Outer Limits 4x4 Board

My young feller is about to have his 1st birthday and we are having a pig on the spit. Instead of hiring one for the weekend like any sane person Ive decided to build my own so I can take it to mud bulls and up the beach. For the motor I have used a serria windscreen motor figuring they run for long periods when its raining. I ran it thew a series of chains and sprockets to get about 1 rev per 10 sec. I gave it a test and the motor gets quite hot. Is this normal? Also is it safe to run this motor of the 12 volt output on my little scorpion genny?
Cheers Rhett

What do you call quite hot? Can you still hold it?

my mate has one used for this, its a fairly large spit too... its not geared down at all, just we run it off a 6??V bat, the ones ya get in ya dolphin torches. its perfct speed then. and coz its a high torque motor it turns the meat no probs...

you can hold it for about 2 sec before its too hot. my guess would be about 80 degrees

are you driving it through the control stuff hung off the motor or direct to the motor?

does it get hot running off a battery?

I would use a battery ..
if it is to hot to hold for more than a few secs . it's days are numbered.

I just found which of the two wires out of the four gave me movment and used them. I m not sure if it gets hot on a battery or not. What about a transformer so I can still use 240v will that damage my motor? I will put pics up tomorrow. I only have the lid left to make. Any Ideas on what sort of glass to put in it?

some pics


good use of a supercheap socket and wobble bar

Is this enough flame? this is on low I have to drill the rest of my burners yet I broke my drill bit last nite

1stly Great Work! I have seen a similar set up using an bed of BBQ Rocks in the tub - it gets bloody hot! and the meat had to be raised about 1m off the pit of coals to stop it burning. not sure how those flames would go, IMHO i think you may need a bit more flame to get a reasonable cook temp. Just my 2c

What we did was have the tub on chains that hang off the legs. When the rocks are burning reall hot, we lower the tub down to the ground and as they peiter out we raised the bed up by shortening the chians closer to the meat (also as you cut the meat down to a smaller diameter) this technique allows you to regulate heat on the meat.

You will need a drain hole in the tub for the fat etc - there is a lot especially on lamb!

i would suggest heat beads! use the gas to light heat beads . looks really good

That looks like a sweet setup.
I would make up some sort of "finger protection" to go over the chain drive .. could end up nasty, kids (of all ages) love to get a "better look" at those kind of thing by stiking their grubby mits into em.

as for the glass .. Round here we have a "junkyard" of sorts that has a few slow combustion heaters rusting away .. Snag the glass from one of them ... will take pretty high heat and is cheap to ( I go a whole unit for $25 to heat my shed) I ended up using the door on the one in the house as my wife broke the glass trying to use the door to push a log into the fire

Looks awsome mate. If the motor is getting that hot i doubt it will last long.

Is the heat due to the extra load of turnging a spit instead of a wiper blade? how hard is it to turn the set up by hand? thats how much load (torque) the motor is having to put out.

Im assuming these tests have been on an empty spit? The load will increase when weight is put onto the spit as the inertia will increase as well as the friction on all of your shafts.

How are the shafts mounted? staright onto metal, or through bushes or with bearings. the way they are mounted may be adding to much friction and thus extra load on the motor.

a few possibilites anyway.

Some kind of splash guard for the burners to stop fat putting it out may be needed.

Im thinking of putting a tray in the bottom with sand or kitty litter to stop the fat catching fire. I don't think the motor was getting hot due to extra load I think it was the genny putting out more than 12 volts. Ive got it all together now all I need is some glass. No stoves at the dump today . Hi gets it up to bout 280degs and Im waiting for it to level out on low and see what temp it is. I got on of those bbq temp guages mounted in the front.
I can amost taste the crackling

Rhett wrote: I don't think the motor was getting hot due to extra load I think it was the genny putting out more than 12 volts.

