Just want to pass on to anyone interested that all, or at least most, of the 1993 240 B230 engines have the L variant.

The L engine variant of the B230 has certain improvements, including an oil passage that squirts additional oil to the underside of the pistons, to better cool them. This is particularly appealing to those who wish to modify them, enabling the engine to tolerate higher combustion chamber temperatures and pressures (viz., turbocharging).

I had originally asked on this list, in
http://www.brickboard.com/RWD/index.htm?id=1043996
(subject: "What's a B230 L (emphasis on the 'L') engine?")
posted a little earlier than this message, if anyone knew how to identify the L engine. I thought that maybe it's only found in turbocharged B230 engines found in the higher level models such as the 900 series (I didn't expect, although I hoped, them to be in our modest 240s). But a few helpful folks explained that I just had to read my timing chain cover's label, to look for the letter L after the serial number. Lo and behold, on both of my '93 240's, there is that L label. Since my two cars are an early and a late 1993 model year car, it appears that maybe this is indicative of the whole line for 1993.
I knew I wanted a '93 when I was looking for additional cars for my family members, because I wanted ABS (also found on '92's) as well as a R134a A/C system (rather than retrofitted) for less expensive A/C repairs. So now I, and you all, have another reason to prefer the '93. :-).

Anyway, other contributors offered the following additional info on the L engine in that aforementioned earlier thread, and I want to thank them and give them credit:
from DaveShan: "...I saw an "L" on the front of a timing belt cover right where the "K" is on 88-89 engines. It was on a '93 940 turbo which was the first year to get the oilers so you're probably right on...."
from Lucid: "...I understand the "L" denotes the piston oilers, and I think I recall a post that cited a marking on the block in addition to the L on the timing belt cover label.
Somehow, I have a hunch that the L block coincides with the advent of the round-toothed timing belt. That would put it at '93, according to the IPD catalog. I know the '93 240 and 940 have that belt, and my 940 has the L on the label. My daughter's 240 lives on the Vineyard, so I can't check the label...."
from McDuck: "...The L block(and crank) also had the thrust bearing moved back to the rear and made 360 degree, istead of 180...."
from c_i_mooney: "..They're also supposedly the one variation of B230 that doesn't have piston slap reminiscent of a diesel on startup...."

My thanks to all you guys for your input.

(BTW, I posted this info on this separate thread, so that it would be readily found in the archives should someone search.)