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Discussion Starter · #1 ·
So I was down at the local bone yard, trying to find a 3.4 to shove into my 71 GT. Problem is that there were none to be found. However, there is a 2000 Grand Prix with a 3800 series 2 supercharged power plant that I can get for next to nothing.( helps when your friends with the junk yard owner:})
Problem 1: Front wheel drive car. Will I be able to plug a rear wheel tranny into it without modifying?
Problem 2: Can I shoehorn a dual overhead motor into a GT body?

Keep in mind my shell has major underbody cancer. I have had to strip the car flip it over and am getting ready to sand blast the undercarrige and repair the floorboard, fill in the big holes whare the trailing arm mounts and rear spring carriges USED to be and I dont want to start until I know how much I have to modify the fender wells in the front.
 

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maybe

The 3800 series 2 was built to use basicly the same transmissions as the 2.8-3.4 60-degree v-6 from an s-10 or Camaro. I *think* however, that it uses the Northstar bolt pattern, which is the same with the exception of one bolt. Several companies cut that one ear off the bell-housing and re-weld it on 1.5" higher up to fit, and you can but them already modified. One of the real challenges is going to be the exhaust.

The DOHC version is very wide, and there would probably be som "clearancing" needed on the drivers side at least, and say good-by to the heater box in it's stock form. The supercharger also adds height to the motor, something the GT may not be able to handle without a scoop. It is a wonderfully smooth motor with gobs of torque, but not a whole lot smaller than a v-8.

It might fit better in a Manta, or my old truck for that matter, if you felt like sending the motor my way. The supercharger alone seems to bring a consistant $300 on ebay, and the heads @$300 as well, so depending on how cheap "next to nothing" is you could probably recoup your investment without much trouble if the project didn't work out.
 

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crazy opeler
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I am curious as to the reliability issue of the rotary engine. That is the motor that I have always thought of installing in a gt. But I never heard of them being un-reliable. I know that they are unrebuildabe so you need to find a good one, but they also are supposed to go 300K miles before realy dieing, at least that is what a mechanic told me.
Has anyone had any experience?

Chris
 

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Discussion Starter · #4 ·
Thanks for the input everyone. I think I'll just wait for a ram air firebird to pop up, less trouble.
As to the TPI or carb ideas. I hate carbs, always have. That is why I became a fuel injection driveability technician, so that I never have to deal with carberators again. As far as TPI? I have found that it is nothing more than a carb on steroids:}
You cant beat the added horsepower, low maintenance, and turn the key and go that you get from multiport.

As to the rotory. I've worked on many over the years and found only one good uses for them.... Boat anchor.
 

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TPI=multiport

Now I'm confused.

Tuned Port Injection (TPI) is, by definition, a multiple port injection system. They are typically a "dry" manifold design with the fuel being injected just before the intake valve.

Throttle Body Injection (TBI) is very much like a carburator, at least in the function and layout of a "wet" manifold system.

As far as 60 degree v-6's go (2.8, 3.1, 3.4) all of the 2.8's prior to 87 were pretty much the same, in Jeep Cherokee's, Fiero's, S-10's, Camaro's, Citation's, Cavilier's, and even marine applications. In 97 there was a shift in thinking, and the front wheel Drive applications, Cavilies Z-24's, Baretta's, Transport minivans (eventually) and the like got a new aluminum head design with taller ridges around the rocker arms and an evenly spaced intake manifold design. All of these motors were either a batch-fire multiport or a sequential multiport design. The rear wheel drive cars, camaro's, Fiero's, and S-10's continued on with the cast iron heads with stamped steel valve covers and 2+1 intake manifold design.

For the rear-drive motors, the S-10's first had carb's, then TBI. The Camaro's and Fiero's went from carbs to multiport to sequential multiport. Those multiport manifolds are easy to use, but the computer needs 65+ wires to operate correctly (I have the harness ready to go in the garage.) The TBI manifold will work with 20 wires. For most of us, that is a "better" option. The other thing to consider is that all rear drive manifolds interchange. Install the motor with a Weber carb on a stock carb or TBI manifold to get the install bugs worked out, then switch to the Multiport when the package works.

The front drive motors shed almost 35# with the aluminum heads, which could be significant with the weight of the car. Later 3.1 models, (92esque) used a manifold layout almost identical to the Camaro's, but with lighter components and a little less height. Those motors and heads are cheaper than dirt, but most of them have intakes out the back of the motor and a goofy cast aluminum timing chain monstrosity, er I mean cover. While it makes them a very short package (almost 8" shorter than the rear drive models) it requires a reverse direction water pump that won't work without the power steering pump installed. There is also no way to install a carb or TBI while you work out the multiport wiring harness, as thes heads won't match-up with older manifolds.

The later front drive motors do not have the same boses cast in them for motor mounts, but all 60 degree motors will bolt to the same rear-drive transmissions. The transmissions behind 2.5 4-cylinders are the same, too.

