ESE's works engine tuner

[F5 Dave]

Dude, glad you've dropped back in.

So have you done cylinder leak tests? Port ideas seem great. But can the rings cope with their primary job after a reasonable period of running?

[adegnes]

A T port at 100% bore as was used in A kit Honda 125/250 GP cylinders had a dead straight timing edge.
This obviously worked very well.
Your 100% port with no bridge , but a much higher floor than the old Honda's had , should have greater duct velocity and work even better.
More so using the reduced duct exit concept as well.

Thanks wobbly, that's what I'm hoping for.

I read it like the effective port area is the whole ex-area, not just the blowdown-which is then reduced to 75%. But what happens when the whole area is more or less the same as the blowdow area?

Been thinking about this too, my duct exit might be too small. Seems fine in simulations though. When things are working I'll cast a few cylinders with more area and compare.

Dude, glad you've dropped back in.

So have you done cylinder leak tests? Port ideas seem great. But can the rings cope with their primary job after a reasonable period of running?

Thanks!
No leak test yet, been mostly focused on if the ring will survive at all. Need to buy/fabricate a tester.
This first batch of rings are too soft, ring gap is growing rapidly.
Might partly be the bore wearing down too, used the wrong type of Boron Nitride in my plating bath, hexagonal vs cubic. Mixed in some Silicon Carbide, next plate will be Nickel/hBN/SC(which I suspect is what's used by several "professionals")


New harder rings in the making. As long as those tabs don't break off these rings should behave and wear just like normal one's I think.
Wonder if composite plating the rings could be beneficial. Can do electroless nickel with whatever small particles I want. Electroless deposits a uniform layer vs electroplating which produces high spots around edges etc.

[dutchpower]

A T port at 100% bore as was used in A kit Honda 125/250 GP cylinders had a dead straight timing edge.
This obviously worked very well.
Your 100% port with no bridge , but a much higher floor than the old Honda's had , should have greater duct velocity and work even better.
More so using the reduced duct exit concept as well.

Wobb from 125cc to 50 cc is complet other bal game

A kit 125 and A kit 250 is totaly different ( pv )

The 75 % on a bidalot 50 exh. prt is totaly bullshit greater then stock will give 23 hp only on the exhaust prt.

[wobbly]

Real A kit RS125s had a PV just like the 250.
Here is a dyno comparison of a real A kit RS125PV ( Tada ) vs a well tuned customer RS125 vs a " not so real A kit " non PV cylinder - easy to see why this was kept in house at Honda.
I dont understand at all the last statement " The 75 % on a bidalot 50 exh. prt is totaly bullshit greater then stock will give 23 hp only on the exhaust prt ". What are you saying ?

[ken seeber]

Thanks wobbly, that's what I'm hoping for.
rings should behave and wear just like normal one's I think.

Alex,
Cuppla thoughts on the ring. As I understand it, you are running the inverted L shaped ring with the vertical section downwards and inside. See pic of how I see this.



From the excess radially outward movement from your vid, it appears that the vertical section has been removed on the ring peg side, but retained on the exhaust side.

Now if this is the case, there are a couple of points that could be made.

1. There is a considerable extra clearance/void volume around the “captured” L ring compared to a simple flat “rail” ring. It is critical that the cylinder pressure can build up here to ensure proper ring sealing, thus this volume must be minimized. The removal of any of the ring material will increase this volume and might detract from obtaining full cylinder pressure behind the ring, potentially causing low compression thru ring seal leakage= bad..



2. The clearance indicated must be such to ensure that the ring can seal against the bore in an extreme piston rocking situation. From the example here, this would need to be 0.3 mm for a 125, say (40/54)*0.3 = 0.22 for square 50.



Keep up the good work on a very interesting & informative project for which you should be very proud considering your “vertically integrated” (ie you do everything) approach.

[adegnes]

Alex,
Cuppla thoughts on the ring. As I understand it, you are running the inverted L shaped ring with the vertical section downwards and inside. See pic of how I see this.



From the excess radially outward movement from your vid, it appears that the vertical section has been removed on the ring peg side, but retained on the exhaust side.

Now if this is the case, there are a couple of points that could be made.

1. There is a considerable extra clearance/void volume around the “captured” L ring compared to a simple flat “rail” ring. It is critical that the cylinder pressure can build up here to ensure proper ring sealing, thus this volume must be minimized. The removal of any of the ring material will increase this volume and might detract from obtaining full cylinder pressure behind the ring, potentially causing low compression thru ring seal leakage= bad..



2. The clearance indicated must be such to ensure that the ring can seal against the bore in an extreme piston rocking situation. From the example here, this would need to be 0.3 mm for a 125, say (40/54)*0.3 = 0.22 for square 50.



