Decarbonizing pistons

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I had my spark plugs out recently because I was bored on my day off and figured I'd see how they were wearing after 40k miles of use. Plugs looked excellent but while they were out I figured I would peer down into the combustion chamber with a flashlight and see what I could see. I wasn't surprised to see carbon buildup on the tops of the pistons(what I could see through the plug hole at least.) I've got a little bit of a rough idle, it isn't erratic, rpm stay the same, but it's enough to be noticeable. My truck has become a hobby and I figured I'd like to take a crack at cleaning up some of the crud on the pistons. I don't usually buy cheap gas, 99% of the time I fill up at chevron, unless the fueler truck is there stirring up any junk in their reservoir, then I go a few more blocks to the next one. I'm not convinced on seafoam or any other cleaner that goes for $9-$15 a bottle. I've heard of people using water introduced into the intake manifold in small amounts while the engine is hot and at ~2500rpm. Supposedly this is an effective practice and perfectly safe if done right, but I'm understandably a little hesitant to put water in any amount into my combustion chamber. I've got a vacuum gauge rigged up in the cab of my truck, so I could probably just cruise down the freeway and use the vacuum hose to suck in some distilled water; most likely with something very constricting on the hose, like one of those needle fittings used to inflate basketballs. So what are your thoughts? Anybody done this themselves?
 
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Originally Posted By: slowdime
I'm not convinced on seafoam or any other cleaner that goes for $9-$15 a bottle. I've heard of people using water introduced into the intake manifold in small amounts while the engine is hot and at ~2500rpm.
Why does the water convince you but chemicals did not? Both seem equal in their plausibility (or snake-oil-ness if you're a skeptic) Why are you're willing to rig up something pretty complex versus trying something simple for $10 first. Try Seafoam and/or like Redline SI-1 for $10 FIRST. Then if you're still not convinced, go ahead and go to home depot and spend way more to rig up your water injection system.
 
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i have used seafoam many times on a variety of vehicles. Some were my own and some were customers. I am sold on seafoam. I did it on my 98 ford ranger 3.0 with over 100,000 and it idled so smooth after you are left thinking is my truck running. I am not saying thats always the case but seafoam is cheap and works for me. But water does also work as well. Eric the car guy on youtube has a short video on how to decarbonise your engine with water. https://www.youtube.com/watch?v=KFtp_jmLF3k
 
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slowdime

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Water believe it or not is an excellent solvent. I've seen people soak pistons overnight in seafoam during rebuilds and there was no difference in the amount of carbon on the pistons. A gallon of distilled water is considerably cheaper than a few ounces of seafoam or any other top end cleaner that may or may not produce similar results. I've seen cars that have had the heads removed to replace a leaking HG, the piston that had the leak was comparatively spotless against the other cylinders that weren't effected by the leak. Also there is no real rigging up to do. I already did that when I put in my vacuum gauge. All I would need to do would be to pull the vacuum hose off the gauge and put on a constricting device to suck water slowly.
 

slowdime

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I've seen a number of Eric the car guy's videos but I'll check that one out. I have to admit tho, Scotty kilmer's channel is much funnier.
 
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Originally Posted By: MolaKule
I prefer the MolaSoke for a slow cleaning of piston crowns and rings.
I've heard that many times, but not what that is exactly.
 

slowdime

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Nm molakule So it's something you came up with? I did some searching and couldn't find the recipe on the boards anywhere. (I am on my phone at work tho, not the easiest to search)
 
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scotty kilmer is to fast for me. Being someone who knows a little sumn sumn about cars i feel like he leaves out valuable info. I like the idea of disconnecting the vacuum gauge and sucking some water while driving down the highway.
 
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<span style="font-family: 'Verdana'">The best way to decarbonize pistons is the remove the cylinder head; spray WD-40 in liberal amounts on top of piston; and then scrub said piston with wire cup wheel at 400 RPM or approximate.</span>
 
I did the exact same thing a couple of months ago, changed my plugs and peered down into the chamber and saw what looked like black flakey pastry haha I also had a bit of a rough idle as well as pinging and sometimes it was very hard to start. I used TBC to clean what i could see and also sprayed bursts into the intake at idle. After that i filled a mini garden spray bottle up with distilled water and after a long highway run on a hot engine I misted it into the intake, changing between idle and 1/4 open throttle. Unlike TBC which made the car want to stall i was surprised that no matter how much water you spray into the intake it doesn't affect the way the car runs! It was going through the system as there was a lot of vapour and water dripping from the tailpipe. I have had no trouble since with hard starting which was pretty severe beforehand but i think i still get some pinging
 

Kestas

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Others report using water injection to decarbonize the tops of pistons. This idea capitalizes off the fact that leaky head gaskets, which leak coolant into the chamber, often result in a clean chamber. Some plumb a line from a gallon jug in the passnger cabin to a vacuum line far ahead on the intake manifold. On a drive, throttle the amount of water consumed so the engine doesn't gulp too much water at idle, where rpm is low and ingestion from vacuum is high. This will help prevent any water lock. This is best done with freeway driving. I've done it myself. Though I didn't check any before or after chamber conditions.
 
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One thing you should do is to compare the vacuum readings before and after. Positive running improvement will be apparent on the increase in the vacuum reading at idle.
 

slowdime

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Originally Posted By: joegreen
scotty kilmer is to fast for me. Being someone who knows a little sumn sumn about cars i feel like he leaves out valuable info. I like the idea of disconnecting the vacuum gauge and sucking some water while driving down the highway.
He does tend to gloss over things quite quickly without much actual hands on stuff. Eric the car guy has excellent step by step info, but Scotty is hilarious IMO. I think I'm going to give some water a shot through my vacuum gauge line on the freeway. I've got a good mental image of what the tops of the pistons look like now, I'll give it a try and see how it works out!
 
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It would be interesting to see how the slow release of water at highway speeds would help in cleaning the slugs. Don't be surprised if your idling issues don't go away though.
 

slowdime

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Originally Posted By: Vikas
One thing you should do is to compare the vacuum readings before and after. Positive running improvement will be apparent on the increase in the vacuum reading at idle.
First start of the day vacuum is at 17" and slowly migrates up to 19" +/- 1" after I've let it warm up. Once the oil has gotten to opersting temp, vacuum is right around 21". I'd be surprised if there was an increase in vacuum at idle since the numbers I've got already show a healthy motor. A quick snap on the throttle drops vacuum to 0" then back up to 24" or so.
 

slowdime

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Originally Posted By: chestand
It would be interesting to see how the slow release of water at highway speeds would help in cleaning the slugs. Don't be surprised if your idling issues don't go away though.
Yeah I'm not holding my breath on it evening out the idle. But hey, clean pistons would make me happy. I'm going to clean the iac and tb and take a look at the injectors as well
 
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