Retiring the Squirrels
Previous Project BMP Page
I have been contemplating a
horsepower upgrade for a few months now but had been hoping to put it off until
summer. events from this last weekend have moved Project Hellraiser up to
the front burner.
The #4 piston rod is now a 3
piece design. I am guessing the piston seized in the block, most likely
due to lack of oiling or galling caused by a bent rod. The rod was bent
over MLK weekend when the motor was hydro locked after I tried to start it after
a flop. The lesson here is ALWAYS pull your plugs after a roll to clear
any oil that has accumulated in the cylinders (put a rag over the hole and
close the hood to avoid spraying oil all over). I had never pulled the plugs in
the past but apparently this flop put the vehicle in the perfect position for
oil to leak down into the #4 cylinder. I figure I have been driving around on 3
cylinders since the flop, after self clearancing itself the #4 piston probably
had close to 0 compression.
I had a lot of time to think
about the engine swap on the way home and I decided to wipe the slate clean and
consider all my options. Some factors I considered:
1. Our wheeling style has
changed along with the terrain. Power to weight ratio was becoming more
important than crawl ratio.
2. My 3 seater wasn't going
to get any lighter. It was roughly 2800lbs with the Toyota axles, I figure
I am at 3200-3400lbs with the 60's.
3. Rigs with automatic
transmissions seemed to handle the verticals easier than the rigs with manual
transmissions. It also seems like you need at least a 6 cylinder engine to
have enough power to spin the tires (ignoring the exotic high hp 4 cylinder
engines out there).
4. Transmission adapters
add a lot of cost to a drive train.
5. Any power upgrade would
make my Toyota transfer cases the weak link (specifically the rear output). It
would be nice to upgrade the transfer case as well to a unit that can handle any
power plant I put in front of it. I would also like to add the ability to do
front digs. For those that don't know a front dig is a way of pivoting the
buggy about it's rear wheels by disengaging the rear driveline (either in the
transfer case or via an adaptor on the rear driveline), locking the brakes on
the rear axle and then using the front wheels to pull the buggy in the desired
6. It would be nice if the
next power plant had an easy upgrade path if more power was needed down the
Option 1 - The easiest
option was to find a 2.7l from a T-100 or Tacoma and swap it into the buggy.
Utilizing the bell housing from a 5 speed model would allow me to bolt up my
existing transmission and transfer cases making for less change over. The
size of the motor was also a plus as it would easily fit into the existing tube
work. Downsides were power, I think it would have been peppy but not an eye
popping upgrade based on this
2.7L Dyno chart I found on Jet Products website. Stock power is
estimated at 150hp and 177 ft/lbs of torque. Future power upgrades would have
been expensive (search TRD supercharger) which seems typical of most small
import motors. Lastly these motors are kind of pricey ranging from
800-$1500 at the junkyards. I have yet to see a 2.7l float thru the
classifieds, I did recently hear about a 2.4l that would have worked (same
motor, smaller bore size rated at 140hp, 160 ft/lbs of torque) but again lack of
hp at the wheels, weak upgrade path and manual transmission were strikes against
Option 2 - A Toyota 3.4l
V6 from later year T-100's was also considered. This compact V6 motor is
rated at 190hp and 220ft/lbs of torque so it filled the power requirements
nicely and would be capable of spinning an automatic transmission. Strike one
was the adaptor needed to use my existing gear driven transfer cases.
Rumors of an adaptor are out on the net but my research revealed Marlin Crawler
had some prototypes that are on hold for now. Even if the adapter existed
I am not convinced my transfer cases would have handled the power of the V6. I
also did not find any transmission adapters to put a domestic automatic
transmission behind the motor. These motors seemed to go for about the same price as the 2.7l
motors in the junkyards.
Option 3 - Chevy 4.3l (or
equivalent) with an automatic transmission. This drive train setup is
cheap because the motors were used in a large number of GM vehicles, looking in
the classifieds yields a 4.3l powered vehicle being parted out on a regular
basis. The 96+ versions are the most desirable for power output,
here is a
4.3ldyno chart. Keep in mind most buggies have all their emissions
related stuff removed so that dyno chart would look much better on a buggy-ready
motor. A variety transmissions are available and a Dana 300 or Atlas
transfer case can easily be mated to the available transmissions. A wide range
of aftermarket parts are available for future power upgrades. Perhaps the
only downside to this motor is it's size, extensive mods would be required to
make it fit but to be fair most of the 90 degree V6's will require some tubing
rework. I added the "or equivalent" to the first line in this option
because I also wanted to consider some of the other popular domestic power
plants you see used in trail rigs ( Ford 5.0's, Chevy 350's, etc).
