I am sending yo a write up of my services. The SU pumps work fine with Weber carbs. Don't bother with the non SU pumps sold by Moss or V/B, both are too expensive. The little, square, run all the time, make a lot of noise, Facet pump sold by Moss for $90 is available from NAPA at about $40, ask for P/N 610-1051. This little pump is a good pump, but somewhat noisy. I recommend it as a permenently installed back up pump for the primary pump, witht he two pumps wired through a switch that will switch the power fro one pump to the other. Good luck - Dave
David DuBois

David,

I was just up in your area last week--visited my brother in Kent. He has a '71 MGB and loves it. Do you guys have a club in the area that he can join?

Thanks for the download and pics. I'll look at them later tonight. I have looked at the rebuild kits on both Moss and VB. Doesn't look too technical, but has to be a better way.

You talking about replacing the inards, points, etc?

shook
Shook

Shook - YOu were only about 15 miles from our place if you do a breast stroke or take a ferry, 60 miles if you were to drive around. Send the following link to your brother http://www.mgccnwc.com/ fo the local MG Car Club Centre.

I replace the points in the pumps with a magnetic reed switch and magnet to trigger a transistor. This eliminates the problem with burned or filmed over points. Cheers - Dave
David DuBois

David When you fit a spare pump do you run the fuel in series or parallel(through one into the other or seperate supplies). Denis
D M HILL

Denis - Plumb them in series. All the pumps on the market have check valves in them, which allows the fuel to go through in one direction only. The check valves also allow the pumps to pump through one another. If you will send me your e-mail address, I'll send you a write up and pictures of how I did the installation. Cheers - Dave
David DuBois

I've fitted electronic SUs and had failures which have been replaced within the guarantee period so I would beware here. Some of the old SUs are still running after 40 years so that is an indication of true reliability. I'd be for fitting a new mechanical or reconditioning your old one. Better still may be David's own conversion. Can you put sone details of this on the web David ??
Iain MacKintosh

Need fuel pump advice.

I'm no master mechanic, but I don't have to be to keep Old Dan running. He's a 1969 MGB in pitiful condition. Just revived from a 7-year sleep in the garage.

S.U. fuel pump new at that time no longer works. As a quick backup to get Old Dan running, I installed an in-line pump. Finally, got the car back running, and the float on the front carburator overflows. Drips gas from back of the air cleaner.

Has the pump too much pressure? Is there a quick fix before I get the S.U. rebuilt?

Wife is very concerned over the gas fumes in the garage.

Thanks, all.
MR Kaylor

It's possible that the pressure is too high but I doubt it as the front one is OK.

Remove the carb bowl screws and lift it the top carefully off. Pull out the float pivot pin and lift the float away taking care not to loose the needle. Lift the needle out and then unscrew the seat. Clean both of these carefully in cellulose thinners and re assemble. I think you have a gummy needle due to age and gummy fuel.
Iain MacKintosh

All,

Very informative thread. I was slightly ignorant of the fuel pump and and inner workings. Thought that only SU pumps could be used only with SU carbs.

Lain,
Are you describing SU Carbs ?

Dave, I sent you E-Mail.

Thanks for the class on fuel pumps

shook
Shook

Dave,

Well I was supposed to be in your territory within the next couple of days but alas I could not get my restoration completed in time for the trip to Olympia for MG 2005.

That's another story - although while on a test drive the little square fuel pump on my '73 GT finally quit on Saturday. It was on the car when I bought it 19 years ago and I was beginning to think those things would never wear out. But no. I walked about two miles to a NAPA and bought a new Facet pump for $36.95 and swapped it out with the old one at roadside - in the rain. All is well now, but...

I take it you are in the business of converting old SUs from points to electronic. Please send me info at my above e-mail address. ' Think I too will go to a converted original and leave the Facet in series. You're right, it's a noisy little devil - particularly when first switched on. Noisier than the old ones which just quietly hummed along.

Thanks!
Allen
Allen Bachelder

Our old, butt ugly Mazda pickup came with a Facet pump in it, which also failed. Had I been driving the MG, I would have jumped right on the fuel pump as the symptoms were right in front of me, but this was not an MG and I spent an inordinate amount of time troubleshooting the problem before the penny finally dropped. This all goes along whith what I have said right along, all fuel pumps, regardless of make will fail eventually and it is my guess, with about the same amount of milage on them.

