ESE's works engine tuner

[Frits Overmars]

Frits, would engmod be any useful for a rygerized engine?

Vannik is working at it.

on the top drawing the diameter tapers down then back up again like a nozzle not far from the piston, is this due to rules specifying the diameter or is it there to generate a stronger wave action?

No rules. The Malossi cylinder's exhaust duct is such that the exhaust pipe is supposed to fit into it. Instead of the whole exhaust pipe, we slid a short piece of pipe into the duct and the exhaust pipe was mounted onto the protruding part. That little piece of pipe lent itself to experimenting and the drawing shows the outcome.

As a geometric compression ratio, I am at about 16.5:1 or so, sometimes lower sometimes higher, depending on the density altitude. Slowly we are starting to find a correlation to compression and the number of head shims in an engine and the density Altitude, but seems that the RAD % is making more sense in tuning, especially for the needle valve position.
But as we go faster, it seems to change a little, as more load is on the engine the more fuel it can handle, and it seems that it actually seems that it needs more compression to get it to run properly. That maybe why Alex runs a 19:1 compression ratio, and may well be the only way to get them to run at over 290 k's and then they use the fuel to assist in the cooling of the engine, not just the air.

The drawback with head shims is that if you alter the combustion volume, you inadvertently also change the squish gap, and the burn speed with it.
High compression ratios reduce the torque dip; low ratios increase power and overrev but may make it more difficult to get the engine onto the pipe.
The F3D engines ran like hell with a 13,4 compression ratio if you could convince them to jump into the power band.
And yes, those methanol engines are all liquid cooled from the inside; they need hardly any cooling fins.

[speedpro]

u never welded anything i guess .

Funny, if you knew Jason, maybe you do?

[richban]

Well I pulled the head of the RS50 tonight for a we look. First thing I did was see if my right angle grinder would fit down the bore. No chance at all.

So I sat down and started filing away sharp edges. I can get at the exhaust port but will not touch anything until I have measured where the barrel is currently sitting.

Filing cast iron barrels is the new knitting.

[teriks]

So I will try some stuff , and will report what works. No point posting what does not work, cause I don't have enough time to type those up.
Neil

Problem is that everything depends on just about everything else so plenty of opportunity to mess up, not to mention discarding a change that would have been a success if one just had optimized some other variable(s) to the new condition. I would just love the luxury of fixed ignition timing, not to mention a programmable ignition curve..

[jasonu]

i suppose. u never welded anything i guess . ?

Couldn't be further from the truth...
Also, I wouldn't have ground on the welds especially for cosmetic purposes. You never know what might be lurking just under the surface, especially on welded cast alumin(i)um.

[Lightbulb]

Here is a piston I am trimming for a friends model diesel engine, 2.5cc
I set the compound over to about 0.75 deg, it is actually at an angle so that
every 0.04mm that the compound moves backwards is 0.001mm diameter cut.
With a dti it is set at 0.5mm per 40 mm travel.
One picture shows the colour change with a 0.003mm diameter cut and the other shows the liner at it's
fitted position and the oil colour change for the amount taken off to fit the piston 0.5 mm more up the bore.
The bore taper is about 0.00061mm per 1mm of travel, so about Ø 0.0012 per 1mm travel.
Measured taper is Ø 0.012 for 10mm

[speedpro]

You'll be dropping the boring bar through that I expect.

I filed the bridge out of the boost ports on a Suzuki AC50 using needle files a long time ago. Still got the files, mostly as a reminder to never do it again. Was a big improvement but took forever

[Frits Overmars]

Here is a piston I am trimming for a friends model diesel engine, 2.5cc. I set the compound over to about 0.75 deg, it is actually at an angle so that every 0.04mm that the compound moves backwards is 0.001mm diameter cut. With a dti it is set at 0.05mm per 40 mm travel. One picture shows the colour change with a 0.003mm diameter cut and the other shows the liner at it's fitted position and the oil colour change for the amount taken off to fit the piston 0.5 mm more up the bore.The bore taper is about 0.00061mm per 1mm of travel, so about Ø 0.0012 per 1mm travel. Measured taper is Ø 0.012 for 10mm

I love the way you work to the nearest foot, Neil .

[richban]

You'll be dropping the boring bar through that I expect.

53cc mike only 53cc.

[Bert]

Couldn't be further from the truth...
Also, I wouldn't have ground on the welds especially for cosmetic purposes. You never know what might be lurking just under the surface, especially on welded cast alumin(i)um.

Post up a pick of your lovely work on the RG400 cylinder conversion... Always loved that bike back in the day.

You lurker you

[jasonu]

Post up a pick of your lovely work on the RG400 cylinder conversion... Always loved that bike back in the day.

You lurker you

That motor is a bit old hat now but hopefully will do the business again some day...

Not so much lurking, just not much else to do these days...

[peewee]

Couldn't be further from the truth...
Also, I wouldn't have ground on the welds especially for cosmetic purposes. You never know what might be lurking just under the surface, especially on welded cast alumin(i)um.

im confident the jacketing will be leak free but lets assume a pin hole turns up. ill plug in the welder and fix it . not sure if thats how a professional would approach it but thats how im gonna do it

[ken seeber]

We are in the process of completing the design of a new Ø54 performance piston with a Ø15 pin, but want to keep the width between the piston pin bosses as narrow as possible. We are aware that Honda RS125 engines used a narrow 18 mm cage, whereas many others (inc RSA) use a cage width of 20, so are wondering if there were any deficiencies or shortcomings with the narrower cage, particularly bearing life.

Don’t worry Frits, this is not another Ryger mock-up, but just for a conventional, old fashioned engine.

[speedpro]

You would need to consider the rod width, surely? You couldn't go wrong using the RSA dimension. What rod was used, for comparison?

[F5 Dave]

[QUOTEpeewee;1130921919]im confident the jacketing will be leak free but lets assume a pin hole turns up. ill plug in the welder and fix it . not sure if thats how a professional would approach it but thats how im gonna do it[/QUOTE]


And I`d drill a small hole and push some devcon in it. but then i once (unsucessfully) glued the outside of a waterjacket on with the stuff. Dont call me Devcon Dave for nuttin.