entropy
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posted April 24, 2009 11:55 AM
build decision
just measured stuff, gotta make a decision, A or B???
hmmmmmmm...
A) 15.8:1 @ .029" quench
- lil higher CR (0.2:1), ?optimum? quench
this motor likes higher CR, lost some w/this build bc KWI went back to dished int valves
or
B) 15.6:1 @ .034" quench
- get 1 degree lower cam CL's
this motor likes lower cam CL's
hmmmmmmmm...
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TRNorBRN6001
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posted April 24, 2009 12:21 PM
My idiots two cents, go for the higher CR. I like the HP and Tq curve your bike makes with low cam CL's, but your not there for long with the LSR stuff. I think 1deg is worth giving up for good tight quench and a little extra CR.
Gary
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entropy
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posted April 24, 2009 01:36 PM
gary, i lean in yr direction but the low cam CL's REALLY boost hp from 10-12K where i spend mosta my time in LSR
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tcchin
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posted April 24, 2009 03:27 PM
Edited By: tcchin on 24 Apr 2009 23:44
Have you run .029" squish before? I thought you were getting piston/head contact at .030". That being the case, I'd go with .034" squish and the lower LC's.
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KZScott

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posted April 24, 2009 04:31 PM
I thought he ran .027 once???
not sure if this is a big factor or not, but would your tighter than you thought bearing clearances allow for tighter squish? are you staying with the tight clearances or opening them up to what you thought you had?
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entropy
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posted April 24, 2009 05:25 PM
quote: Have you run .029" squish before? I thought you were getting piston/head contact at .030". That being the case, I'd go with .034" squish and the lower LC's.
Tim,
I have run lower than .029, and the head contact was the same as it was at .034, always taps the exh side no matter what i do.
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entropy
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posted April 24, 2009 05:28 PM
scott,
i don't feel that bearing clearances impact squish significantly. No matter what i do the exh side hits. Too much rocking? Doesn't seem to bother the bearings tho????
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KZScott

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posted April 24, 2009 05:52 PM
hmmmm try thicker coatings on the skirts??? not enough warm up time?
i wonder how that light contact affects the flame front. basically when it touches theres no squish on that side, but lots on the other? pistons not ballanced F to B??
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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
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whitehendrix

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posted April 24, 2009 08:26 PM
why can't you compromise and do both in one form or another?
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tcchin
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posted April 24, 2009 09:38 PM
I would think, if you're hitting at .034", that you're burying the pistons into the head at .029". I'd stay with .034" if it were my decision.
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entropy
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posted April 24, 2009 11:40 PM
Edited By: entropy on 25 Apr 2009 07:43
quote: why can't you compromise and do both in one form or another?
whitey,
you cannot have it both ways bc of Piston to Valve clearance gets smaller w/smaller quench and w/smaller cam CL's.
I set my cam CL's as low as i can while keeping min exh PTV higher than .058-ish, int .038-ish
the tapping happens on the exh cycle for sure (i guess), gotta be rocking bc the int never hits even at 27
These new pistons have stouter skirts, maybe they won't loosen up so much.
I have 3 mo until Loring event so time for a couple more builds.
This one i will go uber conservative and do the 34 Q, see what happens on the dyno, then prob take it tighter for Loring early Aug.
Thanks for the input.
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Y2KZX12R

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posted April 25, 2009 02:37 AM
Karl, how about milling off .015" off the exhaust pad on the piston and tighten the squish back up .010" Then bring the intake valve to piston to .030" ???
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Halvefast

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posted April 25, 2009 05:24 AM
Edited By: Halvefast on 25 Apr 2009 13:29
Now we're throwing out some creative thinking!
Karl are you still using the huge relief for the spark plug,
didn't notice it in the new piston, or does it still need to be put in?
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tcchin
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posted April 25, 2009 07:25 AM
quote: Karl, how about milling off .015" off the exhaust pad on the piston and tighten the squish back up .010" Then bring the intake valve to piston to .030" ???
I think milling the pistons is how Karl got into trouble in the first place...
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Shane661

