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3800 Series II Engine Overview

This topic consists of custom engineered 355 Ferrari Replica that is powered by a 1999 Buick 3800 Series II V-6 engine specifically adjusted to our individual taste, producing throttle response, torque, horsepower and the good looks the Ferrari 355’s are so well known for without the maintenance. I felt the Buick 3800 Series II would be, a good fit in my car due to the GM heritage and the reputation the 3800 Series II has for overall drivability and long engine life. One of the nice things about the 3800 Series II is that the engine bolts up to the transaxle without modification and looks like GM wanted it that way. The newer 3800 Series II have automatic transmissions and are front wheel drive. Our plans called for shifting the gears so and a new “F” body rear wheel drive Pontiac flywheel (1996 Vintage) was modified slightly to use with the 3800 Series II engine and 5 speed Getrag combination. The 3800 Series II are the standard equipment in large front wheel drive cars in the G/M line up. What I liked most is the expectation of two things that existed in the GM street engines these days, lots of torque and moderate fuel economy. The 3800 Series II engine has them both.

Highway mileage in my 355 Ferrari replica is Over 35 MPG. In town is normally 20+ MPG depending on how cool it is in Tampa. If no A/C, better mileage.

The 3800 engine will develop over 90% of its torque between 1600 RPM to 4800 RPM, 1500 rpm 250 ft lbs (60mph in 5th gear), 3500 rpm 280 ft lbs (max torque), 5200 rpm 240 ft lbs (max hp, what ever that is these days). The 3800 Series II production versions available are in 205 HP (mine) and its supercharged big brother version at 250 HP.

Versions of the 3800 Series II Engine (Normally Aspirated Engine, Fuel Injected)

1986 to 1991 Normally Aspirated Engine - 150 HP. Vin Code – C

(in my opinion, not worth the effort required to change over to this engine)

1990 to 1995 3800 Series II Normally Aspirated Engine - 170 HP. Vin Code - L

1995 to Current – 3800 Series II Normally Aspirated Engine - 205 HP. Vin Code - K -

(I used this one plus modifications)

Big Brother Versions of the 3800 Series II Engine (Supercharged )

1991 to 1993 Supercharged - 205 HP. Vin Code - 1

1994 to 1995 Supercharged - 225 HP. Vin Code - 1

1996 to Current Supercharged - 250 HP. Vin Code - 1

People like the Supercharged - 250 HP 3800 Series II engine as well, but I wanted the higher compression of the non-supercharged version and the ability to add a custom intake manifold that housed six Weber carburetors. During the conversion process I discovered some interesting stuff about the weights of engine and transaxle packages for my normally aspirated 3800 Series II engine compared to a 2.8 V-6 Fiero package.  I uncovered a lot of talk about the different weights of engines and transmissions put into Fieros, but never any hard facts. Simply out of curiosity, I looked up information on the internet but found it was not complete, so I have weighed most of these items myself using a feed scale at the local lumber yard. All weights are dry (no fluids) and just happen to be involved in my swap.

Stock Configuration

140 HP (on a good day, mine had lots of miles)

1986 Pontiac 2.8 liter V6 376 lb.

TH125c 3 speed 124 lb.

Flex plate and torque converter 29 lb.

Total 529 lb.

New Configuration

207 HP

1999 Buick 3800 Series II 360 lb.

1988 Getrag 5 speed 102 lb.

Manual flywheel, pressure plate, and clutch disc 35 lb.

Total 497 lb.

Engines; all weights include starter, alternator, A/C compressor, exhaust and intake manifolds. As it turned out my package is 33lbs lighter than what came in the car from GM.

Part of my desire for something different soon changed some of my initial weight calculations. I fabricated an aluminum sheet metal manifold for the new 3800 Series II engine. I got the idea from Inglese, they make manifolds and Weber carburetor set ups for Ford and Chevy V-8 engines. They used to make them for the Buick V-6 but have nothing for the new style 3800 Series II and the old stuff is out of production, it is a different manifold design than what they used to manufacture, so if I want the Fun with Wheels ride to be unique, a change was in the making. I am in the process of designing and fabricating an aluminum intake manifold to hold Porsche style Weber Carburetors. I want to hear the roar so I went for the Webbers. That will change the weight again to 521lbs, still 8 pounds lighter than Fiero but now it roars with about 100 more ponies to boot.

