E30 Zone

Are the blocks the same?

Could I fit a 325 crank/rods/pistons straight into my 320 crank cases?

Ive heard the heads are different but how?

ta,
ade

you could use the block, needs boring to 84mm from 80mm though, the rods and cranks will also swop across but I gotta ask... why ?

the heads are not interchangable !

M20 bore wear is generally not an issue dude.

The 320 block would need to be bored to 84mm (I think) to take the 325 pistons thus making it a 2.5. The 320 pistons are flat topped as is the head, this is to give torque to offset the power compared to the 2.5. it leads to similar fuel consumption as the 2.5. The 2.5 had domed to pistons and a head to match with combustion chamber to give higher power and efficency, hence the 2.5 is 171bhp with similar fule consumption as the 2.0.

I thought they both had the same bore but it was the longer stroke of the 325 that gave it the extra 500cc?

(Im probably being dumb )

The reason I ask - I fancy upgrading my motor by building a street sleeper

I could just slot in a 2nd hand 325 motor but I know Id be unsure of its history and Id still need to modify it to get the most out of it. +when people are happily spending Ԛ£Ã”šÃ‚£Ãƒ”šÃ‚£ on 2.7 conversions, Id probably be happy with a good bluprinted 2.5 and a warm cam.

(The other reason is that Id get really shafted on the insurance for doing such a big modification, so if the cases say its still only a 320... )
hehehe

so whats the bore and stroke of the 320 and 325?

anyone?

http://home.netpower.no/pberg/Mahle_m20.html

Doesn't list the
320 - bore 80mm, stroke 66mm

325 - bore 84mm, stroke 75mm

327 - bore 84mm, stroke 81mm

OH and the 320 block doesn't have the steam holes between the pistons.
They aid cooling a bit.

cheers Widge - interesting link.

Anyone know what the rod lengths are on 320s?

the link reckoned that theyre 130 for the eta and 135 for the i engine.
Im guessing the stock 320 is even longer?

thanks for the help,
ade

320 is 130mm, as is 323.