What's the difference between the various "models" of Chrysler 3.3 motors?

I have a '99 Grand Caravan with a 3.3 "G" motor (flex fuel) and the bottom
end took a dump. I can rebuild what I have (119k+ miles on it) but I prefer
to swap in a used motor with reasonable miles and then rebuild my old motor.
Thing is I am having trouble finding a compatable engine. I was told that I
cannot use earlier model enigines ( thru '97?) nor can I use later model
engines ('01 - current). I was also told that I cannot use a standard "R"
code motor - even if it is a '99. The last really seams strange as I could
simply swap the my entire existing fuel system on the the "R" motor.

Can anyone tell me whether or not I can use one of the "other" 3.3 motors?
The '01-current motors would be great as I have found a couple of them with
very low milage at a reasonable price.

TIA for taking the time,
Jim

 

http://www.car-part.com , searchable used auto parts nationwide. When you
put in the VIN code of your engine, the search results show only
compatible engines.

 

OK. Thanks. However I still want to know what the difference is between
the differrent 3.3's.

 

97 is one version of the 3.3. Then changes to the engine for 98 and 99. Most
parts interchange between 98 and 99 but not with 97. Mainly due to emissions
reg changes. In other words the 97s were one group of engines and the 98-99
were another group of engines. The biggest difference between the G and the
R engines is the PCM software. The G engine PCM software is capable of
"learning" the use of up to 85% ethanol (E85) in the fuel tank by watching
the O2 sensor (called sensorless flex fuel). Alcohol burns leaner. After it
learns that there is 20% E in the tank, all OBD2 monitors are turned off.
When E content drops below 20%, then the ECM calculates the number of
tankfuls of gas that have to go through the engine before OBD2 monitors are
re-enabled. The EPA awards emissions credits to mfg's that go beyond certain
emissions minimums on a particular engine pkg. They can then use those
credits against other engines that don't quite meet a spec somewhere else.
It's balanced out by the "total emissions produced" by all engines built.
There are people in the auto mfg's that make a living keeping up with this
crap. (emissions credits) (not me). Most of the 3.3's between 96 and 2000
were "G" engines, to earn the credits. "R"s would be sold in areas with less
stringent emissions regulations.

Bill

 

98 and newer. I misspoke
Bill