Here’s one for the purist! One thing I have always tried to do with my classic cars is to try to restore/reproduce them to how they were when they left the factory.
I have been looking at the routing of the wiring to the carb solenoid unit, coil, otter switch etc and I have been trying to reference pictures online. My query relates to a 1952 RHS OTS but probably applies to others.
There is a white braided cable that exists the bulkhead near the starter motor solenoid, this ultimately connects to both the coil SW and the carb solenoid unit, but how does it get there?
Is it routed along the inner wing or directly from the bulkhead along the engine somehow, if the latter how is it held/clipped?
Does it connect to the coil first and then another wire come off the coil to the carb solenoid unit or the other way around?
Is the wire(s) in a plastic sheath?
Here is an unrestored LHD 54. It looks like the SW of the coil has two wires in a plastic sheath, presumeably one from the bulkhead and the other to the carb solenoid unit. The CB of the coil has the lead which goes to the distrubutor which also looks sheathed and both pass through a P-clip.
It looks like the dual cable from the coil passes below the carbs and then one of the wires splits off to the carb solenoid unit, if so what happens to the plastic sheath at this point. It isn’t that I don’t know how to wire things up, but how the cables were routed and presented when the car was built!
Another question I have is regarding HT leads which which run to the back of the engine and over the rear of the engine. According to Viart they were held in place by C.2454 clips and 3204 grommets. Does anyone know if these are available?
Hi Martin,
I also share your interest in trying to get it right.
The answers depend on whether the coil is mounted on the block or above the front carb. Also on whether or not there is a Lucas junction box mounted on the scuttle between the wiper motor and throttle shaft socket. This box was used on cars in late '51 and early '52 only.
If there is, there was a separate harness from the box running along under the carbs and held by two P-clips on two of the intake manifold nuts.
My Nov '51 car has this box, and I have also moved the coil to above the carb.
Otherwise, the white wire from the instrument panel comes out by the solenoid and runs along under the carbs, held by 2 or 3 P-clips. Tadek’s “as found” pictures show this. His coil was above the carb,
In my case I had the new harness from Rhode Island Wiring, which included the green/blue wire for the oil sump level sensor wrapped together with the white wire for the coil in cloth wrapping. I found that if I connected the sump sensor wire, the cloth wrap was not long enough to run the coil wire along under the carbs in the P-clips to the coil above the carbs.
I thus believe I discovered the factory’s reason for the separate harness and the junction box.
I have not yet had time to reproduce the separate harness, and RIW was not aware of it.
The clips and grommets for the plug wires under the carbs were also used on Mark V, and the grommets are available from Worcester Classic Spares and Rock Auto. The Mark V clips might be a different length, longer I think, but could be trimmed off.
Thanks so much Rob for the comprehensive reply and for pointing me in the direction of Tadek’s pictures which I managed to find - what a brilliant record for the restorer! I purchased my car last year ‘restored’ but the attention to detail was lacking somewhat so detailed images of an unrestored car are valuable.
I couldn’t find the clips and grommets online at Worcester Classic Spares but I’ll try to give them a call this week.
One further question that Tadek’s pictures did throw up is the routing of the return pipe to the heater. Viart (I know it has errors) shows a long angled bracket on the second to rear stud of the inlet manifold holding the intermediate return pipe and a bracket on one of the spare coil fixings for the front return pipe. He states that earlier cars with the coil mounted low and two shorter straight brackets from the inlet manifold fixings. Tadek’s car shows this earlier type of fixing but is a late car. Do you know how this should be for a 1952 with high coil but flat topped distributor?
Thanks again, I love this forum, the knowledge base is fantastic!
Martin,
Assuming your model and year/month did have the leads that run round the back of the block, they are fixed as Rob states above, so have a look at SNGB “HT lead clips” C25127SS and “plug lead grommet” 3204. Two of each required.
Simon
Martin,
According to JSPC, Chassis 679222 to 679315 (Jan 52 to Feb 52) had junction box C5258. But also noted in July 1951 chassis 679012 and 679187 (Rob’s). However these are the FHCs.
I was unable to persuade the loom manufacturer to provide a separate loom to accommodate the extra distances required. I don’t think you have the oil sump indicator but I am not sure. I atttach the dimensions of the loom I made up, ignore C5258 and oil sump lead if you don’t have it.
Simon Harness for junction box C5258 with dimensions.pdf (532.7 KB)
Excellent, Simon. You might also want to note that it is 16 gauge wire.
I believe there should also be a white/black wire connecting the coil CB and the distributor, and a black wire connecting the carb solenoid and the otter switch. They were included in the woven cloth wrapping.
I have begun to make this harness.
My 679187 was built in November '51 but for unknown reasons did not leave the factory until February '52, after the cars 679222-679308 had been completed in January, which may possibly explain why I have this junction box but it was not recorded as such among the chassis number range given by the writer of the SPC.
I have attached a sketch of this but you have to ignore:-
1. Oil sump lead
2. Junction box C5258
3. Manual control W/U Otter to dashboard which I embedded during manufacture to future proof but it is not currently connected and hope it will not be required. Bulkhead junction box C5258 679265.pdf (524.6 KB)
Thanks all for the comments. Mine is a July 52 so it wouldn’t have the junction box but does have the oil sender. Both of these wires enter the bulkhead next to the starter solenoid on mine. Was the oil sender wire routed with the coil wire and then split off down the side of the engine?
Rob, Viart suggests that the wire connecting the carb solenoid to the otter switch was white and black rather than plain black?
Simon, many thanks for pointing me in the direction of the HT brackets - they have been ordered to pick up at the Jag spares day next weekend!
Wiring diagram W94601, 94601A & 94641 for the early OTS without turn signals shows it as white/black.
Wiring diagram W94602 for later cars with turn signals shows it as black.
The diagrams for Mark VII show it as white/brown.
For Mark VIII & IX it is green/blue.
For XK140 no color is given.
For XK150 it is green/blue.
So yo pays yo money an yo teks yo choice.
To add confusion, as if there wasn’t enough already, the early 120 diagrams also show a black wire from a second terminal on the otter switch to ground, which doesn’t make any sense, as the otter switch connects to ground internally when it is cold and has only one terminal.
