2.5 litre head on a 2.0 litre engine

Post Wed Dec 07, 2005 5:14 pm

I have recently bought a BMW 320I SE, but when the previous owner replaced the head gasket, he also changed the head. The head came from a 2.5 litre engine. Could this cause any major porblems? and will it effect the fuel economy, as i assume all the other running gear, is the same.

Thanks
Jami.

Post Wed Dec 07, 2005 6:31 pm

Jami, i don't thats possible they won't interchange as the valves etc are alot bigger on a 2.5 head.

I think the guy might of thrown a porky in there i'm afraid.

The only other head which fits on a 2.0 block is the 2.7 eta head from an e28 525e so i believe

Post Wed Dec 07, 2005 8:51 pm

Simon is right, the guy was spinning you a yarn.

Pistons are different sizes too.

Post Thu Dec 08, 2005 1:26 pm

Thanks for your replies on this matter. I have read one or two comments on how to identify a particular head, how would i know if the head is the indeed a 2.0 litre head and not a 2.5 as the guy said.

Thanks
Jami

Post Thu Dec 08, 2005 1:30 pm

Info Here

http://www.e30zone.co.uk/modules.php?na ... ht=#245817

Post Thu Dec 08, 2005 1:34 pm

or check out the pics of the 2 heads I have for sale on this link, page 1

http://www.e30zone.co.uk/modules.php?na ... ic&t=21981

731 is the casting number for a 320 head and 885 is the casting number for 325 head. The combustion chambers are a different shape.

Post Thu Dec 08, 2005 6:38 pm

Also the inlet manifolds are different (320 is more angled, 2.5 is smooth as in the bends! get me?!) for each engine which is the best visual guide as the engine size mate

Post Thu Dec 08, 2005 8:34 pm

2.0 will say 731 on head

Post Thu Dec 08, 2005 8:36 pm

It is possible to fit a 325i head to a 320i block and it will run but not very well as the compression ratio will be low.

On the other hand a 320i head will not fit onto a 325i block and run, the pistons will clash with the head and you'll have a heavy oily paperweight !.

Cheers,

Iain T