I'm new to the forum and not the sharpest pencil when it comes to mechanical workings so don't go too hard on me
* Was the M30B34 engine used in Euro models all the way from 1982 till 1989?
* Does the M30B34 without the catalytic converter used in Europe equal the same engine with the converter used in US cars?
* Is it possible to dismantle/remove the catalytic converter to get the "european" engine?
* Was the M30B35 introduced only for the US market or the 1988+ cars sold in Europe were equipped with this engine as well?
* Was the M30B35 ever offered without the converter?
* Was the M30B34 engine used in Euro models all the way from 1982 till 1989?
No - the M30 B35 came out in 1987
* Does the M30B34 without the catalytic converter used in Europe equal the same engine with the converter used in US cars?
Similar but not the same. The catalytic engine has:
- lower compression (I think its just the pistons)
- different camshaft profile
- different ECU
* Is it possible to dismantle/remove the catalytic converter to get the "european" engine?
You can convert to European spec by changing the items above, ie pistons, camshaft, ECU
* Was the M30B35 introduced only for the US market or the 1988+ cars sold in Europe were equipped with this engine as well?
For all markets, with slight differences as per tables (1987 onwards)
* Was the M30B35 ever offered without the converter?
Yes as per tables, with slightly high compression and power
Not so simple. Another Euro motor in the 635 until '82 was a shorter stroke larger bore motor still making it a 3.5 spec. It was called an M90 and had what was commonly thought to be 10:1compression but in reality had 9.4 to 1. a hotter cam and pulled like a freight train because of the amount of torque it put out.. In looking at the list as you did, these motors do not show up as any special classification and on a cars build sheet only show up as a B34 or M30. It was just a given that a Euro 635 through 82 model year would have it and the motor could be identified by certain exterior characteristics and of course confirmed when the head was removed. And then there are the two different "M" motors.
81 Euro 635 M90 with motronic. Currently under a complete nut and bolt restoration. Pictures at
flickr.com/photos/bertsphotos.
if you are looking at 635CSi in Europe then there are three main versions
E12 base; short stroke motor with either L-jet or motronic fuelling. Numerous other variations with date. Built to 5/82. Obvious feature is that the rear bumper doesn't wrap around the sides.
E28 base; euro-spec B34 motor (high compression, more power than US version). Again numerous variations, built 5/82 to 7/87.
Highline; B35 'world' motor fitted. Easily identified in Europe because of the different bumpers.
If thinking of buying a car from America, then you need to know the chassis number in order to identify the manufacturing date.
