ZRXDean
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posted June 10, 2009 11:23 AM
Combustion chamber deposits
Hey folks, I found 30-40% leakdown in 2 holes a few days ago. Other 2 fine. I pulled the head off last night and couldn't see any signs of valve-piston contact, but there is a lot of grayish dry deposits all over the chamber and valves. Perhaps there is some crud on a seats holding a few valves open.
It got me thinking about what I should expect in the way of chamber deposits, and I don't really know. Any rules of thumb? What is too much? This is a boosted motor, with C16 or the like. Thanks.
  
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ZRXDean
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posted June 10, 2009 12:36 PM
Here's a crappy pic.
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VincentHill
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posted June 10, 2009 12:45 PM
Looks like a LOT of heat in that engine! The good news is that the Head Gasket is keeping it "ALL" inside the cylinder!
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Made History @ Daytona and still one fast old man!!
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Shane661
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posted June 10, 2009 12:45 PM
 Edited By: Shane661 on 10 Jun 2009 20:47
Hey Dean, just curious, how rich do you run the bike? When I switched from Sunoco 112 to C16 Racheal's bike seemed to fatten up a bit. I'm a little concerned about it in the long term. I was thinking it might lead to some excessive build up. It was tuned at about 11:1, but ran 10.4:1 at the top of 6th on 14 psi...
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ZRXDean
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Posts: 2225
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posted June 10, 2009 01:09 PM
Yep, I'm happy to say that I have yet to blow a head gasket in this bike (knock on wood). The ZRX was a constant pain.
I try to run between 11.5 and 12:1 AFR. Sometimes leaner than that, but not much.
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dubious
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posted June 10, 2009 08:15 PM
Edited By: dubious on 11 Jun 2009 04:15
Shane,
I was told to run some seafoam fuel additive through it once in a while, as it will clean all the carbon up... thats what I was told...
Dean,
I discussed this with Doug on the phone, as I was considering o ringing my 14, but he has been told that the 14 hasn't shown a need for Oring.
Noting the zx10 is a monoblock like the 14, maybe the cylinder stability is helping...
The pic is interesting.
I am new to turbo, but that grey rough look would make me think its aluminum... I have seen many 2 strokes look that way just when they begin to burn the exhaust side off the piston and ringland.
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natural selection.....
destiny will overcome intervention.
Some are not worthy of the effort.
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tcchin
Zone Head
Posts: 867
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posted June 10, 2009 10:08 PM
It's tough to tell from the low-res pic, but it looks like either lead or oil ash. Were there any white, salty-looking deposits in the exhaust ports?
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entropy
Moderator
Posts: 8671
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posted June 10, 2009 11:09 PM
quote:
It's tough to tell from the low-res pic, but it looks like either lead or oil ash. Were there any white, salty-looking deposits in the exhaust ports?
those "white, salty-looking deposits in the exhaust ports" taste horrible!
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dubious
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posted June 10, 2009 11:10 PM
hmm,
when I ran U4 in my dirtbike, it left grey deposits....??? the pipe was grey too..
____________
natural selection.....
destiny will overcome intervention.
Some are not worthy of the effort.
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Ricksgsxr
Zone Head
Posts: 511
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posted June 11, 2009 04:33 AM
Edited By: Ricksgsxr on 11 Jun 2009 12:35
Ahh Dean ya add a little NM/Methonal mix and will be purty LOl!
Mine looked great till the head gasket puked and ran a little lean the piston tops, um, wait where did they go?
When you do put together maybe look into Calico Coatings if they are offering DLC coating yet for valves.
They have other coatings that help resist the buildup and my motor which I have yet put back in the frame has just about every coating application they offer maybe awhile before I can confirm if a good investment but seems in theory will.
