Do distributor designs vary much in the Xj6's three series?
the cap on my S2 model looks different from the one on the (assume) S3 distributor i was given at one point, but the S2 car also came wit a new cap which fits the S3 dist but appears different to the S2.
Upshot is could I replace the entire distributor unit in the S2 with the S3 unit if that was ever required or is it just junk to me?
the S3 one calls itself a 41797 > 45DM6 > 3680 and I have two caps for it.
cannot see what the installed one on the engine is.



cap off my S2 engine




spare Dis with extra cap condition unknown but think it was from a series 3 engine

 

The S3 electronic distributor is a direct replacement for any XK 6 cyl engined Jag.

You will require the "black box" that makes up the "KIT" and an electronic spec ignition coil.

When used in a 4.2ltr engine, plug and play basically.

When used in a 3.8/3.4, some fiddling with the timing may be needed, depending on the market of use.

 

electronic spec ignition coil sounds easy to buy after market while the ominous "black box" less so
what does the "black box" do and does electronic spec in regards ignition coil mean the coil bypasses a function not found in basic ignition coils?
yes, the engine i have is a 4.2

 

I just did this upgrade recently, the black box looks like this.

 

As Clarke said.

The Black Box as we call it is the ignition amplifier, and simplistically does the task of contacts points, electronically, and since there are no moving parts is basically trouble free.

These systems require an electronic spec coil, as apposed to a points spec coil. Same to look at, just different resistance inside. Points coils are generally 1.2ohms approx, and electronic coils are 0.75 ish. Points coils used on this system will fry the module inside.

Those amps (black boxes) are readily available if looked for, ?Bay, Jag wreckers etc. the V12 unit looks the same, but is different, so be careful.

 

Its worth noting for anyone that doesn't know, that the module inside said black box is just a gm.part, cheap and plentiful!!

 

electronic spec coil and points spec coil~
assume either works on non-black box but electronic only for the black-box?
or not.

 

Nope.

Points spec coil is "best" on Points ignition system, BUT, any coil will get you home when push comes to shove.

The electronic spec stuff is a tad more fussy, and mix and match can create more issues than you are trying to solve. Same as above, as any coil will get you home, but that module (that is cheap) may fritz with a too high ohm coil being driven by it.

Do it once, do it properly, and repeat in 20 years, quoted from Doug, agreed by thousands.