Introduction | Buick V6 Engine Swap Information | The Conversion Or Swap Concept | Summary Of The Swap Process | Special Rules for Swapping A Nissan 720 | What Is Takes To Get The Swap Done | Keeping Your Spouse Happy While You Swap | Time | The First Step In Doing The Swap | Systems that Must be Modified
Nissan 720s were marketed in America from 1979 to 1986. 720s were replaced by the Nissan D-21 Hard body.
An old Nissan Truck can be built up to run with the big bad Jeeps
or Toyotas.
The only difference is that you have to do the modifing yourself, instead of buying aftermarket build up parts.
In reality, any extremely modified truck is going to have to
be custom built anyway, so it may as well be a Nissan anyway--
that is
it you like Nissans-and just so happen to have one. I bought my
1983 Nissan 720 as a stock vehicle from my brother-in-law. I need
a mini-truck, and he needed the cash. When I got the Nissan, it
had its stock 2.4 liter Z four cylinder engine and a five speed
transmission. It ran good for another 50 thousand miles or so.
The first engine I swapped into the truck was a 1977 231 ci
(3.8 liter) Buick V6 engine. At first I kept the Independent
Front Suspension, but later
I swapped in a 1980 Toyota Front Solid Axle.
The Truck is now powered by a custom fuel injected 1975 231 ci
(3.8 liter) ODD-FIRE Buick V6 engine.
I first swapped in a Saganaw 4 speed manual transmission
(out of a 1972 Chevelle)
But NOW it has an sm420 Granny Tranny out of a 1958 Chevy 1 ton
truck.
The Granny Tranny is a 4 speed. First Gear is "Grandma
Gear" with a 7 to 1 ratio. This gives the Nissan about a 60
to 1 crawl ratio-- that is lower than an old CJ3a Jeep.
The Nissan 720 is now lifted about 5-7 inches and has a Toyota Solid axle and leaf springs installed under the front end.
The truck has "cross over steering". Cross Over
steering uses a single piece tie-rod between each wheel steering
knuckle--- and a single steering control rod that goes up to the
steering gear from the passenger side knuckle.
The wheels are 10 inch wide, with a of 35x12.50 Dunlop/Remington Mud Brutes mounted
The engine has dual exhaust that crosses over to the driver's
side and exits out the rear. The system has two CATs.
The original Rochester 2 barrel carburator was swapped with a 1991 Chevy Throttle Body Electronic Fuel Injection unit. The unit is timed by a Holley Crank Trigger because the engine is an odd-fire.
Steve Redinger
Feburary 1, 2001
1968 Buick V6 225 ci "odd-fire"
A Buick V6 is only 35 pounds heavier than a stock Nissan 2.4
liter four cylinder engine.
A bare Buick V6 weighs 370 pounds.
A Chevy 4.3 liter V6 weighs 425 pounds. A Chevy small block V8
weighs 550 pounds.
The Buick is vertically shorter and not as long horizontally than
the Nissan four cylinder engine
The Buick V6 comes in 155-175 horsepower versions.
With cam, manifold and Headers a Buick V6 can produce 250
horsepower.
Turbo-charged versions are often 300-500 horsepower
The Buick V6 is well known for its high torque at lower RPMs.
The Buick V6 has been a popular conversion engine, performance
parts are widely available.
Many Indy 500 cars use Buick V6s.
Jeeps and Jeepsters came from the factory with Buick V6s from
1967 till 1973.
Buick V6s have been in production from 1962 to 1989 for RWD and
are still in production for FWD vehicle.
Not like an Engine overhaul. With an engine swap, the physical dimensions, placement of components of the new engine and transmission require extensive changes to the major systems of the vehicle. "Massive Retrofit" are suitable words to describe the conversion process.
Engine swaps are for people who like to do machanical work, welding and fabrication for the sake of the work itself.
The Nissan model 720 1980-1986 has a "divorced"(I
hate that word) transfer case. The transfer case is mounted on
its own and is a separate unit from the transmission.
