GX140 Hemi build

[65ShelbyClone]

For a week I have been looking for the old harness, coil, and switch box built for that engine n the last photo.

Found 'em! The modified GX340 side cover was a bonus since I thought it got tossed long ago.

*squints*.....What does that say?

I put the stock GX140 flywheel assembly back on and need to get a crank trigger rigged-up.

I expect that to be on the the menu for this weekend. Once a hot ignition is up and running, getting the engine to fire will be much, much easier. I may use a regular round initially since the ECU is already set up for it, but for later I have a D585 Chevy LS2 coil with integral logic-level(5v) igniter and it's an arc welder! It has the fattest sparks I've seen and it blew the fuse in my power supply. Picked up a variety of spark plug wires for it today and am waiting for some Hall effect sensors in the snail mail, but those won't cause a delay.

And here, photo of an old failed experiment. Because reasons.

 

[Flyinhillbilly]

I like the time bomb logo.

 

[65ShelbyClone]

Thanks. That's exactly what it turned out to be, but the fuse was really short. It broke the rings running isopropanol fuel and hurt the soft CoolBore cylinder early on.

and am waiting for some Hall effect sensors in the snail mail

Oops, turns out they are three-wire VR sensors with the third wire being a shield ground, not a signal output. That's okay because I just outfitted the spare MegaSquirt with toggle switches for all the tach settings. Instead of soldering, unsoldering, and resoldering jumpers everywhere(and risk damaging the board each time), a flip of the switch will do. Still have to do it for the ignition output, but that's more complicated.

I had found out that the industrial inductive proximity sensors I planned on using actually can't trigger fast enough to use anything more than a four-tooth trigger wheel. That's a pretty low count, so I opted to wait and do it right which is why there's no video of it running yet.

 

[karl]

What version of megasquirt is that?

Im never used one, just wondering how it will control a single fuel injector, I thought most use them on multi- cylinder engines, do they fire sequential, simultaneous, or what? Or can it be set for a single injector?

So for now your going to use the megasquirt to control ignition?

Keep us updated!

 

[65ShelbyClone]

What version of megasquirt is that?

It's a processor version 1 (MS1) with board version 3.0 and MSExtra firmware version 029y4.

Im never used one, just wondering how it will control a single fuel injector, I thought most use them on multi- cylinder engines, do they fire sequential, simultaneous, or what? Or can it be set for a single injector?

They were designed to be highly flexible for controlling engines from 1 to 12 cylinders plus ωankels (The "W" spelling gets blanked-out on here lol). It has two injector channels that can be fired together or alternately, but the processor isn't gutsy enough for sequential. It can only do sequential spark for up to four coils.

So for now your going to use the megasquirt to control ignition?

That's the plan. I've done it before and it works quite well. I can command 10° of advance while tugging the rope and have it advance to ~20° or something as soon as it fires. Then there's 3D timing map(s), zero timing jitter, multiple rev limiters, stall recovery, all kinds of things.

 

[65ShelbyClone]

Put in some time crankin' handles this afternoon.

The trigger wheel is really chunky because the sensor above was intended to read reluctor teeth on a car's flywheel. Generally the teeth need to be as wide and long as the sensor tip, so a 3.25" diameter 12-1 (twelve minus one) configuration ended up like this. It's low carbon steel so the sensor's magnet will be less prone to magnetizing the wheel. over time. I'm not afraid to say it; it was a PITA making this without a rotary table.

 

[65ShelbyClone]

It's aliiiiiive.
https://youtu.be/jyh3ZiCTL0w

That's the real first start right there. Being indoors overloaded the mic, so the first and last two seconds are closer to how it really sounded. It's pretty lazy because the map only has 9-10° of advance just to get it fired for now.

 

[65ShelbyClone]

It's been a while a here's why:

It's a dual standoff/shower/etc injector setup that bolts onto the carb. The injectors are always in atmospheric pressure, so no manifold-referenced pressure reg is needed. The injectors have separate feeds so running two fuels is possible. They are also angled toward each other slightly. Obviously the center hole still needs to be bored to size and injector holders needs to be made.

I was going to wait until it was finished and on the engine, but I don't know when it will be finished. Hoping for the next few days, but other stuff might get in the way.

 

[65ShelbyClone]

Needs some minor adjustments, but otherwise ready for plumbing & wiring.

 

[JTSpeedDemon]

Soo, what are you planning to put this BEAST fuel injected-hemi GX140 on?

 

[Tpdingo]

Needs some minor adjustments, but otherwise ready for plumbing & wiring.

The right injector due to its red and green colors just has my brain screaming "ITS A HOT SAUCE INJECTOR SO THE ENGINE CAN RUN HOTTER(and subsequently faster!!)"

 

[65ShelbyClone]

The hot sauce injector in going to be used for warming-up the engine, so you're not far off.

Soo, what are you planning to put this BEAST fuel injected-hemi GX140 on?

I have an old Zebra minibike frame that isn't worth restoring. It needs a lot of work and I envision a drag-style frankenbike.

 

[JTSpeedDemon]

Drag style??
More like pseudo REDNECK style!

 

[J.S.@SMS]

There is not one thing about this build that is redneck style. I mean really, this isn't one of my builds. No jackshaft castle nuts are being held on by bent over nails (I'm serious about the nail). And there's no swapping parts between a minibike and two go karts, in the hopes of getting them running.

On another note, great job on the build. I don't think that I'd be able to build an engine like this.

 

[65ShelbyClone]

Aaaannnndddd update.


https://www.youtube.com/watch?v=TLp3uVPuRCo


It's not properly tuned by any means, but I thought it was a pretty successful first start on EFI considering the fuel base map was for a car. Tweaking the timing got it to rev a bit better.

 

[65ShelbyClone]

Idle vacuum is really bad for some reason and it's a problem keeping me from using MAP-based accel enrichment. I'm going to play with the tune and see how low I can get it. If that doesn't work, I'll have to install a TPS sensor.

It may not be an exciting development, but this has been 13 years in the making:

Back in 2006 I got some upgrade MAP sensors for use with a MegaSquirt-I like I'm using now. MS1 has factory support for four common sensors, but these are non-standard. Making them work involves tweaking the firmware, recompiling it, and tweaking large config files in the tuning software. There were no write-ups or support to speak of back then(and really still aren't). I revisited several times, but lack of knowledge and necessity kept shelving the project.

Since then I've learned a lot about sensors, electronics, and computer code. This week I buckled-down and got it all figured out.

The original sensor pegs at 250kPa absolute. Standard sea-level pressure is 101.3kPa, so it can read 150kPa above that or to about 21psi of boost.

The new one does a bit more:

I actually do have a combination of little turbos and a blower that could be combined into a compound turbo twincharged setup capable of pegging this sensor on this engine, but not so much hardware that could. Parts don't just break at that level, they land in the parking lot.

 

[65ShelbyClone]

Haven't forgotten nor given up. Life just gets in the way sometimes.

 

[Flyinhillbilly]

Are you the same 65shelbyclone that’s on the turbo forums?

 

[65ShelbyClone]

Yuh huh. I've seen you there too.