61 Mk2 2.4 starter swap?

Began the process of “de-pickling” an early 2.4 manual Mk2 over the weekend. First thing I found was the starter is now toast (well…it was smoking just like my toaster anyway…). After some research, it would appear that a 2.4 starter is also made of hens-teeth. It appears to be a Lucas 3M100 unit. Doing searches on line, I have yet to cross-reference that number to anything later (or even a hi-torque unit) or other use to actually find something else that used it (that a run-of-the-mill parts store would have) found here in the States. Anyone have thoughts? Something else that will swap in? 3.4 or 3.8 unit maybe? Any experience out here?


Hi Bill The correct starter for a manual 2.4 mark 2 would be a Lucas inertia model with M418G
stamped on the main body
3…4 and 3.8 models have M45G stamped on them
It’s a long time since I stripped specific 2.4’s but I will search my container and if I have more info I will let you know
Brian UK

I am almost certain that is the starter from a S2/3 XJ6

this is a smaller version of the MG45

(which I replaced in my 420G)

You should know the tooth count in a 2.4 vs 4.2 flywheel to be sure it is ok

I had my M100 rebuilt by an experienced local auto electrician for about $A250,
he said the only NLA part was the “over-running clutch”

It may be a case to fit a geared reduction starter

Thanks JaguarBrian and AWG - two “I should add” comments. I don’t have it off yet so the 3M100 is based on what was able to extract from the web. As for a hi-torque, I am open if I can find a cross-referenced part number. t looks like form web extraction that a HT starter is about half of an original repaired, rebuilt, or new

Just to let you know. The starters from the 4.2s inc the Xj6 are pre engaged therefore different.
The 2.4 starter is most likely common to a lot of the larger English cars of the day. Eg. Rover, Land Rover, Alvis, the big Austin’s, Humber.
I think Stypes will almost certainly be the same as well.

The 2.8 XJ Bendix starter might fit?
The 4.2 will almost certainly be too big due to the solenoid. That’s the reason the 2.8 has a different unit.

heres another thought - why wont an early 3.4 or 3.8 unit work? Those I can find part numbers for everywhere

Contrary to what I first though, it is a different starter on the larger engined cars.
The lock torque on the smaller unit is 17lbs ft and it’s 22lbs ft on the larger. What difference, if any, this makes I don’t know.
Somewhere on the web is a PDF copy of the original Lucas data book containing all the specs and part numbers of all Lucas starters going back to the year dot. It lists all the cars they were fitted to. Might be worth a search

I think it’s a block height issue so no pre engaged starter will fit but Lucas didn’t make so many and the naming scheme is online. Maybe all you need is to fix a wire or a brush came loose. Do you have the starter out already?

I installed a mk2 3,4 engine instead of the 2,4 in my mk1. The starter I use for the 3,4 is still the old 2,4 unit. Works very good. As long as the starter was used for a moss box it should fit.

David - I’m not against rebuilding the starter. But for the same reasons as noted, there are no part numbers for 2.4 starters or parts. I can find 3.4/3.8 brushes/etc but nothing for the 2.4. If this means its all the same thats fine, just would like verification before I do anything down that pathway