Any engine and transmission can be mated to the transfer case
with this truck. With the stock Nissan arrangement, the
transmission and transfer case are attached by an 18 inch long
drive shaft.
With the Buick V6 engine a General Motors (GM) transmission must
be used. I used a Saginaw 4 speed manual tranny out of a 1972
Chevy Chevelle. You could use a SM420 granny tranny too, or a GM
automatic.
The conversion in a Nissan 720 is made by building a
driveshaft between the Stock Nissan Transfer case and new
transmission that is bolted to the Buick V6 engine.
No transmission adapter plate is used.
This means that it is cheap to convert a Nissan truck to a Buick
V6. I spent less than $500.00
BE ADVISED THAT:
Doing engine swaps is not for everyone who likes to do machanical
work. It is an unreasonable amount of work.
THE TOOLS AND SKILLS NEEDED TO DO AN ENGINE CONVERSION to a Nissan 720
Learn to Ware safety glasses
Block-up your vehicle when you have it jacked-up or have lots of
life insurance.
You must be a weldor ( and Spell it with an "O") and
have access to a Welder( the machine is with an "e")
Dedicated Garage Space Extra running automobile Engine Hoist,
chains ect. Arc Welding Machine Oxy/ACE optional Friction Saw
Socket sets, assorted wrenches Drill motor and bits Jacks/ Jack
Stands Utility Trailer/running Pick-up Eye and Breathing
Protection Assortment of angle iron, square tubing, strap iron
C-clamps, a bench vice Wooden blocks 4x4 inches Fire extinguisher
Assortment of nuts and Bolts 1/4 inch 3/8 inch dia. Lots of black
spray paint and extra things like that.
Good social skills with spouse-do not get divorced over some old truck project. Know when to quit before dinner gets served. Do not talk to your wife about your swap very much. Buy your wife flowers twice a month. Take your wife out on Friday nights-- then work on your truck on Saturday--- but not all day. Use social skills to make network of friends with cheap parts, materials, tools. Just when your wife thinks that you are going to work on your truck all Saturday, once a month drop being a mechanic 1/2 the day and give her 100% attention. Even though Nissan trucks are neat, I'd rather sleep in Bed than in the cab of any truck..-
If you are single, are an automotive professional, have a heated shop have a comprehensive set of tools, cranes and hoists. 16-20 days If you are a family person, have a dedicated garage space and tools, a hoist, you will work on this a hour of so a couple nights a week, one Saturday a month, and eat your supper with the spouse and kids--- 6-9 months. It only takes 90 days to get a divorce, and child support is more than a payment on a new truck. Happy machanics have happy marriages.
While your Nissan is still in service Clean your old engine compartment in several stages over several days/weeks Spray paint clean places where raw metal is exposed. WD-40 screws/ bolts that you will have to take apart. Label wiring. Clean-up your V-6. Build Hoists Set-up work areas Get chains, blocks If you don't have an engine stand, figure a way to support the engine upside down for modifying the pan and sump. You do not want to hurt your carburetor and valve covers. Collect small containers 6x6 inches for parts.
Engine CompartmentThe Oil PanMotor MountsTransfer CaseDriveshaftsExhaustClutch Linkage
Cooling-radiatorFuel SystemCharging SystemPower SteeringThrottle Linkage
Buick V-6 Outside dimensions of various versions practically
the same from 1962-1989
No cutting of the firewall needed,
No frame cross members need moved.
Gasoline evaporation system hoses and gasoline fuel lines have to
be rerouted.
A couple of brake lines need moved away form the new exhaust
system route.
The emergency brake cable needs to me moved, because it hits the
driver's side Buick valve cover.
The front differential protrudes into the engine area .
The differential is to stay put so the engine pan will be
modified-or the whole engine elevated. I modified the pan.