Food for pondering?
 

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People that convert FWD GM's for MG's

I found a few comanies that use the 2.8-3.4's as a swap for the MGB's.
first company uses teh FWD motors with the aluminum heads
killerbv6.com
and the other one uses stock RWD motors, whom I can't remember thier address, but I used one of thier kits to install the 3.4 in my old Sunbeam Alpine
 

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oldopelguy said:
The 3800 series 2 was built to use basicly the same transmissions as the 2.8-3.4 60-degree v-6 from an s-10 or Camaro. I *think* however, that it uses the Northstar bolt pattern, which is the same with the exception of one bolt. Several companies cut that one ear off the bell-housing and re-weld it on 1.5" higher up to fit, and you can but them already modified. One of the real challenges is going to be the exhaust.

The DOHC version is very wide, and there would probably be som "clearancing" needed on the drivers side at least, and say good-by to the heater box in it's stock form. The supercharger also adds height to the motor, something the GT may not be able to handle without a scoop. It is a wonderfully smooth motor with gobs of torque, but not a whole lot smaller than a v-8.QUOTE]

i talked to a guy who deals with fiero swaps, and he said the 3800 will bolt up to a 60 degree bell housing. the exhaust will have to be custom, but the size is very simmilar to the 3.4, at close to a half inch shorter front to back, half inch taller with the supercharger installed, and supposedly the same width. as far as the dohc motor, it will probably be too wide to fit at all really, but i suppose it could be done... as far as the hood, check out ogts for their LT10 hood.sharp fiberglass piece, with a small bulge, similar to a ws6 trans am piece. i am planning a 3800 supercharged swap, the first conversion a base 240hp version, with the second getting a 450hp+ version. -ryan
 

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kickinback88 said:
oldopelguy said:
i talked to a guy who deals with fiero swaps, and he said the 3800 will bolt up to a 60 degree bell housing. the exhaust will have to be custom, but the size is very simmilar to the 3.4, at close to a half inch shorter front to back, half inch taller with the supercharger installed, and supposedly the same width. as far as the dohc motor, it will probably be too wide to fit at all really, but i suppose it could be done... as far as the hood, check out ogts for their LT10 hood.sharp fiberglass piece, with a small bulge, similar to a ws6 trans am piece. i am planning a 3800 supercharged swap, the first conversion a base 240hp version, with the second getting a 450hp+ version. -ryan

The 3800 is WAAAY wider than the 3.4, take it from me, I have one of each sitting in my garage. The 3.4 is a 60 degree V, the 3800 is a 90 degree V. In otherwords, the width is the same as a V8 but it is shorter.

The 3.4 DOHC is a cool motor, and it is a 60 degree V, but it is a dead design. I suspect GM will stop making parts for it pretty soon. Also,even though it is a 60 degree motor, the heads make it a bit wider than a 90 degree.

The OTHER DOHC motor is the 3.5 from the olds Intrigue etc. It is a northstar V8 -two cylinders (aka the Shortstar). It is also a cool motor but it is a DOHC 90 degree V motor and is WIDE.

Do yourself a favor and take a look at how little clearance there is with the 60 degree V6 in the pics on this site ( I have some in my gallery) and you will see what you are up against.

Nathan Acree
Albuquerque New Mexico
 

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oldopelguy said:
The 3800 series 2 was built to use basicly the same transmissions as the 2.8-3.4 60-degree v-6 from an s-10 or Camaro. I *think* however, that it uses the Northstar bolt pattern, which is the same with the exception of one bolt. Several companies cut that one ear off the bell-housing and re-weld it on 1.5" higher up to fit, and you can but them already modified. One of the real challenges is going to be the exhaust.

The DOHC version is very wide, and there would probably be som "clearancing" needed on the drivers side at least, and say good-by to the heater box in it's stock form. The supercharger also adds height to the motor, something the GT may not be able to handle without a scoop. It is a wonderfully smooth motor with gobs of torque, but not a whole lot smaller than a v-8.QUOTE]

i talked to a guy who deals with fiero swaps, and he said the 3800 will bolt up to a 60 degree bell housing. the exhaust will have to be custom, but the size is very simmilar to the 3.4, at close to a half inch shorter front to back, half inch taller with the supercharger installed, and supposedly the same width. as far as the dohc motor, it will probably be too wide to fit at all really, but i suppose it could be done... as far as the hood, check out ogts for their LT10 hood.sharp fiberglass piece, with a small bulge, similar to a ws6 trans am piece. i am planning a 3800 supercharged swap, the first conversion a base 240hp version, with the second getting a 450hp+ version. -ryan
 

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Nathan, just for grins and giggles, could you lay a yard stick across the valve covers of both the 3.4 and the 3.8 to get the actual sizes of them. FYI, I got the McMaster-Carr manifolds almost done. All that's left is to weld on the 90 degree down elbow, reducer and the oxygen sensor fittings on both, then the EGR valve plate on the right side. The reducer is a bear, there's almost a 1/4" material thickness where I cut it for the flange. The digital camera gets back tomorrow from the dog show and I'll be putting up some pics of the manifolds in rough weld and the reducers.

