Hi everyone,

We are currently ordering parts to start working on our newly bought 1977 DD6 VdP with the 5.3 V12 pre-HE. One of the first jobs we want to do is replace all rubber hoses of the fuel system and overhaul the injectors. Unfortunately, we do not have access to the car yet, but we already want to order the required hoses to get up and running fast once we have the car.

Does anyone of you know which hoses (inner diameter, outer diameter) are needed and at which length? Which clamps and how many do we need? Maybe one of you has recently done a similar overhaul and still has a rough idea on what we need. In the forum I have only found a similar post on the XJS (Link).

We are looking for hose specs and rough estimates for required total length for:
- All EFI hoses under the hood (anything that is rubber and may have rotten)
- All fuel hoses in the back
- Any other fuel lines that you think we should change

While we are already ordering hoses: Should we already get replacement hoses for any other system (cooling system, etc.)? If yes, what should we get and how much? Might be worth saving some shipping costs while we are at it...

Thanks a lot for helping us out here. Your support is much appreciated

Best,
Sebastian

 

Never mind....

 

I don't know how different your Series II might be, but I tackled a couple of these jobs recently on a SIII V12, specifically all fuel hoses in the boot and replacing all engine coolant hoses. This link was helpful for tips on the size and quantity of fuel hose needed. Fuel Hose Shopping Guide

I had fuel odors in the boot so I wanted to use the lowest permeation hoses I could find, even for the low pressure hoses before the fuel pump. Quality fuel injection hose with 7/16" ID is hard to find so for that size I went with Gates Barricade brand, 0.5" ID and have not had any issues. It's available on Amazon or from O'Reilly auto parts, ebay, etc. I used the same brand for the other sizes. I noticed a substantial improvement in fuel odor in the boot but it's not quite eliminated yet. I need to pull all the carpet out and wash it and scrub down the entire area. The Gates 0.5" ID hose is thick with an OD of about 19mm. After shopping around I found these fuel injection hose clamps on ebay for 19mm-21mm size hoses that worked well. Seller is tmfactory. I added inline fuel filters between each tank and the changeover valve so that adds another 4 clamps. For the rest of the clamps I used FI clamps I had on hand.

https://www.ebay.com/itm/27294769765...EAAOSwHuhfPQQs

I would recommend changing all coolant hoses if you don't know how long they've been in place. I bought a coolant hose kit from Moss motors. It was for an XJS H.E. V12 and I think there was one heater hose that was different on my SIII V12 that I ordered separately. Change all the belts at the same time.

 

Hi LnrB, hi Noah,

Thanks a lot for your tips. That is super helpful already!

Especially the Fuel hose shopping guide you shared, Noah, will come in handy. Here is what I am going to buy based on the guide and based on counting clips in Link:
- Fuel tanks to changeover valve: Standard fuel hose with ID 11 mm (~7/16"), OD 16.5 mm > 1.2 m

- High pressure EFI fuel hose with ID 7.5 mm (~5/16"), OD 13.5 mm, ~2.0 m

- High pressure EFI fuel hose with ID 6 mm (~1/4"), OD 12 mm, ~0.5 m

- High pressure EFI fuel hose with ID 10.0 mm (~3/8"), OD 16 mm, ~1.0 m

- Hose clip ID 15-17 mm, 14 pcs.

- Hose clip ID 12-14 mm, 54 pcs.

- Hose clip ID 11-13 mm, 2 pcs.

Regarding the fuel hoses: Are these typically the same length for XJ12 Series II and Series III? Please let me know if anything looks off.

Do you by chance know if something like the fuel hose shopping guide is also available for the coolant hoses? I will also start googling for it once I am back from work tomorrow, but if someone of you already knows where to look from the back of your head that would be amazing.

Thanks everyone!

Best,

Sebastian

 

I'm not familiar with the differences that may exist between the SII and SIII models regarding fuel hose routing or lengths. You may want to wait until you have access to your car to make your own measurements. Or compare the diagrams in a parts catalog if you have one. If not, it would be worth investing in one. Is your V12 carbureted or fuel injection?

For the coolant hoses, I would contact some of the common parts specialists such as SNG Barratt, Moss Motors, David Manners, for a SII V12 coolant hose kit. There are so many of them I'm not aware of a guide as to the lengths, ID and OD for any model. If they don't offer a kit, you can make a list of each of the hoses needed from the diagrams of a few different components - radiator and coolant hoses, heater hoses, and the bleed system hoses.

 

As Noak has stated, I would wait for the beast.

HE and PreHE, VERY different.

I have never measured the fuel hoses on any of my V12 cars (and there have been many), never got that fussy with them, and that time could be better used consuming beer.

I purchased:
EFI hose 7.5MM ID by the 5mtr roll, MUCH cheaper than per the mtr.
EFI 9.5/10MM by the roll, 5mtrs again.
Standard fuel hose 12.5 (1/2") in a 2mtr bag.

Clamps:

Tridon EFI spec clamps, boxes of 25 in the following

EFI004 = 7.5mm hose.
EFI006 = 10mm hose
HS010 - 12,5 hose, NOT e EFI spec, not needed.

Dont forget the 2 flex hoses at the rear, ABOVE the rear cradle, one each side. The RH being Supply, the LH being Return. They will seriously test your sense of humour. I always replace them when the cradle is out, its just easier.

EFI spec clamps and hoses, on ANYTHING to do with fuel, be it Supply or Return. Only exception is the gravity hoses in the boot.

A couple of mine ran the 10mm for return in the engine bay, the others were the 7.5mm, British Leyland at its best.

That's why I purchased bulk, never goes to waste, and is simply "THERE" when you need it most.

Coolant hoses, OE ONLY, and Noah has suggested the suppliers.
Coolant hose clamps, I forget, I have a wall tray of ALL the sizes, so "go fetch" is the order for the task on hand.