I like the simplicity of a Weber carburetor mounted on my own designed manifold that will run with the best of them. I made sure that I did not restrict the air flow into the engine and decided to do a little work on the heads as well. 3800 engines are usually not at their best unless you open them up and I wanted to check out a few vital components including the design of the underside of the OEM plastic intake manifold. When I found my 3800 Series II it had less than 100 miles on it and still had a desire to look into it and plan a few modifications to my specifications.

The '93 to '02 engines have forged rods, cast crank and good cast pistons with an internally balanced shaft system that keeps engine vibrations to a minimum. They also have roller lifters on the camshafts that help with performance and reduce friction on the lifter and camshaft lobes. '93 to '95 engines came equipped with the OBD-1 computer that will allow the chip to be modified. '96 to '02 engines come with the OBD-II computer that cannot be modified. I

If you search for performance parts, you will find that there is a very limited selection of performance goodies for 3800 Series II engines. There are no custom pistons, rods, cranks, cams, etc. Other modifications such as belt driven blowers and exhaust driven turbo chargers for the 3800 Series II engines are non-existent. You have to decide, “How much horsepower you really want to make”? Then figure out how to accomplish the project by looking at other stuff that is used on Hondas, small block Chevy’s, Fords, etc. then make something similar to what you found.

Here are some of the things I did to produce a little more power. There are always some minor problems with any mass production head. An example of this is when the valve seats are machined, there is a sharp corner left on the short side. I radius the corner along with doing some matching work in the intake and exhaust ports to match up the components.

Headwork with a cam can really wake up this engine. I still need to locate a cam, springs and rockers. Crane Cams is located in Daytona Beach, Florida and manufactures rocker arms and valve springs and hopefully will grind a cam for my engine. With just the Weber intake, headwork, springs and rockers, that should easily produce an increase of 150HP and bring the horsepower to 357HP with excellent drivability without sacrificing parts reliability. All of the project statements above are in my 355 replica. Just having Fun with Wheels. 

Engine Mounts

I selected some bullet proof engine mounts from Chris West, West Coast Fiero, 13456 Beach Avenue, Marina Del Rey, California  90292, 310-305-4111.  The mounts are made of heavy gauge steel and have a through bolt design with neoprene instead of rubber. I don’t use a Fiero type dog bone on my set up.  I simply made up a length of tubing with some threaded eyes in each end, mounted one end to the block and another to an old engine mount.  I installed it so under torque, it pulls on the rod, rather than compressing it.  Seems to work well and looks clean. 

I wanted to do the job once and they appeared to have a well-designed set up that will bold right into place.  I used the V/6 front mount (replaced the stock Fiero unit), rear transmission mount, front transmission mount, 3800 conversion front mount that bolts to the V-6 mount.  

I contacted Rodner Dickman to invest in his bulletproof products for this conversion.  He manufactures engine mount brackets that attach the West Coast mounts that attach to the frame.  They are 33% thicker than stock.  Mine were bent and needed replacement.  If you are installing a 87-88 Getrag transmission, it would be a good investment if you install his bushing rebuild kits for the shift linkage and select lever as part of your conversion.  I also selected the short shift arms that attach to the transmission.  He manufactures (hard to find) replacement cables and short shift levers that make nice enhancements to the overall project. 

A side note:  You must use an oil filter assembly that sticks out to the side or front of the engine.  The 3800 Buick dips back under the front harmonic balance pulley on the end of the crankshaft and interferes with the mounting points with the West Coast mounts.  I purchased a new housing for a Pontiac Transport Van to replace the Buick version.  Most used auto parts yards might have one in stock.  If the car was wrecked it may be damaged, so I went to the Pontiac dealer and ordered a new one Casting Part Number 2450-3994.  The order number on the invoice was 2450-8441 but it was the correct part for the application. 

