Engine Detective
 

I have my eye on what is titled as a 1987 420SEL. The owner insists he has replaced the 420 with a 560 engine. How do I verify this short of changing the oil to measure the capacity?

The oil capacity will have nothing to do with the actual piston swept area, the displacement. Post the serial number off the engine here and we'll see what can be discerned.

what are you talking about? sorry...

The engine code should be stamped on the block somewhere. Also, the 4.2 liter engine is an M116 engine, and the 5.6 liter engine is an M117 engine. They are different blocks.

To make things clearer I am looking at a documented 87 420SEL (from Carfax and the title) via the vin #. The current owner claims that he has replaced the original engine with a 560SEL engine (5.6). Im asking if there is a visual way to determine the validity of his claim short of tearing stuff off the engine to find the actual serial # of the engine. Im aware that the 560 air cleaner has two intake hoses and this engine has one. When I pointed that out the owner reminded me that the 420 grill is designed to accomodate 1 hose so he had to use an original 420 air filter config on this 5.6 engine. Unless theres an easy visual reference other than the serial number then Ill make the potential sale conditional on my Merc mechanics inspection and let him solve my dilemma.

What's the problem? 420, 560, whatever, does the car run? It's not like the car is a "classic collectible". Buy the car, don't pay more because it has an "upgraded" engine and THEN figure it out.

A SEC on the other hand is collectible but a SEL? Nice cars but there's a million of them out there. I bought a '85 for $300 (non-running) and Douge bought one up in Phoenix for $600 which he has running.

Let your Merc mechanic do your examination. All prospective Benz purchases should undergo a PPI by someone qualified.

An examination of the engine number should easily tell you want you want to know. The first three numbers are the engine type - in your case 116 or 117.

Ugh, shouldn't you be able to tell when you step on the gas?

The only visual difference I can think of is the air cleaner assembly mounts. The 560 (117) is about 1 1/4 inch wider than the 420 (116). The air cleaner Assemblies are the same except the duel intakes on the 560. To make up the difference in the width of the engine they added a small bracket to the 420valve covers and the air cleaner is attached to that bracket. The 560 mounts screw into the valve cover and the air cleaner sits directly on top of the mount.
Hope this helps

Paul

the last reply is correct.look at the two nuts that hold air cleaner to top of engine.the 420 is mounted to 2 L shaped brackets to the valve covers the 560 mounts directly to the rubber mounts only.

The engine Part/Casting number is on the drivers side flange(top) that the tranny bolts too and it'll start out 117 as the first numbers. The 420 starts out 116. It'll probably be dirty on that flange. Carb cleaner is your friend. Also the part numbers for the Exhaust manifolds are different and should have the 117 somewhere in the part number. 116 and 117 engines have different exhaust manifolds due to spacing of the cylinders and outlets.