ESE's works engine tuner

[jamathi]

There is just one thing missing in those spark plug reading videos: reading the price tag on a spark plug. I have never in my life chopped a spark plug just to get a better look at its insulator, and to the best of my knowledge neither has Jan Thiel. A 20x-magnifying glass and some light is all you need.

No, I never did!
I always looked at the piston top.....
Even if I had to take off the cylinder head sometimes!!!!
The piston also tells a lot about transfer flow and detonation....
I also looked a lot at the inside of the piston.

[ken seeber]

“What’s is this Ken, another one?”
“Yep”
“Care to explain”
“OK”
Something that has been in the mind for ages. Did make a post about it, see 29 May, 2015. See a couple of pics around a KZ port model
This time, it will be trialled on an ARC watercooled cylinder. (The ARC kart engine was Australian made kart engine that was closely based on the Yamaha KT100S engine, Ø52 *46.1. Many parts were interchangeable. Versions were made with both air and watercooled cylinders and heads, both being piston ported inlet).

Had one kicking around, so why not. Welded on some sideplates at a reasonably appropriate angle and in conjunction with my newest best friend, Devcon F, filled and created two passages aligned and connected to the A ports, no connection to the crankcase at all. This means all flow through the original carb’d inlet, through the crankcase and into the cylinder will be via the small B ports.

The whole operations will depend on all that huffing, blowing and sucking that Wob, Neels and Frits go on about . . The key one here will be the sucking.

Just so many questions:
• Will the small B ports be enough to get to the tuned speed?
• Will it be incredibly noisy?
• Are you going to add more lube to the crankcase inlet when the direct inlets are working?
• Will it possibly create some spectacular fires?
• How to control a mixture into the intakes?
• Will the transition to opening the inlets will be interesting or very interesting?
• How to even test it?
• Do you need a special exh system rather than the regular kart header and muffler?
• Etc.
Unfortunately not enough answers.

Watch this space.

[ken seeber]

More happy snaps:

[pete376403]

No, I never did!
I always looked at the piston top.....
Even if I had to take off the cylinder head sometimes!!!!
The piston also tells a lot about transfer flow and detonation....
I also looked a lot at the inside of the piston.

Gordon Jennings wrote that he jetted according to the charred carbon (or lack of) on the underside of the piston crown. Wrote that was a very good indicator of the heat going into the piston crown, and how close it was to tipping over the ragged edge.

[wobbly]

We dont see any charred carbon on piston undersides nowdays , as the oils are much , much better and cleaner. The rare time would be with too much advance , colouring up the middle only.
A couple of really good oils have lost favour in karting due to being so clean , they hardly colour up the piston top after a couple of practice sessions. Vroom is one.

In KZ and classic bike racing I know exactly the egt/RAD that makes best power , just short of detonation on the piston inlet side timing edge , trapped by the squish band.
So by using the the local airport weather station info on my phone , I dont even need to take the plug out - except to check occasionaly that my calculation is correct .
I just look at the graph made from 3 data points of RAD ( Density Altitude ) and jetting size that achieved the desired egt previously - and fit the correct jet - absolutely repeatable and reliable.
All this is doing technically is replicating the best power bsfc. More air , needs more fuel , makes more power , but will achieve axactly the same egt on the day.

One additional tuning aid not mentioned is that using plugs with Platinum fine wire ground electrodes , the colour heat change point on the leg gives a very accurate metric of the tune.
The very distinct line , when its around 3/4 back from the tip , indicates the combination of jet and timing is on the money.
This point will change much , much quicker than poking your nose down inside the plug insulator , looking for the depth of soot ring with a x20 glass - as this takes quite a few Km of hard running to be
distinct enough , again , more especially with the soot free oils we have now.

When tuning a new setup , I like to use a castor based oil such as Maxima 927 or even the real old but real good Castrol 976 , as the castor esters colour up the piston and plug very quickly.

[sniemisto]

I have not seen any sign of brown ring on insulator after WOT run with fresh spark plug, even with having main jet slightly on rich side. I have tought this is because of 5% ethanol in fuel, but reason might also be good modern synthetic oil (Castrol Power 1).

