Got two extra engine blocks with my '68 280S (Carbs). I want to build a new engine for the car, but I want to make sure the blocks I have are correct. How do you positively ID a block to know what year/model car they will fit?

Something i've noticed with my '79 240D.... MB chassis serial numbers and engine numbers are sometimes very close together. Its like engines and chassis are practically built side by side..... somewhere if you can find serial number/year designations for chassis, you might also apply this to engine serial numbers, i dunno. Just how close are spare shortblock numbers to existing engine serial numbers in the car?

Otherwise i know what you mean - 280 engine can be anything covering alot of years with plenty of changes where engine was fitted into 108/114/116/123 etc..... hell, the 280 probably reaches into modern cars built from 1980 - 2004 too.

Critical questions for me would be compatiability with tranny bell housing, emissions controls, accelerator linkages and sump clearance over subframe as possible booby-traps where conversion wouldnt easily fit.

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Last edited by 300SDog; 02-08-2004 at 10:40 PM.

Well, just about any six from 1965 to 1995 will fit with proper electronics, but the 2.8L SOHC engine is the most desireable -- most power and better economy than the others from head design changes. Also more reliable and burns less oil. You might have hood clearance problems with the DOHC M110.

You can even stuff an M116 or M117 (or M119) in there, or an M-100 (6.3 or 6.9) if the body is post 70 -- earlier six cylinder only models dont' have enough clearance at the brake booster, it was moved to give enough space.

Somebody should be able to tell you what the correct block number is -- should be a xxx.xxx number cast into the block in the normal place.

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

Thanks, 240DD and psfred.
I'm not interested in swapping for a different type of motor. Just want to build another stock motor out of some of the spares I already have, and I want to make sure I'm starting out with the right engine block for my car ('68 280S/108) before I spend a bunch of money sending it out to the machine shop.
Does anyone have the block codes cross referenced to year/model?
I also have two crankshafts and a big box full of 280 rods in sets of six (of course). One set looks a bit different from the next, and I'd like to confirm these cranks will fit and figure out which set of rods is correct for a '68 carburetted 280.

Jeeze Louise..... those are specially ballanced parts. You cant just mix and match cranks, con-rods and pistons at random.

Check your piston crowns and you will see markings such as (A), (B), or (C) indicating exact *weight* of each piston - perfectly ballanced to the crankshaft at Stuttgart. A team of pistons, matched to the crank, might include several of one weight and a couple of another - strategically placed.

Have you seen the bores of these blocks?? If hone marks are still detectable - then light scuffing of the bores and adding special Swedish-made SOFT metal rings that will wear to the bores is probably all you need for pulling another 100k miles from each block.... combined with valve work and fresh seals as needed. And never let anybody plane or shave the cylinder head surface.

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Last edited by 300SDog; 02-12-2004 at 08:08 PM.

Thanks again, 240DD for the slightly hyperbolic response. Does anyone else know how to ID engine blocks, rods, cranks by shape, foundry marks, sizes, weights, or any combination? I'm trying to make an engine for my '68 280S out of a bunch of 280 parts (all in good, useable condition). See my previous requests, above.
If anybody has the info or knows where I can look this stuff up, I'd really appreciate it.
Thanks!

The block is identified by the motor number stamped on a flat spot above the oil filter. A 280S will have the number stamped on the cast iron. Earlier motors have a metal tag riveted in place there.

Also, down and in front of the oil filter should be a block casting number. That's another good starting point, but only to match it against another block, since I'm not aware of anybody writing those down anyplace as a cross-reference.

-CTH

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