The limiting factor on the 2.1 is rod bearings ..
or stretch rod bolts that don't perform right anymore...
eventually oil pressure gets lowish.

the 1.9 is a shorter stroke, smoother engine ..
that does not use stretch rod bolts as I understand it.
Rebuilders he told me they use 1.9 rod bolts in 2.1 rebuilds, fwiw.

I think doing the heads about every 80K miles is about right.
I get very nervous when heads have been on for a long, long time, like
15 to 20 years and 150+ K miles...
due to corrosion build up.

1.9's can do up to 250K like Chris says..
180K miles on them is common.
and ..same thing on the heads ..
about every 80K miles in my opinion.

waterboxer engines are both good and bad.
weakest area is head gaskets ..
the pistons and barrels barely wear.
  no timing belt to fail ...
Engine management can be dodgey/tricky sometimes.
Could use more power and torque of course.
Though their wide torque curve is nice.
my own 2.1 wbxr engine running on 1.9 Digijet EFI in an 85
Adventurewagon goes up most hills in 4th gear at at least 50 mph
...pulls nicely that way.  Doesn't mind going 75 ..though drinks more
fuel at higher speeds.

we love 'em and at times we hate 'em.
I own about 16 of the suckers .some in vans, some not.
scott

On 8/20/2012 8:47 PM, Dave Mcneely wrote:
> ---- neil n <musomuso@GMAIL.COM> wrote:
>> Like if my 2.1 idled properly, didn't surge, had even and higher
>> compression,
> Interesting points to make in a DEFENSE of the waterboxer engine ......... .
>
> So, you'd say the one I have, with a rebuilt dropped in at 110k miles, now at 170k, well maintained since I got it at 139k and behaving very, very well for now should go  .................. forever, right?  :- )
>
> mcneely
>