I was just going to test effect of widening auxiliarys, but I was facing blown head gasket issue I need to deal up first.
Gasket blow up second time after just 3 hrs of racing. Head is not wrapped so I assume it is too flexy, as its only 8,2mm thick compared to 12,2 thick Malossi head.



Time to fabricate new head insert and also start using KTM SX50 viton o-ring gasket instead of original steel. Steel gasket is coolant flow restrictor from head to cylinder and I'm making new head like Malossi, with skirt going over water channels. I have 130mm bar of 6082-T6 aluminium so I will have enough material to leave skirt to manually grind to fit over transfers.



Need to think bit about coolant holes, maybe having slightly bigger holes on back for cooler water around transfer, but that can be restricting amount of water going over head insert.

This is also good time to machine fins on water side of combustion chamber. Thinking about DEA style steps or horizontal fins. I'm doing it in manual lathe, it would be possible to have vertical fin over squish band area if I make some thin tool for it.

[wobbly]

Why do you want steps or fins on the back side of the combustion chamber.
This is one of those old Monkey see Monkey do scenarios.
Cooling the chamber , does nothing but pull heat out of the combustion process.
The more heat in the chamber , the greater the gas expansion , the greater the power.
Throwing away heat into the water , is throwing away horsepower.
The better thing to spend time or money on is to arrange water to get close to the plug threads , and ceramic coat just the chamber , not the squish band , to retard heat loss into the water.

[ken seeber]

Just looked, and relooked, at Alex’s latest 2 stroke stuffing vid and he showed a “sketch” of a possible future engine design. At around the 11 min stage in the vid.

It shows 6 of axisymmetric scavenge/transfer passages. Nothing new there. No conventional exh outlets though? Yet to be drawn in?

No. he is going to rotary valve the exhaust. Early exh valve closure combined with a supercharged crankcase will potentially allow the cylinder pressure to rise above the usual pressure in the cylinder at the time of EPC = increased trapped mass = more power.

Watch his space.

[Vannik]

Early exh valve closure combined with a supercharged crankcase will potentially allow the cylinder pressure to rise above the usual pressure in the cylinder at the time of EPC = increased trapped mass = more power.

My experience with supercharging a 2T is to NOT charge the crankcase but use external scavenging chamber. You end up doing a double amount of pumping work, first by driving the supercharger and then again by compressing it further in the crankcase, it does not make sense.

You will also need the early closing exhaust port otherwise it just pumps everything into the exhaust. And a tuned pipe does not work unless you only charge a few kPa.

[ceci]

My experience with supercharging a 2T is to NOT charge the crankcase but use external scavenging chamber. You end up doing a double amount of pumping work, first by driving the supercharger and then again by compressing it further in the crankcase, it does not make sense.

You will also need the early closing exhaust port otherwise it just pumps everything into the exhaust. And a tuned pipe does not work unless you only charge a few kPa.

That depends on the type of supercharging used.
If you use the auxiliary pump piston, depending on the configuration, you can have both circumstances or just one, example: motobecane 99Z in this one there are both, montesa alcor xlv only the first.

[katinas]

"Sulzer" used rotating exhaust valve in pair with intake reed valve on the two stroke turbo charged old marine engine.

[SwePatrick]

It is true that a piston is tapered, but the taper is calculated so that the piston become more parallel when it is at working temperature. Because the crown and the upper part of the piston has more mass and runs hotter. For both reasons it therefore expands more. Also the same reason pistons are oval and narrower on the sides to accommodate the expansion of the extra mass around the gudgen pin bosses.

Plenty of performance high revving Kart engines had L-ring or Dykes ring configuration.

Yes, and when piston crown is growing the tolerances changes in the ringgroove also, pushing the ring even harder into a port.
not on ordinary pistons as they have room, but that locating ping maybe didn´t.

[Vannik]

That depends on the type of supercharging used.

He plans to use this:

[yatasaki]

"Sulzer" used rotating exhaust valve in pair with intake reed valve on the two stroke turbo charged old marine engine.

And they were disaster to maintain and work with

[ceci]

He plans to use this:

My thoughts are: best supercharger out there for the 2S, it's a tuned pipe.
This Konstantin Starodetko engine doubles the power compared to the same one without supercharging, but it does not get more KW than a yamaha tzr 250