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posted April 25, 2009 10:29 AM
Edited By: Shane661 on 25 Apr 2009 18:29
Karl, you have an engine building hobby that sometimes involves riding.
I bet you could build one of these that would last a long time...if that were your goal. Have you ever considered a milder build and spending more time optimizing overall bike setup?
I guess it is a matter of what the goal is...and on that note...what is your goal?
Shane
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dougmeyer

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posted April 25, 2009 05:07 PM
.034"
The cam CL's don't mean shit if we're banging the piston into stuff.
;-)
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entropy
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posted April 25, 2009 09:18 PM
Edited By: entropy on 26 Apr 2009 07:21
Shane,
two goals: learn how to build and go faster than Phantom (without losing any weight)
i am setting up CL's/PTV right now; went conservative on quench = .034.
(i sure ain't gonna buck the advice of both Doug & Tim, thanks )
just finished
int: CL= 104.3 @ min PTV .039" (corrected .003 for max shim)
exh: CL= 106.1 @ min PTV .062" (corrected .003 for max shim)
the correction is a safety factor
This build has new JE's with .020" less int pocket for strength, glad i could get below 105 on intake.
now it's Abita time!!!!!
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psycho1122

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posted April 26, 2009 06:50 AM
NICE!!
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osti33

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posted April 26, 2009 09:44 AM
Edited By: osti33 on 26 Apr 2009 17:44
quote: Shane,
two goals: learn how to build and go faster than Phantom (without losing any weight)
i am setting up CL's/PTV right now; went conservative on quench = .034.
(i sure ain't gonna buck the advice of both Doug & Tim, thanks )
just finished
int: CL= 104.3 @ min PTV .039" (corrected .003 for max shim)
exh: CL= 106.1 @ min PTV .062" (corrected .003 for max shim)
the correction is a safety factor
This build has new JE's with .020" less int pocket for strength, glad i could get below 105 on intake.
now it's Abita time!!!!!
Good deal!
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dubious

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posted April 26, 2009 12:04 PM
what piston to wall clearance you running to have the piston rock that much?
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entropy
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posted April 26, 2009 03:53 PM
quote: what piston to wall clearance you running to have the piston rock that much?
starts off at .0018-.0020
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whitehendrix

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posted April 26, 2009 07:57 PM
thanks for the explaination Karl. i was just thinking of maybe picking the better or best part of both and putting them together in harmony as best as you can.. compromise lift and/or duration where needed.. stuff like that. just to keep parts from kissing.
got ya tho on what you said
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ill never own a busa unless
someone gives me one.... and then
ill sell it -KZScott
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Dane
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posted April 27, 2009 06:24 AM
now it's Abita time!!!!!
Dont tell me you STILL have Abita...drink up
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entropy
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posted April 27, 2009 06:35 AM
quote: now it's Abita time!!!!!
Dont tell me you STILL have Abita...drink up
i'm saving it, spacing it out with coronas and bud kights!
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Phantom13

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posted April 27, 2009 11:05 AM
Edited By: Phantom13 on 27 Apr 2009 19:07
quote: Shane,
two goals: learn how to build and go faster than Phantom (without losing any weight)
i am setting up CL's/PTV right now; went conservative on quench = .034.
(i sure ain't gonna buck the advice of both Doug & Tim, thanks )
just finished
int: CL= 104.3 @ min PTV .039" (corrected .003 for max shim)
exh: CL= 106.1 @ min PTV .062" (corrected .003 for max shim)
the correction is a safety factor
This build has new JE's with .020" less int pocket for strength, glad i could get below 105 on intake.
now it's Abita time!!!!!
Karl, I take that as a enormous compliment!!! Thank you.
I'm sure we'll get to rub elbows again sooner or later, in fact I'm looking forward to it. Heck, I would be going to Loring this year if this damn Mustang GT project wasn't such a money pit!
I'm taking off the heads today, doing a light clean-up on the ports and some chamberwork. These Ford P.I. SOHC 4.6L engines are pigs from the factory. Your Crown Vic has the same engine, right? It's no wonder cops won't chase bikes....
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