In addition to the new filter mount I installed a larger remote oil filter and two cooling radiators with electric fans manufactured by Long Manufacturing in Canada (A Dana Company).  These heat transfer units have reduced the operating tempeture of the 3800 Series II approximately 28%.  That is important to long engine life here in the Sunshine State.  

3800 Series II Engine Flywheel Options

I had three options available for flywheels for my 3800 Series II conversion:

I located and solicited assistance form David Cole, through the internet for advise on this topic. I considered using the Stock Fiero flywheel – but Dave pointed out the OEM Fiero V6 flywheel has 6 crank bolt holes, 3800 Series II need 8. It takes extensive modifications to adapt the OEM V-6 flywheel to a 3800 Series II. Here are the results of our conversations.

Option 1: modify a F-body Flywheel (choice I used in my car):

I used an F-body flywheel used on the Camaro / Firebird cars 1996 vintage. I located mine at AutoWay Pontiac, GMC-South of Clearwater, Florida, 19320 US 19 North, 727-536-1967. Talk with John Shields, Parts. The F-body flywheel (p.n.#24503285) is 1.110 inch thick. Note: (The cost of the flywheel is about $250.00 at a Pontiac dealer and about $455.00 at the local Chevrolet dealer, same part number, go figure?). The flywheel in OEM form is 1.110 inch thick. This needs to be machined down approximately -. 270 to a thickness of .840 inch to match the V6 Getrag flywheel thickness. I took mine to a machine shop in Clearwater, Florida and had the work completed for $75.00, this will work for a normally aspirated Series II 3800 (1995+). The supercharged Series II 3800 started using the Series II set up in 1996. According to Dave Cole, previous 3800 SC engines had a slightly different imbalance in the flywheel compared to the normally aspirated engines (SC specific rods / pistons required this). First generation 3800's Series I (1987-1994) require a different amount of imbalance than the Series II. Options? - Rebalance the flywheel to match the flex plate removed from the engine or option 3. Cost: new GM flywheel approximately $250 plus machining. Aftermarket sources will eventually appear for this flywheel but I have not found any. Many manufacturers will make up a flywheel for about $650.00, More than I wanted to invest.

Option 2: Modify a stock V6 flywheel.

Due to lack of information on the Series II 3800 imbalance I would not recommend this method. You need to fill the 6 crank mount holes with weld then have the re-welded area machined and drilled to match the 8 crank holes on the Series II 3800. (The crank holes are NOT evenly spaced - 1 is off by 3 degrees to act as a key. Your machinist can use the flex plate to determine the location of the holes). Then neutrally balance the rigged-wheel; then balance it to match the flex plate. This probably works ok. This process was first used by Dave Cole and did not work well, his engine had noticeable shake. He now has the old flywheel door stop in his storage area. The guy balancing his flywheel was off by 60 degrees on the placement of the imbalance! Cost was $300 using his own OEM Fiero flywheel. Dave Cole feels this can be done to work effectively, but my feelings are that reworked flywheel will become a lot of shrapnel sitting behind your head if it decides to come apart. Not my choice!

Option 3: Make a new flywheel (currently in use in Dave Cole’s car) Cost wise; this is not that much more. $650 - $700. Prints can be found on Dave Cole’s the web page. I am using the 96 Pontiac F body option 1, noted above. No hassles, just follow the directions and put it into your car.

Another Option would be to contact the people at ACE or West Coast Fiero’s to get one of their flywheels. ACE uses Option 3, but their own design. Seems to work fine in the installations I have seen. West Coast Fiero’s provides both options.

Other interesting points:

1) With a Series II 3800, Getrag and a flywheel of 0.840 inches thick, the release bearing has about .250 inches of free travel between it's solid point (backed up against the inside of the transmission) and the point at which it contacts the pressure release fingers. When doing an engine/ transmission swap, it is CRITICAL to have at least some free travel here. If there is none, the release bearing will be forced against the release fingers all the time causing the clutch to slip. Translation: I don’t know how you feel about redoing work on your toy, but you'll soon be back doing this job again.