Regarding the all electronic pumps from Burlen Fuel or the conversions using their kits, see my first posting to Steve's quiry. The internal swamping resistors in the pumps can burn out if the pump has stalled in a current on condition and with the power left on for any length of time (as when a filter between the tank and pump clogs. According to a conversation I had with Burlen Fuel's expert on the all electronic pumps, they will not operate properly when that happens. The other common failure of the all electronic pumps is that the magnetic shading piece, becomes loose and moves out of position. This can be rectified with a simple adjustment, but one needs the installation instructions for the conversion kit to know how to do this. If anyone has a problem with one of these pumps and thinks that this may be the problem, I can e-mail you the instructions.

MR - It is possible that the pump you got has excessive pressure as there are several pressure ranges for the Facet pumps. The one for use with the MGs is in the 2 - 4 psi range. If you still have the packaging for the pump, check that for a pressure rating.

To all, to see a write up of my SU fuel pump services and a brief descritpion of my method of converting to solid state, see my write up at http://www.custompistols.com/cars/dave/ddsu_fuel_pump_services.htm
In reading through that write up, I noticed that I didn't make clear that the magnetic reed switch is used to drive a transistor, which in turn controls the pump.

The noise of the Facet pumps can be quieted to almost nothing by installing it on sound mounts available from Pegasus Racing. Go to http://www.pegasusautoracing.com/advcat.asp?CategoryID=AIRFUE
Click on Fuel Pump Acessories and scroll down to mounting kit. I used this kit on the Facet pump I installed as a back up and when the engine is idling (withthe car sitting still, the pump can't be heard). Cheers - Dave
David DuBois

Shook, yes I am describing the SU HS4 carbs with the flat top float chamber held on with three screws.

If you have the older carbs with the float chamber held on by one single hex then remove that and lift the top away. Remove the float lever in the same way and clean the needle valve. Then turn the assembly upsides down and check that the distance between the float lever and the carb lid is 7/16 from memory by passing a bolt through and if not bend the lever to suit. Lift the float out of the bowls and shake them to ensure that they are not leaking.
Iain MacKintosh

A variety of low pressure Japanese pumps can be used.ie carby type cars. I used the pump from an '82 Subaru (that I happened to have) very successfully. I just left the SU where it was and by passed it. Put the Jap'pump up in the engine compartment in an out of the way corner. Job took about half an hour tops. It sounds just like the SU pump, diaphram pump, (ka..puck..ka.puck..ka..puck...) and like the SU activates only when the Bowl needs topping up. It also pulls alot bettter than the SU, also much cheaper. I'm told that the Honda civic has the same pump and a quite a few others.
Peter

I also have had very good luck with a Mazda 1800 (4 cyl) pump. Uses the same fittings and the mechanical levers for the contacts are better designed than SU.
Safety Fast.

Jeff Pintler
Jeff Pintler

"I also have had very good luck with a Mazda 1800 (4 cyl) pump"... and last about the samve amount of time as a SU pump. I had on of those pumps on a Ford Courier (read Mazda) a number of years back and it failed at about the same age/milage as the SU pumps. One advantage withthose pumps though is that repair parts are not available so one is not tempted to try rebuilding them. Cheers - Dave
David DuBois

I just installed a Holley Red rotary vane pump in the original location. No points but it has a different sound. After several raps with a hammer, I knew the SU pump was ready for the trash. Price =$60 delivered, Reliability = Priceless.
Scott

I don't know what the pressure output of the Holley Red pump is, but you may need to install a pressure regulator if it exceeds 4psi. The only Holley fuel pump I have tested was a Holley Blue and it had enough pressure and volumn to totaly overwhelm my test stand, barely giving me enough time to shut the power off before it completely overflowed - a very impressive pump. Cheers - Dave
David DuBois

While we're talking about fuel pumps, I have a comment about Burlen's new mechanical pumps.

I installed a brand-new one about 3 yrs. ago (my old one having been worked over so much that the valves were almost swapping holes).

Pump ran for about 8 mos. and then quit (left me on the roadside). When I pulled it to find out what was wrong, I was really disappointed to see that the phenolic (now plastic) point mount was so poorly molded that the top surface was distorted (this was NOT due to heat - just poorly manufactured) to the point that the little ridge (which, by the way, was almost non-existent) upon which the point blade rests was not parallel to the surface. Points had burned severely. After spending over $100 for this pump, I was not impressed - the quality control issues doomed the pump from the beginning.

Like all of us, I have a couple of old pumps lying around. I replaced the point mount in the new pump with one of the old ones (phenolic), cleaned up an old set of points and got it running again.

That was almost 2-1/2 years ago...
Richard Smith

Richard, I had exactly the same life out of a new SU electronic pump. It just is not good enough. Burlen are not high on my friendly suppliers list either.
Iain MacKintosh

Three years ago I installed a "Moprod" electronic fuel pump. This pump is shaped just like the original SU pump and is sold by MG dealers around the world.