So the search was on. The
night we arrived back from Mammoth I started browsing E-bay and the various 4x4
classifieds sites I frequent trying to get an idea of going rates and what was
available. One particular motor had caught my eye a month ago and I
noticed it was still for sale: a supercharged 3.8l found in a 1999 Pontiac Grand
Am. I started doing some research and discovered this motor had quite a
following on the various message boards and good aftermarket support.
some good information on the GM 3800 series engine I found on Wikipedia.
Stock specs were 240 hp and 280
ft/lbs of torque (non-intercooled), the dyno chart shows the real world numbers
at the wheel. Being a blown engine means added performance is a blower
pulley away, from what I read 300hp is possible without an intercooler, more if
you run an intercooler. Note on the dyno charts above and the ones I linked; I
believe they are all done in second gear and started at 45mph to show peak hp
and torque. Unfortunately this method doesn't show us the low end hp or
torque which would be far more useful for us rockcrawlers. It is fairly
safe to assume the torque and hp will fall of as the rpm's decline so the higher
the start reading the better.
Here is a really
helpful page that has dyno charts of this motor with various
Project 8 Ball.
Along with the motor came a
built TF904 transmission and a Dana 300 transfer case. The TF904 isn't the
strongest transmission out there but with stronger parts it should not be the
weak link in the chain. The Dana 300 is a great choice in transfer cases,
lighter than an Atlas or Stak box but requiring output shaft upgrades to
survive what I plan on putting it thru. The Dana 300 already had an
clocking ring which allows you to rotate the transfer case up for maximum belly
Update 4-2-06 -
This motor has been used many times in various competition buggies
so little of what I am doing here is new but this will be the first
time all of the information will be in one easy to find spot. Here
is some additional background information that may be helpful
if you attempt to use this motor. I found this information on
various internet forums and from individuals who have used this
From Tony K. at
Rock Equipment - A 700r4 from
an S-10 that had a 2.8 V6 bolts right up. The converter will need
about a 3/8" spacer built for each lug. And that case can be updated
with all the later 700r parts. The S-10 trans was garbage stock. You
can also use a 904/999 case. You will have to notch the bellhousing
on the drivers side for the starter and you should tig a support
ring around that area.
In regards to the PCM
- If you are using the 98 and older harness and PCM, then you use
can use the parts as is but need to add an anti theft module from
Speed Scene Wiring. If you use the 99 and newer harness and
PCM, then you can send the computer to Jim at Jim's Performance and
he can flash the correct info for you. He's done several for us over
Here are some links to
sites that carry performance parts and/or have forums related to the
Performance - Performance parts for the L67 Motor
Fiero - Look under "Engine Hardware 60" for some useful custom
Club Grand Prix
- forum devoted to the Pontiac Cars.
L67 Swap - a
great website dedicated entirely to swapping this motor into all
sorts of vehicles. Check out the RWD swap forum
One of the club members has a
brother who runs this motor in his sand car so we went out to take a look.
The motor seems more compact than a 4.3 on initial observation. The only
points of concern are the exhaust manifolds which dump straight out from the
sides and the intake which will wind up at the rear of the motor, possibly in
the cab. I think a set of headers will make the exhaust manifold a
non-issue and some cab modifications will be required to make room for the
intake. Beyond that I believe positioning of the drive train will be
dictated by how far back and how low I can get the automatic transmission. All
lights looked green so I bought the 3.8l drive train and am awaiting it's
arrival in the next few weeks.
When checking out the 3.8
powered sand car I took some measurements and have found some tubes that need to
be moved to make this drive train fit so modifications will begin shortly on the
chassis. Let the fun begin.
Update 3-6-06 - Still in the
process of tearing down the buggy and selling off the old drive train parts.
The motor came out last week and I was able to get a better view at the carnage.
The second bent rod could have occurred when the first one let