Which diesel engines would fit an 87 or 88 large-size GM wagon?

I don't mean to be disrespectful, but something must have been wrong with them. I had a 1980 Olds 98 Diesel in High School and all through College and I didn't pay for fuel for 4 years. My friends liked riding it it because it was big and comfortable and had ice cold A/C. So I charged everyone $2.00 for fuel every night we went out. Friday night, Saturday night, and Sunday night. Typically that was 5 people so I got $10.00 per night or $30.00 per weekend. My tank was always pegged at full. I drove that car 80 miles round trip every day to school for 2 years. It had 2.41:1 gearing and no Overdrive (TH-350C). I almost always averaged between 30-32 MPG with it. We took it on a trip to Vermont, topped off the tank, then to Detroit through Canada, and back to Philadelphia (where I used to live then) and I still had over 1/4 of a tank left. I converted a 1993 2wd Suburban to diesel with a 6.2L and it manages 22 MPG around town, and 27 on the highway. The best it ever did with the TBI 350 was 17 highway, and around town you could watch the fuel gauge drop.

If the injection pump timing was off, or if the EGR valve (which was a very primitive design) were allowing EGR flow into the intake all the time, it could cause the fuel economy to sink like a rock. Another common problem is a muffler that is clogged up with soot that restricts the engine and makes it get poor mileage.

Also, driving habits can cause mileage to suffer also. Diesels can be way more efficient that gasoline engines (at least older ones, newer ones are a different ball of wax) but they have to be driven efficiently to get the results. If you drive like every green light is a chance to fill the Prius in the other lane with black smoke then you are going to get lousy mileage. If you drive like there is a State Trooper following you (without the lights on; we don't mean Hot Pursuit), a gas version can't come close to touching the mileage a diesel will give you.

As much as I like the 350 diesel despite it's undeserved bad reputation, GM was largely to blame for this issue. They tried to pass diesels off as maintenance free and requiring no special care. Witness the lack of a water separator or a means of dumping excess water without dropping the tank as an example of that. If a diesel is not maintained, it's efficiency will quickly drop into the toilet. I don't recommend diesels for a lot of people because of that. For example, my neighbors just bought a Chevy 3500 to tow their camper. They asked me if they should get a diesel. Now I will tell you this. Their truck will travel less than 5,000 miles a year, and only tow that camper 1,000 miles a year. There is no way I'd recommend they get a diesel. They got the 6.2L gas V8 instead. Now if my neighbor was buying the same truck but to use it as a general contractor, or a tradesman (I.E. electrician, plumber, roofer, etc) I would have advised him to get a diesel. 40,000-50,000 miles a year with a full load on, the diesel spanks the gas engine on fuel savings alone. But, not for what they are doing. Also, gas engines are more forgiving of neglect and abuse than diesels are. I drive a diesel in my Suburban because with 4 children in child safety seats, a wife, and myself, and all the kiddie gear that goes with it, we needed a Suburban (because I'd rather walk or take the bus than drive a minivan) for the room, and I needed better than 14 MPG. I am happy with it, but I wouldn't recommend it to the average driver, because it needs maintenance. Diesels don't forgive you for missing maintenance. Nor do they forget. The flip side is if they are well maintained they will last several hundreds of thousands of miles.

Sorry for being long winded, but I am excited for the O.P. because I love GM B body wagons and I love GM IDI diesels from back in the day. I think they are a great combination.

 

I would without hesitation put a 6.2 oil burner in any B-body car. But I would be just as likely to throw a 4.8 or 5.3 gasser in there.

6.5 with the turbo would probably do well also. I look at it this way. If a 1996ish Suburban with the 6.5 turbo and 4L80E and 3.42 or 3.73 gears and huge 33 or 35 inch truck tires can weigh over 5700lbs and get 20-22mpg, imagine what a 6.5 turbo with a built 4L60E and 3.08 gears and 29 inch tires (235/75R15) could do in a 4300lb wagon? I would think it would do better. It's lighter, lower to the ground, the gear change matches the tire size change, and the 4L60E wastes less horsepower than a 4L80E. Make sense?