I have gone to the dark side..................LOL

[dwilfong]

Well a good buddy of mine asked me to help him with a gas eng........................

So here we go........

Tiger King with a 3mm stoker crank........

Gust can't seam to get away from this stuff.....................................LOL

Will post some pics of the eng as I start to do the build up.........

31mm stroke and 35mm bore 55mm rod......29.8cc

 

[Ian Inverarity]

David, what is the height of the piston skirt? Will it keep the exhaust port covered with 31mm stroke?

 

[Ian Inverarity]

Good engines, can go well: https://youtu.be/rfxZImzODaM

 

[dwilfong]

Did all the measurements and more or less 3.5 mm spacer under the jug will keep the ring out of the intake port.

The rod is + 5mm long and the stroke is +3mm that makes a 3.5 mm spacer to get it all right.

Of cores the timing will have to be tweaked and spacers under the button. Then may be a custom button in the future.

Have to open up the case ID some for the crank OD. Will start there this week.

Then adapted the ignition for the short RC crank. Bob Finn sold me a adapter thy used for years to fit the car cranks in marine eng.

Just need to machine the fly wheel to mount to it.

 

[Ian Inverarity]

Interesting project. 50mm rod length?

 

[dwilfong]

55mm rod 31mm stroke 35mm bore stock TK piston.

ADA racing crank. 1.77 R/S ratio

For some reason I can not copy and past on IW any more.

 

[Ian Inverarity]

I ran a 30cc TK prototype for a while, 29.6mm stroke, 36mm bore. It was very good, hopefully they will make it a production engine soon!

The engine in the video I posted was a 27 with the 1.6mm stroker crankshaft.

 

[dwilfong]

Where did you get the 36mm top end?

 

[Ian Inverarity]

Prototype. There were some issues.

 

[Ron Olson]

There was a lot of hype and hope when they first came out, the new world beater. There were bearing issues which I hope have been cured. The cooling jacket bolts run through the water and are subject to rusting. The hype died down almost as fast as it went up.

 

[Ian Inverarity]

Cooling jacket bolts are stainless now and the bearings are no longer an issue. Here is a mod 27TK leaving behind mod Zen300's until the driver back off:

https://youtu.be/VO2FG1toSBU

 

[dwilfong]

Case is done and the crank fits nice.

Opened the case up to 2" and still have .080 of wall left.

The light fly wheel is cut and fitted to the crank spacer also.

Have to change the bearings out in the case as thy don't have the camphor for the crank like the Zen bearings do.

Looks like it will work........................

 

[Ian Inverarity]

What do the timings work out to?

 

[dwilfong]

Not there yet have to get the bearings to finish the bottom end.

 

[dwilfong]

Well got the bottom end and the fly wheel all mocked up.

The fly wheel is adjustable on the adapter to change the timing.

Just loosen the screw clamps and turn it. No resetting the coil gap. Will make for easy tuning at the pond.

Will start on the top end when I get the two Zen bearings to put next to the crank.

 

[Ian Inverarity]

Interesting! How does that adaptor work, machine out the centre of the flywheel to fit it?

 

[dwilfong]

yes and it is not easy.................there are metal plates all layered in the fly wheel.

Did it in the lath with a good 3/4" drill in the tail stock. need to take your time and use lots of oil.

The adapter needed to be cut down on the OD as it was designed for the larger Zen fly wheel.

Also the slots for attaching the fly wheel to it are not quit in the right place. thy need to be opened up some.

Then the clamps need to be made to hold it all together.

Also need to space the coil out some to line up with the magnets in the light weight TK fly wheel.

Not to bad......just a little fussing with one night in the shop.

 

[Ian Inverarity]

Hmmm, I think I would have gone with the Powerspark electronic ignition system then! They have worked well on the engines I have tried them on. Would probably have to machine a custom flywheel, but the flywheel only needs to be pretty simple.

Good work tho!

 

[dwilfong]

If it all pans out power spark will go on it............

Just want to get it going for testing first.

That and the adapter was only $40 to the door.........

This adapter would work with the power spark just need to put the magnet on it.

Would be pretty easy to do.

Just don't know how the eng would react to a rely "LIGHT" fly wheel?

I still have to check the balance on all this after the major work done and the TK piston assembly.

 

[Ian Inverarity]

The Powerspark system works well and the tacho is probably one of the best without silly peak readings. There is a bit of messing around with wiring in the boat tho. And more than $40! If you want to experiment with timing curves (not simply gross timing changes) you can.