3100 to 3800 Engine Swap

[lemons bob]

I know there is alot of love for the 3800, but I kind of don't see why. it is significantly heavier than the engine you have in the car, I just wonder if going to a 3400 or 3500 wouldn't get you better mileage and performance than the 3800, and be an easier swap.

[turbokinetic]

I know there is alot of love for the 3800, but I kind of don't see why. it is significantly heavier than the engine you have in the car, I just wonder if going to a 3400 or 3500 wouldn't get you better mileage and performance than the 3800, and be an easier swap.

One reason is the engine's legendary reliability reputation. It is based on a design from the 50's that has been refined. These engines routinely last 300+ thousand miles without overhaul. It's not a bi-metal engine (iron heads and iron block) so there are far fewer gasket issues.

[Ray_McAvoy]

I'd love to know how the 3800 does on gas mileage compared to the 3100. The original EPA ratings for a 1994 3.1L Ciera Cruiser (or sedan) were 19 city 29 highway, just like a 1995 3.8L LeSabre, so the "modern" ratings of 17 city and 26 highway 20 combined are also the same. Difference is 1994-1995 sedan Cieras have higher user ratings, 24 to 27 mpg, versus 20mpg for the LeSabre users.

The old 3100 that came out of the wagon was so worn out and under powered that you had to practically drive around with the accelerator on the floor just to make it up steep hills and keep up with traffic on the highway. So needless to say it didn't get very good gas mileage to make for a good comparison. I don't think Mom has really been keeping track of the exact gas mileage so I can't say for sure what the 3800 has been getting for mileage.

I know there is alot of love for the 3800, but I kind of don't see why. it is significantly heavier than the engine you have in the car, I just wonder if going to a 3400 or 3500 wouldn't get you better mileage and performance than the 3800, and be an easier swap.

One reason is the engine's legendary reliability reputation. It is based on a design from the 50's that has been refined. These engines routinely last 300+ thousand miles without overhaul. It's not a bi-metal engine (iron heads and iron block) so there are far fewer gasket issues.

Yes, the 3800's reputation for reliability was the primary reason for choosing this engine.

As far as being "significantly heavier", I didn't notice much (if any) difference in the ride height after swapping in the 3800.

[Jr's3800]

Not so sure about the Series II 3800's.... they probably do better than the Series I. I can tell you that the Toronado generally gets around 17mpg all city driving. My Ciera gets anywhere from 17-19 depending on the week and the weather... with that being said that's also with my car having the top swap. As far as the Toronado goes... that car is one heavy son-of-a... so I guess we'd have to take that into consideration too.

The 3800 series II is capable of getting some really good numbers, I'd say +1 or +2 over a 3800 series I... Then 95 was an Odd ball year for the series I, GM got funky with it that year as it had some series II goodies...

In cool weather I would say 17-18 would be about right, and with blended fuel..

In general with a good tune, most will easily do 20 Mpg in town, and 30 on the road.. And then it depends on the gears you have... If your ciera wagon with the 3800 has 2.84 gears then you should have good highway numbers for sure... I'd say 32-35 at 75 mpg or so..

The Tornado is a heavy monster...lol... so that will cost you a bit... But even them with a good tune it should get good numbers..

The 3800 is a torquer motor, its meant to have better low end grunt to move large cars.. So it can run around town all day long without straining... The Series II was also designed with low end grunt in mind, but they were squeezing it for a little more top end power.. The 1995 3800 II was rated for 205 Hp and 230 Ft Lbs.. That torque peak was 4000 Rpms, but 80-85% was there above idle, very flat torque curve( the force that loves to move you )...

The 1993-1995 L27 had some tricks and never had any HP number changes.. Rated at 170 Hp and 225 Ft Lbs.. In 93 the engine went from 8.5 : 1 compression to 9.0 : 1 compression and received roller pivots to reduce rocker friction... I think this engine may have been closer to 175-180 Hp and 230-240 Ft Lbs... and the bin files seem to have an early form of torque management....lol

So I forget what year your tornado is, but if its 90-92 it will have the lower compression 3800..

[SilentWing]

The Toronado is a 92.... we'd love to do a tune on it and get better MPGs. I must say though, when we fixed the exhaust (got rid of the Cat) it started running a hell of a lot better.... that cat must have been darn near melted shut.

[Century7667]

I know there is alot of love for the 3800, but I kind of don't see why. it is significantly heavier than the engine you have in the car, I just wonder if going to a 3400 or 3500 wouldn't get you better mileage and performance than the 3800, and be an easier swap.

