Webster Engine fails to start
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crankshafter
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Hi again serhat.
I see you are using gaskets between the valveblocks, that is good. But then it hits me scratch.gif
oh:: do you have good sealing between the valveblock and the cyl.head? It come to my mind that I had some problem,and I made a small counterbore in the intake port at the cyl.head and used a small O-ring for sealing.
Just another 2cent ;D
CS.
I see you are using gaskets between the valveblocks, that is good. But then it hits me scratch.gif
oh:: do you have good sealing between the valveblock and the cyl.head? It come to my mind that I had some problem,and I made a small counterbore in the intake port at the cyl.head and used a small O-ring for sealing.Just another 2cent ;D
CS.
Longboy
Well-Known Member
..............Remove the lower O-ring from piston. Double check the exhaust valve timing. Closed by TDC. Every attached item to the axle must be tight. Your carb is the right size and distance from valve block. I'm not familiar with glow operation but with spark ignition 1-1/2 turns on the mixture and a cracked open throttle work. If you get some pops or signs of life, the valve block gaskets and valve sealing are fine. Mechanical issues with these small engines..........if it doesn't turn over smoothly with the plug removed, can mimic a carb problem in setting its needle valves when trying to start. If it runs for a few seconds and just dies and you didn't touch it, it could be mechanical. The can-o-worms here is it can feel nice when just fingering the flywheel over. But at start-up and it goes to 1000RPM, things the motor doesn't like compound instantly and it stalls just as fast. I believe true carb problems relate to fuel delivery venting and manifold sealing that affect the vacuum signal.............Back to mechanical problems, your piston and O-ring should move easily in and out of the bore by hand holding the connecting rod with glow plug removed. If it feels like it dragging thru the bore to you , engine ain't gonna like it! :-\ Dave.
If the glow plug is not glowing brightly, it isn't likely to work. Most glow plugs are designed for 1.5 volt operation and do ok with the 1.2 nominal of NiCad cells. The lower internal resistance of the NiCad helps to reduce the voltage drop at high drains and the behavior is similar to a 1.5 volt dry cell. It's difficult to find large 1.5 volt dry cells any more. They were quite common 50 years ago. You can find them, but they tend to be expensive. What I have done in the past is wire up 4 Alkaline "D" cells in PARALLEL to make a nice, fat 1.5 volt dry cell battery.If you wire them in series, your glow plug will have brilliant, but brief career. This will probably make your glow plug happier and it sounds like it needs to be happier.
Hello,
I could not find that battery from the local market and did not order it also from tower hobbies as they usually do not accept international shipment for batteries,paints etc.....
Anyway,I have installed an o-ring between the cylinder head and the manifold as suggested and of course,it increased the intake capacity.
NOW THE GOOD NEWS.
It works.
But only for few seconds and then it stops (even I leave the battery on the glow plug) and does not work again. When I leave it for half an hour and charge the battery at the same time,it works again for few seconds and stops.
Why!!!!!!
I will try to take a video and share it with you tomorrow.
I could not find that battery from the local market and did not order it also from tower hobbies as they usually do not accept international shipment for batteries,paints etc.....
Anyway,I have installed an o-ring between the cylinder head and the manifold as suggested and of course,it increased the intake capacity.
NOW THE GOOD NEWS.
It works.
But only for few seconds and then it stops (even I leave the battery on the glow plug) and does not work again. When I leave it for half an hour and charge the battery at the same time,it works again for few seconds and stops.
Why!!!!!!
I will try to take a video and share it with you tomorrow.
Hello,
Here is the video
engine runs for a few seconds than it stops.
it does not start on the consequent trials.
waiting your comments.
View attachment Benzinli Motor.m4v
Here is the video
engine runs for a few seconds than it stops.
it does not start on the consequent trials.
waiting your comments.
View attachment Benzinli Motor.m4v
Serhat---I just finished my webster build, and it runs very good, with conventional ignition ponts and a 12 volt coil with a sparkplug. You might find it a really big help if you made up an adapter for your electric drill like I did (I show a picture in my thread). This will really be a big help in getting the engine started.---Brian
http://www.homemodelenginemachinist.com/index.php?topic=8388.0
http://www.homemodelenginemachinist.com/index.php?topic=8388.0
After watching your video Serhat and listening to your symptoms of the engine dying and not starting again until the battery has been charged, leads me to wonder whether or not the plug is remaining lit for but just a few brief seconds and the extinguishes itself when the battery voltage drops off. Do you have a means of supplying a voltage to the plug other than by using a battery? An appropriately sized power supply for instance. I'm just wondering if the battery isn't being drained of power in short order and the plug cannot stay lit. When you charge the battery back up it will last for only but a few brief moments and then the process begins again. Also, if I am not mistaken, there is what appears to be a mist of fuel being ejected on first start-up. I have watched the video several times and that is the impression I get each time. Keep after it, you are very close and I would love to see it run unassisted (as I am certain you do as well )
BC1
Jim
)BC1
Jim
Hi,
Brian,
I'll do that adaptor.
Jim,
You are right.
Batterry voltage is dropping quickly.So I will purchase a new glow plug battery (maybe 1,5V instead of 1,2V if I can find) and try again.
What I do not understand is that after a few seconds run,it should continue running even I take out the charger.What do you think?
I also do not understand why the fuel is ejected on first start-up.I carefully checked the intake and exhaust timing several times and also sure about the perfect closing of the valves.
Serhat
Brian,
I'll do that adaptor.
Jim,
You are right.
