Compressor pump engine

[motorhedfred]

Wayne,

Based on what you know, do you think these would work ?

Honda GX 100 Engine Heads Wacker Jumping Jack Parts | eBay

Thanks,
MHF

 

[rustycase]

The redneck go-kart is great!

I like this bike a lot!


Home built engine in old Harley Davidson Hummer - YouTube

 

[wayne z]

Wayne,

Based on what you know, do you think these would work ?

Honda GX 100 Engine Heads Wacker Jumping Jack Parts | eBay

Thanks,
MHF

I don't think those will work easily as the head I found. The boreprint looks much smaller too. My heads came from a motor of about 200cc The closer holes seem to be less than the 2.5 inches of the Speedair pattern, and if new holes were drilled for the other side, it looks like the holes would end up about where the rocker studs are.

 

[motorhedfred]

Ok thanks Wayne....dang it though, a pair and fairly cheap. Since the gokart guys talk about swapping the GX120, 14cc heads onto thier bigger GX160s and 200s, I'm thinking a set from the smaller engine like your 99cc Predator might be a better choice.

I wonder if you can get replacement heads from HF ? Those Speedaire bores are mighty small, aren't they ?

MHF

 

[wayne z]

No, my speedaire has 2.75" pistons. The head I found I think was on a 160-200cc clone. low rpm engines.

Strange fact: I noticed the head stud pattern on the 79 ccHF, 89cc Tractor Supply genset, 99cc HF, and the 212 HF and my found head all have EXACTLY the same pattern. roughly 2.5 x 3.25" The valve and port sizes vary a lot though.
Pretty smart, to make a seriese of different size engines that use the same head casting

 

[motorhedfred]

You must have a much larger capacity compressor pump than mine. The bores on mine measure 1.75" on the old dial calipers, but the head bolt pattern is the same. I was actually considering sleeving it down with a couple of lengths of cast iron water pipe turned down on the outside and bored and honed on the inside. Those cylinder walls look mighty soft to me.

Honda GX35 pistons are right around 1 17/32 (1.5354) diameter and of course designed for I/C engines, but I have no idea what thier pin diameter or compression height is.

MHF

 

[motorhedfred]

I asked the ebay seller for center to center measurments for the head bolts and they're just too close together. Too many other compromises as well.

"Dear motorhedfred,

V-twin, thats sounds interesting... RC??
The two closest together measure 44mm. 70mm & 75mm on the long sides. The other two are 69mm. Hope this helps. BTW I found the reed valve for the the other head spacer.
Thanks Randy"

I'm going to look into the following....

Briggs v-twin camshaft mounted between the cylinders and driven off the output shaft by either a chain or gears depending on what rotation the camshaft needs (it's also 90 degree cylinder angles).

Honda GXxxx or clone pushrod vertical shaft heads, (intake ports on the pushrod side of the head, between the pushrods) that would put my intake ports between the heads in the vee, exhaust ports on the outsides.

As much as I'd like to have exposed pushrods or pushrod tubes on the right side like a hog, I think it's too much for the first go 'round. And I want it to look clean and not cobbled together...at least as much as possible.

If I had the equipment, it would probably be easier to just build one from scratch.

MHF

 

[cannonball2]

Just a thought and it probably wont provide the look you are after, but what about heads from the small Honda 50 -70cc motorcycle engines. They were a small bore with 4 cylinder bolts/studs. They are OHC but two exposed whirring chains would be cool too. OHC engines have been around just about as long as OHV. Maybe some fake push rod tubes would add to it.

 

[wayne z]

Great idea! I think I have some of those heads around. Might could also remove cam and extra metal and use a rocker. You could then mount the head 90 deg off standard and have the in/ex ports on either side.

 

[motorhedfred]

If I stick with the notion of mounting a camshaft in the V between the cylinders and intakes in the middle, these heads should work.

HONDA HR214 GXV120 4.0 HP HEAD | eBay

They're commonly found on Honda HR214 mowers from the '80s.

MHF

 

[motorhedfred]

I received the head in the mail today and it fits ! Two of the bolt holes line up perfectly and I'm hoping I can drill the other two out to line up with the other two holes in the top of the cylinders.

The spark plug hole and valves appear to be sitting well within the cylinder bore too.

I only paid $12 delivered, I hope I can find another one that cheap.

MHF

 

[motorhedfred]

I finally found another head, not quite as cheap as the first one but I have it. Now it would seem best to have camshaft operated intake as well (no vacuum controlled).

I've been pondering where to source a camshaft, how to drive it, mount it, lube it ect. Since the cyilnders are on a 90 degree included angle, a Briggs, Kohler, Honda ect. cam should provide the correct timing. We sell some pulleys at work that are designed for cogged belt driven fuel pumps. The small one is 14 teeth with a 1 inch hole and 1/8 inch keyway. The crank snout is 1 inch with a 1/4 keyway. The big pulley is 28 teeth which makes it a perfect ratio for driving a 4 stroke camshaft.

The next thing is how to mount it between the cylinders. I'm thinking if I could find some octagonal bar stock or tubing, I would have flats at the proper angle for the lifter bores, and some 90 degree angle iron could be used to mount it using the bolts that mount the cylinders to the block.

I feel like I got in over my head a bit here, but I think it's possible. The cylinders, crank, rods and block look stout enough to handle the switch to internal combustion, but the pistons and rings might need to be massaged or replaced. The bores are the same size as a Kawasaki KX65, but the wrist pin size and compression hieght might be different.

If anyone has any ideas or suggestions for oiling or anything else, please fire away.

MHF