Ron
 

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namba209 said:
Nathan, just for grins and giggles, could you lay a yard stick across the valve covers of both the 3.4 and the 3.8 to get the actual sizes of them. FYI, I got the McMaster-Carr manifolds almost done. All that's left is to weld on the 90 degree down elbow, reducer and the oxygen sensor fittings on both, then the EGR valve plate on the right side. The reducer is a bear, there's almost a 1/4" material thickness where I cut it for the flange. The digital camera gets back tomorrow from the dog show and I'll be putting up some pics of the manifolds in rough weld and the reducers.

Ron
Ron,

The 3.4 is about 15" wide at the top of the heads (the widest point) and the 3800 is about 21" wide at the same point, so there is about 6" difference. Of course the accessories add width to both motors, but the 3.8 is a good bit wider. I would post some pics of the bare motors for comparo, but I don't want to strip everything off of the 3800 yet.

I am anxious to see pics of your completed manifolds. Also, do you have the part numbers and measurements for the elbows that you used? I had planned to use the "donuts" from Ron Covell's, but it seems the manufacturer are not making them in 1.5" od anymore (just my luck). I am going to try and make some block hugger style headers because the log style manifolds come too close to the steering column area of the firewall on my car.

Anyway, talk to you later,

Nathan Acree
Albuquerque New Mexico
 

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Nathan, I figured a yard stick across the valve covers would be a good indication of how wide the engines are, as you know the covers are below the cowl area right at the foot well. With my manifold in place there is about a 1/4" gap between the boot on the steering shaft and the manifold. The engine torques away from the driver so I think, I'll have enough room under throttle application so it won't biind on the steering shaft. That and I'm going to use some 1/16" sheet steel to close up the holes in the wells. I'll have to build an access panel for the two rear exhaust port bolts, it's just too close to get a wrench in there without one. When you see the pics I'll take later this afternoon, you'll see how tricky I'm getting in some areas. And Il post the part numbers of the "T"s and elbows I used. If you go that route, be careful of the alignment on the elbows to the flanges. It has to be perfectly perpendicular, 90 degrees to the flat of the flange or the bolts won't line up to the heads. I had to use a 3/4" end mill tool to get bolts to go in through the flange straight, and I've got some more cleanup to do yet. Right now the manifolds are temporarily installed to set the down elbows angles and alignment for the downtube flanges. I'll post the pics in the applicable Phase thread. HTH.

Ron

Ron
 

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hey ron my jag V12 is only 22" wide @ the back then opens to 27" @ the inlets and about 28" long
 

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namba209 said:
Nathan, I figured a yard stick across the valve covers would be a good indication of how wide the engines are, as you know the covers are below the cowl area right at the foot well. With my manifold in place there is about a 1/4" gap between the boot on the steering shaft and the manifold.

Ron,

The dimensions across the valve covers are about the same ~15 inches to the outside edges of the valve cover for the 3.4 and ~20 for the 3800.

Also, I think my engine is lower in the car than yours. As is stands, I can't fit the fiero manifold on the drivers side without actually cuttin into the round hole that the steering shaft fits through.

BTW, do you have your own milling machine? I am contemplating purchasing a "Smithy" style 3-in-1 machine (mill,drill,lathe) and would like some opinions on their functionality.

Later,

Nathan Acree
Albuquerque New Mexico
 

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Baz, without braking out the measuring tape, I couldn't tell you if it will fit without major surgery in the engine bay. It would be interesting to see that application.

Nathan, I'll be going to the airport shortly and then I'll put a couple of pics up in the Phase for the exhaust system. BTW I've got a Sherline mini-lathe with a lot of the attachments so I can do some machine work, but it's mostly small stuff. I had to do the manifold holes by using a machine vise taking the manifold out and turning it around to get all the holes. A machine shop set up is nice to have. I can do small boring, milling, and thread cutting. The original reason I got it was so I could make miniature aircraft wheels on a 1/12 scale model of the Blackbird with operating model jet engines. But that's on hold now until the GT and monza get done. Gotta go, catch ya later.

Ron
 

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I have a 98 Buick Regal GS, which is mechanically identical to the Grand Prix GTP that you are looking at (Supercharged 3800 Series II). I will say that the engine is an absolute delight, but the FWD transaxle leaves a lot to be desired. I just had to put a new transmission in mine at 95,000 miles.

I still have the junk tranny if you would me take at look at the bellhousing pattern. The GT would need some healthy chassis reinforcements to handle the 280 ft lbs of torque at 3400 RPM
 
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