I think DLC is the way to go, just not main stream available when I did my rebuild for small part coating runs.
http://www.calicocoatings.com/industries/coating-solutions/automotive-racing/
I had multiple shipments through Cycle Concepts them not one took more than a 2 week turn around 
Coating Solutions Applications Typical Coating Thickness Typical Colors and Shades
CT-1 Dry Film Lubricating Coating Engine Bearings 0.25 to 0.30 mil Dark Gray
CT-2 Thermal Barrier Coating - Silver Headers
Exhaust Pipes
Piston Tops 1.0 to 1.2 mil Silver Gray
CT-3 Dry Film Lubricating Coating Piston Skirts 0.5 to 1.10 mil Dark Gray
CT-4 Corrosion Resistant Dry Film Lubricating Coating Gear Box Housing Made of Aluminum or Magnesium Alloy
Suspension Parts 0.75 to 1.0 mil Black
Red
Gray
Blue
Yellow
Orange
CT-5 Non-Wetting Dry Film Lubricating Coating Crankshafts
Connecting Rods
Windage Trays 1.0 to 1.2 mil Silver
Black
CT-10 Dry Film Lubricating Coating Piston Rings
Gears
Shafts
Thrust Washers 0.5 to 0.6 mil Dark Gray
CT-15 Dry Film Lubricating Coating Cam Bearings
Bushings 0.35 to 0.40 mil Black
CT-16 Manganese Phosphating Gears
Shafts 0.35 to 0.40 mil Black
CT-23 Coolkrome Headers
Exhaust Pipes 1.0 to 1.2 mil Bright Metallic
CT-24 Coolblack (Thermal Barrier Coating) Headers
Exhaust Pipes 1.0 to 1.2 mil Black
CT-29 Heat Transmitting Coating Radiators
Intercoolers 1.0 to 1.5 mil Black
Calico D (Diamond Like Composite) Lifters
Engine Valves 1-4 µm Violet Blue
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ZRXDean
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Posts: 2225
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posted June 11, 2009 04:51 AM
quote:
It's tough to tell from the low-res pic, but it looks like either lead or oil ash. Were there any white, salty-looking deposits in the exhaust ports?
Yep, exactly, little white crumbly bits in the ex ports. The chamber deposits are dry, ashy, and scrape off pretty easily. It's hard to see in the pic, but there is a radial pattern in the deposits running straight into the ex ports, neat.
I pulled the valves, and I can see rust on the ex seats of the 2 holes with heavy leakage. I'm going to lap the hell out of them all and see if it will seal.
Thanks for the comments, very helpful.
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Shane661
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posted June 11, 2009 05:44 AM
Dean, do you have water injection?
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ZRXDean
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posted June 11, 2009 08:06 AM
Nope, why?
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Shane661
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posted June 11, 2009 08:09 AM
Edited By: Shane661 on 11 Jun 2009 16:15
I was just curious about the rust. There is a lot of moisture in the compressed air anyway. I seem to recall some studies on cars where long term usage of water injection was not good for the rings, etc..
Sorry to use your thread for my own purposes; I'm just gathering information that may apply to our turbo app. 
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dubious
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posted June 11, 2009 06:24 PM
Whats the concensus?
What is causing this?
____________
natural selection.....
destiny will overcome intervention.
Some are not worthy of the effort.
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dougmeyer
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moderated
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posted June 11, 2009 07:35 PM
How much time is on that engine?
Regarding the leak rate, did you not determine where the leak was before you took it apart (by listening at the ports and case vent)? If the valves are still in there set the head on a couple of blocks and squirt some contact cleaner in the ports- see if and where it runs out.
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It's not that I think you're dumb, it's just that so much of what you know isn't true....
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ZRXDean
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Posts: 2225
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posted June 11, 2009 08:20 PM
This engine has been together for about a year, 6 LSR meets and 2 dyno sessions. So quite a while IMO. Mostly with no aftercooling.
I didn't spray the valves before disassembly, but ex seats in #1 and #3 (the leaking cyls) looked the worst, rusty, cruddy. Maybe these were open over a long period and rusted from condensation? Not sure what I can do to minimize this. I know Kevin used to spray WD40 into a promod while turning it over, but that's kinda hard with a turbo.
