How to distinguish between the M20 engines?

[Oz_Striker]

Been having a look at a E30's and some have had new engines put in, but I was wondering how to can you tell apart a 2.5 from either a 2.0 or 2.3?? Is there an easy way to spot a M20B25?

I know you could go out and drive it and gauge how quick they feel, but i've only ever driven a 318is and a 325i, and both of them were pretty shagged out!

Any help or pointed would be much appreciated.

[HJG-E30]

if you can't see inside the engine bay, then the 325i has rear discs.

Under the bonnet some people on here will be able to tell the difference immediately. Otherwise look on the VIN plate, or the engine code stamped on the block

[Nine468]

if you can't see inside the engine bay, then the 325i has rear discs.

Great, what happens if the car has had a rear drum - disc conversion.?

[urfy]

A 2.5 will have two pipes from the oil filter housing going to the oil cooler.
A 2.0 will not have a oil cooler fitted.

[Green]

My 2.5 doesn't have an oil cooler fitted (yet) but someone could easily fit one onto a 2.0l but that would be the easiest OEM way of noticing i'd imagine.

Not sure if there's much at a glance you could notice, but the throttle bodies are different sizes, the FPR are at different pressures (although think the text is underneath. All 2.5s will have two exhausts from underneath the car all the way back and most 2.0s are a single pipe from the midbox back.

[e30topless]

most 2.5's wearing a BMW head have a small round raised bit on the side of the head (above the exhaust manifold) that will have 2.7/2.5 or just 2.5 on it ,

[Oz_Striker]

if you can't see inside the engine bay, then the 325i has rear discs.

Great, what happens if the car has had a rear drum - disc conversion.?

True and also some 320i are advertised as having a 325i engine put in, so how to tell if that is the case?

A 2.5 will have two pipes from the oil filter housing going to the oil cooler.
A 2.0 will not have a oil cooler fitted.

Excellent And ive just checked BMWFansinfo and the 323i didnt have an oil cooler fitted either:

325 oil cooler not present on 323 schematics:

[HJG-E30]

if you can't see inside the engine bay, then the 325i has rear discs.

Great, what happens if the car has had a rear drum - disc conversion.?

Then tell me how else to spot the difference if you can't see the engine? Other than the boot badge of course, or vehicle enquiry - which isn't always accurate given that most people don't tend to inform the DVLA of engine changes.

[Oz_Striker]

My 2.5 doesn't have an oil cooler fitted (yet) but someone could easily fit one onto a 2.0l but that would be the easiest OEM way of noticing i'd imagine.

Not sure if there's much at a glance you could notice, but the throttle bodies are different sizes, the FPR are at different pressures (although think the text is underneath. All 2.5s will have two exhausts from underneath the car all the way back and most 2.0s are a single pipe from the midbox back.

Aww man just when i thought "sorted!"

Ok so check for oil cooler, check for full length dual exhaust, check for rear disc brakes and check for a 2.5 stamp/engraving above the exhaust manifold.

[StuBeeDoo]

if you can't see inside the engine bay, then the 325i has rear discs.

IIRC any E30 spec'd with ABS from the factory had rear discs.
The biggest give-away is the engine number. 2.5s start 256.
Next biggest give-away is the shape of the inlet manifold runners - the 2.5 manifold is curvier.

[bilun777]

Stubeedoo has got it in one...If you look at any engine bay photo's,the 320 inlet manifold tubes are almost straight,whereas the 325 tubes do a gentle curve through almost 45 degrees.

[Brianmoooore]

Stubeedoo has got it in one...If you look at any engine bay photo's,the 320 inlet manifold tubes are almost straight,whereas the 325 tubes do a gentle curve through almost 45 degrees.

Unfortunately, it's a popular mod. to fit a 325 inlet and T/B to a 320.

[Brianmoooore]

Look under the rear, and count the number of bolts holding the cover on the rear of the diff. 2 litre cars have 6 bolts and 2.5 litre's have 8.