ESE's works engine tuner

[WilDun]

That looks good, makes sense!- Is that that similar to the system tried by Konig on their flat fours? - the twisted belt will do away with any convoluted and expensive gearing!

[adegnes]

PVL 458 coil.
I dunno the exact function of PVL´s coils, but they have some sort of internal electronic that one could say very simplified has a function of a cdi.

From stator to coil there is only two wires that controls everything *lol*

Ahh, too bad. Difficult to test different units then.

[Peter1962]

That looks good, makes sense!- Is that that similar to the system tried by Konig on their flat fours? - the twisted belt will do away with any convoluted and expensive gearing!

If I remember correct wobbly wrote on that subject that it is not suitable for a Kart engine, because of the pretty violent way of downshifting makes the belt slip.

[dark art]

I knocked this up the other day.

It's just a prototype to test whether the twisted belt arrangement is capable of high revs.
To my surprise, it was untroubled by blips to 14,000RPM and sustained 12,000 for a few seconds.
Here's a video of it running: https://youtu.be/7Ffs1x145zw

I set the timing to: Open 135º BTDC, Close 80º ATDC, but once assembled, I found it was 5º late (at both ends, obviously) so it ran a bit hairy. I can fix that of course. Main object was to prove the belt drive.

I have no idea whether this setup will provide more power, although I suspect it might produce a better mid-range curve.
I'd appreciate any comments or advice.
Dyno time needed...

I really like the way you used the autolube pump mechanism to drive the valve. Very ingenuous.

Cant remember where but saw some pictures of kart engine rotary valve driven by belt, from the crank. Usually kart engines do a lot of rpm.

EDIT: I did remember where I saw the picture, in A. Graham bell's book "two-stroke performance tuning":

[adegnes]

I can imagine a reed valved engine making more power without the obstruction of the reed in place - but does a rotary valved engine benefit in the same way? A rotary valve, when open, gives no more resistance to flow than if there was no valve at all... and if the longer duration does give a power increase wouldn't this have shown up in the timing tests that so many have done?

I've been thinking.
Has there ever been experimented with multiple cutout valves?
If everyone has been using the tried and true method of increasing timing in small increments until powerloss then one step back, there could be more power say ten steps forward but no one ever went there.

If valveless makes more power:

Mean crankcase pressure vs atmospheric in the typical valve closed period(say from 85atdc to 140btdc) has to be positive.

Maybe a carefully designed multiple cutout valve could be even better than no valve?

Does this make any sense?
I'll see what engmod has to say on the matter.

BTW Frits, you might have received a mail about something.

[Frits Overmars]

I knocked this up the other day. It's just a prototype to test whether the twisted belt arrangement is capable of high revs. https://youtu.be/7Ffs1x145zw

I like it very much. If I wasn't already involved in 24/7, I'd try your system right away.

Has there ever been experimented with multiple cutout valves? If everyone has been using the tried and true method of increasing timing in small increments until powerloss then one step back, there could be more power say ten steps forward but no one ever went there. BTW Frits, you might have received a mail about something.

Alex, you may want to look here:
https://www.kiwibiker.co.nz/forums/s...post1130300158
https://www.kiwibiker.co.nz/forums/s...post1130820832
https://www.kiwibiker.co.nz/forums/s...post1131036800

BTW: I didn't receive any mails.

[jonny quest]

There was a right angle grinder on the market with contra rotating blades to eliminate kick back.

Pull out the electric motor, rig up a drive system to your engine, two carbs... get where I'm going with this?

https://youtu.be/nr7SkiBJI3w

[F5 Dave]

Um? Lots of ally shavings in the crankcase??

[jonny quest]

Lol, no.

2 disk valves. Front or rearward facing. 2 carbs, one for left side transfer tunnel, one for right side.

Each disk is a mirror image of each other.

[adegnes]

I like it very much. If I wasn't already involved in 24/7, I'd try your system right away.

Alex, you may want to look here:
https://www.kiwibiker.co.nz/forums/s...post1130300158
https://www.kiwibiker.co.nz/forums/s...post1130820832
https://www.kiwibiker.co.nz/forums/s...post1131036800

BTW: I didn't receive any mails today.

Thanks Frits, I'll read up! I forget how much has been covered here over the years.

I tried registering to another two stroke forum(saw alot of traffic from there to my youtube channel, thought I'd check it out) was invites only, I was like "Frits Overmars sent me", and it went through. Currently waiting for my account to be approved. Thought maybe you'd get a mail about it. Or you're not on there and my registration attempt went straight into the trash...

[oldjohnno]

I've been thinking...

If valveless makes more power:

Mean crankcase pressure vs atmospheric in the typical valve closed period(say from 85atdc to 140btdc) has to be positive.

Perhaps the disc-less dyno test should include various intake tract lengths?

[adegnes]

Perhaps the disc-less dyno test should include various intake tract lengths?

Absolutely!

[wobbly]

The PVL coil is a CDI and coil in one, and there are no different winding ratios available.
One magnet on the rotor supplies the power to the CDI the other activates the trigger.
There are various stator windings available,and the more turns ( like 4000 ) the greater the retard available but less " power " at the plug.
I got 5000 turn coils made years ago ( no plastic covering ) to use on Banshee quads as the kick start hardly turns the thing over and the high ratio
winding gives a fatter spark at kickover ( also more retard as a bonus ).
But anything other than a pretty much stock engine and the plugs would misfire at higher rpm.
The kart stators are the lowest number of turns ( 50 ohms ) and have no trouble at all with high speed high power engines, but that has a useless dead straight ( flat ) line ignition curve.
They do run best with no resistance, in the cap or the plug, but sadly there are no trick rare earth plugs available with no internal resistance - that would be the best case scenario.

Edit - TM sell a Brisk plug with no resistance that does work well with the PVL - part on box is L08S Silver 1827

[lodgernz]

If I remember correct wobbly wrote on that subject that it is not suitable for a Kart engine, because of the pretty violent way of downshifting makes the belt slip.

Yes, it still has to be proven on the track, and my shitty downshifts could well throw the belt. Yesterday was just the first (static) run of the RV, so there's still much to sort out.

Of course, because the NSR engine is cylinder reed rather than case reed, an RV like this, mounted on the reed block housing, won't necessarily offer any improvement over reeds.
The plan is to rip lots of alloy and cast iron out of anywhere in the engine that looks to impede inlet flow, but I wanted to try it first on this 50 engine, as it was already running quite well on reeds, with almost 12HP at the wheel.

[2T Institute]

I knocked this up the other day.

It's just a prototype to test whether the twisted belt arrangement is capable of high revs.
To my surprise, it was untroubled by blips to 14,000RPM and sustained 12,000 for a few seconds.
Here's a video of it running: https://youtu.be/7Ffs1x145zw

I set the timing to: Open 135º BTDC, Close 80º ATDC, but once assembled, I found it was 5º late (at both ends, obviously) so it ran a bit hairy. I can fix that of course. Main object was to prove the belt drive.

I have no idea whether this setup will provide more power, although I suspect it might produce a better mid-range curve.
I'd appreciate any comments or advice.
Dyno time needed...

love it, make closing at 90* atdc