entropy
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posted December 24, 2008 08:16 PM
 Edited By: entropy on 25 Dec 2008 04:38
building a tight-spec motor??? - valves!
these two ZX12 os exhaust valves look identical, eh??
nope, the one on the left has a contact area which puts the face of the valve .007" closer to the piston than the valve on the right.
Andy cut the seats so that all valves protrude into the cyl within .002", everything was fine till he hit the "ringer" exh valve. Luckily i had a spare, got my head back on Christmas eve.
Santa Rick bored the bucket wells for Busa buckets:
Santa Jim did the porting:
Santa Andy cut the seats and did a .038" "skim":
Santa entropy getting set up to cc #2,3 combustion chambers tomorrow (after setting up valve springs, etc)
BTW: those pistons are old soldiers, just came out of a build with squish at .027"...
(I don't recommend .027" unless you like to measure stuff  )
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Y2KZX12R
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posted December 25, 2008 04:25 AM
Looking good Karl.
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entropy
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posted December 25, 2008 06:58 AM
Edited By: entropy on 25 Dec 2008 15:02
quote:
Looking good Karl.
Jim,
Many thanks to Jim / Y2K / Competition CNC for the beautiful porting job!!!
It's weird seeing identical overall length valves with significantly different "grind depths", eh?
Merry Christmas, Santa Jim!!!!
Karl
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Y2KZX12R
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posted December 25, 2008 07:36 AM
quote:
Merry Christmas, Santa Jim!!!!
You too Karl.
Hey, were those valves new from KW?
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entropy
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posted December 25, 2008 08:25 AM
quote:
quote:
Merry Christmas, Santa Jim!!!!
You too Karl.
Hey, were those valves new from KW?
yep, brand new KWI ss.
.007" isn't much, but when I am setting up cam CL's some o' my experiments take the PTV to the absolute min (hi 30's on int and hi 50's on exh), and I only measure #1 int and #1 exh, i assume the others are close to the same.
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whitehendrix
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posted December 26, 2008 12:37 AM
lookin BADASS, bossman!!
whats the advantage(s) of the busa buckets?
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Duct tape is the handyman's secret
weapon. The black is for formal
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ill never own a busa unless
someone gives me one.... and then
ill sell it -KZScott
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entropy
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posted December 26, 2008 05:20 AM
quote:
lookin BADASS, bossman!!
whats the advantage(s) of the busa buckets?
handles bigger cams without stress
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entropy
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posted December 26, 2008 10:16 AM
On the 1st go-around, I had Andy intentionally cut the seats "high" so that we could go to the "right" seat depth incrementally.
Last night i mocked up the motor and determined CR = 17.6:1.
That sounds fine/a bit high, but as expected the valves needed to be sunk a bit more to get acceptable PTV at even big cam CL #'s.
At 4am, I broke it all down again and brought the head to Andy this morning to recut seats just a lil deeper.
Experiments R us
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Shane661
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posted December 26, 2008 10:26 AM
Edited By: Shane661 on 26 Dec 2008 18:27
Karl, I'm sure this subject has been done to death...but isn't that compression ratio tremendous? Is there not an area of diminishing returns as far as heat,etc. vs. hp. gained?
What is the effective compression of a turbo motor under boost or a nitrous motor while spraying?
Again, bear with me, I don't know much about such things.
Shane
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ZRXDean
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posted December 26, 2008 12:05 PM
Great work Karl. Shane I think the effective CR of a turbo motor is over 20:1 at moderate boost.
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KZScott
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posted December 26, 2008 12:13 PM
NICE stuff Karl. you must have been a good boy this year.
stock sized valves?
is the black a special coating on the combustion chambers?(or just carbon?)
going by memory, stock buckets are 26mm, busa are 28mm and aftermarket KWI buckets are 28.5? higher lift cams hit the edge of a stock bucket causing it to rock a bit, making things wear out at an accelerated rate, or break.
doesnt 14.7 psi of boost double the CR in a turbo motor? (9:1 turbo pistons at about 15 psi =18:1ish CR?)