Batterry voltage is dropping quickly.So I will purchase a new glow plug battery (maybe 1,5V instead of 1,2V if I can find) and try again.
What I do not understand is that after a few seconds run,it should continue running even I take out the charger.What do you think?
I also do not understand why the fuel is ejected on first start-up.I carefully checked the intake and exhaust timing several times and also sure about the perfect closing of the valves.
Serhat
Good morning Serhat, I apologize for the misleading statement I made previously regarding the voltage dropping off, what I was thinking (and not being very clear verbally) was that the current capacity (milliamp hour) of your battery cell was not sufficient to keep the plug lit for more than a brief period of time. Like a flashlight when the batteries are dying. A voltage source that has a very high MAH capacity at a 1.2-1.5volts is in order. If you are electronically inclined or know of someone that is, perhaps a voltage converter/regulator could be assembled and then use a 6volt wet cell for the input power source. I'm just throwing out some ideas here. As far as the fuel being ejected, that is a bit of a mystery but it too could be compounding the engine running problem by literally 'putting out the fire'. Like tossing bucket of water on a burning piece of wood, so is the excess fuel acting upon the glowplug. Most likely though, I think that if you can obtain a power source that will sustain the plug for several minutes you will be in business. Once the engine is to the point of continuous running, then getting it to stay running after removing the battery voltage can be addressed. It may be that a constant power source will be required for continuous running.
BC1
Jim
BC1
Jim
Hi, I am brand new to this, and this is my first post, so please forgive me if this isn't right, but I just wanted to say thank you to all who were involved with helping someone who had build a Webster engine and couldn't get it to work. I just completed my Webster yesterday and today, I was excited to put the fuel in, in anticipation of seeing it run, but it just wouldn't. I had checked the piston for compression and it seemed adequate, and it freely moved back and forth in the cylinder. I had good spark, and I rechecked and made small tweaks to the carburetor and to the timing of the ignition and exhaust valve and nothing worked. On the forum, someone made mention of the spring that held the intake valve closed, and that made me think about my own which was slightly compressed in the rest position. I was able to cut off about .1 of the height, which still left a tiny amount of compression at rest. That was it! My engine took off on the first try and I am now a happy camper. I am surprised at how sensitive the engine is to such a small adjustment. Thanks guys!
Has anyone else tried this engine with a glow plug? It just might be that the internal layout of the cylinder head won't allow it to run for any length of time.
It might be that the direction of the fuel entry is straight onto the glow tip, in which case, once the engine started to fire and run, the fuel hitting it just might put it out, no matter how much battery power you feed to it.
My dealings have always been that the temp and compression in the cylinder has to be enough to keep the platinum wire glowing thru a catalytic process after the battery is disconnected.
Some of my glow engines required them to run for a while before that critical moment is reached, otherwise the charge of cold fuel going in extinguished the glow.
Have you tried a higher nitro mix, or a plug with a heat bar across the tip to try to retain some heat, or a shorter plug, so that it doesn't protrude into the cylinder so much, to try to protect the glo tip from any cooling fuel?
Try a 5% mix of petrol in the fuel, that was used as an old trick when nitro wasn't available over here. Don't mix up a whole batch, just say 1/4 of a tank, just in case it doesn't work for you.
If glo plug running hasn't been done before, then you have no means of knowing what will eventually be required to get it to run, if ever.
Bogs
It might be that the direction of the fuel entry is straight onto the glow tip, in which case, once the engine started to fire and run, the fuel hitting it just might put it out, no matter how much battery power you feed to it.
My dealings have always been that the temp and compression in the cylinder has to be enough to keep the platinum wire glowing thru a catalytic process after the battery is disconnected.
Some of my glow engines required them to run for a while before that critical moment is reached, otherwise the charge of cold fuel going in extinguished the glow.
Have you tried a higher nitro mix, or a plug with a heat bar across the tip to try to retain some heat, or a shorter plug, so that it doesn't protrude into the cylinder so much, to try to protect the glo tip from any cooling fuel?
Try a 5% mix of petrol in the fuel, that was used as an old trick when nitro wasn't available over here. Don't mix up a whole batch, just say 1/4 of a tank, just in case it doesn't work for you.
If glo plug running hasn't been done before, then you have no means of knowing what will eventually be required to get it to run, if ever.
Bogs
zeeprogrammer
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- Mar 14, 2009
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Welcome to the forum RickA.
Congratulations on your engine!
I echo the request for pics (and video).
Congratulations on your engine!
I echo the request for pics (and video).
Hi RickA,
Welcome.
Bogstandart,
I have decided to choose the glow plug version after reading the notes of Joe Webster.
He says that the first few runs were too short but does not mention about any problem with glow plug version.
However,I agree with you on the cooling factor of the fuel on the glow plug.
I will add some gasoline ,as you advised, and see if it make any difference.
Brgds
Welcome.
Bogstandart,
I have decided to choose the glow plug version after reading the notes of Joe Webster.
He says that the first few runs were too short but does not mention about any problem with glow plug version.
However,I agree with you on the cooling factor of the fuel on the glow plug.
I will add some gasoline ,as you advised, and see if it make any difference.
Brgds
Serhat,
Am afraid I can't give any advice, not experienced at this but am sure this post will be of help when I get to that stage of building my first i.c. engine.
Hope you get it sorted quick, you can't be far away.
Nick
Am afraid I can't give any advice, not experienced at this but am sure this post will be of help when I get to that stage of building my first i.c. engine.
Hope you get it sorted quick, you can't be far away.
Nick