Systems that Need Modified List
The Oil Pan
THE BIG CHALLENGE
This is about modifying Buick V-6 oil pan and oil pick because
the front differential is in the way. Oil pan/pick-up tube
modifications will make it possible to fit the engine under the
stock hood. The stock 2.4 liter 4x4 pan and a Buick pan are
mated. The welding is extensive. I arc welded mine, then brazed
the seams, if it springs leaks I will JB weld epoxy the outside
of the pan. A special bracket was constructed to prevent warping
of the pan flange(where it bolts to the Buick engine) This is a
pains taking job. In the mating several "patches" were
required to fill the gaps were the pans do not meet. I created a
fist sized hole in the right-rear lower corner of the pan until I
designed the oil pick-up tube. The fist sized opening allowed me
to see and place the end of the pick-up tube. Afterwards, I built
a hole cover and arc welded it, then brazed it water tight.
I used Nissan and Buick oil tube parts in the fabrication of
the new oil pick-up. The tube is made of three curved tubes that
are brazed into one long skewed "S" curve tube
assembly. I carefully arc welded a 1/4 inch dia bolt to a third
main bearing cap stud hex head, This 1/4 inch bolt is the anchor
for a support bracket so the extended oil pick-up tube won't
break. Welding on a stud should be done with care not to damage
the strength of the big bearing cap bolt. I removed it for the
welding procedure, reinstalled and retorted it. Welding on such a
bolt is Bad engineering, and must be done with extreme care.
Make preparation with a wet wrap to protect the bolt shaft from
heating. A iron bracket was fabricated and brazed to the tube and
bolted to the welded 1/4 in stud.
Prime your engine oil pump with petroleum jelly--- just take the
oil pump cover off and pack the gears with vasoline-- otherwise
you might burn you bearings if the pump drys out and will not
suck oil up that new oil pick-up tube.
Systems that Need Modified List
Motor Mounts
I built a saddle style mount that rests on 1950 Willys Jeep
generic mount pads. I used the same mount pads for the tranny
too. The saddle has a bracket that attaches the standard mounting
bolt holes that Buick uses for regular motor mounts. 1/4 inch by
2 inch strap iron was used for the construction.
Systems that Need Modified List
Leave it as is.--
Systems that Need Modified List
Only the drive shaft between the transmission and transfer case will be modified. This is the second most critical aspect of the conversion. For the transmission end of the Main drive shaft, a Chevy spliced yoke /shaft is used, for the Transfer case end, the original yoke and shaft is used. In other words, a Chevy and Nissan drives are mated at the needed length.
Systems that Need Modified List
Run pipes out the back or the engine and build a cross over pipe under the engine and tranny--to run a single 2" pipe down the left side thorough a cat and muffler.
Systems that Need Modified List
The standard Slave cylinder will be tried with adaptation.
Systems that Need Modified List
Buick 225s run cool, but 3.8L series run need more radiator. I plan on eventually using a 4 core super heavy duty custom radiator. Note: Recently I got another radiator out of a 1985 Chevy Malibu that had a 4.3 liter Chevy V6-- it is the right size and will fit in the truck too.
Systems that Need Modified List
Stock Electric fuel pump for a Carburated engine. An Airtex fuel injection pump for a TBI unit if you go fuel injection.
Systems that Need Modified List
CHARGING SYSTEM
The one that came with the Buick V-6-- the one wire Delco
Alternator.
Stock Nissan that came on the rig. The Buick(GM) pump will be used. Hose fittings adapted by Brazing hydraulic tubing..
EMISSIONS
The TBI, CATS, MAP sensors and O2 sensor make it legal-- but not in Califorina.
I like little ball joints but at first will just shorten the stock Nissan throttle cable set-up.Adapting a Chevy Truck throttle cable is also one way.
Systems that Need Modified List
http://www.off-road.com/4x4web/toyota/buick_v6_swap.html
You can e-mail comments or questions to me at: srrco@hotmail.com
Systems that Need Modified List