FAQ: Series II Supercharged V-6 Engine

The Series II Supercharged V-6 is one of the last versions of the long-running 3800 series of Buick engines that originated back in 1962, when the car maker unveiled America's first V-6, the 198 cid "Fireball". The design was created by chopping two cylinders from their innovative all-aluminum 215 V-8 block. Since that time, the engine has evolved into the supercharged 231 cid (3.8 L) version, named L67, used in various GM vehicles from 1995-2005. The L67 started as the Series I Supercharged in 1992 (optional on the '95 Riviera), then became the Series II Supercharged in 1996, and was replaced by the L32 (Series III Supercharged) beginning in 2004.

The history of the 3800 is significant because, due to the fact that it still uses older push-rod technology vs. newer OHC (overhead cams), the L67 makes a lot of low end torque for its small physical size. Combine the fat torque curve with a supercharged induction system, and you have a powerful engine that can be made even more powerful for relatively little cost. On top of that, you can still have decent fuel economy, reliability, and driveability comparable to a completely stock engine.

The Series II L67 used in the Riviera is basically the same one used in the Buick GS and Pontiac GTP, which are part of the W-body family of GM cars. The Riviera is a G-body, a platform shared with the Oldsmobile Aurora, Buick Park Avenue, and Pontiac Bonneville. G-bodies have some differences such as certain brackets, pulleys, belts, and exhaust parts that make doing some things easier and other things more challenging.

Performance engine parts designed for the GS and GTP likely will fit our engines, too. The thing to remember: any internal engine parts, such as a cam, connecting rod, pistons, crankshaft, rocker arms, push rods, valve springs, etc. are interchangeable. The M90 blower, which sits atop the engine is also the same, so using a smaller supercharger pulley designed for the W-Body cars will work just fine. More info at: gmtuners.com:

3800 Series II & III 90° V6

1995-04? 3800 Series II SFI Naturally Aspirated V-6 vin K RPO L36

* 200-205hp @ 5200 rpm
* 225-230tq @ 4000 rpm
* 9.4:1 Compression
* FWD and RWD, balance shaft, crank driven oil pump, DIS, hydraulic roller camshaft, integral PCV, rocker arms
* 22 lb/hr injectors

1996-04 3800 Series II Supercharged V-6 vin 1 RPO L67

* 240hp @ 5200 rpm
* 280tq @ 3600 rpm
* 8.5:1 Compression
* FWD, balance shaft, crank driven oil pump, DIS, hydraulic roller camshaft, integral PCV, rocker arms, M90 Supercharger
* 36 lb/hr injectors

2004-08 3800 Series III Supercharged V-6 RPO L32

* 260hp @ 5400 rpm
* 280tq @ 3600 rpm
* 8.5:1 Compression
* FWD, balance shaft, crank driven oil pump, DIS, hydraulic roller camshaft, integral PCV, rocker arms, Gen5 M90 Supercharger, powdered metal connecting rods

Special notes considering the 3800 Series II N/A and SC engines: The series II 3800 is a redesigned version of the 3800 Series I V-6. The Series II block has a shorter deck height, symmetrical design cylinder heads & cross-bolted main bearing caps among most of the major differences it has with its predecessor. The Supercharged version of the Series II engine shares the same crankshaft and heads as the naturally aspirated version but the heads on the SC version have bosses machined for injectors, and the crank is balanced differently because the SC version has beefier connecting rods and pistons. The SC pistons are also of a special casting and have a thermal coating on their tops designed to reflect heat back into the combustion process. The pistons and connecting rods used in the naturally aspirated versions of this engine are NOT designed for use with boost and are significantly weaker than their supercharged counterparts. Other differences between the N/A and SC engines are the balance of the harmonic balancer, flexplate/flywheel, and balance shaft. All 3800 Series II engines are considered to be "externally balanced".


Where you see differences between the Riviera and the W-bodies are in the parts around the engine: CAI (cold air intake) systems, exhaust manifolds and pipes, drive pulleys and belts, engine mounts, alternator, and the PCM (powertrain control module) for W-Bodies are different and may not work on the Riviera without special modification.

Note the Riviera is bigger, heavier, and better balanced than the W-bodies, which means we are slightly slower at accelerating due to traction issues and the extra weight. However, the more evenly distributed weight (aluminum hood, and having the battery in the rear, for example) means a more even F/R distribution of weight, which in theory is better for overall handling performance. Another positive note, Rivieras happen to be fairly aerodynamic with a .32 Cd spec.

