Non hemi predator existence?

[J.S.@SMS]

Ok, long story short, engine on my mini bike was loosing power and ticking. Drained the oil, and it looked like a black metallic paint job, but with more metallic than black. The rod is out of round by 5 thousandths, and oil clearance is now 7 thousandths (according to my caliper). Also the cam is ruined (the lifters weren’t turning and the cam and lifters are both worn pretty bad). So I went to harbor freight for a new engine. Checked the part number on the box before I bought it, 69730. There was a picture of a hemi on the box, but I assumed it was just something to do with marketing. Got home opened it up, and inside was an engine with a hemi head. I haven’t been on here in a while, so did I miss something? Did the part numbers change, or are they not selling non hemis any more?

 

[Denny]

Yes you can buy a non-hemi predator. Just gotta look around.

 

[pearl111]

Wow sounds like maybe they changed the number on the box. The no. on the box for the hemi was always 60363.
So yea i don't know what they did with shipping box serial no. .

 

[65ShelbyClone]

So I went to harbor freight for a new engine. Checked the part number on the box before I bought it, 69730. There was a picture of a hemi on the box, but I assumed it was just something to do with marketing. Got home opened it up, and inside was an engine with a hemi head. I haven’t been on here in a while, so did I miss something? Did the part numbers change, or are they not selling non hemis any more?

Unless the 60363 hemi is now CARB-legal in CA and interchangable in that regard with the 69730, then it was a packaging mistake. What's weird is that 60363 brings up the 49-state engine with a picture of a non-hemi, but the 50-state SKU 60727 brings up a picture of a hemi. On HF's end, they don't care whether it has a hemi head or not. It only has to fit in place of a GX200 or similar. Besides that, the hemi isn't better in any way than the standard Honda design and is in some ways worse.

 

[pearl111]

Unless the 60363 hemi is now CARB-legal in CA and interchangable in that regard with the 69730, then it was a packaging mistake. What's weird is that 60363 brings up the 49-state engine with a picture of a non-hemi, but the 50-state SKU 60727 brings up a picture of a hemi. On HF's end, they don't care whether it has a hemi head or not. It only has to fit in place of a GX200 or similar. Besides that, the hemi isn't better in any way than the standard Honda design and is in some ways worse.

In what way (ways) would you consider the hemi to be worse then a non hemi? Thanks.

 

[txluke]

In what way (ways) would you consider the hemi to be worse then a non hemi? Thanks.

The biggest difference is in the head. The old non-hemi (NH) head has 24mm/25mm valves with a 5.5mm stem. The hemi (H) has 25mm/27mm valves with a 5.5mm stem. They both use a slip on type valve retainer. The newer NH heads have the larger 25mm/27mm valves but with a 5mm stem. This head uses a better automotive style retainer with split keepers. I personally like to use a new style NH head. They are basically a clone head so there are more parts out there. You can get a set of 1.3:1 stamped rocker arms for $20. If you are looking for bulletproof rockers, $30 for a set of champion rockers is the way to go. When you start upgrading the springs be sure to check for coil bind. The H have been known to bind with taller springs. You could always cut a deeper valve pocket.
Both the H and NH use the same rod. The H engine blocks will accept a clone cam so you have a wider range of options. The H crank has a unique taper so you have to use an aftermarket flywheel specifically for the H. They say that the NH flywheel taper is just slightly different from a clone but most companies sell flywheels that are advertised to fit either a clone or a NH. I have swapped 7 or 8 clone flywheels to a NH. I lap them and they seem to have a perfect fit.
The engine on my main bike has a shaved, ported NH head on a hemi block. I am running 26lb springs with a set of 1.3:1 ratio rockers. The dowel pins are in different locations on the H, NH, and clone heads so omit them and use head studs if swapping. I have an ARC rod, with the H flat-top piston on a NH crank. The H block lets me run a clone cam (Banzai 265) and the NH crank lets me use a clone flywheel (PVL cast aluminum). I did this because I already had all the parts and I didn't feel like spending money. If you are not going to build a 20hp engine, either will work. If you really want to build a powerhouse, the Tillotson engines are better built. They offer a 212 H. It takes clone cams and flywheels. My buddy has one on his mini bike and out of the box it out preformed my predator. Their 225cc has a 2mm bigger bore than the 212. They use a NH/clone type head on it.

 

[Denny]

It involves complex engine theory.
Wedge engine = gasoline or gasoline/ethanol mix.
Hemi engine = methanol or methanol/nitromethane mix.

 

[65ShelbyClone]

That's may have merit if the hemi chamber has no quench and the wedge chamber does, but there are examples of hemi chambers that do and wedge chambers that don't.

In what way (ways) would you consider the hemi to be worse then a non hemi? Thanks.

In addition to what txluke said, they have very little quench area, almost no way to put a decent short turn radius in the ports, the rocker pedestals can break off and effectively ruin the head, and it's difficult to change the valvetrain geometry because the pedestals are part of the head.

 

[Denny]

Hemi engines generally have poor quench areas without some work. I have never seen a wedge style head without a quench area. Maybe a little large but never the less there. Just my experience.

 

[65ShelbyClone]

To be technically accurate, the non-hemi 212 head isn't a wedge chamber anyway;' it's a bathtub design. The GX390 and clones have a wedge chamber and many have no quench pads. Ford 351C two-barrel heads are an example of even a canted-valve wedge head variant with no quench.

 

[Denny]

I stand by my statements. Heart, bathtub and even Pontiac dished piston all have a quench. Pontiac & hemi are the smallest. Flat head to 348/409, quench. Heart/Bathtub have more than one quench area.

 

[65ShelbyClone]

I stand by my statements.

That's fine. I just pointed-out that there are many exceptions to them.

 

[madprofessor]

All HF cartons I've seen here in Jacksonville have a pic of a NH on them, but the 60363 is accurate if it's a hemi inside. Stuck my hand thru the handhole in about 8 cartons to feel the valve covers before I found my last hemi, didn't even try the numbers because I didn't trust any of it.
Been building hemis, but a conversation with Mark at EC Carburetors has convinced me to buy a NH next because of the lower volume head. Will put a hemi flattop piston in it, .010 head gasket, ARC .020 overlength rod, and stay with the Superman .265 low end cam from diyperformance.