Electronic solutions to modifying glow engines of all sizes to gasoline
Today, 06:00 AM
#2176
Senior Member
Thread Starter
Mind you: for lubrication it is not strictly necessary. Any decent sythetic oil will do the job.
The reason for castor is its tendency to create teflon-like deposits on the hottest parts, which will be the running surface of the piston and liner. This will basically "replace" the pistonring that these engines do not have.
The reason for castor is its tendency to create teflon-like deposits on the hottest parts, which will be the running surface of the piston and liner. This will basically "replace" the pistonring that these engines do not have.
Today, 07:11 AM
#2177
Yes I understand for the effect of the castor oil like a little piston ring. Thank you!
The seal on the solenoid, it's aim to separate the inlet from the outlet of the valve, or just avoid leaking from the top of the valve?
I try a lot of things this morning, change again hose, change tank location, change position of the valve (outlet up, outlet down,...), test all the fuel line to search any leak, but nothing form me solve the bubbles problem.
I noticed when the outlet of the housing of the valve is down (toward the ground) and hose came up to the carb, I have no more micro bubbles, but every ~10s a big bubbles, like if micro bubbles agglomerate in one big bubbles.
And always no bubbles from the hose between the tank and the valve.
I'm thinking there is a micro leak but where? May be if I worn the seal during the assembly of the valve with the housing?
The seal on the solenoid, it's aim to separate the inlet from the outlet of the valve, or just avoid leaking from the top of the valve?
I try a lot of things this morning, change again hose, change tank location, change position of the valve (outlet up, outlet down,...), test all the fuel line to search any leak, but nothing form me solve the bubbles problem.
I noticed when the outlet of the housing of the valve is down (toward the ground) and hose came up to the carb, I have no more micro bubbles, but every ~10s a big bubbles, like if micro bubbles agglomerate in one big bubbles.
And always no bubbles from the hose between the tank and the valve.
I'm thinking there is a micro leak but where? May be if I worn the seal during the assembly of the valve with the housing?
Today, 08:56 AM
#2178
Senior Member
Thread Starter
Yes I understand for the effect of the castor oil like a little piston ring. Thank you!
The seal on the solenoid, it's aim to separate the inlet from the outlet of the valve, or just avoid leaking from the top of the valve?
I try a lot of things this morning, change again hose, change tank location, change position of the valve (outlet up, outlet down,...), test all the fuel line to search any leak, but nothing form me solve the bubbles problem.
I noticed when the outlet of the housing of the valve is down (toward the ground) and hose came up to the carb, I have no more micro bubbles, but every ~10s a big bubbles, like if micro bubbles agglomerate in one big bubbles.
And always no bubbles from the hose between the tank and the valve.
I'm thinking there is a micro leak but where? May be if I worn the seal during the assembly of the valve with the housing?
The seal on the solenoid, it's aim to separate the inlet from the outlet of the valve, or just avoid leaking from the top of the valve?
I try a lot of things this morning, change again hose, change tank location, change position of the valve (outlet up, outlet down,...), test all the fuel line to search any leak, but nothing form me solve the bubbles problem.
I noticed when the outlet of the housing of the valve is down (toward the ground) and hose came up to the carb, I have no more micro bubbles, but every ~10s a big bubbles, like if micro bubbles agglomerate in one big bubbles.
And always no bubbles from the hose between the tank and the valve.
I'm thinking there is a micro leak but where? May be if I worn the seal during the assembly of the valve with the housing?
The microbubbles form due to cavitation, the valve opens and closes and this creates tiny shockwaves in the fuel. If the fuel has too much volatile components, this creates microbubbles.
Indeed, these can agglomerate into larger bubbles.
The O-ring seal only seals the outside of the solenoid, it is near impossible that this O-ring is leaking, but did you push the solenoid in all the way? There is a square ridge on the solenoid, and it is imperative that this ridge is in full contact with the metal of the housing..
Did you mount the solenoid with a thin smear of vaseline?
What you can do, this is a bit of a crude method, is to mix a bit of fuel, and leave the container open for half an hour (to let the most volatile components evaporate. Then test that fuel. The engine might be a bit harder to start, but should run, and chances are, this will cure the vapour issues.
Normally however, the volatile content of gasoline is tailored to the climate and the season (wintertime, gasoline is more volatile than summertime) and I have not even seen this issue in tropical climates (one of my own planes is located in Indonesia, and functions there on the local fuel exactly the same as it did in wintertime the Netherlands, did not even need to adjust the curves...)
Which exact kind of fuel are you using? E10, 98 or Alkylate fuel?
Last edited by 1967brutus; Today at 09:11 AM.
Today, 01:22 PM
#2179
If I put the valve with the outlet up, there are continuously micro bubbles that go into the pipe and finally agglomerate into big bubbles.
Yes, I put the solenoid in the housing (contact between the square edge and the housing).
I mounted the solenoid with oil (10w40 for car engine).
I agree with your explanation about the shock wave created when the valve turns, but is it surprising that I am one of the only guys to have this problem?
I use the fuel of my lawn mower, 95E10 + 10% synthetic 2-stroke oil (I think this fuel is 3 months old)
Yes, I put the solenoid in the housing (contact between the square edge and the housing).
I mounted the solenoid with oil (10w40 for car engine).
I agree with your explanation about the shock wave created when the valve turns, but is it surprising that I am one of the only guys to have this problem?
I use the fuel of my lawn mower, 95E10 + 10% synthetic 2-stroke oil (I think this fuel is 3 months old)
Today, 03:16 PM
#2180
Senior Member
Thread Starter
The microbubbles I see in nearly all my engines. But I don't see them agglomerating into big bubbles.
If the solenoid is making hard contact with the housing, then that should be OK, especially if you used lubricant (oil is as good as vaseline, heck, a drop of spit would do the job).
The fuel should be OK, I use 95E10 as well, and my fuel jug (11 litres when mixed) easily lasts for one year or more without causing any problems, so 3 months old fuel should most definitely be OK.
I am a bit stomped here, and all I can think is to see what happens if you put a bit of fuel into an open jar for 30 minutes before filling your plane with it, just as an experiment to see whether the evaporation of the most volatile components does reduce the problem.
Meanwhile, keep working on the fuel curve, get the engine as lean as possible in the midrange. Leaner running reduces vibration.
Remember: as long as ignition timing is set properly (28 deg before TDC), it is near impossible to damage the engine with a lean run: It is not a glow engine anymore, and gassers simply stop when too lean.
If the solenoid is making hard contact with the housing, then that should be OK, especially if you used lubricant (oil is as good as vaseline, heck, a drop of spit would do the job).
I am a bit stomped here, and all I can think is to see what happens if you put a bit of fuel into an open jar for 30 minutes before filling your plane with it, just as an experiment to see whether the evaporation of the most volatile components does reduce the problem.
Meanwhile, keep working on the fuel curve, get the engine as lean as possible in the midrange. Leaner running reduces vibration.
Remember: as long as ignition timing is set properly (28 deg before TDC), it is near impossible to damage the engine with a lean run: It is not a glow engine anymore, and gassers simply stop when too lean.