I would have thought a 12 volt gen would have a capacitor/regulator or what ever they are called to regulate the voltage output. otherwise what use are they to any 12 volt appliance. Does it get as hot when running of a 12 volt battery? If not does it also turn slower?

awsome project mate

It does spin faster with the genny than with 12 volt battery. I was thinking of using a transformer and backing it off to only 9 volts

Rhett wrote:It does spin faster with the genny than with 12 volt battery. I was thinking of using a transformer and backing it off to only 9 volts

Give it a go and see what happens ..

Mate of mine had a similar settup.. go a 12v bat, the 9v will make the motor shag out sooner... traditionally where the axle goes over the firebox edge we put some fat of the pig to lubricate... looks the business by the way...

Make sure you get pics when you test run it!

Rhett wrote:some pics


good use of a supercheap socket and wobble bar

Is this enough flame? this is on low I have to drill the rest of my burners yet I broke my drill bit last nite

You might've planned this? But it would be advisable to have a adjustable weight block attached to the non driven end of the shaft.
Trying to get the weight even by feeding the shaft thru can be very, very difficult depending on what your cooking. and this will affect
rotation/torque/ smoothness.

the weight is a good idea I have enough shaft to do this. I have finished it other than the spikes to hold the pig from spinning. Any one know what these should look like?. Might change a sprocket or two as well and drop it a few rpm. It is running at the moment whith chicken pieces threaded on the bar. Some finished pics


glass didn't fit in the middle with the temp guage.

vent at the top to regulate oxygen and heat.
i also cut the motor housing off and made it removable for transporting to Landcruser park

In this pic you can see the holes I cut in to alow oxygen in the bottom.

ok pig on the spit sounds the goods now stop playin and get back onto the zook

the holding spikes are either 2 or 4 prongs.
using wing nuts to secure in place!
You could make a small flat edge to help hold onto shaft by using a grinder ?

while eating my chicken I came up with a great idea on saving power and keeping motor cool. tomorrow Im gunna pull relay out that makes wiper run intermittent and hook it up to the spit. So it does a bit of a turn waits a few seconds then a bit more of a turn. The chicken was great, sorry I didn't get any pics as it tasted to good

Looking bloody good Rhett.
I reckon you will have to mill at least one side of that shaft flat so the bolts/wingnuts don't slip on it.
Spits I have hired had square shaft so the spikes couldn't slip and little bolts to hold them tight in the meat.


Pics of spike arrangement.....

or... you could drill holes throught the shaft at 12, 3, 6 & 9 positions and then thread spikes through the meat and through the holes then lock of the spikes with wire or similar? they wont spin on the shaft then

My dad made one years ago (open topped/wood fired) from an old 45Kg gas cylinder that would not pass "the test"
He welded a small bar across the big long skewer pole and litterly tied the meat to it with some wire.

I made a spit recently (not as flash as yours, and uses a REAL (wood) fire

I made the spit/shaft from 25mm ID / 30mm OD stainless. For the spikes I used 8mm stainless solid bar. I welded one set (4 spikes) on the shaft at one end, and put the others on a clamp bracket that uses an 8mm bolt to clamp it. They alone would have held everything fixed, but I also drilled a few 8mm holes through the spit, and made up a few spikes that could be driven through the beast and the shaft.

Hope that makes sense? I will be cutting off the fixed bracket and making it slide as well for next time.

Still having motor problems. It runs on a 6v 8ah battery fine and doesnt get hot as I cooked a leg of pork yesterday(Tasted good too). But it only lasted about two hours, so I went to jaycar today and got a 3-12 volt 4 amp transformer and gave it a go this sarve. It seems to get hot on the 12 volt setting and stalls and won't restart under load on the 6 volt setting. What sort of transformer do I need? As I don't want to rely on batteries

The wiper motor draws more current then the transformer can supply.

My advice would be use a car battery and run a battery charger on it.

Whilst the charger won't keep up with the current draw (unless it's a biggie!) it will extend the run time sufficiently to cook the pig.

If you use a decent sized battery and a 7 amp charger you should get 20 or so hours out of it before the battery goes flat.