Carbon in combustion chamber

[jaywish]

I have been having a long term issue with pinging/breaking up under load with the wagon. If I used low-test it would clatter, lose power and blow smoke out the pipes when I hit the gas hard.

Eventually it even pinged slightly with hi-test on hot days. The timeing is set to stock.

I started to work on this problem maybe a month ago. I pulled the plugs and put a scope in the cylinders and found the pistons covered in carbon and the plugs in good shape.

I used "Run-rite" cleaner thru the throttle body and started useing their fuel additive product. A few days before Scottfest I pulled the plugs, inserted about an oz. of AC Delco top engine cleaner in each cylinder, put the plugs back and let it sit overnight.

Next day removed the plugs, spun the motor over and small chunks of carbon spit out along with the cleaner fluid. Put in new plugs, wires, cap, rotor. Gave it another throttle body treatment and changed the oil/filter as I was concerned that the top engine cleaner might have diluted the oil. I have been useing the fuel tank additive right along for about 5 tanks.

Went to Scottfest and returned, about 600 miles all told. Last Thursday I borrowed the camera again, pulled the plugs, they were nice looking but with a carbonny coating on the outer ring. I ran a compression check. It came out great, had a range of 132 to 140 lbs.
When I looked at the pistons with the camera, easily 75% of the carbon was gone. The remaining crust is primarily a circle around the outer edge of each piston. There are in addition, occasional adhesions scattered on the piston tops.

I can not attribute the carbon reduction to any specific treatment. I wonder if I am wasteing my money on the fuel additives? Maybe the soak and TB treatments are the solution? Anyone gone through this process? Any suggestions? I have not tried low octane gas as yet as there is still significant carbon in place. Wish I could get a look at the valves but I can not get the camera to look up.

I am hopeing that after the carbon is eliminated I can boost the timeing a bit as the exhaust is a little bit more open than stock.

Jay

[BigT]

It may be eliminated for now, but it will come back. Unfortunately it’s a side effect of the EGR (exhaust gas recirculation). That carbon rich exhaust gas will start recoating the cylinders again. There may be other cause too, but ever since I disconnected my EGR valve, I don’t get the buildup like I used to.

[jaywish]

Good point. I am hopeing that it would take quite some time for it to build up a thick coat after it is finally cleaned. Perhaps a can of fuel treatment would keep it under control and prevent any buildup?

[miamibob]

SEAFOAM it! Works for me!! Bobby

[jaywish]

Seafoam actually removed encrusted carbon from the pistons?

I know it will clean the TB.

[miamibob]

Never took any of my cars that far to say for sure but they run good so perhaps it does????

[gadget73]

I used to have severe detonation problems with my S10. I tried a few things but largely ignored it for years. At some point I gave the Seafoam through the vacuum line treatment a shot, and it completely quit pinging. Its been probably 6 years since I did that, and its still quiet. I don't expect what I did is more effective than pouring the stuff in the cylinders and letting it soak, since basically thats what you do with it, but it definitely made a difference. I have long been a disbeliever in "mechanic in a can", but at least in that case it worked.

[jaywish]

Perhaps it does. I have a few more cans of the "run-rite" intake cleaner. Maybe I will try another cleaning with it and then check the pistons as my friend let me hang on the camera for a while. If there is no change then maybe Seafoam.

Maybe somebody else has gone through this and can post up how to get it all out. Maybe a tool of some kind?

Jay

[sick88tbird]

I just got all the carbon out of my 351w while it was torn apart...when I first assembled it approximately 5,000miles ago it was clean as could be...but short trip driving and never getting the oil completely up to temperature had taken it's toll. Up north we used to have the Cat products bottle and "Run-Rite" treatment...it was recommended every 15k miles and I always thought it was a scam...until we pulled the head of off the store manager's mercedes(treated every 15k miles) and everything was clean enough to eat off of...ports, valves, chambers and pistons. Highly polished parts help reduce carbon build up because it doesn't have much to stick to, polished surfaces have minimal porosity.

Keep us posted,
Don

[turbo2256b]

I just use water most of the time.

[86VickyLX]

Water works, as long as you don't drown the engine. Though that's true for any liquid carbon removing solvent. At work we do what's called a 3 step fuel system cleaning. Which basically consists of a throttle body cleaning, tank additive, and another solvent that's sucked through a vacuum line. I've done a few and it has helped a lot with cars with carbon build up/pinging. Though basically what you're doing is the same thing.

[jaywish]

That is what I started with, I neglected to mention the throttle body cleaner. Then instead of into a vacuum line The run-rite is injected into the TB intake. It is atomized with assistance of shop air. Then the techron based tank additives.

Still quite a bit left to be removed. I would soak the pistons again but I put in mobil 1 oil and do not want to waste another expensive oil change, so I will keep up with the tank additives and an occasional TB. treatment. Then Seafoam if they do not work. It seems to take a considerable effort to get this under control.

Jay

[sick88tbird]

It definitely does take considerable effort...that carbon is hard, tough stuff.