I think the biggest barrier for the 3500 is the technology gap and mounting. The electronics alone would be a lot tougher. The a-body was designed to carry the Buick V6 from the very beginning and grew up with it for almost the entire production run. I have no bias here, I own TWO 3100 engines in my a-body cars. They are fine engines, but my Dad's '95 LeSabre will always set the record straight with it's all cast iron 3800 which is identical to Ray's. That thing just effortlessly moves the car, and the feeder ramps in Houston freeways are a joy with the naturally aspirated 3800. I can only dream what a forced air induction car like the ones David built must feel like.

Ken T.

[86euro]

I think the biggest barrier for the 3500 is the technology gap and mounting. The electronics alone would be a lot tougher. The a-body was designed to carry the Buick V6 from the very beginning and grew up with it for almost the entire production run. I have no bias here, I own TWO 3100 engines in my a-body cars. They are fine engines, but my Dad's '95 LeSabre will always set the record straight with it's all cast iron 3800 which is identical to Ray's. That thing just effortlessly moves the car, and the feeder ramps in Houston freeways are a joy with the naturally aspirated 3800. I can only dream what a forced air induction car like the ones David built must feel like.

Ken T.

There's the basic 3500 without the variable timing that would probably swap in place of a 3100 real easy. The difference in power over the early 3100 is incredible.

[Century7667]

There's the basic 3500 without the variable timing that would probably swap in place of a 3100 real easy. The difference in power over the early 3100 is incredible.

Oh yeah, no doubt about it. I drove a '12 Impala rental with the 3500, and it was very quick, but the drive by wire nearly got me killed near the airport. My 3100 tips in much better with a real throttle cable. The thing that impressed me the most was how clean the engine compartment was.

Ken T.

[smallcastle]

Ray,
Greetings! I hope you you are monitoring this thread. This was just the kind of information that I was looking for. Explaining what you were planning on doing. The research that you did. How you were going to do it verses how it turned out. But the best part of what you did was how detailed your threads were. Hats off to you! The engine transplant that I am planning is similar. But the year spread between the engine and the car that I am going to put it in is somewhat greater. Spanning OB1 to OBII, replacing a 2.8L MFI V-6 with a supercharged 3.8L V-6. Retaining the factory T440 instead of changing it out to a 4T60E. I only hope that my in diver you turn out as well as yours did. Again, hats off to you.
Smallcastle

[Ray_McAvoy]

Welcome Smallcastle !!

I'm glad to hear that you found the info helpful. Sounds like you have an interesting swap planned with the supercharged 3.8!

It's been about a year since I last posted to this thread so I figure now would be a good time for a little update ... The 3800 has been running great. We checked the mileage last summer and it was averaging a consistent 26 to 27 mpg with a mixture of highway and around town driving. Swapping in the full-gauge instrument cluster is still on the to-do list. I had been planning on doing that last summer but had some other projects that took priority.

Ray

[smallcastle]

Ray,

Like I said I believe that the swap that I want perform is going to be a bit more challenging. The lower motor mount, air conditioning compressor bracket and oil filter mount info is going to be a big help. The current air filter box and plumbing is on the opposite side of engine compartment on a 2.8. So knowing what year make and model you used on yours will be helpful too. My coolant overflow tank will have to be moved from left to right side. The windshield washer tank might have to be moved too. Hoping that it won't. The issues with the power steering hoses, radiator hoses, heater hoses, fuel lines, brake lines, transmission cooling lines, exhaust hook up and the like are all kind of minor issues to me. Like I said the biggest challenge is the mostly in the wiring harness and ECM to PCM aspect part. I found a web site from a guy in Dallas Texas that does engine swaps on Fieros. Doing basically what I want to do by taking OBI controlled L44 2.8 V6's out and putting in OBII controlled series II L-67 and series III L-32 supercharged 3.8L V6's. All I have to do is give him the wiring harness and the ECM out of my Celebrity. The donor wiring harness and PCM out the 1997 Buick Park Ave that the engine came out of. And he can make me up a complete wiring harness along with getting the functions on the PCM that I need changed or turned off. It will cost me a few hundred bucks but this way it will be "plug and play". And I know that when it's done I won't have to worry about it. I might have to start my own thread when I get going with this thing.

Smallcastle

[pshojo]

Good thread, I actually has been wondering which engine to swap in 96 ciera wagon.

[Century7667]

Good thread, I actually has been wondering which engine to swap in 96 ciera wagon.

I like the L27, same era, but a Buick engine with tons of torque. You could tow with that wagon with that motor!

Ken T.