ESE's works engine tuner

[Twopints]

On the Clisby one cylinder test engine the exhaust port is placed on the piston thrust face,

but on the multi cylinder engine it is rotated 90 deg and is aligned on the gudgeon pin side of the piston, E.G. the carb and exhaust port are on the same face, has this configuration been used elsewhere, the piston requires a skirt on one side to cover the exhaust port at TDC

also the divider between the crankcase and cylinder base ?

any thoughts gentlemen ?

[Muhr]

also the divider between the crankcase and cylinder base ?

If you only take TM

The J60 is open
OK-closed
MX85-closed when I think about it, maybe it's just halfway down
KZ10c-closed with a half-moon

[Grumph]

On the Clisby one cylinder test engine the exhaust port is placed on the piston thrust face,

but on the multi cylinder engine it is rotated 90 deg and is aligned on the gudgeon pin side of the piston, E.G. the carb and exhaust port are on the same face, has this configuration been used elsewhere, the piston requires a skirt on one side to cover the exhaust port at TDC

also the divider between the crankcase and cylinder base ?

any thoughts gentlemen ?

I went back and looked at your post where there was a pic of an assembled engine - possibly a mockup. It looks to me like he was going to - or had - cast a set of cases as a monoblock with multiple crank chambers. It makes sense then that the prototype single is a one piece case with a coverplate carrying one bearing and the rotary valve.
It also makes sense that the prototype has the inlet and exhaust at right angles as he'd purchased a Yamaha piston I think you said ? If he'd gone ahead with the arrangement of the assembled engine, he'd have had to find suitable pistons - with full skirts.
The arrangement has been used before - but not recently AFAIK. It's awkward - but given the packaging problems he was looking at, probably the easy solution.

[SwePatrick]

respect your opinion

Remember that the next time you feel the need to write some 'cool' oneliner reply´s then.

[ief]

A normal exhaust pipe to this form :



some exhaust pipe have this shape :



Does the shape affect the operation of the exhaust pipe ?

May I add one, has been bouncing in my head for who knows how long, pretty sure it never been tried? (maybe with good reason)

[Jannem]

May I add one, has been bouncing in my head for who knows how long, pretty sure it never been tried? (maybe with good reason)

Wouldn’t that equal to having a concave belly?

Welcome to the distinguished foil hat club!

[ief]

Wouldn’t that equal to having a concave belly?

Welcome to the distinguished foil hat club!

No, in my logic that would do the opposite.

Tnx

[wobbly]

If you plot the area's as seen by the wave action traveling along the mid section it would indeed encounter the same rate of change
as having a concave belly section.
And this is good - because ?

[ief]

I was thinking about the 'shape' of the the pressure wave due to differences in temp on the outside of the pipe and the inside.

Witch might be one of the explanations of the straight vs bend pipe.

I know, I only focus on one part...


Just an idear

[JanBros]

On the Clisby one cylinder test engine the exhaust port is placed on the piston thrust face,

but on the multi cylinder engine it is rotated 90 deg and is aligned on the gudgeon pin side of the piston, E.G. the carb and exhaust port are on the same face, has this configuration been used elsewhere, the piston requires a skirt on one side to cover the exhaust port at TDC

also the divider between the crankcase and cylinder base ?

any thoughts gentlemen ?

I think this setup definitly needs closed piston pins !

[RomeuPT]

I was thinking about the 'shape' of the the pressure wave due to differences in temp on the outside of the pipe and the inside.

Witch might be one of the explanations of the straight vs bend pipe.

I know, I only focus on one part...


Just an idear

I think this little things on the pipe are not enought significant, has I understood with all the past reading the engines with the intake to the front of the bike and exhaust to the back that allow for a straight pipe are not better because of the intake facing the rotation of the cranckshaft against the flow, loss of one or two horse power in a 50cv engine!? And the straight pipe and other improvements possible did not seem to be capable to recover the lost power.

I took this has knowlegde, but I like things to be discussed further

[Grumph]

I think this setup definitly needs closed piston pins !

Have a look at twopints bottom pic - Clisby wan't shy of moving everything around....But if those are a pair of boost ports at the back, you may still be right, LOL.

[wobbly]

Well finally boys and girls here is the evidence of what happens when you ceramic coat an Exhaust duct.
The duct was coated with TBC ( Thermal Barrier Coating ) by HPC as is used to coat 4T piston crowns and exhaust pipes.
It was masked off about 10mm into the duct such that the surrounding metal of the port itself would not overheat and create bore distortion.
The result is a drop of about 1Hp all the way up the front side, but more importantly the egt at lower rpm is about 50*C hotter.
From this area upward the deto level was over double that of the stock uncoated cylinder, and under normal test conditions I would have richened the jetting
to try to get back to the same deto level - obviously to the detriment of an extra power loss.
But this test shows that the actual top end jetting was all but identical.

Based on this I now firmly believe in changing the cylinder cooling regime ( TM KZ10C ) to increase the water flow under the duct, and to extend that cooling right out
to the back of the pipe spigot flange face.
I am permitted to machine say 5mm off the cylinder duct exit - and increase the flange thickness by the same amount, allowing a water passage within the fixing flange
to lengthen the cooled length of the exit flow.

[Jannem]

Well finally boys and girls here is the evidence of what happens when you ceramic coat an Exhaust duct.
The duct was coated with TBC ( Thermal Barrier Coating ) by HPC as is used to coat 4T piston crowns and exhaust pipes.
It was masked off about 10mm into the duct such that the surrounding metal of the port itself would not overheat and create bore distortion.
The result is a drop of about 1Hp all the way up the front side, but more importantly the egt at lower rpm is about 50*C hotter.
From this area upward the deto level was over double that of the stock uncoated cylinder, and under normal test conditions I would have richened the jetting
to try to get back to the same deto level - obviously to the detriment of an extra power loss.
But this test shows that the actual top end jetting was all but identical.

Based on this I now firmly believe in changing the cylinder cooling regime ( TM KZ10C ) to increase the water flow under the duct, and to extend that cooling right out
to the back of the pipe spigot flange face.
I am permitted to machine say 5mm off the cylinder duct exit - and increase the flange thickness by the same amount, allowing a water passage within the fixing flange
to lengthen the cooled length of the exit flow.

Good stuff, thank you! Doesn’t leave much room for speculation...

[Jannem]

May I add one, has been bouncing in my head for who knows how long, pretty sure it never been tried? (maybe with good reason)

Taking this a into a bit different direction, an internal plate dividing the rapidly expanding part of the diffuser in two halves might improve the pressure recovery. The resulting two halves would have smaller rate of area expansion change, which should reduce the flow separation. Perhaps even 4 sections with horizontal and vertical crossing plates could be used.