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Webster IC Engine build log.
raynerd:
Yes, cheers guys. Albeit a short quick burst, it did run!
I have a few further thoughts. The fact that it runs does suggest the the timing of exhaust and ignition is OK for now. I know I`ve just been speaking to Kwackers and I think fuel could be the problem. The engine seems to behave differently and some of my best results not caught on camera (but not massively better !!) were when I was leaning the petrol tank back and the inlet was below the fuel line like in a bubble vapour carb.
Just to add that I`ve not had any luck with the lighter gas - a squirt doesn`t seem to let the engine fire, it is just dead!
I`m wondering if the inlet valve isn`t opening as it should and especially at low revs. I think it is a bit sticky. I opened it by hand on a few attempts and that kicked it up but didn`t keep the cycle going. I also felt like in those videos you have seen that I wanted to give it a pull on the throttle to kick up the revs as it seemed to run out of steam and fall dead!
--- Quote from: NickG on May 09, 2011, 07:58:19 AM ---What was your piston made from again? If it's aluminium and it's too close, it could be binding in the cylinder. It expands a lot faster than cast iron.
--- End quote ---
--- Quote from: Anzaniste on May 09, 2011, 05:51:03 PM ---The abrupt stop suggests tp me a tightening up probably as a result of piston expansion due to ignition temperatures.
--- End quote ---
I forgot to answer this earlier on - piston and cylinder are both cast iron so I`m guessing thermal expansion shouldn`t be a problem as they will expand at the same rate?
There is a little air leak from the edge of the valve block and head, I noticed just now when I saw some spare oil bubbling slowly. It isn`t a big leak and certainly not enough to considerably reduce compression but it may be worth putting another paper gasket on.
I`m also using this http://madmodder.net/index.php?topic=4838.0 Aspen's Fuel rather than colemans suggested by Jan Ridders. I`m almost naturally insulting John-Som when asking this question as he has clearly stated it is good with his Webster but could this be perhaps more difficult to combust than Coleman's especially on a young engine? Or is a fuel a fuel and either work just as well.
All the best
Chris
dbvandy:
YEEEAAAAAA!
I have watched the video about 10 times and do not see anything mechanically wrong.
Have you tried it without the check valve? The vapor tank should be should be sloshing WAY more than that which explains why it runs for a bit, burns off the rich vapors, then nothing...
Try some real gas... way more aromatic, so should provide more bang... don't know what that Aspen stuff is that you are burning now... don't mix any oil with it, just squirt some WD-40 directly into the cylinder when it is running.
Put some more advance in the timing. My webster loves 20 degrees advance (spark before top dead center) and runs up to 5600 rpm with a lean mixture, so yours could do this as well.
After watching the video, I now think it is a fuel issue. Raising it will not make any difference with a vapor carb. You should see the fuel indented a great deal each stroke, yours is barely moving which leads me to think the intake stroke is not pulling a vacuum.
1. Make sure the exhaust valve has some clearance (.010 in) between the valve and the rocker tappet when not on the exhaust stroke.
2. try some gas (petrol 87)
3. remove check valve to help with intake vacuum
4. seal ANY leaks
5. put a little piece of fuel line on the end of the tank tube so that it is below the fill level (will help agitate it)
EXCELLENT JOB!!!!!!!!!!!! It will run smooth VERY SOON!!!!!!!!
:clap: :clap: :clap: :clap: :clap: :clap: :clap: :clap: :clap: :clap: :clap: :clap: :clap:
Doug
lordedmond:
good progress there Chris keep at it
Stuart
Stilldrillin:
Well done Chris! :clap:
Yer in the right street...... :thumbup:
I'm sitting here with a big silly grin..... Very pleased for you! :D
David D
NickG:
:( I can't see the vids at work - got to wait 6h to see it! :lol:
Well done Chris, on the home straight now.
Your posts have inspired me to get back in the workshop. I had no motivation but I went in, all be it only for an hour, last night and got a little done on poppin no. 2. Trying to clear project back log before starting something else!
Nick
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