slant head dead

biknut said:
I don't think it should make any difference. The combustion chamber is over the center of the piston whether it's an angle head or straight head. The spark plug electrode is in the same place either way.
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biknut said:
I don't think it should make any difference. The combustion chamber is over the center of the piston whether it's an angle head or straight head. The spark plug electrode is in the same place either way.
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i have to disagree with regards to the electrode bein in the same place..the only way to verify that would be to mark the plug in relation to where the tip of the electrode is open (unshrouded) because no 2 plugs are rarely the same due to the threads of the plug itself and where the plug hits bottom with in the threads of the head...try it...take one plug and mark it then thread it into a "hemi head"..... and see where the sharpie mark is ....mark the fin on the head or the chamber...now take the same plug and do it to the "angle plug head".....then take a completely diff plug and do it again......the electrode position changes in relation to where the threads were cut on the plug's and where they were cut in the head's

there is gonna be a difference between the 2 heads just because of the way the plug hole is bored into the casting..and heres why...take the 2 heads and set them on a bench..look at them from say the right side (chain guard side)....the "hemi" has the plug seated at 12 o'clock.....the "angle" has the plug at 1 o'clock...that right of the bat is a 30 degree difference in position of the plug.....now look at both heads from the front...if you screw a plug into the "angle" head where does the unshrouded part of the electrode end up?....12 o'clock facing the top of the chamber.....6 o'clock facing the exhaust port and aiming at the dome of the piston?... if its 3 or 9 o'clock its off to the side no?...which is my point about flame travel of the ignited plug......now with the "hemi" head the electrode can be rotated to any degree so to speak...but the electrode will never get closer to the piston surface....the easiest analogy i can think of is how the earth changes its axis with the change of season's...(i hope that make sense)......now does this all make a difference..i dont know....but in theory by useing the indexing method you can an should be able to tailor the spark flame pattern..especially since were not talking about a multiple spark discharge cdi ignition system........this once again is in theory.........


in order for the plug to line up at the same point in every head the boring tool for spark plug threads would have to start at the same position on each and every head...and the same goes for the assembly of the spark plug itself the electrode would have to be afixed at the same point in regards to the start of the threads........
 
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On my beater bike slant head makes a difference for only one reason. Compression is MUCH higher.
 
mr.charlie said:
i have to disagree with regards to the electrode bein in the same place..the only way to verify that would be to mark the plug in relation to where the tip of the electrode is open (unshrouded) because no 2 plugs are rarely the same due to the threads of the plug itself and where the plug hits bottom with in the threads of the head...try it...take one plug and mark it then thread it into a "hemi head"..... and see where the sharpie mark is ....mark the fin on the head or the chamber...now take the same plug and do it to the "angle plug head".....then take a completely diff plug and do it again......the electrode position changes in relation to where the threads were cut on the plug's and where they were cut in the head's

there is gonna be a difference between the 2 heads just because of the way the plug hole is bored into the casting..and heres why...take the 2 heads and set them on a bench..look at them from say the right side (chain guard side)....the "hemi" has the plug seated at 12 o'clock.....the "angle" has the plug at 1 o'clock...that right of the bat is a 30 degree difference in position of the plug.....now look at both heads from the front...if you screw a plug into the "angle" head where does the unshrouded part of the electrode end up?....12 o'clock facing the top of the chamber.....6 o'clock facing the exhaust port and aiming at the dome of the piston?... if its 3 or 9 o'clock its off to the side no?...which is my point about flame travel of the ignited plug......now with the "hemi" head the electrode can be rotated to any degree so to speak...but the electrode will never get closer to the piston surface....the easiest analogy i can think of is how the earth changes its axis with the change of season's...(i hope that make sense)......now does this all make a difference..i dont know....but in theory by useing the indexing method you can an should be able to tailor the spark flame pattern..especially since were not talking about a multiple spark discharge cdi ignition system........this once again is in theory.........


in order for the plug to line up at the same point in every head the boring tool for spark plug threads would have to start at the same position on each and every head...and the same goes for the assembly of the spark plug itself the electrode would have to be afixed at the same point in regards to the start of the threads........
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What I think you're talking about is more like the indexing of the plug. For a little China Girl motor that's not going to make much difference.

If you mean some heads allow the plug to screw in deeper than others, then yeah that will affect compression, but that's the only reason there would be any difference in power. Nothing to do with slant or straight.
 
What I think you're talking about is more like the indexing of the plug. For a little China Girl motor that's not going to make much difference.

