ESE's works engine tuner

[TZ350]

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Because I secretly love the sound of a good four stroke.

Thomas and I went around to the local engine re-conditioners to see if we could get a photo of a cam grinder and cam profile master but sadly they didn't have one.

Got a photo of a boring bar in action and Thomas posing with a crank grinder.

We did get a photo of a page in a book that talked about cam profiles. The pictures neatly illustrate how the cam overlap is symmetrical about Top Dead Center.

This symmetry can be used on a single cam, twin cam, quad cam, anywhere from a 4 stroke lawn mower to a V12 Alison Aircraft engine, to check if the cam timing is correct, its all the same principle.

Simply rock the crank back and forth past TDC and an exhaust/inlet pair should just crack open/closed equally as the crank is gently moved back and forth. Look at the pictures and you should get the idea.

Now you know how to check this you should never be stuck getting cams setup to run.

I wasn’t able to get a photo of a cam grinder myself but here is a URL to a page with pictures and a bit of a story about how they develop their cam profiles.

http://www.jonescams.com/circle_track_story.pdf

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[koba]

Gordon Jennings:
"Actually, making a new cylinder head is fairly easy (it can be either cast or simply
machined from a block of aluminum) while the cylinder itself presents a far more
difficult problem in fabrication. So you may very well want to use an oversized, deeplyfinned
cylinder head to help cool a particular engine's stock, cast-iron cylinder. And if
that should be the case, remember that you'll need a maximum contact area between head
and barrel, and surfaces that will seal without any kind of gasket. There is a very sharp
temperature gradient across any joint, and even a solid copper gasket presents one more
pair of surfaces across which heat must flow."

Hmmm, may not be all good with that lovley looking base spacer you made but probably worth trying all the same.

[bucketracer]

I am wondering if some cooling of the incoming charge can be achieved by modifying the properties of the fuel itselfand lets just say it was all in the premix

Tell me more, are you suggesting adding something to the petrol or using something else altogether?

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[koba]

That Cam info seems interesting!

[TZ350]

Thanks for the ideas. I am actually finding it very hard to make real performance improvements that actually work.

Gordon Jennings:
"Actually, making a new cylinder head is fairly easy (it can be either cast or simply
machined from a block of aluminum) while the cylinder itself presents a far more
difficult problem in fabrication. So you may very well want to use an oversized, deeplyfinned
cylinder head to help cool a particular engine's stock, cast-iron cylinder. And if
that should be the case, remember that you'll need a maximum contact area between head
and barrel, and surfaces that will seal without any kind of gasket. There is a very sharp
temperature gradient across any joint, and even a solid copper gasket presents one more
pair of surfaces across which heat must flow."

Hmmm, may not be all good with that lovley looking base spacer you made but probably worth trying all the same.

My thoughts are that some heat must flow from the barrel to the crankcase and if that is so then if it has to flow through a copper fin first some heat must be radiated before it can get to the crankcase and the crankcase must then run cooler.

You would think that all this cooper would be positive but the saying is "Best by Test" we will just have to try it and see but I am hopefully.

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[TZ350]

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The good old faithful points ignition on the Red GP125 finally died and Tomas set about replacing it with a CDI unit. He rummaged around in the container of junk we have and came out with a couple of TF100 flywheels and Stators, CDI coil and a CDI box of unknown origin.

First step was to throw the lighting coils away and bolt every thing up and see if we get a spark. Our efforts are rewarded with a big phat blue crackling bolt of God’s own lightning.

Then Tomas used a DTI in the sparkplug hole to set the piston at the right advance and carefully marked the flywheel where the ignition should fire.

He ran the bike up and used a timing-light to see where the ignition was actually firing and it turned out to be randomly all over the place.

When he looked into it he found one of the magnets had been loose and was moving about and shifting the ignition point.

He replaced the flywheel with the other one and ran the bike up again and found out that the real ignition point was way off. After some more investigation he found that the TF100 cases have the barrel in a different place to the GP125.

The TF’s barrel is about 20 degrees advanced and so the ignition was advanced too.

