Engine displacement

[Timothy Keith-Lucas]

Is there a simple way to confirm engine displacement in my 1962 S2 America with an Austin engine? Not only do the sources I can find contradict each other or allow for options, the car was raced in SCCA FP class with two engines (I have both) being traded out. I do have the original engine (not in the car at present) with the dataplate AEA-17 RS19576.  Best bet seems to be the 948 CC version at 43 HP. The carbs (SU AUC549, AUC930R) which I'm told are wrong for that car just complicate the issue.

[jbcollier]

Pull the head, measure the bore and stroke, and then you know.

[11Budlite]

 

You won't be able to tell if it's been bored or stroked without removing the head, but this should give you an idea of what you have. I'm not familiar with that number on your dataplate. My 948cc engine from my old Bugeye had a 9CG prefix if I remember correctly.

Edited November 5, 2023 by 11Budlite

[Christopher smith]

If I recall correctly, the FP class was limited to 948 expanded slightly with 0.040 inch maximum overbore. If all previous owners complied with the rules back when it was raced, it should have complied but pulling the head is the only sure way to know. I raced against them in my FP class Sunbeam Alpine that was 1725 + 0.040 over bore. They always outcornered me but lost on the longer straight sections.

[Timothy Keith-Lucas]

Wonderful! That's the sort of answer I was hoping for. I'll stop and compute the added displacement from the overbore, assuming that the very successful first owner took advantage of that allowance, and know for sure.  Thank you.

 

That comes to 5.39 cc, for a total of 953.4 cc. Got it.