Black deposits on pistons

swest wrote: Being clean around the edges suggest rings. Classic. Put up pics of your build and if any questions just ask.
Steve

Steve,
When you say, "clean around the edges", do you mean my pistons in the pictures I posted look clean around the edges?
I take it you have run into this issue before?
Thanks for the help!

Yes, my rings didn't seat and that's what they looked like. I've seen it on others too. Make sure your not running too rich.
Lean is mean.
Steve

Here's a link to one of several KZr threads about removing carbon from the combustion chamber.

kzrider.com/forum/2-engine/369254-piston-top-cleaning#369273

Good Fortune!

Simply put....

Soak + toothbrush, don't use metal/wire wheel brush (use soft Nylon if required) for will scratch the dome surface....

Simple Green...
Can of Copper Coat...
While head off, new seals....
New rings a must...
New Piston clip rings...
Hone the cylinder bores...
New gasket kit (base & head)...

KzChop82 wrote: Swest- just ordered the new rings and seals.
Thanks for the advice.
A friend of mine was saying that the buildup of char on the Pistons could also be caused by the timing being a bit off. Do you think this is a possibility?

Some carbon can't be avoided, that's normal. It's only when oil or excess fuel gets into the combustion chamber it will become bad enough to cause problems. Detonation is the worst thing that can happen. The carbon will "glow" after ignition causing pre detonation on the compression stroke forcing the piston back down as it is coming up and possibly destroying the engine. Pinging can also be a symptom of pre detonation. Yes poor gas, spark too advanced and other things can cause this, but carbon is the leading cause. A spray mist from time to time can get rid of carbon but in a good running motor, it's seldom necessary.
Steve

+1 with what OMR posted. I would suggest removing the pistons for sure. The carbon deposits are really hard and will scratch everything they touch in a running motor.

A good shop vac and carb spray can clean it out but there is no better way than a complete cleaning. In this case, he's changing rings so it will be done anyway.
I like pics, more pics.
Steve

Started removing the gaskets from the head and base:





I tried to use this to aid the removal. It was useless.


Took a while, but got it looking good.

Here is what my valve area is looking like:


Should I use the same method to remove the buildup (soak in simple green)?
I tried to use this:


Again, useless- didn't even soften the deposits.

Couple of questions:
1. Should I just soak the entire head in simple green and slowly work the grime away with a toothbrush?
2. The honing of the cylinder- Is there a thread that goes into this process with a little more detail? Seams like a very important step, and I don't want to screw it up. OMR suggested a "flex-hone" tool, but there were also 3 drill attachment brushes (soft, medium, coarse)- are these used to hone the cylinders as well as the flex tool? or are they used to give everything a real good cleaning?

3. How essential are the "new piston clip rings"? Can they not be re-used?
4. What is "copper coat", and what is it used for?
5. The spring compression tool that OMR pictured, is the bottom piece something I need to fabricate?
5. How difficult is the process of removing, cleaning, and reinstalling all of the valves properly- and with the correct shimming? I have read a lot of posts about this process- and it seams difficult. Is there a fool proof procedure for this?

Again- can't thank you all enough for your help and advice.
Sincerely,
Arthur

KzChop82 wrote: Here is what my valve area is looking like:

Attachment IMG_3413.jpg not found

So, I'm just asking because I rarely see this side of the head... looks to me like the plug is far recessed. Does anyone think the wrong plugs have been run in this motor, based on the PIC above?

Arthur... what plug are in the head? ...and, are the plugs fully seated, in the PIC?

TIA...

Very observant!
B8ES, they were backed out to gain access to the side bolts on the head.

It depends on the condition of the bores. Is there a ridge at the top? I like the three block hones. A good mechanic can pull out a slight ridge with one but for most people it's best to have it done. That hone job is a little too much for my liking. It's easy to take away too much metal and have a sloppy bore. A good 45 Deg. cross hatch is ideal. You use the course stones for this. I use a wire brush attachment to clean the head. Leave the valves in while doing this. Fine clean after the valves are removed. I use a C clamp and a piece of 3/4 PVC to extract the valve keepers. First use a deep socket to loosen the valve retainers then use the PVC cutout to remove the keepers with a magnet. Tweezers to put them back in. I was going to donate a deep spark plug socket to do it but I don't do enough of these to justify ruining a good socket.

Great idea, thanks Steve.
By the way- happy new year everyone!