To correct this Tomas cut a new keyway using a hacksaw fitted with three blades to get the right width for the key and elongated the slots in the stator plate.

The steps were.

1: Set the piston position at the correct firing point using a DTI in the plughole.

2: Clean and re-mark the flywheel so the actual firing point can be checked with a Timing light.

3: Make adjustments and go back to 1: Repeat untill you get it right.

There is about 15 degrees of retard built into the CDI and Tomas set the advance at 35 degrees BTDC at idle so the ignition retarded to the correct setting of 20 degrees BTDC at 8,000 rpm which is the point that the GP comes onto the pipe.

Tomas had to go through the process of making adjustments, setting the piston position and remarking the flywheel several times to get it right but it runs like a charm now.


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[koba]

hmm, worth noting all that as at some point I hope to see if I can get the roadgoing A100 working with RGV150 electrics.
I wan't to do this so I have lights that actually allow me to see at night.
It is quite interesting how similar the parts are even tho they are so many years apart in manufacture.
The thing stopping a direct bolt on in this case is the RGV's flywheel has a slightly longer (but same angle) taper so I need to tunt about 5-10 mm off that to position it corectly. The stator plate just screws straight in and all the timing marks line up.

[TZ350]

Gordon Jennings: remember that you'll need a maximum contact area between head and barrel, and surfaces that will seal without any kind of gasket.

I have that now, but I think the head gets to hot.

Gordon Jennings: There is a very sharp
temperature gradient across any joint, and even a solid copper gasket presents one more
pair of surfaces across which heat must flow."

But why must the heat flow from the barrel through the head gasket and its two disruptive joints and then into the head before it is conducted to the air?

Imagine if that head gasket was thick say 2mm and extended out the front, back and both sides adding a great deal more fin area. Copper conducts heat nearly twice as fast as alluminium and so should shed a lot of heat.

The heat from the barrel crosses one joint to go into the new copper head gasket/fin and is conducted out to the air without adding more heat load to the head.

Likewise for the head, excess heat from the head crosses one barrier into the head gasket/fin and is conducted out to the air too.

Possible? I hope so as I have been working on this for a while and I all ready have got most of it made, but I may not be finished for next weekends racing and have to take the bike along with the old setup.

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[koba]

Yeah, I like what you have been playing with!

I was just thinking of copper you used in your barrel spacer, how it was made of pieces joined together, maybe that wont conduct as good as it could?

I see your logic tho and as I'm no expert I have no idea whats waht but thought of your experiments while I read that bit and thought it might be helpful.

He goes on to talk of O-ringing heads to get rid of the 2 gasket joints.
He also points out somthing you know and this is somthing along the lines of "heads are easy to make, Barrels are hard" you can ad fins much easier by playing with heads (Or spacers under the barrel!!)

I really do like the insulator block.
As you say, we will never know until you try it.
I'm interested to see if it makes a difference.

[craisin]

Tell me more, are you suggesting adding something to the petrol or using something else altogether?

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Im just stimulating conversation about that type of thing and the rules surrounding that type of practice. Personally I think that too many opinions leads to what i call group mentality and leads to competitors getting the upperhand or maybe Im insane

[F5 Dave]

. . . or maybe Im insane

I think it's the last one. The rules are quite clear. Easy to find on various websites.

[TZ350]

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Having decided that ceramic coating is this centuries biggest performance marketing con like last centuries shiny port and polish "boy racer must have" is.

Thomas and I have had a cylinder head copper sprayed in the combustion chamber and right across the underside. The copper is about 1.25mm thick and the objective is to have a thin combustion shell that readily sheds waste combustion heat to the furtherest fins.

As copper has nearly twice the thermal conductivity of aluminum we expect to see less localized heat build up in the combustion chamber and faster transfer of heat to the outer fins on the head.

The forth picture is the original head showing localised hot spots.

In the first picture the copper head is on the left and a standard head (less its outer fins) on the right.

The second picture is a better view of the copper head.

The plan is to make a copper head gasket/fin that's squeezed between the head and barrel and we expect all this copper to greatly aid the rejection of waste heat from the cylinder and combustion chamber.

