Full steam ahead

After a bit of a break because my parents have been here on holiday,
FULL STEAM AHEAD again !!   🙂

Because the idea is to change the valve timing a bit and because there is something not right at the length the exhaust valve for the #1 cylinder is open, I have done another set of measurements for the #2 cylinder valves this time.


Below is the valve open timing shown at 6 thou:


And the valve position:



Just checked the time these two valves are open and they are identical. For the mixture valve its 274 deg and for the exhaust valve its 280 deg, so that’s good. The reason I am saying this is that when I did the measurements on the #1 valves, the exhaust valve was open longer then the inlet (mixture) valve. So when I open up the engine sometime soon, that will be one thing I want to have a look at. We ( Warren and I ) expect that the cam-roller for that valve is bigger then the other ones, but will see.
I also did a measurement to see when the 5 pistons reach the TDC position (Top Dead Center)




The reason I did these measurements (see results below) is this:

In a radial engine with one master rod to the #1 piston and 4 connecting rods (con rod) connecting the 4 pistons with the master rod, the #1 piston will make a nice movement, but the other 4 won’t be ideal, and will have a timing that slightly of the theoretical one of 72 deg between each piston.
Now one of the thoughts Warren had was to give each piston its own triggered timing pulse to optimize the ignition, but I don’t think that’s necessary now.

Very low error, so I am not going top worry about the ignition timing !!


While I was doing my measurements, a guy walked in and started asking questions. He wanted lots of figures, angles etc etc. I noticed straight away he knew what he was talking about.
This is Wayne Lindebaum, he has a hangar next to me with the opening the other way, maybe that’s why I never met him…..
Wayne has a business there, and one of the things is engines. Has been doing it “all his life”.


The valve timing instructions in my manual say to set the EVC (Exhaust Valve Close) time to the TDC (Top Dead Center), this is with a tappet clearance of 35 thou.
Now if you look in all the literature you can find on engines, you see that the EVC is past the TDC, and that the IVO (Inlet Valve Open) is before the TDC. Wayne called this the valve rocking point, where exhaust is closing and inlet is opening.

Wayne tells me to change the cam timing so that the exhaust closes later. Make it symmetrical around the TDC.
This means that the EVO (Exhaust Valve Open) will be later, which is what I want, and also the IVC (Inlet Valve Close) will be later, so that more fuel can be drawn into the cylinder.
I compared the TDC of all 5 pistons (see 5 measurements just above) with the IVO and EVC times I have measured earlier.

On average the CAM needs to be moved by 25 deg, to delay the valve movements. This is what I always wanted !!!  🙂
By doing this I should get what you see below. Yes I think it looks good.



Oh yes the other thing Wayne was saying is that the LSA (Lobe Separation Angle) that’s currently about 120 deg and maybe needs to be reduced a bit, possibly to 105 deg, is not changing that much. Moving the cam to make the valves rock around the TDC is going to double the power !!!

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