E30 Zone

Hi,
I'm looking for a new M20 for my 325i - a mate of a mate is breaking a car that is badged as a 320i, but he assures me the engine was replaced with a 2.5.

How do I make sure this is the truth? Is there difference I can see easily - e.g. throttle body, ECU, etc? Can I tell from the engine number?

Cheers for any help you can give,
CGL

If the numbers on the side of the cylinder head end with '731' it's a 2.0L.

The 2.5L should be '885'.

Most immediately identifiable is the inlet manifold (that sits on top of the engine); on the 325i it has rounded curves while on the 320i it's angular, although they can be interchanged so it's no guarantee.

On the head between plugs 1 and 2 on a 2.5 there should be something like this (I think some 2.5s only have 2.5 stamped on them)......



Not sure what it says on a 2.0ltr.

Engine number (by the LH engine mount) . First two numbers are capacity, IIRC.

325i block also has an 'E' (High compression, pre late '88) or 'K' for low compression (late '88 on) following the engine no.

Thanks for all the help fellas,
I went to look at the engine last night - numbers stamped on the block next to the LH mount are as follows:
20 6KA
24424533
(I presume the "20" is the number I am interested in)

I didn't take the rocker cover off to see the number on the head, but there was no number "knob" cast between plugs 1&2

Intake manifold runners were angular rather than curved.

Looks like it's a 2 litre then......

You dont have to take the rocker cover off to see any numbers - the '731' or '885' numbers are on the side of the head (inlet side I think, but could be wrong).

It does sound like a 2.0l though.