Eco mod my predator 459cc times 2
 

I'm running 2 predator 459cc engines now.
The stump grinder and the wood chipper have predator 459cc engines.
First ecomod, the leaf, riding lawnmower, wood chipper, stump grinder and some day the pressure washer all use the U1 battery size. I have two U1 batteries of AGM construction and an old walmart flooded U1 that will probably last through this year. The newest AGM U1 battery goes in the leaf and stays there. The other 2 get passed around like a joint, all the machines have Anderson connectors so I can just plug and unplug the battery. When the flooded U1 battery dies it's final death I probably won't replace it.

The stump grinder eco mods are a 4 foot long straight pipe and the recommended #97 main jet for my 4,000ft elevation. With the straight pipe and ethanol free gas it doesn't seem to run very rich, doesn't sputter or die on start up.
The straight pipe blows the exhaust away with the debris off cutter head.
I'm going to try a #95 main jet and see if it it will run decent. If it sputters or has preignition I'll go back to a 97 or try a 96.

The wood chipper engine has the 6,000 to 8,000ft elevation #95 jet installed. Runs pretty good, wants to die on start up until the engine warms up a little.
I have ordered a go-kart pipe kit and it will get a 4 to 5 foot long pipe that blasts exhaust gas and noise straight up and away from people.
May not run satisfactory with the 95 jet and long straight pipe. I would like at least a 5 foot straight pipe because that will allow for negative super charging even at a pedestrian 3,600rpm.

I ran the wood chipper hard yesterday. Ran a full tank of gas through it and no sputtering with the 95 jet.
Still has the factory exhaust.

Ran about 2 gallons of gas through the woodchipper 459cc engine with the next size smaller jet for my elevation and pulled the spark plug. The ceramic is still white.
Started the straight pipe install.

Wood chipper:
Burned about 2 gallons with the 6,000 to 8,000ft jet but otherwise stock and about 1 gallon with the 75 inch straight pipe.
It's struggling a little more on start up.
https://ecomodder.com/forum/attachme...1&d=1687745021

Probably got a free engine and is simping:
https://youtu.be/VpN-9ce0Uq0
https://m.youtube.com/watch?v=VpN-9c...ature=youtu.be
The video has been up for a year, has 60k views so he definitely sold a few engines.

Hemi head
Pretty tough looking rocker setup
Cast valve cover
Light weight race piston
Pressurized and splash oil system
Big 1.25 inch exhaust port
Electric start, because you ain't pull starting it
Big gas tank
Very simple wiring
You can clearly see it doesn't have roller bearings. RB doesn't try to hide it but also fails to note it.


Grumpy old man yelling at a piece of machinery:
https://youtu.be/w04p1BPJp-0
https://m.youtube.com/watch?v=w04p1B...ature=youtu.be

"Piston is 80 thousands down in the hole"
Mmmhem, aftermarket anyone?
Sounds like an opportunity to bring the piston further up in the hole, one way or another.

"Doesn't have roller bearings and the crank isn't cross drilled".
The only reason to give up roller bearings on the crank is so you can cross drill the crank and give the rod oil pressure. The crank isn't cross drilled.
Designed obsolescence or aftermarket opportunity?
Again no cross drill on the crank and the piston is 2mm down in the hole? Can I get an aftermarket +2mm stroke crank that's cross drilled with an appropriate rod?

Who's more correct?
I think red goat nailed it but grey beard had some good points too.
The predator 459cc is great for its intended application.
The performance parts availability kind of sucks, that doesn't really apply to me.
The kings of performance are still the Honda gx390 and predator 420cc.
But that could all change in 2 weeks like watching tucker Carson on Fox news with a budlite.

Hemi head, how about hemi piston for the 2mm? The harley guys stroke engines by welding the crank pin on one side. Do it wrong and you destroke.

Lawnmowers are known to be splash lubed successfully, mines 20 years old. My airplane engine was demonstrated and certified to run at least 30 minutes on reduced power with no oil pressure.

As far as I can tell little engines like these don't have a crank pin like a bike engine. It's all one solid piece.

If you put a +2mm stroker crank increased displacement to 471cc and that would reduce at the same time reduce chamber volume 6cc and would give you a compression ratio of about 10:1.
If they tried to fill the hole by moving metal to the too of the piston you can only move about 6cc of metal, that's about like making a little over 10:1 compression the piston 1mm do in in the hole with a little 3cc hemi ridge.
That's assuming the stock engine is 9:1 compression with 51cc of total chamber volume, that's down in the hole plus head gasket plus chamber volume.

The welding technique makes things offset by adding material on one side and re machining the part to standard when you cant remove it from whatever it's attached to, next best description is regrinding a cam shaft for more lift, but not quite the same.

In the late '60s Iskaderian would take your factory stock cam, weld onto the lobes and regrind it any way you wanted

I think the cranks on these are cast iron so welding them could be a bit tricky.

How much oil pressure does a predator 459cc make?
About 50psi cold 40psi hot at idle, idle bing 2000rpm as my 459cc engine is on a woodchipper.
At full speed 3,800rpm it's about 50 hot or cold.