Decarbonizing pistons

[Bisbee]

Is there any magic elixir that I can add to the fuel that would blast accumulated carbon off the piston , etc. surface? The bike has suffered from short , low mileage trips for many years. Don’t want to pull the heads off and scrape. Bike runs well though. Or just forget about it?

[pete mcgee]

Try adding some upper cylinder lube to the tank and then go and ride it in a "sportsman like fashion".
Include as many steep twisty roads as possible,  high speed freeways, etc. Use most of your rev range.
One full tank out, one full tank back.
Repeat every 7 days😁.
This will also get you out of the commuter cycle, good for you as well as the bike.
Cheers

[rschrum]

Spray a fine mist of water into the intake while reving the engine, steam cleaning.

[old head]

Water will do it, but very little at a time and when engine is hot.  I have used water a lot especially when all cars ran with carburetors.  It will smoke a lot, just be careful, water doesnt' compress.  Just be sure to check the oil when you finish to be sure you haven't diluted the oil with water.

marvel Mystery will do the job over a period of time.

Run at a higher rpm for extended periods will also help burn off carbon.

Project Farm on Youtube has several videos comparing MM, seafoam and water to cleaning carbon.

Old Head

[bmc5733946]

I am old and learned some tricks from some real oldtimers when I was much younger. I learned that there are many things that will go through an engine as it is running that one would never think of running through an engine. Water is one, uncooked rice for cleaning valves,  ground walnut nutshells for the same etc, etc. Does any of it work? I'll give it a qualified yes in that I have seen engines run better after some of these treatments but I've never torn down the engine before and after to know what really took place inside. Best one for me was a six cylinder Ford with a miss on one cylinder, seemed like intake was hanging open, popped through carb occasionally,  low compression, could hear it leaking through carb, ran rice through it as last resort while owner watched, ran better for quite some time. Compression came up, couldn't hear anything in carb, no popping. Shrug! Guess it worked.

Brian

[mechanicsavant]

I haven’t checked in a while , but there was an aerosol  sold by car dealers designed for specifically that problem . AMC called it “carb & combustion cleaner “ GM had a similar product .Very popular in the 80’s when fuel was erratic & engine control systems were in flux dealing with emissions . Possibly @ parts stores for diesels Sea Foam maybe.

[Scout63]

I shouldn’t take more than a couple of hours to pull each head and do the credit card thing on each piston crown.  I would think that mechanical cleaning works better.  Plus you get the satisfaction of seeing your pistons. 

[Wayne Orwig]

No detonation or other problems, why bother?

[Ncdan]

No detonation or other problems, why bother?

How goes one know if this process needs doing?

[Mayor_of_BBQ]

how do you put raw rice in a running engine? or walnut hulls for that matter?

[SIR REAL ED]

I shouldn’t take more than a couple of hours to pull each head and do the credit card thing on each piston crown.  I would think that mechanical cleaning works better.  Plus you get the satisfaction of seeing your pistons.

Yep!  Wire brush with piston at TDC.  Wipe off with a rag soaked in penetrating oil to get rid of the carbon that should just blow out the exhaust valve anyway.

Might as well scribe your initials and date in the top of the piston while you're at it.

Next owner might see it and wonder....

[bmc5733946]

how do you put raw rice in a running engine? or walnut hulls for that matter?

Straight down the carb while running, hand on throttle to keep it running, same with water. Needs to be running pretty quickly or will stall.

Brian

[lucky phil]

how do you put raw rice in a running engine? or walnut hulls for that matter?

Walnut shells are sometimes used for compressor cleaning on gas turbine engines but it's not for ICE's EXCEPT for cleaning the backs of inlet valves in direct injection engines. It's not done with the engine running but stationary with the inlet manifold off and the piston at TDC with the valves closed. You then pressure blast the valves and inlet tract with ground walnut shells to remove carbon deposits while at the same time a shop vac extracts the used shell and carbon. There is a cheap and simple tool to do it with a home compressor. God knows where people come up with all this weird stuff like rice and shells in a running engine and why, morons I suppose.

