Hello
Does the 3.5 litre Mk1V motor have a metal tube conduit for spark plug leads 6, 5, 4? In my box of bits I found the tube that fits behind the exhaust manifolds & could carry the above mentioned plug leads & obviously protect them from the manifold. I have never seen a photo of an engine with one installed. Is it fitted below or above the fastening bolt?
Regards Peter
Hi Peter
In my car that metal tube is a solid pipe for the heater water - the hose from the radiator hooks into the front end and short hose joins the rear to the pipe at the firewall. I guess to stop an otherwise very long heater hose flopping around. Note that the pipe on my car is quite a bit longer. In my case and many others in Aus it is blanked off rather than create another source of leaks.
Cheers
Darryl
Heater water tube. On my Mark V there is a drain valve on that tube.
Hello, thanks Darryl & Rob, that makes sense about a heater tube, but my tube is 160mm long, 22.5 mm OD, 19.3 mm ID, thus too large & light gauge to carry water. Perhaps the heater water rail (1/2" Cu) passed through it for support?
Peter
Hi,
Ditto on mine. Of course in my case the engine is MKIV from 1948 #SL2199, but the car is a MKV DHC from 1950. Still it is needed to keep the heater return water pipe and hoses so they would not touch the exhaust manifolds or flap around. I have the conduits now for the spark plug wires.
If I wouldn’t have done the rest of my engine under heavy pressure and a tight scedhule, I should have replaced the spark plug wires with new ones, new caps and and nice labels.
Anyone know where (in Europe?) one could easily get those round rubber collectors for the spark plug wires? Which cars had them from the factory?
I have a brand new shiny side entry distributor cap, but for now I used the one I had replaced ca 10 years ago. My previous fault in the ignition system was due to the feed form the coil having broken off due to vibration, as it is the only connection in the cap which is compressed by the screw in the cap, all the other six connections have a spiky screw entering the cable and securing it well.
Cheers!
This is the heater arrangement from behind the motor. There is a rubber pipe which goes from the back of the alloy water rail and attaches to the heater 'Hot / Cold Tap" in the photo. When the tap is on the coolant passes through the heater then back out as you can see. The rubber pipe on the left of the photo attaches to the tube you have, then another goes forward to the water pump. My MKV has had a copper tube fitted at some stage to replace the original steel pipe with suitable clamp to hold it in place.
If you don’t have or don’t want to have the heater connected then you can run a rubber tube from the back of the water rail on the left hand side of the motor, round the back of the motor, though the said metal tube then onto the water pump. That’s how my car is at present.
Both MKIV’s and MKV’s have them fitted.
Barretts have them Part Number 3204
Do you have the clips which hold them?
Two are needed, 3091 one on the exhaust side.
and one C4190 on the inlet side.
Hi TIm,
Yes, thanks I have all those fitted to my engine and spark plug wires. I meant the round rubber things, that probably have three holes for the spark plug wires, to keep them together again very near to the exhaust manifolds. (that get very hot).
Also those are difficult to fit while the engine is in the car as there is very little room.
Easy if you have the engine and gearbox out. 
Cheers!
I managed to fit them to my motor with the engine in place with fine ratcheted spanners and a lot of patience.
I’ve never seen the “rubber things” though I did source some heat resistant HT Lead separators which were used on modern race cars.
They look something like this and come in various configurations - 4 hole, 3 hole and 2 hole on eBay as HT Lead Separators.
Hi,
Thanks! Maybe I get a couple of those.
You must have smaller fingers than. me, or just more patience as I was happy wit just one on the exhaust side before the engine rebuild, it helped stop the wires from hitting ground to the engine block etc. I had just a black clip tie on distributor side to help, but now that I had the engine off the car I mounted both of the wire guides.
Cheers!
Ps. I have seen the round, black rubber three wire separators on some older XK engines.
Although on all XK engines the wires are a piece of cake to organise in comparison to a LHD MKV!
Dontcha hate it when late at night you realize you wrote something that’s wrong on the forum…
I remembered there is this plate in the Mark V Service Manual.
Hi Rob,
I think these are the same 1-3 MKV prototypes that show many diffrences to the production cars, even if a few things made it to early orodutuon cars;
MKIV type of water pump back plate, associated with the belt line 1” back, dynamo mounting etc.
Black top SU carbs.
The front carpets starting from further back than the edge if the front seat rails.
Many other details I have missed, like the spark plug wire conduit.
Cheers!
I remember that we had a discussion about this image from the Service Manual and many concluded that it was never fitted during production.
You could probably modify one of the HT Lead Shields from the XK motors which run across the top of the motor? Just a thought.
Getting back to Peter’s unknown tube, my guess is this is someone’s homemade arrangement for a spark plug cable carrier, sounds about big enough for 3 wires. Must have thought it a good idea at the time.
We’ve seen various ideas like this on early 120s where someone has substituted the top entry distributor cap for the original side entry, and ran the wires up over the cam cover without bothering about the conduit as used on later 120s, came up with their own idea instead.
You are probably right Rob, a home made fitting for the leads or perhaps a support for the heater tube. Was the heater tube 1/2" or 5/8" diam., both would fit through the fitting? I will probably leave it off & use rubber O rings as suggested & the weight gained should be good for a couple of extra MPH.
Peter
The real heater tube is 9/16" OD x 18" long. No need for a support, it has it’s own tab welded on.
