SteddyTeddy
Pro
Posts: 1664
|
posted February 27, 2009 07:54 AM
Thermal coated pistons
I have thermal coated pistons in my new big bore and stroked engine. I was hoping they would help the engine to run a little cooler but I think they are having the opposite effect. Except for the 2mm bore and 4mm stroke everything else is for the most part the same as my stock bore motor was. This new engine just does not like to get hot, at all. I've installed a larger radiator and that has helped alot but I'm still having issues when the bike is at full temp. It just doesn't want to idle right. Starts trying to drop a cylinder. I give a kwick blip and it's fine for a few seconds then same thing. It idles and runs flawless untill it gets hot. Same carbs, same head and cams that were on my stock bore motor and never had these problems. Could the coating be holding too much heat in the top end? I'm running out of things to try.
  
|
Shane661
Needs a life
Posts: 11494
|
posted February 27, 2009 07:56 AM
Are you sure you don't have any sort of vacuum leaks that are being aggravated by the heat? Just a thought...
Shane
|
SteddyTeddy
Pro
Posts: 1664
|
posted February 27, 2009 08:13 AM
Positive. No vacuum lines to break. Carbs are jetted at 13:1 and it idles at about 13.2. It's just a PITA stitting a stop light. If I shut if off and let it sit for a minute or 2 it's also a pain to get back started.
|
Shane661
Needs a life
Posts: 11494
|
posted February 27, 2009 08:20 AM
 Edited By: Shane661 on 27 Feb 2009 16:21
I assume it's not puddling fuel or anything like that? Sorry I can't be of more help...I'm sure someone else will chime in.
Regarding the vacuum, I was more thinking at the manifolds.
Shane
|
SteddyTeddy
Pro
Posts: 1664
|
posted February 27, 2009 08:38 AM
Not puddling that I can tell. It's definitely heat related. New plugs will help the problem some at first, but then right back. Manifolds are in good shape. I have stick coils installed and have tried 2 different sets. Tempted to throw the stock ingition back on and try that.
|
aliveagain
Needs a life
Posts: 5033
|
posted February 27, 2009 09:23 AM
quote:
Positive. No vacuum lines to break. Carbs are jetted at 13:1 and it idles at about 13.2. It's just a PITA stitting a stop light. If I shut if off and let it sit for a minute or 2 it's also a pain to get back started.
Doesn't mean the boots might have a leak.
____________
I wondered why the baseball kept getting bigger. Then it hit me.
|
osti33
Needs a job
Posts: 2973
|
posted February 27, 2009 09:34 AM
I would guess the added displacement of the +2mm bore and the +4mm stroke is what is causing your extra heat. That is also why it is harder to start when the engine is hot.
|
SteddyTeddy
Pro
Posts: 1664
|
posted February 27, 2009 10:00 AM
This engine does run a lot hotter now but the new radiator has helped a lot. My problems are occuring before the fan even kicks in. I believe the fan is set to run at 210* and the thermostat is rated to open between 176 - 183*. Both are working. The thermostat cycles nice now with the larger radiator. My issue still may be somewhere else?? This is the first time I've use coated pistons. I know the coating is meant to keep heat from dissapating through the piston and to the rest of the engine. Just wondering if it's allowing too much heat to build up in the combustion chambers. It may be something else yet. I was also thinking of making up a heat sheild between the engine and carbs. Also still not ruling out weak spark when hot.
|
entropy
Moderator
Posts: 8671
|
posted February 27, 2009 10:03 AM
Edited By: entropy on 27 Feb 2009 18:04
what is your piston/cyl clearance?
what CR?
cold cranking pressure?
____________
This moderator uses moderation in moderation
|
BrooklynNYZX12
Zone Head
Posts: 520
|
posted February 27, 2009 10:18 AM
Teddy did you check all the clearances that Entropy asked about before you coated the pistons or after?
____________
Orient Express Top Street Bike Winner 8-4-07
|
2000redrocket
Pro
Posts: 1662
|
posted February 27, 2009 10:45 AM
what about vaporlock? also valve clearence. i would think about going back to the stock coils just to emiminate that. to start you need the 3 things we all know about so it is either spark or fuel. i doupt the compression it going away when it gets up to temp.
|
SteddyTeddy
Pro
Posts: 1664
|
posted February 27, 2009 10:47 AM
Edited By: SteddyTeddy on 27 Feb 2009 18:49
quote:
what is your piston/cyl clearance?
what CR?
cold cranking pressure?
CR is 12.5:1. Piston to head is .033". CCP was 210 psi last time I checked. Millennium bored and plated the cylinders with the pistons already coated. Specs called for .0025". 93 octane is all it ever sees. She has just under 1k miles now and several good nights at the strip.
|
SteddyTeddy
Pro
Posts: 1664
|
posted February 27, 2009 10:57 AM
quote:
what about vaporlock? also valve clearence. i would think about going back to the stock coils just to emiminate that. to start you need the 3 things we all know about so it is either spark or fuel. i doupt the compression it going away when it gets up to temp.
I've been trying to eliminate any chance of vapor lock but was never an issue before with the same setup. I've installed heat shielding over the fuel lines and under the gas tank so far. Been thinking hard of picking up a set of stock coils to try. There are always issues to over come when you hotrod. Just gets aggrivating sometimes. I'll play around with it tomorrow and double check a few things, again.
|
Stuart Racing
Zone Head
N.H.R.A . Dragracing.
Posts: 999
|
posted February 27, 2009 01:11 PM
You have any additive in the coolant, watter wetter,engine ice?????Have the fan on a swutch????Timming, too much advance????Battery good???Mine wouldn`t start after heating up, found out is was the battery.....You keep saying carb.`s I assume you mean fuel inj. right....I know you have fuel inj.....Just giving you some things to check.....
