GM LE2 engine conversion

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Chris Matheny

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Got the mold gel coated for making the carbon fiber valve cover. I will now sand and buff this and take a plug from it to then lay up the carbon valve cover on. I shaved 2" of height at the highest point and 1.5" off what will be the front of the engine. These dimensions along with my gearbox will keep the propeller centerline the same as a Lycoming 235-320 and also the height of the engine. I haven't progressed as much as I wanted lately but I had a cervical fusion in my neck yesterday so when I start feeling better progress should pick back up.
 

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Vigilant1

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Chris,
Thanks for the update. I'm surprised GM left the valve covers so much higher than absolutely required, getting the hoodline as low as possible is an important consideration in some installations. Putiing prop at the same height as an O-320 will be a real plus.
Take care of that neck. We only get one chance to do that post-op care right. It's >possible< the medical community will be a bit busy for awhile, so try to stay out of their clutches.
Best wishes.
Mark
 

Chris Matheny

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Mark, they used that space for baffling for the PCV system. It was very well baffled since these engines are direct injected from the factory and have to keep oil off the intake valves. I'll be using port injectors and a different PCV system.
 

Chris Matheny

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Been playing with the throttle body and injectors idea, I think I'm going to make this a single injector per ECM setup at this point. Port injection smooths out low rpm idle and idle emissions but does very little for power and usually kills a little torque. I mocked up an intake today and will probably finish it this coming week. This will also shed a little more weight and simplify plumbing.
 

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Chris Matheny

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Made the prototype dual thermostat housing today. Still think I can shed some weight but hate to with the two bolt attachment and housing flex. It's very stable and would have at least triple redundancy with this design. This has a 180 a 195 and a bypass circuit. You'd know if any of them stuck and could plan accordingly. Cut almost 2" off the installed length. Will determine the fittings and sensors where I need them in the housings and machine them into place this week. I do not want any slip on hoses or hose clamps on this conversion. All The fittings will be AN fittings with safety wires. The thermostats you see will be replaced as they have been ground in areas I will not need. This did add about 14oz but I think it's worth it.
 

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Jazz30-06

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Been playing with the throttle body and injectors idea, I think I'm going to make this a single injector per ECM setup at this point. Port injection smooths out low rpm idle and idle emissions but does very little for power and usually kills a little torque. I mocked up an intake today and will probably finish it this coming week. This will also shed a little more weight and simplify plumbing.
Wait, you're switching to a single TB injector? Have you thought about fuel distribution issues that might arise?
 

Chris Matheny

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I also designed an intake manifold for it. Fuel distribution shouldn't be an issue. Sorry progress has been slow since I'm back working but it will resume very shortly.
 

wsimpso1

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Machined the pulley to fit the water pump today. The water pump will now spin an equivalent RPM of 4500 at my expected cruise rpm of 3800. Also shed another .8# with the swap.
Chris,

Am i getting this right? You are spinning your accessories faster than stock? Please explain the reasoning for doing so...

Bill
 

Chris Matheny

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Yes Bill, I will be spinning the water pump impeller at a higher equivalent speed than the engine but will not be anywhere near redline RPM on it. The tip speed will still be well below cavitation speed. I am running smaller than stock diameter coolant lines so will see more restriction. This was also because the pulley I used is an aluminum one I can source easily and shed some weight but also fit the alternator where I want. It's all a compromise isn't it?
 

Chris Matheny

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Machined the fuel injector rail with built in return style pressure regulator. Two injectors, one in use at a time. All easy to source Bosch parts. 220g total weight. Sorry for the slow progress but it's still moving forward.
 

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Jazz30-06

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Machined the fuel injector rail with built in return style pressure regulator. Two injectors, one in use at a time. All easy to source Bosch parts. 220g total weight. Sorry for the slow progress but it's still moving forward.
The piece looks great, but you might want to take a look at this: Fuel Pressure Regs - is there much of a difference?

As far as fuel distribution, my point was more related to valve overlap conditions in which you are going to have cross-talk between cylinders. Even in a multipoint system, where you are spraying directly into the port, there are imbalances in fuel caused by this. Moving the injectors even further away will only make it worse. My advice, if unsolicited, would be to make sure you have, ideally, a WBO2 sensor on each exhaust runner or, at the very least, some good thermocouples to monitor EGTs.

Not trying to be a pain, I just really like the idea of this engine and even more so the diesel mentioned earlier in this thread. Just want your chances for success to be as high as possible if I can help it. :)
 
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