Difference between flywheels?

I´m restoring the engine of my -53 XK120 SE with engine no F1216-8S

From litterature (Viarts book) I believe I have the crankshaft called C4808 (10bolt + 2 studs) and Flywheel C5808.
SNG Barratt have a new aftermarket flywheel C4809. Will that fit to my crankshaft?
What is the difference between flywheel C4809 and C5808?

The only stamping I can read on my flywheel is N 16XB

My idea is to buy the SNG Barratt flywheel, but will that fit my crankshaft?

I don’t think fitting the flywheel to the crankshaft will be the issue, if there is an issue.
The very early XK120 crank and flywheel just have four less bolts and a center dowel.
You can see that here in a very early XK120 in our shop that has the later lock plate for the cars with 10 bolts plus 2 dowels that they went to in the early 1950s. Any difference in the C4809 and C5808 Flywheel is likely to be elsewhere.

Thanks, Greg.
Then the SNG Barratt flywheel might be alright I suppose for my engine F1216-8S. Anyone have a clue what difference there are between flywheel C4809 and C5808?

Yep, we solved that question back in 2012. :man_student:
C4809 is 30 pounds or 14 kg. C5808 is 21 pounds or 9.5 kg.


I ordered the SNG Barratt replacement flywheel. The weight of it is 10,3 kg. My old is 9,3 kg (likely flattened for clutch change earlier in the 60´s from original 9,5. My mashine shop will adjust the weight of the new one before balancing.

The link to discussion really helped me. Thanks for great help.

I received the SNG Barratt Flywheel today and it is actually 9,36kg which makes it more C5808 like than ever. That please me having the latest engine version in my XK120. It was delivered in an OSB wodden box which I assume add the 1 kg. The guy at SNG apparently weighted the complete box…