If you mean some heads allow the plug to screw in deeper than others, then yeah that will affect compression, but that's the only reason there would be any difference in power. Nothing to do with slant or straight.




what im discussing is yes, indexing as a possible way to aleviate the problem, possible solution to the original post concerning "splat pattern" on the piston. will it make a difference?...im not sayin it will.....but the fact that the problem caused me to think about it...i felt it wouldn't hurt any to offer this up...and you never know until you try something what the end result might be....even on something on a smaller scale as these "chop-stick" engines....nothing ventured...nothin gained.......the issue of compression, never came into thought......just the issues of warpage, torque values, and head configurations.........


what came to thought today in my twisted mind....im wondering if the process of "JET HOT COATING"..which is used on headers on racin apps could be applied to the pistons as well as the cylindar walls?.....would the rings actually seat up?......would it scuff off?....would it work just on the piston itself?....would it solve an issue that is sorta common as to engine life?



i dont know?????...but i'd like to run it by a guy like Foureasy and or Jim manic mechanic.............
 
corgi1 said:
I for one,would like to know what/how this hot coating is/works
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i guess that "hot dip" galvanizeing would be the grandaddy to this technology?......

i came across it i'll guess back in the late 80's early 90's?..from what i know it is a coating that is applied to virtuly any metal that provides a really nice finish that is chip resistant, stain resistant, rust preventive, heat resistant, etc.....not sure but i think it improves flow characteristics as well, ie headers, intakes......guys were also experimentin with various ceramic based coatings as well.....the jet coat also makes things alot easier to keep clean as you only really have to hose them off....my experience has been limited to pro stock suspension pieces as well as headers.....nothing ever internal...but who knows till its tried or negated by jet coat themselves..........and if so it might be a process guys might gain from?.....just remember where /who mentioned it here....mr.charlie
 
sorry I thought it was for the inside of the cylinders like a teflon liner or something,must have missed part of the discription
 
corgi1 said:
sorry i thought it was for the inside of the cylinders like a teflon liner or something,must have missed part of the discription
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thats just it corgi i dont have a clue if it would i just know that its out there and withstands high exhaust temps as well as its beenused in the aerospace industry????..it very well might

sorry for the caps as i just got done replyin to something and forgot to click off...mr charlie
 
I'm sorry ,I didn't maen to make you mad,I just thought it (the hot liner stuff might be a way to make the motors piston and cylinder last and run better,I'll try to reade better ,and thanks
 
corgi1 said:
I'm sorry ,I didn't maen to make you mad,I just thought it (the hot liner stuff might be a way to make the motors piston and cylinder last and run better,I'll try to reade better ,and thanks
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no corgi i did not mean you!! i was bein taunted into controversy by an individual from the leftcoast.....
 
hot dip galvi wouldn't work. it's a very rough surface. it's what they dip steel tower pieces in to keep them from rusting out. i spent 12 years climbing towers, so i'm pretty familiar with the stuff.

it might work as an exhaust coating, but i've never seen it in colors, only dull gray, and kinda shiny gray.
 
bairdco said:
hot dip galvi wouldn't work. it's a very rough surface. it's what they dip steel tower pieces in to keep them from rusting out. i spent 12 years climbing towers, so i'm pretty familiar with the stuff.

it might work as an exhaust coating, but i've never seen it in colors, only dull gray, and kinda shiny gray.
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yea and very chalky...what i ment was that the hot dip was the fore runner to jet coat.. as an analogy kinda as far as a protective coating process
 
wezwheels said:
the design is and has a flaw. the way the plug sets in the head causes an over heating of one side of the piston top. the plug does not fall in at top dead center. an unequal heating of the piston top causes a weld splatter effect over time. the piston top is getting hot on the one side and not distributing the heat over the whole piston. which starts a melting or a splatter of the metal on the top of the piston. the splatter builds up and causes it to gouge the cylinder and piston. the gouging has lead to the splatter getting down to the rings and jamming the rings in there slots. before you ask or tell yourself i`m and idiot, the oil ratio is a 16/1 to a 20/1. the denso plug is equal to the ngk b6hs. so its not a hot plug or a lack of oil that caused the issue. just a poor design? or am i missing something? you decide? thanks again. wez. :-||
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Use a NGK B8HS or a B9HS...They're a colder plug and a cooler engine runs better. Less heat more POWER.shft.
 
Creative Engineering said:
You guys are killing me here!

The plug was put in at an angle in order to clear the top tube of frames that might of otherwise been unsuitable for an engine installation.

About a year ago, forum hype gave credence to the slant head. Just as a matter of coincidence it had a slightly better chamber shape...And I do mean slightly! These engines are so archaic that it would not make any difference where the plug was located in the cylinder head.

Jim
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I've been running one of Jim's billet heads as soon as they came out. What a great piece. I run a 18mm Mikuni with one of his straight intake manifolds that I opened up for the bigger carb to work to its potential. I also use his billet rear sprocket assy. His prices are great and the products flawless. BUT, you need some knowledge to make everything work to its potential without destroying your engine. Manic Mechanics #1 in my bookdance1
 
Re: slant head not dead

I have a 49cc Grubee slant. Its been great 1000 mi, runs like a champ. I do use a cooler plug like NGK-B8HS but I spring for the triplefire/ or platinium tips and hand gap them before intstallation. I also run 20:1 Amsoil in Premium 92oct. fuel. I've thought about mix'n up some avaition unleaded but 111 oct. seems to hot without lead to lube up the process and bearings. These motors were designed in the 1930's the first 2stroke I saw like this was a beutiful 50cc turbine starter motor off a german Me262 JET that MOTOR was a work of art, cast Aluminum crank box, stainless loooking head/jug and many brass parts all made by slave watchmakers I guess. It looked like a 1 cylinder porche motor. But it was made to have leaded gas (as a high temp lubricant). I bet they would all run better with lead but I haven't tried mixing in lead additive. I might just for giggles on a tank. .wee.
 
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