Scot, the two flywheels shown in a previous post are both 104 tooth , fitted to any
model MK1 / 2 , S type,3.8 MK10 or 3.8 E type , or indeed, 2.8 XJ.
The wheel marked 4.2 is standard weight the other is the optional lightweight.
You have a correct 133 standard weight wheel with a correct bell.
you look to have a correct early pre-engaged starter tapped 3/8 NF, the slightly later
starter is tapped 3/8 NC, both require the spacer.
Steve, I cannot find a RAC 303 at SNG. Perhaps I should just call?
Peter, the two flywheels were not intended to demonstrate tooth count, but rather the shape of a 4.2 flywheel vs. 3.8. The pic came from J-L… We’ve discovered my wheel and bell housing are correct for my bastard all-synchro gearbox hooked to my engine, as you say.
The starter does not have mounting threads at all. Rather it has nuts and bolts - both locations. It surprised me earlier in this discussion that I noted references to the starters having threaded taps to accept the bolts. No nuts. Either way works for me though. I have a spacer (spigot plate) and I have 3 of those ring dowels. Two are in the bell housing and one is in the spacer. The engine builder did not use the spacer when installing the starter. If I get the right geared starter I will not need one.
Scot there is no difference in shape twixt 3.8 and 4.2 flywheels other than the teeth. The 3.8 inertia starter is held by
nuts and bolts, Jaguar eventually connected the bolts together by a
semi-circular hoop, perhaps the engine
builder intended to use this method
and bored the pre-engaged starter.
Oh, sh***,,**, ******,*****tch 
Oh, I see now. heh heh
1 Like
Peter, you’re saying the C26252A starter that I removed from my car should have had bolts going into the starter from the backside of the bell housing? Instead of the two bolts going through the starter with nuts? I’ll be danged.
Well there’s another surprise with this car. I’m surprised the engine is facing forward…
Hi Scot…re which starter model to fit…as iv said befor if purchasing a Powerlite model then its an RAC 303…SNGB do sell various model and i assume use their own code number…so if talking to them you need to ensure you get tbe correct one…they do sell Powerlite models for other 4.2 Jags like the RAC300/302/301 etc all are slightly different and not what you want…you could look on the Powerlight website…if you get a starter from another manufacturer you will have to check compatability…Steve powerlite 303 link https://www.powerlite-units.com/starters/rac303.html I think this is the same unit as sold by SNG but check with them https://www.sngbarratt.com/English/#/UK/parts/d3120340-670e-4b1a-b254-1606e9274a5a
Okay, got it Steve. Your link tried to take me to SNG UK, but it attempts to switch me back to the US site. I forced it to stay in the UK and got the product code. Then I went back to the US site and found the right one that way. I’ll order tomorrow. Thank you.
If it was me, I’d wait. You have rather a lot of unknowns on this project as it is, engine distributor, ignition. Why invite more variables? Changing a starter is no harder to do later than now and there is nothing fundamentally wrong with the original starters. Mine has purred for 20 years.
Well, I’ve the old starter out. I have someone who wants it and I just see prices going higher and shipping going out of sight. I’m thinking it makes sense to move now. I am not going to do the distributor now as it is truly accessible later on whereas with this starter I had to remove my filter adapter, the vacuum tank and also my mudflaps are off the car. But thanks for the idea. 
You’re quite right. It’s an XK150 flywheel. (I know that because the photo that Scott used is one of mine but someone has written in “4.2”) 
1 Like
Hi Clive. I originally got the photo from you without the numbers on it in my “Engine Never Started” thread. See below from August 2. I don’t know where I got the version with the numbers on it. But it came during that conversation. At any rate, I used the pic with the numbers on it to believe I had a 4.2 flywheel.
Aug 2, 2020
lkinson
ScotThompson
Scot,
The 3.8 E-Type flywheel is scooped right out on the front side and is much lighter than the 4.2 version. The extra machining will be seen if the inspection cover is removed from the front of the bell housing.
The engine number will also be stamped on the periphery of the flywheel and can probably be seen though the timing hole in the top of the bell housing.
Here’s a 3.8 E-Type flywheel on the right beside a regular 3.8 item
1 Reply
That is, I thought I was safe until I found in talking to Steve in this thread that there was more to the story. Fortunately it all turned out well and I have a set of matching components to get a new geared starter that is compatible with the 4.2 engine.
A milestone today. I installed the starter bought from SNGB, a RAC303 (not RAC304 as incorrectly typed!)…they insisted this was correct for my all-synchro box, 133 tooth flywheel and 4.2 bellhousing. Anyway it turned over! I still don’t have the oil pan on it (see different thread) so I could do more than one or two seconds.
BTW the flywheel serial number (maybe part number?) is 18517. Stamped on the front side.
2 Likes
I thought I’d add a bit here. This RAC303 starter is SNGB P/N: USM003/1E Starter Motor Uprate. Identical to that recommended as not requiring the spigot on installation. The starter has the electrical connections on the “outside” of the engine so it is very easy to connect electrically. Two bolts of 3/8 UNC came with the starter…both with shoulders too long to allow the starter to be tightened.
Also, contrary to many E-type owners having said, I was able to install this starter by using a ratcheting 9/16 box wrench on the top bolt, accessible from the engine bay, and a 12-pt 9/16" socket (3/8" drive) on the bottom with a step-down adapter to allow 1/4" drive extensions and a 1/4" ratchet. The small ratchet allowed me to work within the narrow confines of the transmission-to-tunnel cavity. Then I switched to a full 3/8 ratchet for the final tightening. This was all accessible from underneath the car. Both both were simple hex heads.
Please note I had previously said 304…that is a typo. RAC303 is correct.
And finally some pics. This installation was quite easy. I do have the vacuum tank off, the carbs off, and the filter adapter as well, but I think this starter is so small and so easy to hold with one hand, it would not be difficult with all that still installed.
2 Likes
i dont see the dowel where is it
Peter…did you mean to reply to me…ring dowles fit the spigot plate the the bellhouseing on a 4.2 if the standard starter is used…the plate is also needed for some high torque starters…for the starter Scott used a plate is not required…Steve
Steve is correct Pete. The benefit of this part number Starter is two-fold, in addition to its being a modern geared starter. 1) it has the electrical connections on the outside of the starter and away from the block. Other starter models have the connections between the starter and the engine block. 2) there is no need for the spigot plate and the two ring dowels that fit around the mounting bolts and insert into the (no longer needed) spigot plate… See the pic way above called, “counting teeth.” Steve is the one to thank for sorting out the Powerlite numbers.
Scott,annnnd how does she crank?
Gtjoey1314
Hi Joey…enjoying my book!! Found it under the Christmas Tree!
The starter will work great, I don’t have the oil pan fixed as yet, so no oil and I’ve only cranked it to make sure it turns.