Identifying the year on an M20B25

[In The Pines]

Hi all,

I am trying to sell an M20B25. Someone asked me what year the engine was and I told him I would have to get back to him on it.
I've spent some time looking online for ways to decode the serial number on the block but all the threads I've come across are inconclusive. I've found "BMW 1289 575.c 6G88" and there is another code lower on the block that I'll need to spend some time cleaning up with a brass wire brush and degreaser to see.
Otherwise, is there a good way to find out if an engine is a late or early model?

I am a bit of a newbie to this.
Thanks!

[McGyver]

Why would it matter?

AFAIK, US M20 engines all came with an 84mm bore and either early or late style crank bearing (single vs double tang on the bearing). If its actually an m20b25 (885 head), then it should be 1987 or newer.

[digger]

https://www.e46fanatics.com/attachments/bmw-engine-id-sheet-pdf.910963/

not sure this helps

[TobyB]

Yup- you're looking for a large 885 cast into the head-
and then you can look at the date codes cast into the head and block
to pin down when the thing was actually poured.

But other than the displacement often being stamped into the coding pad,
most mere mortals confirm bore, stroke, head casting, and maybe number of cam bearings
and send it.

t

[reelizmpro]

Detailed pictures would help since many things changed over the years. Can't just go off one date code on the head as it may have been changed at some point.

[In The Pines]

Can the stamps on the manifolds indicate if its an 885? I haven't ripped down the block yet but the exhaust manifolds have 1710824 and 1710888 stamped on them, and searching this on eBay indicates it came in the 1988-1991 525i e34...

[McGyver]

You can literally see the part number cast into the head. You should see "1 705 885" above the center intake ports. It's kind of hard to see around the intake, but is perfectly accessible, even with the engine in the car.