Anyone know why ZZP doesm't list anything for the Riv. just 3800 stuff just cobalt, pontiac, monte carlo etc.

Most vendors don't list products for the riv because we're not that big of a market .

A lot of the 3800 GP/Regal GS stuff also applies to our Rivs. Not ALL, but a lot. The Riv market is too small for them to be model specific for us.

How do I know if I have a M62 or M90 SC on my 96 ?
Thanks Bob

On a 96, you have a M90.

I'm looking for a replacement for my '98 SC engine. Minor issue of bulging holes in the lower block.
Can anyone direct me to data on the board that tells me which other GM cars will yield a L67 short block?

Thanks Dave.
From where did you grab that data?
I'll bet there's more I should be aware of for a perfect match. This is a good start

denim wrote:

Thanks Dave.
From where did you grab that data?
I'll bet there's more I should be aware of for a perfect match. This is a good start

LINK: http://en.wikipedia.org/wiki/Buick_V6_engine

Oh snap!

AA,
Your Riv desc. states "intercooled."
Does that refer to the tranny cooler?

No, it refers to a high performance Riviera made by GM, tested by a group of automotive press writers in the late '90s.

Gotcha. Wouldn't have a link, would you?

Yes, here you go: https://rivperformance.editboard.com/t6550-road-track-drove-high-performance-riviera-in-96

Hello,
I bought a very nice '97 Riviera with a blown engine. Going through the offerings from my local junkyards, two choices come to the top of the list:

- Complete engine from '97 Riv w/ 125K miles (no core), $500
- Complete engine from 1998 Pontiac Grand Prix, 83K miles (with core) $500

My two questions are:
- Any differences between a SC3.8 from a '98 Grand Prix and my '97 Riv?
- Given that I can probably get $300 parting my old engine, I've been tempted to cheap out and get the higher mileage engine. Bad idea...?

Thank you.
Mikel

best way to tell would be to do a leakdown test on both engines then take the best of the 2.

Albert, you NY native, I've a question along the same lines.
My new '98 engine is blown. I have a line on a '96 complete engine that the owner will swap for '95 engine (which I have).
Question: Are the '96 and '98 engines twins? I'd like to be sure before I invest mucho time and money.
What do you think?

Mikel wrote:

Hello,
I bought a very nice '97 Riviera with a blown engine. Going through the offerings from my local junkyards, two choices come to the top of the list:

- Complete engine from '97 Riv w/ 125K miles (no core), $500
- Complete engine from 1998 Pontiac Grand Prix, 83K miles (with core) $500

My two questions are:
- Any differences between a SC3.8 from a '98 Grand Prix and my '97 Riv?
- Given that I can probably get $300 parting my old engine, I've been tempted to cheap out and get the higher mileage engine. Bad idea...?

Thank you.
Mikel

Mike,

I'm more interested in your tow rig? Dual rear axles what? Some kind of ex military vehicle I assume?

There are a few differences between the GTP and Riv engine, all in the accessories. The engine internals and block are the same.

Make sure your "blown engine" doesn't simply require intake manifold gaskets. It's a very very common mistake. Either of the engines you listed are likely to be in similar condition. These things have been known to run to 250K and beyond without a problem if they are properly maintained.

Did you guys know the L67 only weighs 392lbs? I had no idea. I thought it was ~500lbs!

Crank HP is 240, right? What is the power at the wheel? I don't know why but I can't seem to find a number? is ~190 about right?

Now I am seeing that it's 260HP crank and 240HP wheel for the L67? That can't be right...
Wheel HP has to be < 240 HP, right?

Neither is correct for Series II SC. Stock crank HP is 240, stock wheel HP is ~200. 260 is stock crank HP for Series III SC (not used in Rivs).

Quote :

Did you guys know the L67 only weighs 392lbs? I had no idea. I thought it was ~500lbs!

This info is incorrect. The L36 (NA) engine weighs 392 lb. The L67 adds a supercharger and other parts, which probably pushes the weight up to at least 450 lb.

Gotcha. So how about that L67 stock wheel power?

Where do I find a used series 2 supercharged running engine? Or rather the first place to start? Figured I could build it slowly and then drop it in later while still having my buick as a daily

The Series II 3800 V-6 just took the #5 spot in a recent Jalopnik poll:

http://jalopnik.com/the-10-best-engines-of-the-last-20-years-1510676043

  

I saw that, but it's not the supercharged version. Made me mad