ESE's works engine tuner

[F5 Dave]

I had my steel bore plated in Auss a decade or so ago, & it lasted. . .well it didn't last the meeting.

US Chrome did it next & it has only recently worn a bit too oval on a 50cc turning to 14.

Clearly the others have learnt how to do it.

Kept the same piston size which needed a plated bore for soft rings.

It lost 0.3hp, which I put down to another thermal barrier, but it could also have been the transfer ports were a little more messy at the exits (harder to work than a huge 54mm bore) where they had cleaned them up a bit averagely & I was a bit scared to remove plating. But it was a good trade off.

[Kickaha]

I had my steel bore plated in Auss a decade or so ago, & it lasted. . .well it didn't last the meeting.

When I was racing my TZ250 a decade or so ago we were told not to get anything done in Oz, the guys I knew shipped their stuff to Langcourts in the UK

[speedpro]

Attachment 309034Fixed that for ye .

In practice the copper got hot closest to the clutch cover and was cold at the end closest to the pipe. Hard to say if it made any real difference but it can't have hurt. It certainly hurt less than whatever caused the ceramic to come off the centre electrode of the plug.

[wobbly]

The only way to spec what thickness will be OK for a head insert is to do a FEA analysis on it with 80 Bar or so of peak cylinder pressure
acting as a UDL over the inner surface.
Using whatever head cover restraints and clamping studs etc this will tell you if the UTS is exceeded.
But a simple way to get away with pretty much murder in this scenario is to use brass, it doesnt seem to have any better thermal effects but is shit loads stronger in bending.

The only thing that will make a plug ceramic crack and fall off is deto.
In an ordinary Iridium even a few light deto pings will make it happen instantly.
A whole large batch of B9 or 10 EGV plugs the ceramic fell off for no reason, and NGK have acknowledged this in writing but I bet the importer will deny all culpability ( lawyer word for the day ).
But none of this dumb shit would ever happen if you wankers would listen to me and use a RACING plug in a RACING engine - B7376 has never once lost a ceramic or a fine wire laser welded
earth strap due to any tuning issue.
This is why they cost a bit more, still,its less of a piss off than loosing a race, and way less than the cost of a new piston etc.

[speedpro]

, still,its less of a piss off than loosing a race, and way less than the cost of a new piston etc.

The happy place we were in was that we had a spare competitive bike in the van, and I have a box of KT pistons that cost $6ea

[seattle smitty]

Where do you boat people get your nikasiling done, Smitty?

I thought you knew Rossi, Frits. For my part, all my boxes of stuff is Pleistocene Era with iron sleeves.

dont[/U] want to do is add fins to the back side of the chamber and allow the water to cool that area more.
Without simply giving away a really successful secret, what we do want to cool as effectively as possible is the squish band area, to keep the end gases away from
the killer deto heat range.

Assume you have addressed the exhaust port area cooling aspect. Now if you are getting detonation, the region of interest becomes the combustion chamber, right? If you want to draw heat from the metal around the plug body, instead of making the water jacket thinner there per Jan Thiel, with structural integrity becoming an issue, it would seem to me better to have a cooling fin at that point, with lots of surface area from which to draw heat, and structurally stronger as a side benefit. And/or, to cool a squishband (to my dumb welder's intuition this sounds right-on, Wobbly!!), again how about a cooling fin configurated as a vertical ring in the water jacket directly above the squishband, again to add a lot of surface area (and strength) exposed to coolant.

In days of yore, I fabricated a couple of heads for Konigs with vertical mill and lathe. Has to be two-piece: you machine the combustion chambers on one side of your head, and shape the water jacket on the opposite side, and cap the water jacket with your second piece. Simple to do even for a very modestly-skilled amateur machinist like me. I didn't think of it then, but when carving the water-jacket side of the head, it would be dead-simple to form an annular (I think that's the word) cooling fin or two above/opposite the squishband, . . . and easy enough to do one for the the metal around the sparkplug hole. Given a lot better knowledge than I had 45 years ago, a guy could make himself a head in which the coolant flows in a directed pattern rather than they appear to me to do in even modern engines' water jackets I've seen.

I did this stuff with ordinary machine shop tools and would still do it that way, but understand that you can make pretty tricky internal passages with modern lost-foam foundry techniques, and have a one-piece head. OTOH, the photo of the combustion chamber insert that TeeZee posted intrigues me; maybe I'll make a THREE-piece head on my new (to me) Bridgeport mill. Computer-ignorant old man that I am, I've gotta get a pad of paper and pen, and start sketching . . . .

Wobbly, as I said and you say, the combustion chamber is where the engine makes power, so I imagined a possibility that one could over-do the cooling fins in the head and lose power. Frits says you can't over-cool (but I might misunderstand exactly how he meant this; Frits?).

(EDIT) For reasons known only to software engineers, the program has ignored the way I laid out this post. I hope you can decipher the original emphasis and order. The little pencil-necked dorks keep yammering about "user-friendly;" what a damned LOAD that is!!!

