Dmarchand said:
You are wrong. Call you local DMV. Ask them about "re-powering" a vehicle and amending the title to state "diesel".
The reason there aren't more diesels is:
a) the tdi is not federally approved
b) it is expensive
c) it is prohibitively expensive and the cost benefit is not there
d) did I mention it's not cheap?
California does not have the "repower" to "diesel" option like Massachusetts does. If I'm not mistaken federal is 48 state and we are 50 state. This means you cannot take a gas powered car that is CARB (California Air Resources Board) compliant which requires a bi-annual smog and put in a diesel for which California currently do not have SMOG tests. Remember out here the main focus is the emissions standards for which California has the most restrictive regulations and laws. Brand new federal cars are not sold in California because they cannot meet CARB standards. The Touareg diesel V10TT and (now) VW TDi are the first two off the top of my head.
In California you can only swap a motor into your car if it is of the same age or newer, same displacement, and all of the smog equipment is intact for the vehicles VIN number. Gas for gas, diesel for diesel, diesel for gas (because there are no smog test standards for currently available diesels yet) are all O.K. I am not just talking about the Rover diesel. There are guys who would love to take the 2.0 8v motors out of their VW Golf/Jetta/Cabriolet and put in a 1.9TDi for better fuel economy and power output but cannot despite being federal and CARB compliant. The motor does not match the VIN therefore it will not me compliant for the CARB standard.
It is also tough to do gas engine swaps in California as well. For instance it is illegal to swap a same year or newer gas motor into a car if that motor was never offered in that vehicle as OE, even with a CARB compliant motor. So you can't take a CARB compliant 1999 Civic H/B which only came with the SOHC motor and swap in a DOHC motor from a CARB compliant 1999 Civic 2 Door. Even though the DOHC motor will pass all of the emissions tests it was never available in the Civic H/B therefore illegal.
Unlike the Rover motors, neither of the aforementioned examples are cost prohibitive because both the VW diesel and Honda gas motors can be purchased for around $1500. Cheap (Honda/VW) or expensive (Rover), many swaps cannot be done legally. Teri Ann also makes the good point that if the motor is not in the California DMV database as being available all bets are off.
The theme of all of this is that it is not a matter of re-labeling your title, cost, or federal standards it is a matter of being 50 state and CARB compliant along with the implementation, regulation, and enforcement of CARB standards. As we speak CARB has been testing pollution sniffers that sit on a freeway on ramp to read the emissions coming from your car under load. If it is found to be a "Gross Polluter" you get a ticket with a compliance letter. CARB is considering ways to smog test motorcycles (which are 50 state vs. your 48 state) since they are currently unregulated and typically modified for power.
Trust me, if it were easy there would be a ton of diesel powered VW's (and Rovers) over here.