Building a Bonzer Bonzer

[Brian Rupnow]

Is it possible that you have tuned the valve and ignition timing to run in one direction, while attempting to start it in the opposite direction?

 

[Philjoe5]

Brian,
I must admit a few weeks ago I couldn't spell "ignishun sistem" and now I made one

Seriously, let's review since anything's possible. As I face the side of the engine, I'm turning the flywheel clockwise. As the piston approaches TDC the spark fires. I've tried from 20 degrees before TDC to maybe 10 degrees after. The short running episodes I had a few days ago showed a spark at 10 degrees before TDC.

Like wise on the exhaust stroke I'm just starting to lift the valve at about 10 degrees before BDC, and I've varied that +/- 10 degrees.

I found the source of the binding cam gear. This photo shows the cam gear with red loctite residue on it. I tried pressing the steel eccentric shaft out of the bronze bushing, but the bushing broke clear of the gear.



That steel shaft is supposed to turn freely in the bushing. It's seized but good. I'm going to make a new bushing out of a piece of bronze oilite I have as well as a new eccentric shaft. I have no idea what happened to the timing as a result of that.

I'm going to walk the battery across the street so my buddy can check it for output.

The water tank lossened up in all the fooling around, so I'm replacing the blue silicone gasket maker with JB Weld.

So, I'm down for the count but I've got some fixes to attend to. I was very close 2 days ago, now not so much. I'll return when I've got her running.

Cheers,
Phil

 

[Brian Rupnow]

Phil--I have always set my engines up so that the exhaust valve just begins to feel the effect of the exhaust valve cam at 1/8" before the piston reaches bottom dead center on the power stroke. Believe it or not, this actually translated to 50 degrees of travel remaining on the crankshaft before the piston actually reached the bottom dead center.--That was on my opposed piston engine, at any rate. I am going to open my cad files right now on the Philip Duclos "Odds and Ends' engine to see what 1/8" of piston travel translates to in degrees of crankshaft movement, because it is more representative of your engine.---Brian

 

[Brian Rupnow]

Even on my Odds and Ends engine that angle works out to 40 degrees of crankshaft rotation left to get the final 1/8" travel of the piston to bottom dead center. You may want to ask some of the other model engine engineers on here, but perhaps it would be better to set your exhaust valve timing closer to the 40 degrees of advance. I know that when I was trying to get my Opposed piston engine to run, I had to make a new cam, because I hadn't built the first cam accurately enough. The cam I give in the plans for my opposed piston engine seems to be about perfect for hit and miss engines, as that is where it originated. I believe it has a total of 250 degrees of "influence" on the exhaust valve. It starts to open it at 50 degrees advance, holds it open through the full exhaust stroke, and 20 degrees into the intake stroke. I have this same cam on the Odds and Ends engine, the Rupnow engine, and the Opposed piston engine.---Brian

 

[Philjoe5]

Thanks for that tip Brian. I forgot where I read a 10 degree advance on the exhaust valve was good to start. It will be a while before I get to try it.

I do know for this engine, at 10 degrees before BDC, I'm sure the rocker arm is off of the valve before TDC. Maybe some of the Bonza or Bonzer builders could chime in on that.

Cheers,
Phil

 

[Brian Rupnow]

Thanks for that tip Brian. I forgot where I read a 10 degree advance on the exhaust valve was good to start. It will be a while before I get to try it.

I do know for this engine, at 10 degrees before BDC, I'm sure the rocker arm is off of the valve before TDC. Maybe some of the Bonza or Bonzer builders could chime in on that.

Cheers,
Phil

Phil--Remember--Those figures I gave you are theoretical figures only, making the assumption that there is absolutely no valve "lash" clearance. In a real world scenario, the minimum acceptable valve lash is about .005"
which will ****** the opening a few degrees from theoretical numbers.

 

[Philjoe5]

I made a new eccentric shaft and cam gear bushing after the first pair seized up. Using an arbor press I manage to separate the pieces but I have no clue why they failed, bearing bronze bushing and a steel shaft. The replacement parts were installed and work fine. The evil twin parts :shrug: are shown alongside the engine here.



The battery I purchased a week ago was exchanged for a new one. The original wouldn’t charge up past 10 V.

A few more details to attend to and I’ll have another trial run. But first, a reunion with 2 brothers in Florida, at the beach no less. woohoo1

Cheers,
Phil

 

[AussieJimG]

I hope you have a good time in Florida and come back with a suntan to finish the Bonzer (and shovel the rest of the snow aside).

Jim

 

[Philjoe5]

Jim,
I'll be using these tools for the week



Cheers,
Phil

 

[Brian Rupnow]

More power to ya, Phil---Catch some rays and drink some coconut rum for me!!!---Brian

 

[Philjoe5]

[FONT=&quot]I have an update after surviving a week at a sunny Florida beach for a get together with 2 of my brothers (I have 5). [/FONT]

[FONT=&quot]I made a new eccentric for the cam gear and its bushing. I used the same materials, bronze for the bushing and steel for the shaft.[/FONT]

[FONT=&quot]I reassembled the engine with the carburetor and its fuel tank. Checked for spark with my new 12V battery and everything looked OK but I failed to get a single “pop”. When I disconnected the fuel line I expected to see fuel drip from it, but there wasn’t a drop. Meaning I’m not sucking fuel up to the carb, hence, no “pop”. [/FONT]

[FONT=&quot]Rather than troubleshoot this problem now I decided to go back to the vapor carb. The good news is that I could get short 10 – 15 second bursts, then it would coast to a stop and bounce back at the compression cycle. I was able to get the engine very warm. Then suddenly, I got a good cloud of smoke coming from the coil so I had to shut down. The coil had 2 outputs (for a twin cylinder motorcycle) and I had put insulation on one of them. [/FONT]