Keep up the good work on a very interesting & informative project for which you should be very proud considering your “vertically integrated” (ie you do everything) approach.

Thank you Ken.
You described everything correctly, except the ring has a "T" shape vs. "L".
After grinding there's two ~5mm tabs top/bottom.

Good point about volume behind the ring, it was already excessive without parts of the vertical ring portion removed.

I think a good solution for V2 is a normal ring groove with short slots for said tabs to sit in. That would eliminate the need for a ring peg too.

[SwePatrick]

Now i can start tuning again.
I have tried a lot this weekend:
Dual coils(still on video)
Richen the mixture
Leaner mixture
Checked reeds, modified a little.
checked compression
Changed plugs, four different models
Changed plugwires, three different models
Wen´t through the carbs, floatlevel etc etc.
E85 fuel
Petrol

And finally found it, almost ashamed of it..
As the engine is quite fresh and i haven´t got the feeling for what it want´s yet i have been very careful about adding more advance to the timing.
Finally when i had ran out of options, i said to myself f_ck it, so i added 10 more degrees to the advance over the whole curve.(do not compare with 2nd curve on screen)

Result in video.

[wobbly]

I can see on the screen that the base advance is 0* . So is the trailing edge of the flywheel lobe over the center of the trigger pole at TDC. If so , why.
Never seen that before.

[SwePatrick]

If having a longer lobe i have found that one doesn´t need baseadvance.

Say if you are having a 38degree long lobe, your max advance is 38degree´s
And if you are having a 20 degree long lobe your max advance is 20degree´s, but if you setup baseadvance 18degree´s you can set timing to 38 degree´s again.
But you need to advance the rising triggerpoint the same degrees, as the baseadvance actually is just pulling back the virtual falling signal.

I have strobbed it and it seems to work just fine, 30degrees in software is 30degrees on the 'flywheel'.

[ken seeber]

Thank you Ken.
You described everything correctly, except the ring has a "T" shape vs. "L".
After grinding there's two ~5mm tabs top/bottom.

Alex,

You have got us going on rings. So, after the minimal use of powerful drugs, we came up with some thoughts:
1. Use a conventional Dykes ring, flush with the crown edge, but with virtually no tension. This would rely on the cylinder gas pressure to expand and seal the ring.

2. Flat rail ring, but with a pegged inner projection. See pic. With the 2 piece piston, a suitable vertical pin would control the radial movement. Could allow for adjustment by elongating the hole to allow for ring wear. Alternatively a vertical pin permanently installed, via the crown, thru the hole on the ring. Would be a total pain to work with though.


3. Flat rail ring, but with an eccentric centre, the stiffer side against the exhaust. See pic. Hopefully the extra stiffness of that section of the ring will, in part, eliminate some of the bulging.




4. With both of the above 2 thoughts, one must consider how a ring could be made. Over the last year or so, I have fallen in love with wire cutting. See pic of some examples of this I used for the UHV project, 0.2 thick. If using ground (spring) steel, it would need to be chrome plated at the edge, so this would be a hassle. The other option is to go for a more conventional ring material, say F14 cast iron. Would have to be made into ground discs and then wire cut in the case of 2., but simply turned in 3. It has the advantage it can run direct on the bore.



5. Just don’t run a ring and just rely on the huge volume of nitro & oil to do the sealing, ala model plane/boat engines.

[lohring]

We had some bad experiences with ringless pistons in larger than 15 cc engines. Our 35 cc engine originally came with a ringless piston. We tore up all the available pistons and sleeves searching for an oil and break in combination that would work. The manufacturer eventually went back to a ringed piston.

Lohring Miller

[Makr]

Alex,

You have got us going on rings. So, after the minimal use of powerful drugs, we came up with some thoughts:
1. Use a conventional Dykes ring, flush with the crown edge, but with virtually no tension. This would rely on the cylinder gas pressure to expand and seal the ring.

2. Flat rail ring, but with a pegged inner projection. See pic. With the 2 piece piston, a suitable vertical pin would control the radial movement. Could allow for adjustment by elongating the hole to allow for ring wear. Alternatively a vertical pin permanently installed, via the crown, thru the hole on the ring. Would be a total pain to work with though.


3. Flat rail ring, but with an eccentric centre, the stiffer side against the exhaust. See pic. Hopefully the extra stiffness of that section of the ring will, in part, eliminate some of the bulging.




4. With both of the above 2 thoughts, one must consider how a ring could be made. Over the last year or so, I have fallen in love with wire cutting. See pic of some examples of this I used for the UHV project, 0.2 thick. If using ground (spring) steel, it would need to be chrome plated at the edge, so this would be a hassle. The other option is to go for a more conventional ring material, say F14 cast iron. Would have to be made into ground discs and then wire cut in the case of 2., but simply turned in 3. It has the advantage it can run direct on the bore.



