Hi all...

I am a GM guy, but this is my first diesel. I am the not-so-proud owner of a 1982 Fleetwood Pace Arrow, on a Chevrolet P20 chassis (think old StepVan Frito-Lay / Wise delivery trucks). Not-so-proud because I bought this thing with the plan of being a fulltimer, and found out it has some major electrical and roof problems. However, its 6.2L diesel runs well and while I can still use it for parts to fix up a similar motorhome I am buying, I hate to send a perfectly good engine to the junkyard when I am finished stripping this thing.

Here are my thoughts. I have an '84 Buick Regal coupe that runs well, but I'm thinking I may want a diesel in it if gasoline gets much more expensive. I have found many YouTubers with cars that have 6.2 conversions.

As far as I know, the 6.2 had no electronic controls for 1982, so there are no provisions for a throttle position sensor, therefore I believe I am limited to what transmissions will work properly behind it, as 94-up 4L60 / 4L80s require a TPS input.

The Buick came factory with a 200-4R overdrive, which I know will need modification to live behind a 6.2. Do I have to do anything special to adapt the 200-4R / 700-R4's TV cable to an 82 6.2L's injection pump? I have read about someone who put a 6.2L in an S-10 with a 200-4R.

I am curious what kind of fuel economy I can expect with this engine in the Regal. These cars are typically around 3400-3800 lbs with a gasoline engine, quite a bit less than a typical GM truck application. The owner of the diesel S-10 I mentioned claims 33 mpg, and S-10s are about in the same ballpark in regards to weight. I am told, however, that weight is of little concern to a diesel, and that less weight won't necessarily help economy. If I had to guess, this car has a 3.08 or 3.42 differential, the original 4.1 Buick V6 is very relaxed on the highway in overdrive. I imagine this is a somewhat higher ratio than 6.2s are usually paired with, but I have also heard that higher gearing is actually better with a diesel, as it has the torque to pull higher gearing.

I have been in contact with someone who has owned a Cutlass with the Oldsmobile 4.3L V6 diesel, which was derived from their 5.7L V8 diesel. He claims 30 mpg combined and up to 43 highway.

I know that being a bigger engine, a 6.2L may not achieve that, but that might also work to its advantage. I have seen a few vehicles that did better with a bigger engine (Mercury Grand Marquis - 17 mpg with a 4.6 Ford vs a Buick Roadmaster's 20 mpg with a 5.7 Chevy, of course those are gassers, not diesels).

It might seem like a lot of work for a few mpg, but if the 6.2 can top 30 mpg, I think I would be happy with it. This car would likely be my daily driver once done, and even 30 miles for $6.00 sounds better than 20 miles for $5.00 (my estimate for the 4.1L). I am basing my estimates of what I expect fuel to be at this summer, and preparing for the possibility of it not coming back down.

I guess the biggest question is, would it be worth it? And if not, what is this engine worth to someone looking to do a more worthwhile swap? It ran perfectly with no smoke and good power last time it was fired.

 

Since the 6.2 is all mechanical, it really shouldnt be too hard of a swap, it wont be easy, but surely not too difficult. If youve got the time and the money, heck youve got the engine right there, might as well use it for something IMO.

 

Time and money... how much time and money should I expect to spend?

 

what tranny does the 6.2 have behind it now I would find a 700r4 that was behind a 6.2 drop that in as a unit and I would budget 1500 and figure 2 weeks working off and on on it

 

It is a 3-speed automatic. I am assuming it is something heavy-duty like a TH475, I highly doubt it will fit the Regal without cutting the tunnel.

 

Okay, change of plans...

The 4.3 V6 gasser in my '98 GMC Safari van bit the dust a couple weeks ago... I suspect weak head gaskets and extremely high mileage contributed... Odometer shows 171k but I think it has been swapped from the original unit... This van, being a taxicab, is my bread and butter and I need it back on the road ASAP, a friend has been kind enough to set me up with a Crown Victoria to run in the meantime.

I have been less than impressed with the fuel economy of the 4.3, though it is slightly better than my friend's 5.7 Vortec Tahoe (I get 12-14 in town, 18 highway, compared to his 11 city / 18 highway), and I have decided that diesel power may be the way to go. A remanufactured 4.3 is $1,600-$2,000, and seeing as the van's rear differential and transmission are both in trouble as well, I feel this money would be better spent on drive-line upgrades to handle the diesel, since I already have the 6.2.

My van has the 4L60E, but it requires a TPS input the 6.2 does not have, and my research indicates the 700-R4 is a direct bolt-in. I hear the 4L60E is actually a better trans, but unless anyone has any ideas on equipping a 6.2 with a throttle-position sensor, the 700-R4 is my only option... Though I have my doubts from prior experience, I do know the 700-R4 is commonly used in street/strip race cars, so I would imagine if built with proper modifications, a 700-R4 WILL last behind a 6.2.

I have found a fellow on the InterNet who has successfully swapped a 6.5/4L80E into a '94 Astro van. Rick’s Site » 1994 Chevy Astro

Seeing as the '94 has a slightly shorter nose and lower hood-line in the front, I think the 6.2 would be an easy swap into my van. This fellow claims it sits on standard SBC V-8 engine mounts, and gets 22 mpg average, which is twice what I get now. A friend who once owned a Suburban with a 6.2 said he got 24! The 6.5, having electronic injection control, requires some wiring modifications that my mechanically-injected 6.2 will not, so from an electronic standpoint, this swap should be EASY. Almost seems like there is more room in this van than there is in my Buick!

The photos show a minimal amount of massaging required to clear the body and dog-house in this van, mainly minor tweaks to clear injector lines. My van is all-wheel-drive, and I had concerns about clearing the front differential until I read someone's thread on about successfully swapping a 5.7 Vortec into an '01 AWD model with an aftermarket 8-quart pan:

http://www.astrosafari.com/viewtopic...1+AWD+5.7+Swap

I presume the 6.2's oil pan is more or less about the same contour and capacity. My only concern is whether the Safari's front steering and suspension can really handle the extra weight of the 6.2. Research indicates a 6.2 weighs 700 lbs fully dressed, a bit more than a SBC V-8, which is a common swap for these vans. Also am curious about connecting a throttle valve cable to the 6.2's injector pump... I am assuming that since 700-R4s were a factory offering with later 6.2s, that factory pieces to make this work can be found at any boneyard? Also, what gears would be best for the 6.2 to get optimum fuel economy? I am guessing 3.08s?