I had to recently verify my engine number.
There is a bar-coded paper sticker on the RHS top of engine, but this is only a paper sticker and I wanted to actually see the metal stamped engine number.
It has been said that it can be seem from underneath, if you have a car hoist, but I have found another method from the top.

So, I thought I would post how I went about it.

Items Needed:
1: Strong tourch
2: Small mirror (2"x2") with 1 ft reach (I glued a wire hanger to the wifes spare makeup compact (She still hasn't missed it!)
3: 10 mm socket.
4: Spray on Window cleaner
5: Scrap piece of rag
6: Pencil and paper
7: Sturdy box to stand on when leaning over engine bay
8: A good Chiropractor Onhand. (if required)

What to do:
1: Wait till night time
2: Make sure that engine is cold
3: Unclip front of softtop
4: Unclip back of softtop 5 retaining clips and push forward
5: Remove back shelf carpet tray
7: Remove the engine access cover (11 X 10 mm bolts)
8: Spray rag with window cleaner.
9: From the drivers side of car (RHD), step up on box
and use the tourch and mirror to first locate the flat part where the engine number is stamped. This will be between the exhaust mainfold pipes and bell housing. Here is a good link that shows it's location.
http://www.mgfcar.de/wreck_engine/dkcp_3904.jpg
(Engine number will most likely be very hard to read at this stage)
10: Now place rag over fingers and sprayed with window cleaner and lean over and reach in between the exhaust pipes and the bell housing and clean the flat part of the block. Just feel your way with this. It will become obvious when you do it.
11: Use the extended mirror and shine tourch onto the mirror and manouver it so that you can see the engine number. This takes only a little practice.
12: The number and letters will appear in the mirror reversed.
13: Write them all down and there you have it.
14: At this stage you will need to decide if the standby chiropractor is needed or not.

Hope this helps someone.

Branko.

The "K" Series engine has its roots in the 1980s when it won government funding from politicians renowned for their dislike of state support for the manufacturing industry. The elegance of its design, with one set of bolts clamping the whole engine together, is still considered to be world class in many respects.

K Series 1.1l, 1.4l & 1.6l engine
The major components of the unit - the five "Cs" - are largely produced in-house (Cylinder Block, Cylinder Head, Crankshaft, Camshaft and Conrods). Castings for the Cylinder Block and Cylinder Head are made from raw aluminium billets using the LPS (Low-Pressure Sand) process in the Foundry and Conrods are processed from forgings to final machined condition. The transformation of these raw castings into machined components also takes place on-site in East Works. Cast blanks are bought in as the starting point for crankshafts and camshafts. Precision turning, grinding and finishing transforms these blanks into the heart and soul of the engine. Following these parts through the assembly process is not as easy as you might think. There are two assembly tracks running side-by-side. One of these does a subterranean "U" turn half way through. Between and around the lines are sub-assembly loops for manifolds and cylinder heads obscuring the overall pattern.
Sophistication in the process takes many forms. Automatic assembly of valve train components hides behind unassuming metal panels. Selection of different grades of bearing to suit individual combinations of crankshaft, cylinder block and connecting rods ensures the highest level of refinement. Mechanical and electrical tests ensure no faults pass forward down the lines. Continuous improvement of assembly line facilities and tooling ensures that the quality of the product has continually improved since its first shift in 1989. A very high proportion of engines are produced "right first time".

More amazing than its manufacture is the power output of this unit. What started out as a weight - and strength - optimised 1400cc with 1100cc younger brother has grown up through 1600cc and 1800cc variants to become the VVC (Variable Valve Control) unit developing more than twice as much power than originally planned. This goes some way towards explaining why "K" Series engines have been adopted for so many small high performance vehicles such as the Lotus Elise.

From Powertrain, Engine manufacturer

There is no cross reference of an actual engine serial number to a VIN number from the engine number.

Sample 18K4FL49 244175, was made for a Rover 45 1800cc Auto with air con. (Notice the different flywheel size there.)
(For the auto build, it would be part number PSD102230. For a manual you would need to replace it with a PSD101690.)

When Powertrain assembled engines they where assembled as complete power units including Transmission, air con compressor, wiring, and all the external trimmings. These where then transported from Powertrain up to the CAB assembly buildings and put into storage until that engine/transmission variant was required. They where then fitted to the car as complete power/transmission units. Powertrain therefore had no record of what individual engine was fitted to a vehicle by VIN.

I can however sometimes get the engine number from a VIN. Oddity of how the system was set up.

Here is a very basic breakdown of how to "read" an engine number. For instance 18K 4FL49 244175
18 = cc ( 1800 )
K = K Series
4 = valves per cylinder ( 16 valve engine in this case)
F = Multi point injection with Catalyst.

Now comes the good bit !

L49 = complete assembly designater ( far, far too many variants to list here )

244175= actual serial number of the unit.

Slight correction to previous comments in this thread from Robert Matthews.
1800cc Steptronic designater is in fact M14. The "F" refers to the fuel delivery type.