2) The Getrag release shaft assembly has about a 2:1 leverage ratio between the point at which the slave push rod contacts the arm and the two fingers that operate the release bearing. Some people attempt to use Isuzu slave cylinders or a 4-speed cylinder. After all of that work contained in doing the swap, why not use the correct Getrag large bore slave cylinder. It costs about twice as much as a cheaper version but is designed to work with the 5-speed set up.

3) A 0.840 thick flywheel and a new clutch package (by LUK) will spin free without hitting anything inside the transmission bell housing. I purchased my clutch at PEP Boys Auto Parts, Tampa, Florida for $125.00

4) You will need longer bolts to hold your new flywheel to your Series II 3800 engine. ARP hardened bolts for a Chevrolet cam shaft gear will do the job here. They are quite strong, 190,000 PSI, Part Number234-1001 (CV Products @ 800-448-1223) and will work just fine. If those are not available, Crane Cams, Daytona, Florida makes a set of them as well. Part number 99168-1. If CV Products is out of the question for you, then both brands can be purchased from Jeg’s, Columbus, Ohio, and Summit Racing, Cleveland, Ohio. You will need 8 bolts. They are packaged 3 per package; you will need to get 3 packages to do the job as well as a tube of Locktite. Torque each bolt to 29lbs using a cross center torque pattern, that will hold it all together just fine.

Getrag/Muncie 5-speed Transaxle, General Information

Designed by the Getrag Co. of Germany for GM as the high output 5 speed transaxle, built by Detroit Diesel Allison in Muncie, Indiana. (usually referred to as the Getrag to cut down on confusion)

Each of these transaxles are used on many different GM front wheel drive cars as well as on the Fiero. There is a range of different final drive axle ratios available depending on the car and the year etc. but they are all basically the same internally and have the same bell housing bolt pattern. This means that any of them can bolt up to either the 2.5 litre 4 cylinder engine, 2.8 litre 6 cylinder, Quad-4, 3.8 or the 3800 Series II as in my car. The difference is in their capacity for torque and in the arrangements of the external shifting mechanism that is a bit unique on the Fiero. Thus, you should be able to adapt a 5 speed Getrag from a Cavalier (J-car) for use in a Fiero with only a couple of minor modifications on the OUTSIDE of the transmission. This is an important and useful fact now that Fiero Getrag’s are getting rare. The modified parts look very simple and should not pose a big problem for anyone who is capable of an engine swap.

As for the torque capacity - the Isuzu will fit the V6 cars but is really built strong enough to take the torque – in my opinion this is not a good candidate for an engine swap. This seems to be open for debate depending on who you speak with on the topic. V8 Archie, and others, will tell you the Isuzu's work fine with the V6's and V8's without problems. My money is on the tougher Getrag 5-Speed out of an 87 – 88 Fiero. The V6 engines, 4 speed Muncie is a very heavily built unit and can be used with virtually any engine including a V8 with under 400 HP. The 1989 and up Getrag’s use a different speedometer drive arrangement which uses a magnetic Hall effect sensor instead of the cam driven gear driven VSS Units I have located a few comments on the gear falling off causing some rework. Best to look on the web site of Rodney Dickman for help on the Getrag issues. I have found him to be very helpful and he also manufactures some trick parts for your Getrag as well. Rodney Dickman (1-414-762-9244) makes a kit which does this conversion. I got his name from the Fiero Web Ring several months ago and found him a pleasure to work with. He pronounces Getrag as Ga-Trog like it is a good bottle of wine it is all in how you say it. 

If you invest in a post 1989 Getrag Rodney has the new components to properly convert your transaxle to a Fiero set up. VDO makes a sensor to assist with getting the Fiero Speedometer to function properly. The change over kit from Rodney consists of some custom made brackets to convert a Cavalier type shifter linkage to a Fiero linkage – the Getrag internally functions the same as the Fiero. The standard shift axles will hook up without modification unless you are like me and need them 4 inches longer with S-10 Front Splines, Siera Uprights etc.


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Copyright © 2002 David J. Newman
For questions regarding this web information contact: [newmdav@ispwest.com].
Last updated: 07/10/02.