Ciao

[Muzz]

Spray a fine mist of water into the intake while reving the engine, steam cleaning.

Engine must be hot, water a mist.  Actually forms producer gas.  C + H2O -> CO + H2  Do it in bursts if you are going to do it as the reaction is highly endothermic.

[chuck peterson]

Friend of mine ran an International. The original Suburban...we used it as transport vehicle for towing a sailboat across the east coast 1975-1978.

He had a quart jug set off to the side, w a hose over to the carb. He had it set up to siphon water out of the jug to the carb.

350k plus miles on that motor, last i heard in the 80s...And he claimed better mileage

[Bisbee]

Thanks for the suggestions. I’ll put some MMO in and leave it be since it runs well. I do remember 50+ years ago reading WWII Pacific air stories that told of hellcats and corsairs being equipped with emergency water injection for a good boost in power. Only to be used in emergency due to decreased engine life. Then there are the old dieselers that swear by adding a quart of ATF to the tank , the motor would run much better. I’ll pass on that.

[Wayne Orwig]

I do remember 50+ years ago reading WWII Pacific air stories that told of hellcats and corsairs being equipped with emergency water injection for a good boost in power. Only to be used in emergency due to decreased engine life.

I don't recall the details, but it was something like that would crank up the superchargers to boost power, and the water was to reduce detonation from the higher pressure.

[pete mcgee]

I don't recall the details, but it was something like that would crank up the superchargers to boost power, and the water was to reduce detonation from the higher pressure.

And it was generally a water methanol mix.
And distilled water not tap water.
These systems were an answer to a problem, cooled the supercharged air and changed the density. Also the system to inject it was controlled so the amount of water would be both atomised and a limited percentage of the ingoing charge.

[leroy_can]

 The water isn't providing power it is reducing detonation thus allowing larger throttle openings and more boost from the supercharger. It's actually water methanol which is mostly water. It might take an engine that was limited to 52 or 53 in. of manifold pressure at takeoff and allow it to go to 60+ assuming the supercharger was capable of more.

[lucky phil]

The water isn't providing power it is reducing detonation thus allowing larger throttle openings and more boost from the supercharger. It's actually water methanol which is mostly water. It might take an engine that was limited to 52 or 53 in. of manifold pressure at takeoff and allow it to go to 60+ assuming the supercharger was capable of more.

Yes used on many piston engines in WW2 and also Jets. The original Pratt& Whitney JT9 jet engines on the very early 747's also use it for take off for much the same reasons.

Ciao

[leroy_can]

  Why does everybody keep saying WWII ? I was still working almost exclusively on aircraft with 18 cyl. 2800 cu. in. radials until 2018. Never personally worked on any with water injection. In engines that used it the horsepower maximum would be listed as dry vs wet horsepower. I would roughly say the difference was 5 to 700 more horsepower in the big radials. The Max RPM remained at usually 2700-2800 but the power increase meant the variable pitch propeller would be driven to a courser pitch by the governor basically taking larger bites of air. Not intending to de-rail the OP but it seems he has come to a conclusion anyways.

[lucky phil]

  Why does everybody keep saying WWII ? I was still working almost exclusively on aircraft with 18 cyl. 2800 cu. in. radials until 2018. Never personally worked on any with water injection. In engines that used it the horsepower maximum would be listed as dry vs wet horsepower. I would roughly say the difference was 5 to 700 more horsepower in the big radials. The Max RPM remained at usually 2700-2800 but the power increase meant the variable pitch propeller would be driven to a courser pitch by the governor basically taking larger bites of air. Not intending to de-rail the OP but it seems he has come to a conclusion anyways.

You've just answered your own question, because the practice of water injecting aircraft piston engines was most common in that era as they were trying to squeeze the last drop of power out of them. That and Nitros oxide injection as well used by the Germans.