____________
01 ZX-12R 8.84 @ 156.3 no bars, DOT tires. Pump Gas, NA.... turbo 8.47 @ 164.
00 ZX-12R 8.62 @ 165.2 no bars, slicks, Pump Gas, 55 shot.... turbo 8.32 @173
00 ZX-12R Fastest NA Kawasaki in the world 1: 222.046 1.5: 226.390 Loring AFB
00 ZX-12R street turbo 1: 227.9 1.5: 234.1 Loring AFB
00 ZX-12R LSR turbo 1: 263.1 1.5: 266.5 Loring AFB Worlds fastest ZX-12R
CMG Racing RCC Turbos
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entropy
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posted December 26, 2008 01:37 PM
Edited By: entropy on 26 Dec 2008 21:44
CR will drop as the seats are cut. I will end up with around 16:1.
Jim has told me that there is indeed a point of diminishing returns on CR, but i don't know what that is for my motor as i haven't done systematic testing on CR. Generally it likes "more" but no idea what is the sweet spot. I work on squish, PTV & cam CL's, then CR is what it is.
The valves are 1 mm over Kibblewhite.
The head is brand new, "coating" is Kwak paint
KZ is correct-o on the buckets.
My concentration right now is on keeping PTV reasonable at desired cam CL's, but knowing exactly what PTV is on all valves when I only measure #1 exh & #1 intake is "interesting".
Especially interesting when the valves themselves are different. .007 isn't much, but it's the difference between exh PTV of .060" (OK-tight), and .053" (not OK for me). .007-8" is about the difference in PTV of cam CL of 108 & 109.
Experiments are FUN!
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Y2KZX12R
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posted December 26, 2008 01:45 PM
I love a good experiment !!!! 
The zx12 buckets are actually 26.5mm stock.
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entropy
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posted December 26, 2008 03:27 PM
quote:
I love a good experiment !!!!
The zx12 buckets are actually 26.5mm stock.
yep, with Y2K & Andy rapid turn-around, experiments are as addicting as drugs 
OCD in action!
Just got my re-seated head back, later tonight I'll re-cc #2, 3 on mocked up motor, see what sinking both int and exh seats by .020" does to CR. Any guesses?
First got to go to Hooters and meet up with a few Labusians. After that i oughta be plenty enough lubed up for garage work
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whitehendrix
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posted December 26, 2008 04:39 PM
awesome.. interesting trick
sadly, just when i think i know a good bit about motors, you guys blow my mind 
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Duct tape is the handyman's secret
weapon. The black is for formal
occasions. - ZRXDean
ill never own a busa unless
someone gives me one.... and then
ill sell it -KZScott
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2000redrocket
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posted December 26, 2008 07:19 PM
i am intrested on the effect on say too much compression and power output. i am thinking the piston pins need to be up to the task like in a diesel. does not more initial compression help low ent torque with bigger cams account of the large duration bleeding the compression out at slower revs? then it could be more the better except pins. but on our tripples some of the people in the tripple club said to try to stay below i think something like 210psi or u loose torque. am i remembering this about the 2 cycle good old tripple i doubt it would be the the same on 4cycle bike at that low psi anyway. this is intresting. 16 to 1 is good methonal compression to get the extra torque and cool running.
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KZScott
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posted December 26, 2008 09:07 PM
Edited By: KZScott on 27 Dec 2008 05:09
last i checked you were running VP C-44 eh Karl?
my guess is 16.4:1 CR? cranking compression of 245psi?
are stock seats able to take 1mm os valves with just a valve job?
____________
01 ZX-12R 8.84 @ 156.3 no bars, DOT tires. Pump Gas, NA.... turbo 8.47 @ 164.
00 ZX-12R 8.62 @ 165.2 no bars, slicks, Pump Gas, 55 shot.... turbo 8.32 @173
00 ZX-12R Fastest NA Kawasaki in the world 1: 222.046 1.5: 226.390 Loring AFB
00 ZX-12R street turbo 1: 227.9 1.5: 234.1 Loring AFB
00 ZX-12R LSR turbo 1: 263.1 1.5: 266.5 Loring AFB Worlds fastest ZX-12R
CMG Racing RCC Turbos
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tcchin
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posted December 26, 2008 10:26 PM
The problem with high compression and two-strokes, especially air-cooled two-strokes, is detonation. You can run whatever compression you want in a two-stroke, as long as you can control detonation and manage your cylinder head temps and sealing. The problem them boils down to port timing affecting the shape of your powerband. Power valves help, as do water pipes (!) and variable-length chambers. Like a musical instrument, it's all about the resonance.
