From: John De Armond
Subject: Re: camry engine for generator?
Date: Sun, 09 Jul 2006 03:47:56 -0400
Bill, the folks who replied in the negative have obviously never
actually built a generator using a car engine. I have.
If you do it properly and that engine isn't ragged out to begin with
then you'll have one of the quietest and fuel efficient gas generators
out there. The tradeoff is weight and complexity.
A few years I built a 10kw generator using a Toyota Corolla engine. I
designed a timing belt pulley adapter that mounted on the flywheel and
lashed the generator and engine together with a suitable timing belt
(cog belt). Timing belts are generally more efficient and less noisy
I found that the engine made sufficient power to turn the 10 kw
generator while running at 1100 RPM so I selected the pulley ratio
accordingly. I kept the entire electronic fuel injection and cat
converter because where I intended to use the generator (concessions),
the lack of exhaust fumes meant that I didn't have to locate the
generator so far away from populated areas.
With a fiberglass-lined sheetmetal enclosure around the generator, it
was hard to tell that it was running from 20 ft away. It's been too
long for me to remember the specific fuel consumption but I do
remember that it was one of the lowest I'd ever measured.
This was such a nice generator that someone offered me a LOT more than
I thought it was worth so it found a new home. I bought a Generac
QuietPack RV generator to replace it. This generator uses the same
design philosophy - a large engine running slowly but being based on
an industrial engine (briggs Vanguard) and being carbureted, it is
significantly less fuel efficient. No surprise considering how much
R&D money is spent on making car engines efficient.
I would NOT waste time and money trying to build the generator around
the car and transaxle. Remove the engine, fuel system and computer
and scrap the car. Use the money you get from the carcass to have a
proper pulley adapter machined. Save the motor mounts, as they make
mounting the engine to a new frame much easier.
In addition to the engine and the generator you'll need a governor.
Belt-driven self-contained governors are quite common, being used on
larger welders, some tractors and all sorts of stationary engines.
Hoof is a major brand name. Here is an example:
Here are some photos of the belt driven version:
This one has a splined shaft which makes fitting a pulley only
slightly more complicated. Surplus Center frequently has the belt
driven version. I bought a number of 'em the last time they came up.
If all else fails, you can always buy the governor as a spare part for
a tractor or a Miller or Lincoln welder.
This governor generates force proportional to the RPM over a narrow
range. All you have to do is drive it from the accessory belt at the
proper speed, connect the output arm to the throttle and balance the
force with a spring to set the speed.
I haven't seen your particular car so I can't say whether it's a
suitable donor but in general, a car engine is an excellent prime
mover for a generator.
Something else to think about. Many moons ago I built what I called a
universal construction site power pack. It supplied 120vac, welding
power and compressed air all from one package.
I used a conventional generator and an aircraft starter for the AC and
welding current respectively. For the air compressor, I converted two
cylinders of the small block chevy engine.
This involved removing the rocker arms, fitting each intake valve with
a very light spring, light enough that it would be pulled open on the
intake stroke, taking the compressed air out through the spark plug
hole through a check valve.
I controlled the air pressure via unloader cylinders that held the
intake valve open when the pressure reached the setpoint.
I cut the intake manifold runners for the compressor cylinders, brazed
in plates to close them off on the carburetor side and brazed in
fittings so that I could fit individual air cleaners to each intake.
This let the compressor cylinders draw clean air independent of the
I realized after the fact that with less work I could have fitted a
Buick V6 intake manifold and dispensed with the cutting and brazing. I
gave some thought to using V6 heads and machining flat plates
containing single valves for intakes on the rear two cylinders but I
never tried it. The V8 head, suitably modified, worked well enough
that I never got motivated.
I removed the heads and brazed up as much of the combustion chambers
as I could to raise the compression ratio on the two cylinders and
improve the efficiency. This was not strictly necessary, at least for
100 psi air, and if I did it again, I'd probably skip this part. Lots
of labor for little return. For higher pressure, raising the
compression would be necessary but steel-filled epoxy (JB Weld or
equiv) would have done the job since there is no combustion heat in
I built this rig on a small trailer for a friend of Dad's who was a
general contractor. This was in the mid-70s. He ran it for years.
When he died, it was sold as part of his estate and I lost track of
it. I'd not be surprised to find that it was still running. The
engine only turned about 1200 RPM so it should have lasted for
thousands of hours.
On Sat, 08 Jul 2006 08:03:12 -0500, Bill wrote:
>Thanks for all the replies. After consideration, I'm leaning toward
>selling it thru an ad. Maybe I'll get $100. I guess it would really
>be over powered unless I went off grid, which I'm not prepared to do.
>It's pretty junky so not worth the new trannie. (I'd actually given
>it to my nephew and trannie went out on him after 50 miles or so,
>hadn't been driven much for 2 years.)
>Tractor PTO generator sounds interesting ... I have an old Farmall M,
>so no diesel, still an option for emergency though. If I'd grown up
>on a farm I'd probably know all this stuff ... I'm learning slowly ...
From: John De Armond
Subject: Re: camry engine for generator?
Date: Sun, 09 Jul 2006 20:08:22 -0400
On Sun, 09 Jul 2006 07:47:32 -0500, Bill wrote:
>On Sun, 09 Jul 2006 03:47:56 -0400, Neon John <email@example.com> wrote:
>>Bill, the folks who replied in the negative have obviously never
>>actually built a generator using a car engine. I have.
>ok, great info ... except now I'm undecided again LOL That info is
>fascinating though, and just what I was wondering about. The 2.0
>liter engine was still getting over 30 mph and sounded very smooth,
>always started right up. I was the only owner.
Bill, if you have the need for a medium sized generator AND you're
handy with tools AND you have the shop to work in then building an
automotive engine powered generator is a VERY rewarding experience.
If the generator is to be used heavily and/or one leg of the 240/120
volt winding is to be loaded more heavily than the other (lots of
neutral current) then I recommend not using those 2 pole (3600 RPM)
aluminum framed Italian made generators like Northern and Harbor
Those generators have long, small diameter and not very rigid rotors
that do not handle the cogging vibration that loading only one side of
the line sets up. Mine will make a loud growl sometimes, reflecting
the torsional vibrations underway. I've seen reports on the net of
the vibration twisting the shaft in two, twisting the laminations
until the field winding shorts and other bad things.
This type of generator also has the bad habit of de-exciting under
overload long before the overload would overheat it.
The big boat-anchor ChiCom generators such as the ones used here:
These 4 pole 1800 RPM generators are bullet-proof, can stand any
amount of load imbalance and if they break, can be fixed with a hammer
and a rat-tailed file :-) Everything that Rocketboy says there is
spot-on. With the slip rings feeding the field, you can control the
generator's output externally and do as much or as little regulation
as you desire.
With an 1800 RPM generator, you could run the engine a little faster
and direct-couple the generator to the engine. You'd give up some
efficiency, as 1800 RPM is getting up out of the sweet spot for max
efficiency on that engine but it would work. I personally like the
belt drive. A belt drive covers a LOT of ills. 11-1200 RPM on the
engine and 1800 on the generator is a sweet combination.
Do some googling around the net. There are LOTs of folks building and
operating homemade generators. Some are quite cleverly done.