Ciao

[Perazzimx14]

If you decide to remove the heads there is no need to scrape or wire brush the carbon deposits. Get you a quart of Aircraft paint stripper (avalaible at all the mega marts, home improvement centers and chain auto parts stores) with methylene chloride as the active ingredient. Dab it on with an old tooth brush and watch the carbon melt to a black ooze right before your eyes. Wipe clean with a paper tower. For really heavy deposits another 1 or 2 applications may be needed or a longer dwell time and some agitation with the toothbrush.

Klean Strip is the most common brand around here and it works a treat!

[bmc5733946]

Water injection also used in 60s on turbo charged GM aluminum V8 in Olds, Pontiac, Buick!

I have watched as an elderly gentleman I knew poured crushed walnut shells into a running Ford V8, 312ci I think. It can be done. In the 80s the stopped engine process was a factory recommended procedure for GM cars with deposits on the valves. Some GM techs I knew claimed it worked just as well to put it through the vertical throttle body injectors but couldn't figure out a process for horizontal throttle bodies hence the engine partial tear down. I've apparently met a lot of morons, I guess I'm one as well. There are all sorts of things that will do allsorts of things we may never know if not tried. Risk, reward. Your personal experiences may differ greatly from those of others!

Brian

[leroy_can]

 

Water injection also used in 60s on turbo charged GM aluminum V8 in Olds, Pontiac, Buick!

I have watched as an elderly gentleman I knew poured crushed walnut shells into a running Ford V8, 312ci I think. It can be done. In the 80s the stopped engine process was a factory recommended procedure for GM cars with deposits on the valves. Some GM techs I knew claimed it worked just as well to put it through the vertical throttle body injectors but couldn't figure out a process for horizontal throttle bodies hence the engine partial tear down. I've apparently met a lot of morons, I guess I'm one as well. There are all sorts of things that will do allsorts of things we may never know if not tried. Risk, reward. Your personal experiences may differ greatly from those of others!

Brian

Well said

[LowRyter]

Can't a little carbon on the top of the piston be considered a free compression boost?   So long as it's running right and not detonating, isn't that a good thing? 

Carbon is lightweight and strong.

Just asking.

[lucky phil]

Water injection also used in 60s on turbo charged GM aluminum V8 in Olds, Pontiac, Buick!

I have watched as an elderly gentleman I knew poured crushed walnut shells into a running Ford V8, 312ci I think. It can be done. In the 80s the stopped engine process was a factory recommended procedure for GM cars with deposits on the valves. Some GM techs I knew claimed it worked just as well to put it through the vertical throttle body injectors but couldn't figure out a process for horizontal throttle bodies hence the engine partial tear down. I've apparently met a lot of morons, I guess I'm one as well. There are all sorts of things that will do allsorts of things we may never know if not tried. Risk, reward. Your personal experiences may differ greatly from those of others!

Brian

I've seen a lot of people do a lot of stupid things over the years as well. Just because you can doesn't mean you should.

Ciao

[Moparnut72]

Another one that was common ack in the day was to lightly pour some Bon Ami into the carb to seat the piston rings. Something I would never do but I guess it was quite common from what I heard.
kk

[bmc5733946]

I had a 1965 Mercury Comet with the all conquering 200ci 6cyl engine. Bought it from the Grandparents of a friend. Not a lot of miles but a rusty car none the less, strong engine. It burned a quart of oil every tank of gas. I was headed to a job interview a ways from home that required travel by freeway, at about 70mph in a very busy spot on a long bridge it overheated. Once I got pulled over I could hear the engine oil crackling, cooking, on the top of the cylinder head. I finally got it sussed out. Upper radiator had separated and collapsed the inner liner. I knew I needed to change that engine oil after the overheating, having little money I knew I couldn't afford the Pennzoil I had been using so I bought some rerefined oil at a local store. That car never burned another quart of oil in the time I had it. Some theorize that the overheating caused the oil control rings to come free from being stuck, others said that those engines were built with chrome rings and they finally seated properly. I fall somewhere in between, the engine actually was built with chrome rings, the engine was subjected to a lot of short trips prior to my ownership, who knows, glad it stopped burning oil.

Brian