It just failed after three years of service. The failure was due to its plastic construction (the housing developed a crack and subsequent leak).

This is unfortunate because the pump still works (electronics still ticking away like new) but there is no way to repair the cracked housing.

I am going to see if I can remove its electronic components and install them in one of my spare SU pumps.
S Rechter

Richard and Ian - Have either or both of you written to Burlen Fuel Systems regarding the short life span of your pumps? If not, you should be doing so now so that they will know what is happening. While it is fine to let people know that there maybe/is problems withthe pumps, it is rather unfair to badmouth them publicly if you have not notified them of the problems so they have a chance to rectify them. Bureln Fuel Systems has always been responsive to my concerns when I have written to them about any problems.

Ian - The problem you are having with your pump could be a simple adjustment of the magnetic shading tab having moved out of place. I have an appointment that I have to get to right now, but on my return I'll send you some information on how to make that adjustment.

S Rechter - It is really too bad that the pump bodies of the Moprod pumps are plastic and crack the way they do. I had one of them do exactly the same thing a number of years ago (15 to be exact). Otherwise, they are good pumps. Cheers - Dave
David DuBois

Iain - I tried twice to send the adjustment data to you at the link on your posting, but both times it bounced with the following message: Sorry. Your message could not be delivered to: iain mackintosh (The name was not found at the remote site. Check that the name has been entered correctly.)

After all these years, we find out that you are a figment of our imagination ;) Send me an e-mail and I'll try again. Cheers - Dave
David DuBois

Dave,

Of course, you are correct. At one time I always did exactly what you advise. However, in the last 10-15 years I have seen a noticeable decline in response from companies regarding faulty products. I am guilty of not bothering because it seems to have absolutely no effect. I rarely even get a response, thank you or anything from most companies.
Richard Smith

Richard - While you may get a response from Burlen Fuel Systems regarding the pedestal, it probably won't be the one you are looking for. Several years ago the pedestals came out as plastic, which didn't thrill me either, but they seemed to work ok. They have since gone to a pedestal that is made out of a different type of plastic, more the type you find on high end tool housings. These are not as distorted as the others. I just checked the raised portion that the stationary points rest on and compared it to one of the old bakelite pedestal and they were about the same height (old one 0.003" and new one 0.005"), close enough that it wouldn't make a difference in operation.

I am sure that what we are seeing is a matter of economics. Nothing is made of bakelite (or in the case of really old pumps, hard, black rubber) anymore and to get something made of that kind of material would be prohibitively expensive. Also, it is not just the new pumps that have flaws that can be attributed to poor workmanship. I am restoring an old double ended pump for somebody with a Rolls Royce. When I put it on the test stand and started pumping kerosene through it, the outlet port started leaking. Inspection revealed that the surface was damaged (my fault for not noticing it sooner). The troubling part about the damage is that it revealed a large hole in the top of the threaded portion where there had been a large bubble in the casting. On the other hand, the pump body castings on the pumps put out today are all very well done and smooth, with the casting for the large LCS pumps used on the Austin Healeys and Jags are a work of art.

Unfortunately, things slip by periodically and when they do, it causes a black eye for the manufacture. Cheers - Dave
David DuBois

Dave,

I am glad to hear that Burlen has changed the pedestal to better material. Obviously they are aware of the problems. I have no issues with using plastic as long as the proper plastic for the job is being used. Actually, some plastic replacements are definitely superior to the older materials.

I am only a mechanical engineer with little background in plastics. From what I see today, a plastics engineer probably faces such a dizzying array of plastic to choose from that it is easy to pick the wrong one.
Richard Smith

David, I like it "figment of your imagination" !! Sincere apologies. I have not actively used that e-mail address for a few years but had is linked to auto transfer all my messages to my current one. I started to receive a lot of spam and unsavoury messages (not from you good people I would add) so I broke the link and it all stopped. I too was under the impression at that time that somebody was using the e-mail addresses from this BBS site to distribute this rubbish so I asked the administrator to remove my mail box from his server but left the link on.

Under these circumstances I'm reluctant to update the link but have e-mailed you direct.

Now I didn't quite bad mouth Burlen because I dealt through a very respected UK supplier. I have had two pumps fail and the supplier kindly agreed to replace but they were at pains to point out that Burlen are very niggly when it comes to replacements, guarantees etc and the only part of the guarantee that a consumer will get is that remaining after the supplier passes the pump on to the end user. This could be long or short depending on the suppliers turn over etc. They were at pains to point out the difficulties that they have had. Obviously with shipment to the States etc this could be an even shorter time


All the best.

Iain

Iain MacKintosh

This thread was discussed between 28/06/2005 and 15/07/2005

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