5. Just don’t run a ring and just rely on the huge volume of nitro & oil to do the sealing, ala model plane/boat engines.

Good thoughts Ken. I wish I had an EDM.

I used a ductile iron for Alex's rings and the ones in my engine (although I hard chromed the ones in mine).

I was going to use 8620 (not sure what alloy is comparable in your world) carburizing grade steel and mask everything but the face of the ring, and then Nitride it. Getting anyone to do a moly or similar has turned into a dead end on my budget for now.

When I made the first rings for Alex I did a 1mm ring and after I hardening it was way too stiff. The T section adds too much material. I drew the hardness back until it was reasonable. I think going to a .5 mm ring and cutting some of the T away will allow me to keep it stiff and have reasonable wear for this prototype stage.


What do you think?

Makr

[adegnes]

Alex,

2. Flat rail ring, but with a pegged inner projection. See pic. With the 2 piece piston, a suitable vertical pin would control the radial movement. Could allow for adjustment by elongating the hole to allow for ring wear. Alternatively a vertical pin permanently installed, via the crown, thru the hole on the ring. Would be a total pain to work with though.

Nice suggestions Ken, one of them are strangely familiar.

Here's a variation on my "pinned" ring idea.

Attachment 339223

The ring is located with the hole in the middle of the 100% exhaust port.
The cylinder could be turned 90° to normal orientation and the pin could be pressed(or threaded) into the piston from the underside through a hole in the wrispin boss.
A conventional piston could be used, and as the exhaust side of the wristpin would never encounter any transfer ports, only that side would need to be blocked, maybe even just plugging the pin with something would suffice.

Watcha think? Mumbo jumbo?

I could happily spend the rest of my days failing trying "stupid" stuff.

My neighbor works at a place they do wire cutting(and grinding), if we move away from the partial "T" ring I'll ask how they feel about doing it for me.

Sorry for being so short, really appreciate the input, lots of stuff on the plate atm.

[wobbly]

SwePatrick , yes your system is fine - using a very small rotor as you have.
I spent days , just like you did , years ago trying to discover why my new TZ based race engine was misfiring past 6000 rpm.
It had a new 100mm rotor on it as is used in many Chinese pit bikes.
This had a long ( 45mm ) lobe and I used two triggers.

In deperation I put a scope on the trigger signal , and discovered that the output from the reluctor coil in the trigger would jump up as soon as the lobe front edge passed the pole.
But about 1/2 way along the lobe , the signal was gone.
And as the ECU is designed to be seeing the falling signal off the trailing edge ( where there was no signal ) it got lost.
So I cut the lobe length in 1/2 , down to about 20mm and suddenly all was fine.

Later I discovered Ignitech had a " long lobe " option , but I have never tested this.

One other point regarding your small trigger rotor setup. This is exactly what HRC used on the RS125 factory bikes with a total loss battery system.
They discovered that with the stock crank , and the very small inertia flywheel plate , they lost a huge amount of overev power.
Thus part of the total loss kitset was a new crank , with alot of extra heavy metal around the wheels to get back the inertia lost from removing the flywheel.
VHM made high inertia cranks for the same reason - in effect loosing any advantage in acceleration gained from taking off the flywheel.
This effect was first seen at Queens Uni where Dr Fleck discovered that the same engine made more power on a eddy current dyno with more inertia.
His opinion was that the extra inertia reduced the in cycle speed difference of the crank as it was sped up on the power stroke - effectively slowing down the crank at BDC , thus giving more time to the
transfer STA number in reality.

[ken seeber]

Good thoughts Ken. I wish I had an EDM.

I used a ductile iron for Alex's rings and the ones in my engine (although I hard chromed the ones in mine).

I was going to use 8620 (not sure what alloy is comparable in your world) carburizing grade steel and mask everything but the face of the ring, and then Nitride it. Getting anyone to do a moly or similar has turned into a dead end on my budget for now.

When I made the first rings for Alex I did a 1mm ring and after I hardening it was way too stiff. The T section adds too much material. I drew the hardness back until it was reasonable. I think going to a .5 mm ring and cutting some of the T away will allow me to keep it stiff and have reasonable wear for this prototype stage.


What do you think?

Makr

Mark, Can see you have considered many options. Obviously one main consideration with anything you may want to try is to make it as easy as possible. To me, getting wire cutting is relatively easy, just sandwich the flat stock between two aluminium plates (in my case we had to cos the material was very thin 0.2 mm). Easy for me as I have a buddy that looks after a machine at a local uni, but still relatively cheap and . Just a simple .dxf file. If you can hard chrome the edge and finish it, then this looks the go, for flat rail type rings anyway.

If Alex is experiencing premature wear of the ring, possibly due to the composition of the plating or honing finish, then a chrome edged ring may be helpful.