1981 E21

I have a 1981 320is with the 1.8L M10. In 1980, BMW destroked this
engine from a 2.0L to a 1.8L. The engine in my car is going to need a
rebuild and I was wondering how involved it would be to stroke the
engine back up to a 2.0L? Is it just a matter of changing the
crankshaft and rods, or is it more involved than that? I figured I
have an opportunity to do this since the engine needs a rebuild
anyways. I've tried searching on the internet about this and came up
empty handed. Thanks.

"PaulG" > wrote in message
ups.com...
>I have a 1981 320is with the 1.8L M10. In 1980, BMW destroked this
> engine from a 2.0L to a 1.8L. The engine in my car is going to need a
> rebuild and I was wondering how involved it would be to stroke the
> engine back up to a 2.0L? Is it just a matter of changing the
> crankshaft and rods, or is it more involved than that? I figured I
> have an opportunity to do this since the engine needs a rebuild
> anyways. I've tried searching on the internet about this and came up
> empty handed. Thanks.
>

They probably shaved a couple of mm off the block as well, so I doubt your
experiment will work. OTOH if you need to rebore the block (and it can take
it) then you gain a few cc anyway.

Not sure if the engine you are talking about is the 4 or 6 cylinder. If the
four, I would sell / scrap the car and buy a ~1984 320i, whose straight six
was a sweet as a nut.

It's a 4-cylinder.

"PaulG" > wrote in message
ups.com...
> I have a 1981 320is with the 1.8L M10. In 1980, BMW destroked this
> engine from a 2.0L to a 1.8L. The engine in my car is going to need a
> rebuild and I was wondering how involved it would be to stroke the
> engine back up to a 2.0L? Is it just a matter of changing the
> crankshaft and rods, or is it more involved than that? I figured I
> have an opportunity to do this since the engine needs a rebuild
> anyways. I've tried searching on the internet about this and came up
> empty handed. Thanks.

You might just consider picking up a good used 2L M10, I know that wasn't
the question, but they can be found. I wonder if the 1991 version of the M10
might work, it has considerably more power btw. For your specific question,
I'd ask over at the www.bmwe30.net site or else list,
that question is a bit deep for this forum. Even the
list might help you even though it's a bit OT for them. But they're nice
guys too and very knowledgeble.

-Russ.

A 320 should have a 2.0, otherwise you have a 318i.

320i has a 1.8 liter here in the US.They did have a 2.0 liter but was
changed in 1980 to 1.8 but retained the 320i badges.The 1.8 liter is
smoother and more economical than the 2.0 liter.The only E21 variant to
make it to the US was the 320i,but in europe they have
315,316,318,318i,320,320i,320 with 6 cylinder,and 323i with 6 cylinder.

Yes, that's correct. I probably should have clarified that I live in
the US. It is definitely a 320is with a 1.8L engine.

What level of performance are you tring to achieve?
You stated a rebuild is coming up but do you want moderate power
increase or pucker up your butthole performance?Either way,let us know!

At the moment, I was just looking for a moderate power increase.
Stroking the engine back up to 2.0L seemed to be a good idea to me for
a start. I just don't know how involved it would be. I have other
issues in the car that I need to have repaired as well. As it stands,
the car won't pass emissions right now. The BMW dealer I went to
suspected that the car might have been overheated at some point in time
prior to my ownership. It's an '81 and only has 81,000 miles on it. I
think the car might have been sitting idle in someone's garage for a
very long time. The car is very clean, inside and out, to have been
sitting outside for an extended period of time.