[FONT=&quot]I had the guy who sold it to me check it but it’s dead, fried, kaput. He suggested that the second output should have been grounded but he was as surprised as I was that it was cooked.[/FONT]

[FONT=&quot]So, today, with a new 12V automobile coil I set everything up for another trial. This was my best run:

[/FONT] http://www.youtube.com/watch?v=TclA09OX0eM

[FONT=&quot]I’m very happy about that, especially since I didn't break anything!. I think I need to fiddle with the fuel/air mix a bit. Anyone have any suggestions why it won’t keep running?[/FONT]

[FONT=&quot]Cheers,[/FONT]
[FONT=&quot]Phil[/FONT]

 

[cheepo45]

Great to see it run, Phil. I'm looking forward to seeing it at Cabin Fever. Have you been following Brian Rupnow's I.C. Carb thread? It looks like a good design, if you can't get the one you have to work.
cheepo45

 

[Brian Rupnow]

Congratulations on your first run. Shure makes your heart go pitter-Patter, doesn't it!!! I don't know why it wasn't sucking up fuel with the carb I sent you. It worked on the Rupnow hit and miss engine. Maybe there is some dirt in the needle valve. One of the things that will make you crazy is an engine that runs for a while and then quits for no apparent reason.--Like--What changes?? I would think that with the vapor fuel tank nothing is changing--at least not that quickly. If the coil is questionable, that is one possibility---but if the coil is bad enough to stop the engine, the engine wouldn't start right away again. That was the main reason I bought a complete electronic ignition for the Rupnow engine. It would start, run like a charm for 20 seconds or so---just enough to make you lunge for the video camera---and then quit for no apparent reason. Once I got the electronic ignition on it, the problem went away, so I have the coil I was using tagged as "possibly bad". Many people will tell you to pull the sparkplug and see if its dry or wet, indicating fuel starvation or flooding. Personally, I have found that if the engine is warm at all, by the time you get the sparkplug out to look at it, it will always be dry, even if it was flooded when it quit. Good Luck.--When I make a carburetor, I have a real Rube Goldberg method of testing the carb to see if there is enough vacuum being created by Venturi effect to suck fuel up from the gas tank. Air reacts differently, depending on whether its being "sucked" or "blown" (at least I find it does). I have an old 1 quart sandblaster gun that creates a vacuum at the sand pick up end when air is blown thru it. I run a hose from the vacuum pick up tube to the side of my carb which normally attaches to the cylinder head. I run a gas line from the carb fuel pick up end into a glass of water. If all is right with the world, triggering the gun under very low pressure creates "suction" at the carb, just as an engine would, and you can watch it pull water up from the glass if the Venturi effect has been achieved properly.

 

[Brian Rupnow]

Cheepo--That new carb I am working on is a throttled carb. Hit and miss engines don't use a carb with a throttle on it. The speed is controlled by the governors. The hit and miss carb runs "wide open" all the time.

 

[Philjoe5]

Brian,
I may be able to use the carb. I haven't gotten to the governor yet, so I should be able to use it. I've been following your WIP

Cheepo45,
It probably won't be ready for CF this year. But for sure, the Kinzers steam up in May. What a sacrilege to show an IC engine at "Steam up"

Cheers,
Phil

 

[brucetoo]

all the links just take me to adds that don't relate to the article?What am I doing wrong?

 

[Generatorgus]

That looks and sounds like a running engine. That's GREAT!!
Why it doesn't stay running??
If you switched back to the Brian's carb and you choked or primed it to start it, then I'd guess you're running out of fuel when the prime is gone.
Try putting the fuel supply a little or a lot higher, see what happens.

Although CF is still almost a month away and you still may solve the mystery, bring it anyway, as work in progress. You may end up leaving with a fully running engine, you never know.

 

[cheepo45]

Thanks for the carb info, Brian. I guess I was going by the video and the hit and miss mechanism isn't hooked up yet.
I built a throttled carb for my Ushur engine (without any hit and miss mechanism) and being able to close the venturi down has really improved the running of the engine. The higher velocity helps to pull the fuel up from the tank. The distance from the fuel level in the tank to the carb venture is somewhat critical. My engine runs differently with a full tank than it does when it's getting close to empty.
I'm sure the Bonzer will be running great soon. I.C. engines do take some fiddling to get them running well.
cheepo45

 

[Philjoe5]

OK, here's a theory for target practice.

Before I went on vacation I wanted to grind up some branches that came down in the last storm. I used a 20 year old 4 hp chipper I inherited. It has a cantankerous Tecumseh engine on it. The day, in early March was 15 F and I could not coax a pop out of it so I gave up.

Today, it's 50F out, I put the chipper in the sun, and 1st pull she starts.

Now onto my problem Bonzer. My basement is 64F and my first attempt at starting was like yesterday's, a "long" 15 second run at full choke. Subsequent efforts gave shorter runs. I felt the fuel tank and it was cold.

I put a 60 watt lamp near the tank for about 20 minutes just to get back to room temp or maybe a shade more. Gave it a start and it ran for the longest yet, maybe 20 -25 seconds.

Tomorrow, when I get back to it, I'll start by warming up the fuel and give it a try. I'll time it and see what happens.

Brucetoo, not sure what your problem is, it seems to link up OK here.

Cheers,
Phil

 

[Brian Rupnow]

Be careful warming up fuel. Somehow that seems, aahhhh---a bit dangerous.