Lister HR3 injector oddity (rubber seal)

[Sparky1234]

Hi guys,

I have a lovely old HR3, running a 20kVa generator.
Recently, I noticed diesel fuel was leaking from the elevated tank, into the sump.

On closer inspection, we discovered that the fuel was seeping out from under the injector clamps/bridges.

When we removed the injector clamps, we discovered there are ~6mm, smooth bored holes drilled through the injector cap/spacer and these holes run into the waste/return fuel line. The holes are (normally) sealed with conical shaped rubber plugs.

The rubber plugs have obviously perished/shrunk over the years and have begun to leak. As the fuel is gravity fed, obviously the fuel is running back through the filter and in a reverse direction, along the return fuel line and out via these odd injector ports.

Has anyone seen these injectors in the past?

Is there a source for the conical rubber plugs?

The parts manual for the HR3 does not show this model injector. It appears the 'standard' injector has a sealed cap at the top.

I would post photos, if I could figure out how to upload

Cheers,
Richard
NSW, Australia

[Diesel Engineering]

It was quite common for Lister to use this type of injector at the time. As you say over a period of time they tend to shrink and harden. Back in the day they were offered as a spares item by Lister. So maybe some of the old Lister dealers may still have in stock. Or maybe an injector specialist will carry stock.

[Sparky1234]

Thanks

Yes, I did find a (relatively) in-Country supplier who had some old stock, from obsolete gasket kits, floating around.
The conical rubber seals never did have an individual part number, apparently, which makes ordering rather challenging!

The local dealer was very helpful. Apparently, on the early engines, Lister originally intended to run the waste fuel out of
the top of the injector, rather than the side opposite the HP inlet. Neither of us understood how this would have worked
mechanically, given that is where the injector clamping bar sits.

Regardless, it is rather odd that the spacer at the top of the injector wasn't replaced by a solid, or capped-off unit and their
rather dodgy solution, was to simply bung a conical rubber seal in there to fill the hole and hope for the best

Certainly, something for HR series owners to keep an eye on, especially if running gravity-fed/elevated fuel tanks.
When these seals start leaking, very bad things start happening.. 

Cheers,
Richard