End of hijack.
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entropy
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posted December 27, 2008 06:30 AM
quote:
last i checked you were running VP C-44 eh Karl?
my guess is 16.4:1 CR? cranking compression of 245psi?
are stock seats able to take 1mm os valves with just a valve job?
i used stock seats & os valves for 4-5 years with no trouble. It was only when i started intentionally drastically "shaving" the head and experimenting w/ way sunk valves i ran into problems & went to os bronze seats.
This experiment is starting out with stock seats
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TRNorBRN6001
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posted December 27, 2008 07:57 AM
Dang, I liked that 17:1 look you were sporting Karl. Wish you could keep it with out getting out of your comfort range. Just Have Andy weld on it a little!!!!! Just kidding.
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Y2KZX12R
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posted December 27, 2008 08:03 AM
Red, as far as compression.... you are correct that the gains from added compression start to deminish and the torque losses from having to do more compression work go up. On every engine there is a cross over where you start to see no gain and then see a hp loss. Every engine is different as to where this crossover is.
Also the added strain on the parts becomes a factor.
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entropy
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posted December 27, 2008 08:30 AM
quote:
Dang, I liked that 17:1 look you were sporting Karl. Wish you could keep it with out getting out of your comfort range. Just Have Andy weld on it a little!!!!! Just kidding.
hey Gary!
Are you making progress on yr 12 & yr mojo Busa??
BTW: I had beers last night with Sleeperbusa, and he is heading to Johnny Cheese's today.
higher CR and lower cam CL's are a trade-off.
the more i sink my valves the lower i can get cam CL's BUT the CR also goes down
If I knew my motor's crossover point (Jim expln above), it would be easy
The .020 which Andy took off my seats yesterday will gain me about 3 degrees lower CL's but cost me 1 full point in CR, i.e. it dropped from 17.6 to 16.7 (just measured).
I am approaching mods to this head incrementally. mucho labor intensive, but the build numbers are jiving. whew so far.
Tonight i'll build the motor for real and see what min CL's I can get while keeping PTV "safe".
I don't know how ANY of my motors held together before TimChin kicked my ass into making careful PTV measurement an integral part of motor building.
Oh, that's right, my motors DIDN'T hold together.
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tcchin
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posted December 27, 2008 09:48 AM
quote:
Red, as far as compression.... you are correct that the gains from added compression start to deminish and the torque losses from having to do more compression work go up. On every engine there is a cross over where you start to see no gain and then see a hp loss. Every engine is different as to where this crossover is.
Also the added strain on the parts becomes a factor.
I worked with a team who hired a famous and decorated crew chief to run their pro racing show. He had an aversion to using measurement devices to the point where he was convinced that he could eyeball TDC and didn't need no stinking degree wheel. He ran so much compression on his motors, mostly by accident, that they routinely split their cylinder walls from the excessive loads.
On the other hand, one of the factory race teams used to use high compression to help slow the pistons as they reached the top of their stroke. This allegedly allowed them to increase their redline. I'm not sure how much testing it took to find a cam timing/squish/CR combo that would yield the results they were after, but it sounded like a good story and they had good mechanical reliability.
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TRNorBRN6001
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posted December 27, 2008 11:04 PM
Beers with Mr. Sleepy, Hooters? Any talk about 1.5 Mile LSR stuff? I heard He is sending his cases up to Rick to have them massaged a little. Can't wait to see his green Busa running with that monster motor.
I don't like to skim heads, but it sure seems to keep them head gaskets perty happy.
16.7 CR sure is perty!
Mr. Entropy do you ever do any reading for leisure? If so I have a little book that has a recent story of three bikes that ran on the great white dyno. I'd like to send it to you, since there is not much else I can think of sending you that you would accept.
Thanks for all the help,
Gary
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Y2KZX12R
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posted December 28, 2008 05:54 AM
Karl, explain to flight what squish is. He has aparently has no clue.
I could explain why most of what he says is just plain wrong and inaccurate, but I dont have time and its easier to just warn people to disreguard his posts.
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