Hemi GX140 build

#42
Yeah, lol... You have to be really careful with nitro when the temps drop. I'll never forget one year at Rockingham on the morning of eliminations... the temps were down and the air a bit damp. I bet I heard 6 fuel engines blow up, one right at the line when he wicked it for the burnout... BOOOOM! It was a deadly morning for the nitro motors!
 

65ShelbyClone

Well-Known Member
#43
Something else they talked about was how much more durable and reliable the engine became as they improved fuel control and vaporization. The vapor burns while liquid tends to detonate and break things when the burn and/or piston is trying to compress it. A lot of those engines were running low compression (The Surfers in particular) and no quench to speak of.

Yesterday I got the starter cup finished, today the magneto bracket done and mounted. The only thing really left is to set the timing, check fluids, and see if it'll pop on gas....and I think it will.

Decades ago this is what racers used in their fuelers. Mine came in today for the more serious fuel:
 
#44
Something else they talked about was how much more durable and reliable the engine became as they improved fuel control and vaporization. The vapor burns while liquid tends to detonate and break things when the burn and/or piston is trying to compress it. A lot of those engines were running low compression (The Surfers in particular) and no quench to speak of.

Yesterday I got the starter cup finished, today the magneto bracket done and mounted. The only thing really left is to set the timing, check fluids, and see if it'll pop on gas....and I think it will.

Decades ago this is what racers used in their fuelers. Mine came in today for the more serious fuel:
This is some great info that you'd hear nowhere else. Keep it comin'!
 
#45
Something else they talked about was how much more durable and reliable the engine became as they improved fuel control and vaporization. The vapor burns while liquid tends to detonate and break things when the burn and/or piston is trying to compress it. A lot of those engines were running low compression (The Surfers in particular) and no quench to speak of.

Yesterday I got the starter cup finished, today the magneto bracket done and mounted. The only thing really left is to set the timing, check fluids, and see if it'll pop on gas....and I think it will.

Decades ago this is what racers used in their fuelers. Mine came in today for the more serious fuel:
Cool, never seen those. Kinda reminds me of the old "Fire Injectors" JC Whitney sold back in the 70's. We always used Autolites in the drag bikes. You speak of vaporization... It was Really strange, the Pro Drag bikes (carb'd) smelled way different than the Pro Fuel and Top Fuel bikes (injected) running the same fuel. All due to atomization.
 

65ShelbyClone

Well-Known Member
#46
The only thing really left is to set the timing, check fluids, and see if it'll pop on gas....and I think it will.
I used a piston stop and degree wheel to set timing at about 34°, cranked it over with a drill motor and timing light to verify, and then put the recoil on and gave it a few tugs. Despite the tiny flywheel, it's not that hard to turn over with such low compression and a stock cam. It gave me two little pops on ether and then the rope gave up. Not much to see, so here's finding TDC:

 
#47
After beating the tar out of my arm last week, I'm thinking that the magneto is suspect. Spark strength has become erratic and the engine doesn't want to stay lit. No change in air gap and you'll notice no kill switch, so it wasn't that either. I've had problems with these weed wacker ignitions on weed wackers. The eBay Tillotson clone is also junk, so this part of the experiment was fun, but over.

There's one thing I have have had excellent results with, and that's the combination of an inductive coil, 12v power, and a microcontroller. Different engine;
 

delray

Well-Known Member
#49
I see on your application trying to go with a lite flywheel setup. being that it's a honda crank and the engine not going to spin super high rev's. have you thought maybe trying a kohler aluminum flywheel. they are lite and cheap to find too. might be easier setup with that, then trying to reinvent the wheel or in your case the ignition. just a thought?
 
#50
After beating the tar out of my arm last week, I'm thinking that the magneto is suspect. Spark strength has become erratic and the engine doesn't want to stay lit. No change in air gap and you'll notice no kill switch, so it wasn't that either. I've had problems with these weed wacker ignitions on weed wackers. The eBay Tillotson clone is also junk, so this part of the experiment was fun, but over.

There's one thing I have have had excellent results with, and that's the combination of an inductive coil, 12v power, and a microcontroller. Different engine;
What uC do you use?
 
#51
Thanks for posting some feed back on that carb. The frustration level with a bad carb, and a bad spark on a recoil started engine can be high.
I always make the joke that most persistent carb problems are caused by ignition. ;)

I see on your application trying to go with a lite flywheel setup. being that it's a honda crank and the engine not going to spin super high rev's. have you thought maybe trying a kohler aluminum flywheel. they are lite and cheap to find too. might be easier setup with that, then trying to reinvent the wheel or in your case the ignition. just a thought?
Will it fit a GX140 crank? There's also the complication that I don't have the 140 magneto any more whereas I do have all the parts to run digital. I wanted to in the long run ayway; it's just happening sooner now.

Ye olden MegaSquirt-I. It's not highly regarded anymore, but still does a fine job and has tons of fun features. Table switching, launch control, flat shift, flex fuel, yadda yadda.
 

delray

Well-Known Member
#52
Will it fit a GX140 crank? There's also the complication that I don't have the 140 magneto any more whereas I do have all the parts to run digital. I wanted to in the long run ayway; it's just happening sooner now.
I do remember the kohler aluminum flywheel fitting the greyhound crank for sure and if I am correct that crank is the same has the gx200. i'm assuming your gx140 also has the same tapper shaft as the gx200? either way here is the part number for the Kohler 1402502-S ,cheap on ebay $25 or offer.
little off the subject,but have you seen the new small block clone motor that now comes with a larger head bolt pattern and thicker cylinder casting for bigger bores. when that motor hits the market it will kill everything else .
 
#53
I do remember the kohler aluminum flywheel fitting the greyhound crank for sure and if I am correct that crank is the same has the gx200. i'm assuming your gx140 also has the same tapper shaft as the gx200?
What little I've been able to find over the years suggests that the 140 has a smaller flywheel taper, perhaps similar to a GX110 or 120.

little off the subject,but have you seen the new small block clone motor that now comes with a larger head bolt pattern and thicker cylinder casting for bigger bores. when that motor hits the market it will kill everything else .
No, hadn't even heard about it.
 
#54
I do remember the kohler aluminum flywheel fitting the greyhound crank for sure and if I am correct that crank is the same has the gx200. i'm assuming your gx140 also has the same tapper shaft as the gx200? either way here is the part number for the Kohler 1402502-S ,cheap on ebay $25 or offer.
little off the subject,but have you seen the new small block clone motor that now comes with a larger head bolt pattern and thicker cylinder casting for bigger bores. when that motor hits the market it will kill everything else .
A Greyhound crank and GX200 crank are identical.
 

Top