m52b25 or m52b28?! no way of knowing

[Dirtnap30]

ok so this is beginning to drive me nuts. I recently swapped an m52 into my car and its been running strong. however my issue is that I have no real way of telling if its a 2.5 or 2.8. I never saw the car it came out of (sat in my bosses storage container for like 3 years, claims it came out of a 94' 325i....obviously wrong, clearly an obd2 motor) but anyways, the badge on the block is not readable and I NEED to find out cause I'm running a 3.0l turner tune which turner claims is ok for a 2.8. any suggestions?

[pandaboo911]

There should be a piece of the headgasket that sticks out past the block that lists displacement. It's on the exhaust side next to the vanos

[328ijunkie]

Stamp on drivers side of block

[Dirtnap30]

I've yet to been able to clean the block tag up enough to even read a single digit :(

[Dirtnap30]

There should be a piece of the headgasket that sticks out past the block that lists displacement. It's on the exhaust side next to the vanos

just confirmed it, says 2.5 :sad: not stoked right now. I should probably get a new tune asap

[DesertBMW]

just confirmed it, says 2.5 :sad: not stoked right now. I should probably get a new tune asap

That is not correct way of knowing because all 2.8 head gaskets will have 2.5L on them, even the cylinder heads.

You got to look at the driver side right by the engine mount on the bottom of the block it will say 28 s 01 if its 2.8l

Or take one of the spark plugs out and use long screw driver and measure the stroke, 2.8L will have 84 mm stroke.

[DesertBMW]

There should be a piece of the headgasket that sticks out past the block that lists displacement. It's on the exhaust side next to the vanos

This is wrong information, 2.5L and 2.8L share the same head gasket and gaskets are all marked as 2.5L

[328ijunkie]

^That.

Take a plug out and put an extension in the plug hole. Measure the stroke while rotating the crank.

2.95" = 2.5L
3.31" = 2.8L

[eurosport22]

damn i would have made sure i knew all that before i put the motor in. but hopefully you ended up with a 2.8

[Dirtnap30]

I'm gonna measure the stroke asap and pray its not a 2.5....