Banjo Washers - Fibre or Aluminium ?

[44DHR]

In follow up to my previous post “SU Overflow Pipe” - many thanks for the replies, but a further associated issue has arisen.
We have now fitted the SU Overflow pipe to the rearmost SU Carburettor on the 4.2 Series 1 2+2 and successfully managed to get the Banjo of the Overflow pipe to clear the top moulding of the Float Chamber lid, using the washers in the correct sequence.
I now realise the critical importance in the requirement to ensure the Serrated Fibre Washer is placed against the Lid to ensure an air passage - and presumably the petrol in an overflow situation - to track up around the cylindrical body of the Float Chamber Lid Bolt and out of the “overflow” pipe to ensure an air breathing path. I struggled to find any reference in formal documentation as to how important it was that this Serrated Washer was used as if the air passage was blocked by the use of a normal washer to be tight around the bolt, the SU potentially would not operate correctly if the fuel could not enter the Chamber correctly due to air pressure in the Chamber not being vented which would also cause fuel starvation assuming it could start in the first place. A very important washer !
I have digressed. So - carb choke all fixed, carb reattached and pipes coupled up. The original main fuel line to all three carbs on this particular car used Aluminium washers on each side of the Banjo bolts.
My official original 1960s Jaguar Spare Parts Catalogue identifies these washers as C.11489 Washer (Fibre) on Banjo Bolt (AUC. 2141). I ordered these Fibre Washers from my usual big supplier (their part number was AUC2141*) and received some red fibre washers. However on turning on the ignition one of the Banjos leaked petrol badly. The car has a later electronic SU petrol pump and the original aluminium washers did not leak before.
The mystery to me is Aluminium washers were originally fitted to his car and why other Suppliers - such as the one near a certain Southern Airport with a nice detailed parts catalogue, although I never use them - do show these specifically as “Aluminium Washer on Banjo bolt SJ5138 (C 11489).
Even the SU Spare Parts and Specification Catalogue shows on the HD Type Carburettor page that the Banjo Washer as part number AUC 2141, but their illustration number of 47 has an asterisk to show that “Alternative aluminium Washer AUD 2374” can be used. I expect the soft aluminium washer deforms to seal and would be a “one only use item”.
So, which is correct or was there a change over from Fibre to Aluminium ?
Regards,
Dave

[mgcjag]

Hi Dave...you say the original washers for the car were aluminium. .....do you mean what was on the car when your friend got it....or originally from the factory.....the parts catalogue shows S1 4.2 as fibre washers......its not uncommon for new ones to leak......its supprising and scary how tight you have to do the banjo up.......iv found it does help to soak the washers for a few hours in a small jar of petrol prior to fitting......even then they may leak and need retightening after a few runs......personaly i would get them direct from Burlan......have a close look at how your fitting them ...think the banjo has a recess for them to sit in one side so make sure they are sitting proud and can tighten properly......some use sealant on the washers.......plenty of others posts on the forum for fibre washers........Steve

[44DHR]

Hi Steve,
Thank for the prompt reply.
The guy is the second owner and it is a low mileage unrestored completely original example at 30,000 mileage. He has had it many years and the problem is he has other old cars and this car just doesn’t get much use.
Potentially these aluminium washers are the original ones supplied with the car. We had great difficulty undoing the banjos and we were extremely concerned with the amount of torque we had to apply to undo them. They all made a “crack” as we final freed them, which makes me think they were the original factory fitted items.
I got the HD8 rebuild kit from Burlen for the single troublesome carb, but the other fuel bowl washers and fibre washers for the fuel feed banjos from my usual well known supplier up North. I noticed the Burlen fibre washers - although the same size and dimensions, were a darker red than the other supplier. I am going to phone Burlen tomorrow to get their advice and hopefully order the aluminium washers to cover all bases.
That’s a really good tip about soaking the fibre washers. As we have a new set of six from our usual supplier, plus the two in the HD8 rebuild kit, I will do just that before I go and see the guys next week for our now regular “Wednesday Morning Club” to work on his cars.
Thanks again !
Dave

[Gfhug]

When I visited Burlen for some carb parts and overhaul kits I was surprised by the inconsistency in the size of the banjo washers, fibre and aluminium, not fitting properly into the banjos and they didn’t seem to realise or have an answer to that. Let’s hope they’ve improved them, but worth checking before fitting.

Geoff

[abowie]

The combination of dissimilar metals and ingress of fuel into the threads which evaporates and leaves solid residue does make undoing the banjo bolts (and other SU carb fasteners) a fraught task. I snapped a MK2 auto choke "enrichment device" in half recently trying to disassemble it.

I personally do have success with the aluminium washers.

You do need to use a long spanner and do them up frighteningly tight, although I have yet to break a fuel reservoir cap. I think doing them up very tight is the key to success.