Fuel Pump in earlier V8s

[Nick Challacombe]

Hi John,

Unless your car has been altered to an electric fuel pump, many have.
The mechanical fuel pump is located on the LH side of the engine block,
looking
from the front.
It is a Carter M2504 S on my 407

Hand book say no maintenance is normally required ( it is mechanical).
The pump can be removed from the engine and dismantled and cleaned
the following parts will need to be renewed at re-assembly,
M.203-89S Diaphragm Assembly
M.203-46 Outlet Airdome Diaphragm
M.121-124 Flange gasket.

The Fuel filter. Moper 2084 258 should be changed every 10,000 miles.

Hope this helps, I have converted my 407 to an electric fuel pump located
under the offside wing on the
wheel arch. The filter is an in line particulate transparent filter located
under the bonnet between the
new fuel pump and the carburettor.

Nick Challacombe

[Sam410]

My 410 has an SU electric pump, located high up in the boot on the right hand side. I think some other cars also have had them fitted in the boot. The diaphragms (it's a double pump) do not last forever and I had to rebuild mine a few years ago after it failed without warning on the motorway. If it's not original, I would guess it was fitted when the car was restored circa 1990.

[Geoff Kingston]

John
My fuel pump in my 410 is in the boot as described in Sam's reply. On my 411 which was a mechanical pump but not working properly due to slight wear on the rod and cam we conveted to an electrical pump.
The first attempt with a Holly pump was a disaster, mounted on the boot bulkhead it made more noise than the engine on tick over and low speeds, this was replaced with a Facet pump also bulkhead mounted and much better, just the priming sound before start up. I am told this pump would also work mounted up front near the battery but have not tried that so can't be sure.On my 410 I had the pump rebuilt with an electronic update to do away with the points and I must say it works very well.
Geoff

[John Keighley]

Thank you all for replying, I should have known where to look but as the car was going in to my local mechanic,didn't have time to search. It is on the right hand side of the boot floor. As it happened, the pump turned out not to be the culprit but we discovered this afternoon, the filter was almost fully blocked due to having sat around for an extended period of time. At this point, a new filter has restored normal operation. Since emerging from restoration the car has covered about 3500Ml, so I'll have to keep a lookout for crud in the fuel system.
John Keighley.

[pasini s]

Hello,

reading this thread made me wonder if I knew anything about the fuel pump
installed on my 409, and the answer was negative. I was quite sure that I
didn't see any mechanical pump in the engine bay so I asked to the guys at
the body shop (where my 409 sits now for some minor work) to check into the
boot. In fact the pump is there, exactly as described by Sam on his 410, and
looks like a double pump. This is a picture of my pump:

http://www.stefanopasini.it/Bristol_...uel_Pump_1.htm

I cannot see any numbers on it because it is installed in a position where
is not very easy to check; I would like to ask if anybody has any idea of
what model this pump might be and what could be the correct replacement for
this pump. Maybe an 'electronic' pump might be better? I have checked Burlen
site:

http://www.sucarb.co.uk/ProductCateg...px?ParentId=16

to find several types of double pumps, but I couldn't decide what would the
right choice be for my 409. high or low pressure? Points or electronic?

Thanks, as usual, for your help,

Stefano

[Sam410]

Mine was a double pump like yours, part number AUF406, equivalent to the AZX1404, which is in turn identical apart from the fittings it is supplied with to the AZX1405, sold by Burlen. I would presume that the AZX1405EN is simply an electronic version of the same pump. I'm no expert, but I suspect an electronic pump would give similar advantages and drawbacks to electronic over points ignition

This is what I put on the BOC Wiki about it at the time (July 2007):

"The fuel pump on my 410 recently gave up the ghost, and so I was obliged to investigate current replacement options. Burlen Fuel Systems were very helpful; my car had an SU twin pump, model AUF406, fitted as described above, in the boot. The AUF406 is now known as an AZX1404. The AZX1405 is apparently the same but comes with different fittings for the fuel lines, although if you are replacing a pump you would already have the correct fittings so it should be trivial to swap them over. Burlens offer a restoration service, but that (at time of writing) has an 8-week turn around, and costs only a few pounds less than buying a new pump. However, they also sell overhaul kits, which contain new diaphragms, gaskets, points, and all the consumables apart from the main coil. These were fairly straighforward to fit, and have the part number EPK300. You need two kits for the twin pump obviously. Mine initially still didn't work, but once I'd taken it apart, checked all the setup, and put it back together a second time it seemed fine. If the coil itself has failed (which according to Burlens is extremely unusual) the unit will need complete restoration or replacement and the overhaul kits will be of no use."

[pasini s]

Hello Sam,


thank you for your message. My pump looks very similar to the AUF406/AZX1404
that you mention, so I think that I could just order one and be safe with
that. I'm wondering if it is better to buy the electronic version AZX1405EN
or the classic 'points' type, though. Maybe some of you with a real
understanding of these pumps has a definite opinion on the possible choice?
It would be a great help.

Thanks

Stefano

[geo]

Originally Posted by Nick Challacombe

Hi John,

Unless your car has been altered to an electric fuel pump, many have.
The mechanical fuel pump is located on the LH side of the engine block,
looking
from the front.

Both my 408s had mechanical ones and according to the Bristol parts book (p. 19 item 16) the part numbers are:

1843400 Fuel Pump up to Chassis No. 7350
and
909-1-33012 Fuel Pump Chassis No. 7351 on & 410

George

[Kevin H]

I didn't realise that the fitting of electric fuel pumps to V8 Bristols was so common. I suppose I shouldn't be so surprised given that you can buy a Mopar branded blanking plate for the spot where the mechanical pump goes (for B/RB engines at least). That suggests it is very common practice. It certainly makes starting the 400 CID engines much easier from cold.

I don't think it really matters what pump you have so long as it can supply an adequate flow rate and the pressure isn't too high. You wouldn't want any more than 5 psi, but you can use a fuel pressure regulator if necessary, I have one on my 411.