entropy
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posted January 01, 2004 10:02 AM
quote:
quote:
... made sure the pistons were at Zero deck before bolting on the head...
YIKES! Even assuming you measured yr deck height with the base gasket(s) compressed, that leaves only .033" or so squish/quench height (if you use 3 piece ss coated headgasket).
For a short while I had my ole 1361 set up that way, and the pistons were hitting the head.
This time around, I will set up the deck height to achieve about .045" squish height. Tomorrow's the day!
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entropy
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posted January 01, 2004 10:03 AM
quote:
I don't think I'd adjust those exhaust valves too tightly on a big engine...
huh???
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BA
Pro
Posts: 1592
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posted January 01, 2004 10:04 AM
You're right Jim, part of my question is about reliability.
Seems like the 1290 has gone many miles for a lot of people, but I'm not sure that they were running nitrous, which I want to be able to do frequently, without fear of a weak cylinder. 
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silver01bullit
Expert Class
on here too much
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posted January 01, 2004 11:25 AM
exhaust valves dissipate heat through the valve seat, if they stay open too long there's more chance of burning one
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entropy
Moderator
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posted January 01, 2004 03:04 PM
silver,
OK, i got it. I've never messed with valve settings other than OEM. hmmmmm... maybe an opportunity to break something else, seeing as I have experimented with and broken just about every other part. 
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Y2KZX12R
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posted January 02, 2004 05:17 AM
I've been running .028" clearance in the squish area for 2 seasons and 15,000 miles without any trouble.
The setup is all factory parts with the block shim removed.
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Y2KZX12R
CompetitionCNC.com
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psycho1122
Pro
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posted January 02, 2004 09:50 AM
 Edited By: psycho1122 on 2 Jan 2004 11:02
Y2K....Right on!! I also did not use a base gasket below the Block. My piston to valve clearance was a roomy .035" Of course, properly degereed cams insure things stay happy.
entropy....How I figured out my CR, was by following the procedure on page 171 of Kevin Cameron's "Streetbike Performance Handbook" To explain it all here would take too long. (oh! and psycho is spelled ps"Y"cho) 
I strongly recommend this EXCELLENT book to everyone here. It's the best $25.00 anyone can spend.
East bay.......I can fax you any of my graphs if you really want to be dissapointed. Send me an e-mail!!
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justoyz2
Zone Head
Justoyz Racing
Posts: 858
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posted January 02, 2004 03:30 PM
1270 is a 2.4mm overbore with 13.5 to 1 compression
1290 is a 3 mm overbore with 13.0 to 1 compression
The ring information was correct. I don't know where you guys are running your bikes, but let me go there. One of you mentioned that your bike made 200 hp with a 1270 kit.
I find that very hard to believe. The most we have seen with a muzzy kit was 202, that was a 1361, stock cams, ported head, heavy duty valve springs. I know dyno's read high, but that's crazy
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zxlnt
Needs a job
Kawpuke Extraordinare
Posts: 2853
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posted January 02, 2004 03:36 PM
Yeah same bike made 173 stock on same dyno. So look at the gain with kit and pipe 173-202 and my bike 153.2-181.6 Relative gain is about same.
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psycho1122
Pro
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posted January 02, 2004 10:11 PM
justoyz2....These 12 engines respond MORE to compression than the cc increase. So a 1270 can easily stay on par w/ a 1290 kit or do better mod for mod.
We use a MJP dyno (www.mjpeng.dk) and did our tuning at North Valley Honda here in PHOENIX.
If you don't believe the #'s, just look at the gains!
mrsantafe also expirienced the same results....see the thread at DRAGBIKE ZONE.
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entropy
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posted January 03, 2004 12:43 AM
Y2K & psYcho,
since you two haven't had any problems running zero deck, i guess my former problems were due to something else?
my motor is out and yesterday the Cheeseman & I cc'd the combustion chamber, seems like I was running just a tad under 14:1.
I wanna run the best compromise of CR & squish height, keeping CR reasonable so it will start when hot.
Any suggestions?
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Y2KZX12R
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posted January 03, 2004 05:33 AM
Edited By: Y2KZX12R on 3 Jan 2004 07:02
Entropy, I dont know what the factory distance is from the crank CL to the deck of the block with the shim in place.