The third picture is the Fan CPU Coolers we want to use.

With 4 CPU heat-sinks attached to the copper the effective fin area will be greatly increased (more than doubled) and we will try the fans on the heat sinks to see how they go and hopefully the CPU Heat-Sinks won't get so hot that the fans melt.

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[koba]

Now THAT is cool!

[TZ350]

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Thanks Koba

Why copper and not ceramic?

Well we were all for ceramic coating the combustion chamber to keep the combustion heat in and get more power out but then thought about it a bit and read some on the Internet and concluded that performance ceramic coating specialists were talking more advertising true speak than making technical sense.

If ceramic coating in performance engines actually worked they would not have to gild the lily extolling its virtues, like a snake oil salesman. Some simple facts and figures would do. But a lot of the blurb was contradictory and plain down right copywriter’s fevered imagination and not factual.

At first I thought it a good idea and I can see how ceramic coatings are useful in a turbine engine where you don’t want heat escaping into the turbines mechanicals.

I can also see where the thermal insulation of a ceramic coated combustion chamber and piston is useful in a diesel where you don’t want the heat created in the air from the compression stroke to escape before the fuel is injected. You want that air to stay hot so the fuel is ignited more efficiently, that’s what a diesel is about.

They claim that an air cooled two stroke will run cooler with a ceramic coated combustion chamber, that’s true I guess because the ceramic coating is an insulator, one side is hot, the other side the head side is cooler.

It retains more heat in the combustion chamber and is also hotter on that side. Do we want a big hotspot? I don’t think so, we don’t want an glow plug auto ignition two stroke. Ok if the auto ignition point is after the firing point but if the thermal condition changes (more load) and advances the auto ignition point to pre-ignition we could quickly go into detonation.

I suspect ceramic coated two strokes are detuned (although their owners think they are tuning them up) so as to stay within their reduced thermal limits. I accept that because of the retained heat in the combustion process they may be more fuel-efficient. But I don’t believe they can be made to produce sustained power because of localised over heating of the ceramic coating on the combustion chamber side.

If keeping heat in the combustion chamber is the go, then performance heads would be made of cast iron or stainless steel, any metal with pore thermal conductivity. But performance heads of all kinds are universally made of alloy and not just for lightness, they are looking to shed waste combustion heat.

In no way could all the heat leave the combustion process through the head. If it did the exhaust would not be hot and the motor would not produce any power and the head would melt.

Remember its roughly 1/3 of the combustion process heat for work 1/3 for the exhaust and 1/3 lost to the cooling system.

The thing that keeps heat in the engine to do some useful work is the small boundary layer of air/fuel charge clinging to the combustion chamber walls and piston. Detonation blows this boundary layer away, which allows the combustion gases to touch the metal of the combustion chamber/piston and over heat the piston and cooling system (head).

It’s this boundary layer that protects the engine and makes some of the heat of combustion do some useful work.

The combustion chamber shell needs to be cool, cold even. Not coated with ceramic that can run hot enough on its surface to auto-ignite the freshly compressed air/fuel charge.

I think once thermal energy (heat) has crossed the boundary layer its wasted and needs to be shed as efficiently and quickly as possible.

For what its worth we are going to try to improve the waste heat shedding ability of the combustion chamber shell cooling system by using a material with better thermal conductivity than aluminium.

Ceramic coatings, the Holy Grail! I now don't think so!

I would welcome any thoughtful explanations of the benefits of ceramic coatings especially if it points out where I may be wrong.

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[koba]

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Thanks Koba

It retains more heat in the combustion chamber and is also hotter on that side. Do we want a big hotspot? I don’t think so, we don’t want an auto ignition (pre-ignition) two stroke. Ok if the auto ignition point is after the firing point but if the thermal condition changes (more load) and advances the auto ignition point to pre-ignition we could quickly go into detonation.

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I believe the idea is the ceramic coating helps spread the heap more evenly over the combustion chamber thus minimising localised hotspots.
Like you though I am sceptical of the benefits in insulating layer an aircooled engine thats power output is limited by its lack of ability to shed heat...