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tcchin
Zone Head
Posts: 867
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posted June 11, 2009 08:56 PM
When we used to run nasty fuels like MR1 and MR9, valve seat corrosion used to be a big problem. After just a week of sitting, the cylinders whose valves were open would leak 20-50%. Once we fired the motor up and the valves seated back into the seats, the leakdown would go back to normal.
BTW, those white crumbly bits in the exhaust ports are lead deposits.
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dubious
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Needs more time to ride!
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posted June 11, 2009 09:05 PM
quote:
Coating Solutions Applications Typical Coating Thickness Typical Colors and Shades
CT-1 Dry Film Lubricating Coating Engine Bearings 0.25 to 0.30 mil Dark Gray
CT-2 Thermal Barrier Coating - Silver Headers
Exhaust Pipes
Piston Tops 1.0 to 1.2 mil Silver Gray
CT-3 Dry Film Lubricating Coating Piston Skirts 0.5 to 1.10 mil Dark Gray
CT-4 Corrosion Resistant Dry Film Lubricating Coating Gear Box Housing Made of Aluminum or Magnesium Alloy
Suspension Parts 0.75 to 1.0 mil Black
Red
Gray
Blue
Yellow
Orange
CT-5 Non-Wetting Dry Film Lubricating Coating Crankshafts
Connecting Rods
Windage Trays 1.0 to 1.2 mil Silver
Black
CT-10 Dry Film Lubricating Coating Piston Rings
Gears
Shafts
Thrust Washers 0.5 to 0.6 mil Dark Gray
CT-15 Dry Film Lubricating Coating Cam Bearings
Bushings 0.35 to 0.40 mil Black
CT-16 Manganese Phosphating Gears
Shafts 0.35 to 0.40 mil Black
CT-23 Coolkrome Headers
Exhaust Pipes 1.0 to 1.2 mil Bright Metallic
CT-24 Coolblack (Thermal Barrier Coating) Headers
Exhaust Pipes 1.0 to 1.2 mil Black
CT-29 Heat Transmitting Coating Radiators
Intercoolers 1.0 to 1.5 mil Black
Calico D (Diamond Like Composite) Lifters
Engine Valves 1-4 µm Violet Blue
Aren't you guys worried about putting all that stuff in your engine?
I would imagine its pretty difficult to perform oil analysis?
Can this stuff be trusted and applied evenly enough to determine concentricity and final bearing clearances down to.0001 " ?
Maybe its just me, and correct me if I am wrong......Maybe I am old school ?
I did the outside of my header and turbo, but was told not to do the insides...
____________
natural selection.....
destiny will overcome intervention.
Some are not worthy of the effort.
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dougmeyer
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moderated
Posts: 2713
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posted June 12, 2009 11:28 AM
I concur with tcchin.
Race fuels are not blended with any consideration for corrosion resistance and who knows what sort of compounds fester in there when you shut it off and park it for weeks. Those little white nodules are metallic salts from the fuel anti detonation metallics in the fuel and the moisture.
One only has to run at Bonneville once to see what unattended-to corrosion can do. When I finish running something on anything but pump gas and am going to leave it sit for a while, I always spin it over with the plugs out and spray some WD or other anti corrosive down the inlet ports.
Dubious- Coatings can be very effective if used where and when needed, but I wouldn't go nuts with them without having a specific goal.
____________
It's not that I think you're dumb, it's just that so much of what you know isn't true....
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ZRXDean
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posted June 12, 2009 04:17 PM
Thanks folks, I'm glad it not a sign of anything serious.
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Ricksgsxr
Zone Head
Posts: 511
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posted June 13, 2009 04:16 AM
Longer part life was the main goal of the coatings except coating the CC and piston tops were for performance.
Everything else, friction/pumping loss and possible gains are prolly going to similar to when I installed ceramic bearings and light wheels the combo was worth a whopping 1hp on the dyno now a ride down the road feels like whole lot more than 1hp...
This is another service my inquiring mind tried and remains to be seen if works.
http://www.procryo.com/RemGears.html
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