So i cant say I'm running a zero deck height. With a tight squish area you can get away with more compression due to the increased velocity of the turbulance in the chamber. I dont know what that ratio threashold is.
One thing to note, I have cleaned the combustion chambers twice with this combo at the end of each season. Its easy to do, just get an aerosol can of GM's Top engine cleaner and follow the directions. Make sure the engine is HOT when you do it. Just remove the inspection covers on the frame/airbox and remove the exhaust Can to keep from cloging it up, and your o2 sensor if you have one. The stuff is ok for o2 sensors but why make it have to burn it off. You will be amaized how much black carbon will shoot out of the exhaust. Follow the directions.
Some of you guys running late intake cam timing for top-end power may notice a buildup behind the intake valves. This robs air flow bigtime if it gets thick and nasty. This stuff will take care of that also. Read the directions carefully, its important to let it heatsoak.
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Y2KZX12R
CompetitionCNC.com
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psycho1122
Pro
Posts: 1608
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posted January 03, 2004 07:00 AM
I'm w/ Y2K on this one....."Technically" my pistons were .020 (C@#T Hair)
below deck....Damn Close!
Cam Timing is probably the most Critical.
Remember....Engines that have altered from stock deck hights, milled heads etc. Cannot be timed exclusively by the "Timing Marks", they will be off just a hint and it is easy to be a tooth off. Do a Mock assembly and use clay or solder to check piston to valve clearence.
I have no problems what so ever starting mine when it hot...and believe me! Out here in PHOENIX....it can get plenty HOT!
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entropy
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posted January 03, 2004 09:12 AM
Edited By: entropy on 3 Jan 2004 09:28
my motor is f-a-r from stock. The head was fly cut .003 to clean it up, and the billet big block was welded & replated to cure results from a dropped valve, then the surface was ground 2 times (by Millennium) to cure results of welding.
I have Muzzy cams set up at 109/111 (big int # to help hot starting).
I have MTC pistons, but will be changing to JE's since I have a wrist pin loose in the piston; change em all... 
So... no stock set up anywhere, this is why I am being anal about deck height, squish height and CR.
What I understood is that total squish height (flat part of top of the piston to head, incl torqued thickness of the headgasket) should be .040-.045". Is this too much???
with my .030" headgasket, I was figuring on setting the piston (TDC) at .010-.015" in the hole (this is what I am calling deck height); this would give me a squish of .040-.045. changing deck height is accomplished by changing the base gasket/base spacer combo.
Then I will check CR by cc-ing the CC, and hope it is 13.5 or so.
I would really appreciate yr input , because the motor is completely apart, and now is the time to finally "do it right".
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BA
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posted January 03, 2004 09:20 AM
this is good info guys.
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entropy
Moderator
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posted January 03, 2004 09:41 AM
BA, sorry to hijack yr thread, but this stuff is at the very heart of go fast (as i am sure you'd agree). High compression definitely = hi power on zx12, but "allah is in the details". Y2K & psYcho (among some notable others) have the details, and if they are kind enough maybe we both can learn something!
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BA
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posted January 03, 2004 11:19 AM
not a problem Entropy. I'm all about learning, .....and not busting up my engine.
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psycho1122
Pro
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posted January 03, 2004 11:45 AM
Edited By: psycho1122 on 3 Jan 2004 11:47
I learned the Hard way myself guys.....Big, Smooth, reliable power is in the time consuming little details.
I have to correct my earlier post re; my piston to valve clearance...I had .045 after my mock up assembly....
entropy;
You don't want to be any closer than .030 on the intakes and .040 on the exhaust. .045 should be "roomy".
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krexken
Zone Head
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posted January 03, 2004 02:56 PM
Not all pistons ride nice and straight in the bores. That is why some pistons will rock in the bores and hit the head. it could the brand of piston is machined slightly differently from others or the bore is a tad loose. Karl, your big assed motor with it long stroke and bore will probably need more room than a 1270 just cause of the extra ccs making the comp. ratio higher. The pistons in my stoked and bored 1278 are now around .050 in the hole just to deal with detonation on pump gas. I do not have a clue what the comp. ratio is but it is about as high as I can get away with. I have had to shim a deck to adjust for this.