[RAW]

A couple of head designs. The finned one is from the current benchmark in superkart engines. DEA & the other with the passages about the plug may be a Thijs Hessels design.
Frits the DEA head seems to go against what has been described for performance, however this engine is extremely powerful. Given your friendship & confidential nature with Andrea I hope it wouldn't be asking to much to have you explain how / why this style is employed within the DEA inline engines.
Thanks in advance

[Frits Overmars]

A couple of head designs. The finned one is from the current benchmark in superkart engines. DEA & the other with the passages about the plug may be a Thijs Hessels design.
Frits the DEA head seems to go against what has been described for performance, however this engine is extremely powerful. Given your friendship & confidential nature with Andrea I hope it wouldn't be asking to much to have you explain how / why this style is employed within the DEA inline engines.

You are more or less right about the Thijs Hessels inserts. Thijs produced them, but they were designed by Dolph van der Woude (who also designed the original Aprilia 250 cc V-twin race engine).
The DEA insert is completely in line with my ideas about cooling. I suppose you are referring to Wobbly's remarks?

[RAW]

Yes Frits, Wobbs remarks may to some degree contradict the DEA insert. As such would you explain the reasons for the DEA insert and how it fits with your views on insert designs. This I'm sure would assist us all in better understanding the 2 stroke principals & requirements.

[Frits Overmars]

would you explain the reasons for the DEA insert and how it fits with your views on insert designs.

I tried to be explicit before and I don't know how to say it any clearer: cool it.
Wobbly is right in that a cooler chamber surface conducts more heat away from the burnt gases, lowering both their temperature and their pressure.
But in our experience that's what it takes to allow optimizing the mixture strength and the ignition timing without running into the deto zone.
The cool chamber is already important before combustion even begins; the fresh charge should not pick up too much heat from the surrounding metal during the compression phase.

[wobbly]

In all current designs ( exactly like the two shown for Superkarts ) there is NO attempt to do anything clever about explicitly cooling the squishband.
The cutaway design gets water up to the threads,no better or different than Jans original,the step design is just bulk cooling everything in site, and this probably helps pull heat away from the
end gas area, by default - not design.
As I said the theoretical best scenario is to have as cool a squish as is possible and then have a reduced temp delta across the chamber area.
A possible solution is to have 2 cooling circuits, one that keeps the transfers and squishband coolest, and a second hotter one that surrounds the chamber.
But this seems an impossible pipe dream to implement.
Im not giving away the solution to this, but it is possible to do exactly as the theoretically best scenario suggests and in a KZ2 this allows way more advance and a leaner mixture
without the spectre of death deto ,constantly looming over the piston edge trapped in the squish.
I am, as everyone should be, very wary of contradicting what Frits has to say, but in this case he is citing the result gained from the DEA head as being exactly what he found in practice works best.
That is, cool the hell out of everything - the carpet bombing approach.
What I am suggesting is slightly more elegant, in that the next step to what we really want cooled the most is the end gases trapped between the piston and the insert.

[seattle smitty]

. . . I don't know how to say it any clearer . . .

I beg your pardon, Frits. Certainly what you wrote was clear, but when our two chief experts appeared to me to disagree on a point and I am citing one of them to the other, I thought it just good manners to suggest that I might have missed something. Besides that, I thought I shouldn't ignore that you are advising a readership comprised overwhelmingly of motorcycle racers, and probably some kart racers; for both of them, the coolant enters their engines already twice as hot as the water entering a racing outboard engine, AND they are burning gasoline rather than methanol having a "refrigerant effect" that a student like me would guess might (?) make you modify your straightforward assertion, were you addressing outboard racers.

[2T Institute]

The only thing that will make a plug ceramic crack and fall off is deto.
In an ordinary Iridium even a few light deto pings will make it happen instantly.
A whole large batch of B9 or 10 EGV plugs the ceramic fell off for no reason, and NGK have acknowledged this in writing but I bet the importer will deny all culpability ( lawyer word for the day ).
But none of this dumb shit would ever happen if you wankers would listen to me and use a RACING plug in a RACING engine - B7376 has never once lost a ceramic or a fine wire laser welded
earth strap due to any tuning issue.
This is why they cost a bit more, still,its less of a piss off than loosing a race, and way less than the cost of a new piston etc.

As proof was ever needed on this but the life expectancy of a shitty ES style plug in a TZ 250 is about from 9000-11,500 once. Moral is if your using ES, EV, EG or EGV your tuning has a long way to go.

[lodgernz]

But none of this dumb shit would ever happen if you wankers would listen to me and use a RACING plug in a RACING engine - B7376 has never once lost a ceramic or a fine wire laser welded earth strap due to any tuning issue.
This is why they cost a bit more, still,its less of a piss off than loosing a race, and way less than the cost of a new piston etc.

Wobbly, I've had B9HCS plugs recommended to me, and I currently use BR9EGV to try and save the engine in case of detonation.
Do you have any experience with these plugs? Any comments?

[TZ350]

I've had B9HCS plugs recommended to me, and I currently use BR9EGV Any comments?

The NGK B9HCS is a 14mm x 1/2" reach plug while a BR9EGV is a 14 x 3/4" reach plug.