____________
Life in the Fast Lane..........
|
KZScott
Needs a life
high on speed
Posts: 7235
|
posted February 27, 2009 02:53 PM
its a zrx so its carbed
____________
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
|
entropy
Moderator
Posts: 8671
|
posted February 27, 2009 03:03 PM
bad power commander?
____________
This moderator uses moderation in moderation
|
2000redrocket
Pro
Posts: 1662
|
posted February 27, 2009 03:08 PM
guys remember it is a ZRX old skool zx carb engine.
|
Y2KZX12R
Needs a job
CompetitionCNC.com
Posts: 3762
|
posted February 27, 2009 04:18 PM
Sounds to me like a carb problem. Can you isolate what cylinder is causing the problem?
You need to figure out if its fuel (most likely) or spark.
Valve clearances are all ok?
Are the carbs syncronized?
Plugs are out of the box new and not "cleaned" reused ones?
Start it up cold and monitor the exhaust pipe temps close to the head as the engine warms up. check each one every 10 seconds and see if one cylinder is hotter than the others.
As the engine gets to the temp where the problem starts carefully watch the temps.
Let it misfire and watch the temps. If you dont have pyrometers use an IR temp gun.
When its idling and misfiring, spray a TINY BIT of carb clean (with the little red tube supplied) in each carb and see what cylinder smooths the engine out.
Once you know what cylinder it is then you can spray some carb clean around the intake boot and see if theres a vacuum leak. Then take apart that carb and take the little piece if crud out of the idle circut.
Typically an engine that idles well cold or as its warming up is rich. An engine that doesnt run well cold but good fully warmed up is lean.
so you could also have one carb idle circut extremely rich. Or a float level too high.
Are the floats all the same weight? is one saturated with fuel? Are they foam or brass?
Start with that and we can go from there.
____________
Y2KZX12R
CompetitionCNC.com
|
kawasakijockey
Pro
Posts: 1876
|
posted February 27, 2009 04:27 PM
Edited By: kawasakijockey on 28 Feb 2009 00:29
It could very well be the carb pilot jet problems. Since the engine has been modded the actual vacuum could be dropping at temp causing inconsistent fuel draw problems. Been this go- round before myself. You try raising the idle speed to check?
____________
Get on the shortbus boys 'cause its time to get schooled.
2007 ZX-14
1.38 60ft
9.03 @ 149mph
8.95 @153 small shot n2o
8.68 @160mph 5lbs boost
|
Stuart Racing
Zone Head
N.H.R.A . Dragracing.
Posts: 999
|
posted February 27, 2009 05:32 PM
quote:
its a zrx so its carbed
AAAH. That`s right, I remember now that sweet ZRX he was building.....Sorry bout that....
The infa red test is a good trouble shooter....along with the carb spray too...Good one...
____________
Life in the Fast Lane..........
|
2000redrocket
Pro
Posts: 1662
|
posted February 27, 2009 07:04 PM
just to put this out there. before you go tareing into the carbs that use to work. when you use y2ks dead on method of finding the cylinder that is acting up change out the stick coil of that cylinder to a cylinder that was working ok. just so you do not chase your ass. if you installed them you will know if it is easier to swap a coil before taking the carbs apart. it is all part of the trouble shooting but i think it would be eaiser to rule out the electrical problem first. if you find the temp issue (you most likely will find a temp issue) is accross two cylinders, it may be a pickup.
also i also had a valve drop to .002" after a fresh rebuild from the old action machine in NJ and i chased my ass for a while on it being rich when warm but i could not jet it at all. so i had to go looking and it was the tight valve.
good luck.
|
Halvefast
Zone Head
Posts: 806
|
posted February 27, 2009 08:45 PM
Sounds lean at idle to me, try going up on the pilot 2 sizes
____________
Texas Mile 200.256mph - Oct. 2007 (Update 202.577mph Oct 2008) NOS assisted
ECTA Ohio Mile 195.132mph
TexasMile 2012 199.9 mph all motor!
Streetriders Shootout 2008 series Pro/ET Champ!
Streetriders Shootout 2007 Series Pro/ET Runner-up!
|
whitehendrix
Zone Head
fails!
Posts: 757
|
posted February 27, 2009 08:49 PM
i'll +1 the fuel stuff.. again, i won't rule out a thermal defect in the ignition, but that'll make itself obvious with an audible crackle with insulation breakdown at high temps.. typically, once insulation is broken down. it'll arc over no matter what the ambient temp it.. remember, you burn something and it turns to carbon..
carbon is conductive!
thus the reason as well if you do a circuit board repair, you gotta file off all the burnt crap before commencing on repairs.
have you monitored cold and hot A/F ratios? you migh benefit at this point from that...
____________
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
|
SteddyTeddy
Pro
Posts: 1664
|
posted February 28, 2009 09:58 AM
Thanks for the reply's everyone. I have an IR temp gun so I'll start with that and try to narrow things down a little. I've been running the bike with idle set up to 1500 rpm and it helps some but not fully. I'm planning on resetting my cam timing so will double check all valve clearances and throw in a new set of plugs again and start fresh. I had the carbs off and apart twice since the build and only found a pinched pilot screw oring. Float level was equal and they are plastic. Sync was double checked and compression double checked at the same time.
|
SteddyTeddy
Pro
Posts: 1664
|
posted March 02, 2009 05:47 AM
#2 is dropping. Plug was dry with black soot. The other 3 were a nice light brown. Valves are spot on. I switched the stick coil out and shifted that plug to another cylinder for now. If #2 drops out again I'll pull the carbs. If the cylinder that got that plug drops then I have another fouled plug.
|
|
|
HOME
NEW TOPIC