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entropy
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posted January 03, 2004 03:49 PM
Ken,
good to hear from you.
The big bore 12 pistons sure do rock in the hole, holy scuffed skirts, Batman. I was amazed how clean the skirts on a Busa looked as compared to mine.
I aslo had mojo detonation when I did the Texas Mile a couple mo ago, blew a headgasket at the very least. I DON'T wanna do that again. Yep, CR is only part of it, but I want to set up my CR and squish height to minimize the chances the det happens again.
JohnnyCheese is set up to measure CR via buret & spreadsheet. With as much info as I can gather, we will set up my motor the "right" way. I am planning on changing squish & CR with the base gasket/spacer combo.
BTW Ken,
you gonna do the TXO in 2004?
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Y2KZX12R
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posted January 03, 2004 05:10 PM
Edited By: Y2KZX12R on 3 Jan 2004 17:15
Ok, I dug up the sheet on my engine. I had to change my last post because i was going off memory and it isnt as good as it once was...
So I'll try and keep it as simple as possable.
One thing to note, milling the head does not change the piston to head clearance but it does reduce the piston to valve clearance.
From Kawasaki, my intake valve to piston clearance was .022" because the intake cam was at 102.5 Spec is 104 so it was advanced 1.5 degrees from the factory. A degree of change on the intake valve is .0045" change (on the zx12r engine only)in intake valve clearance. This is just for reference. You must actually check the clearance.
So this puts the factory intake valve to piston clearance when the cam is at 104 at about .0285"-.029" I know its hard to believe that its that tight in there. Kawi stuffed the biggest cams they could in there.
Deck height .018"
Head gasket .023"
Piston to head (squish) .041
The removed block shim was .010"
This puts the piston to head clearance (squish) at .031"
But the torqued clearance using clay came out to .028"
So compression went from 12.2 to 1 to 12.8 to 1
And squish from .041" to .028"
My actual deck height now is .008" in otherwords the pistons are .008" in the hole.
Intake cam lift is .310" and duration is 300 degrees (advertised)
Exhaust cam lift is .295" and duration is 294 degrees (advertized)
Sorry I must not have written down the duration at .050" I have some notes on calculated ramp speeds, this is when i would have charted the cam ramps but i only see notes on the closing ramps. I dont think i charted the opening ramp if i did i cant find it, so i cant say for sure if the lobes are symetrical. Maybe lees cams or muzzys can verrify if the lobe is symetrical.
Hope this helps.
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Y2KZX12R
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entropy
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posted January 03, 2004 07:03 PM
GREAT stuff Y2K!
Since valve clearance varies with cam timing and where the piston is its cycle, how are you determining where the min clearance is????
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EastBayDave
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posted January 04, 2004 05:25 AM
awesome stuff guys....especially for the dense....;P
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02' ZRX1200
00' ZX12R sold
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Y2KZX12R
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posted January 04, 2004 06:55 AM
Well, the piston and the intake valve (on otto cycle engines) are on a colision course at the beginning of the intake stroke. The piston is moving up and the exhaust valve is closing as the intake valve is opening. When the piston is at tdc the intake valve is off of the part of the lobe ramp that takes up the slack and is on the acceleration part of the ramp. so the intake valve is approaching its maximum opening velocity going right towards the piston. The piston is now actually going back down the bore but at a slower (much slower) rate than the valve is opening and moving towards the piston. This typically happens at about 8 degrees past TDC depending on the engine.
At this point the valve is open say 80%, and the bucket is nearing the nose of the cam lobe and its velocity is slowing rapidly, but the piston is gaining speed as swept volume is increasing at an ever faster rate untill the piston reaches its maximum speed in the bore when the crank throw is purpendicular to the rod center line.
This is why you must turn the engine thru a complete cycle (720 degrees) when checking the valve clearance.
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entropy
Moderator
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posted January 04, 2004 07:18 AM
quote:
awesome stuff guys....especially for the dense....;P
EBD,
yes it is awesome, and like you say, especially for the dense (like me). I have to smash something before I get a clue how it works.
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