What distributor is this

This distributor came out of a box of MK7-9 parts, but I a dont think it is from those vehicles, as they are clearly stamped with a model number on the body

This unit has no markings on the body at all, (except the normal advance script info)

It may be from a MK10/420G or possibly an XJ6 S1 or S2

Can anyone ID it ?

It looks like a DVX 6A to me. If you show a photo of the distributor clamp, that will confirm it.

Thanks Mike,

here is some pics of the clamp

I suspect it came out of a MK8, so a DVX 6A makes sense, but no markings, unlike a MK7 one I also have pictured, which is full of detail

below early MK7 dizzy

The two piece body would suggest 120/140/ 7.

Tony, the backwards clamp with the (impossible) tightening nut facing to the engine block definitely makes this a DVX 6A or possibly an earlier DVX H6A distributor. These were used on the Mark 5 and Mark VII and XK120 and XK140. However, the advance curves were different depending on the application.

If you take it apart, you will get a better idea what model it came from. You’ll need to remove the three screws that secure the top half of the distributor to the bottom half. Then remove the screw at the top of the points cam and remove the cam. Then lift out the springs and weights. Now you’ll see the stamped number on the action plate.

The number in the photo below means it provides 14 degrees of total mechanical advance (at the distributor) or 28 degrees of total mechanical advance at the crankshaft. That makes it an XK120 or XK140 action plate.

The DVX 6A distributors used in the early Jaguar sedans, typically had action plates stamped 17, giving 34 degrees total mechanical advance at the crankshaft. (However, in my collection I have one action plate stamped 21 degrees - but I suspect it did not come out of a Jaguar distributor.

Thanks very much again Mike, your knowledge is appreciated

My dizzies pictured would be from sedans, so as you say different advance curves
From XK

I am presuming the springs and probably vacuum capsule would be different

Are the bob weights also different (Sedan vs XK) ?

I am thinking from what you say they probably are, and have a different number stamped on them ?

I will try to strip it down, so I can ID it, write the model num in black texter, and put it back in its box for the time being

Both the pictured dizzies appear to be in good condition, and have been not in use for many years

The second one is from an early MKVII, it has the letter B in its designation, which calls it out as different to XK120 which have an A or D suffix

Tony, I’m almost certain the weights were the same in all these DVX 6A distributors. But different springs, action plates, and vacuum capsules were used for different model Jaguars.

Additionally, the points cams were eventually updated from “standard” to “high lift”. With the standard cams, you set the points gap at .010 - .012. With the later high lift cams, you set the points gap at .014 - .016. If you provide the measurements across the “peaks” and “valleys” of the points cam, I should be able to tell you whether it is standard or high lift.

An update, I feel a bit stupid, as I did find stampings once I dismantled it.

They were faint and small, and hidden behind the vacuum capsule, nothing like the earlier ones with very clear obvious stamping on the body face

This one has the following designation;

DVX 6A 40372A GC53 9/55

Vacuum capsule end has 4/18/12

Stamping on the action plate is 15

My parts manual call this out as correct for late MK7 or early MK8

I have a question Mike, (or anyone else).

After marking most parts for re-alignment, in a moments inattention, I lifted and twisted the part in below diagram marked 'Cam"

DVX 6A Lucas parts cat-crop

The Cam has a cutout to mate with the rotor button, and can be installed 180* out

In my opinion, this would cause the wires to be 180* degrees out, as the rotor would be 180 out from offset dog ?

Luckily I was able to observe on the DVXH unit, that with the cam cutout facing me, the “wider” side of the offset distributor dog was on the right, and that is how I assembled the DVX

You’re right about the spark plug wires being 180 degrees out depending on how the points cam is oriented. Below is a diagram showing the “standard” plug wire setup for an XK engine.


If the DVX distributor is installed according to the diagram, with the rotor pointing to #6, then the “wider” side of the drive dog offset will be on the right in my photo below.

It appears you should flip the points cam 180 degrees for a standard setup.

One reason I asked that question is because, over the years, and there was a few recently, confused and wondering if the drive gear had been assembled 180 out, with all sorts of gruesome engine surgery needed

I say just swap plugs wires and make a note of the situation

However, swapping this cam around would be an easy “fix”

Fiendishly bodgy though, dizzy put together all wrong, be very hard to detect for any future owner or technician (although they may never need to know, as it all should work)

I will double check your pic tomorrow on the cam orientation

If the plug wires are out 180 degrees and you don’t want to disassemble the distributor to flip the points cam, another way is to drive out the pin for the drive dog and flip that 180 degrees. I’ve done it both ways in the past.

I thought that as well.

I am not sure why pan off engine surgery was suggested, but presumably there must be a circumstance where that is needed to make everything fully right ?

I had to fix a blown head gasket on my first Jag, and managed somehow (dont know how) to assemble 180* out, I think I may have used this list to work out the possible issue and drove the car for about 15yrs with the plug wires reversed

Eventually I took the head off again and rectified it

while I have your attention, is that drive pin tapered, meaning it can only be driven out one way ?

No, it’s a tight-fitting straight pin.

1 Like

Thanks for your astute reply, when I checked, I found I had assembled it backwards, despite having a similar one to copy, so have now corrected this

I took it apart but did not take digi cam pics, or mark certain parts with nail polish, but did scribe most parts, I was watching sport on TV, chatting, and it was night

The weights and springs can easily fall out, and they can also be put back together various incorrect ways

I have had them apart before, and its super important to mark everything and take pics

Given how easy it is to install the cam backwards, I suspect that is most likely the issue with individuals who have taken the distributor apart and then find themselves 180 out

1 Like