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cleaning carbon buildup in engine w water?


delco1946

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Random story, but i just had the transmission rebuilt in my '55 ford w a 292 y block. The shop mentioned they heard pinging and asked about my gas. I use normal premium aka not pure-gas premium. Anywho, this got me to researching pinging, piston slap, knocking etc. I don't know if i've ever heard any of those/couldn't discern between them even if i tried, but i started seeing videos and threads suggesting pinging is often related to carbon buildup in engines and that a easy way to de-carbon them is by (carefully) pouring water down the carburetor. I also saw some people saying that this should only be done on vehicles without a catalytic converters as you could blow crud out the exhaust that gets stuck in the cat converter. Some people said they did this weekly even, especially on older vehicles to clean out the carbon generally created on short trips. Does anyone here do this? Is this harmful? Helpful? I'm asking for both my '55 Ford and my '81 Bullnose (with cat).
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On the 1955 Y-block, yes, it works quite well. Just be sure that (a) no one you like is downwind and (b) pour it slowly down each side of the carburetor with the engine revved up a bit. As the water enters the cylinders, it will probably start missing, slow the pour rate (I used to use Pepsi bottles) I also ran the engine at what would be a good cruise rpm, and as it started to slow down open the throttle more.

The 1981, if you are going to do it, I would disconnect the catalytic converter while doing it, the carbon sometimes comes out in chunks.

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On the 1955 Y-block, yes, it works quite well. Just be sure that (a) no one you like is downwind and (b) pour it slowly down each side of the carburetor with the engine revved up a bit. As the water enters the cylinders, it will probably start missing, slow the pour rate (I used to use Pepsi bottles) I also ran the engine at what would be a good cruise rpm, and as it started to slow down open the throttle more.

The 1981, if you are going to do it, I would disconnect the catalytic converter while doing it, the carbon sometimes comes out in chunks.

Well I did this to my 55 ford. I honestly didn’t notice much happen so I probably didn’t use enough water? I also just found a gas station the sells pure gas/ clear gas. It’s about a 1.70 more than regular w ethanol for pure/ clear premium ( they have regular but can’t sell it for car due to not having a road tax of it- seems silly. Are that many lawn mowers coming in?).

My truck Hasn’t been taken care of nearly as well by previous owners so I’m guessing it would benefit more from this treatment. Although removing the catalytic converter is definitely a project for another day.

I will say both vehicles operate substantially better with the pure/clear gas. Especially during idle. I just thought it was natural that during idle a v8 would just cause the whole chassis to subtly rock back-and-forth but after switching that’s gone away in both my vehicles, and I was using premium before with ethanol still, suggesting it is indeed the ethanol’s fault. My truck also starts and runs much better when cold!

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Well I did this to my 55 ford. I honestly didn’t notice much happen so I probably didn’t use enough water? I also just found a gas station the sells pure gas/ clear gas. It’s about a 1.70 more than regular w ethanol for pure/ clear premium ( they have regular but can’t sell it for car due to not having a road tax of it- seems silly. Are that many lawn mowers coming in?).

My truck Hasn’t been taken care of nearly as well by previous owners so I’m guessing it would benefit more from this treatment. Although removing the catalytic converter is definitely a project for another day.

I will say both vehicles operate substantially better with the pure/clear gas. Especially during idle. I just thought it was natural that during idle a v8 would just cause the whole chassis to subtly rock back-and-forth but after switching that’s gone away in both my vehicles, and I was using premium before with ethanol still, suggesting it is indeed the ethanol’s fault. My truck also starts and runs much better when cold!

The issue is, the older engines, even EFI ones were not calibrated for the 10% ethanol the government mandated. I am fortunate in the fact that I have a station at the North end of town that sells ethanol free premium (lots of boats here). I use it in all my small engines and have only put that in my project car (1986 Chrysler Lebaron convertible with the turbo II intercooled 2.2L engine.

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...a easy way to de-carbon them is by (carefully) pouring water down the carburetor.
No matter how careful you WANT to be, accidents can happen. And if you accidentally slosh the water into the intake of a running engine, it doesn't run any more. So I've always used a common hand-pump spray bottle, with an adjustable nozzle. Start off with the nozzle screwed nearly closed (fine spray - hard to pull), and work your way up (heavy stream - easy to pull). That will prevent chunks, and hydraulic'ing the engine.

What it does is lower the compression ratio by restoring the combustion chamber to its original size. Any buildup in it reduces its volume, increasing CR, which causes preignition/knock/ping/detonation/clatter/dieseling...

I've never removed a cat before doing it, but I've only done it on EFIs.

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...a easy way to de-carbon them is by (carefully) pouring water down the carburetor.
No matter how careful you WANT to be, accidents can happen. And if you accidentally slosh the water into the intake of a running engine, it doesn't run any more. So I've always used a common hand-pump spray bottle, with an adjustable nozzle. Start off with the nozzle screwed nearly closed (fine spray - hard to pull), and work your way up (heavy stream - easy to pull). That will prevent chunks, and hydraulic'ing the engine.

What it does is lower the compression ratio by restoring the combustion chamber to its original size. Any buildup in it reduces its volume, increasing CR, which causes preignition/knock/ping/detonation/clatter/dieseling...

I've never removed a cat before doing it, but I've only done it on EFIs.

Sea Foam suggests using its product instead of water. The process is to get the engine warm, slowly pour the bottle into the intake on a running engine, and then shut it down and let it sit for X minutes. On my '82 Explorer, which was running very roughly, I chose to let it sit overnight.

The next morning I fired it up and the smoke started rolling. I hopped in and took off and did a better job fogging out the mosquitoes than the city does. Other vehicles held back at least a block. But after about a mile either it burned out or the catalytic converter kicked in as the smoke stopped abruptly.

However, it didn't make a bit of difference in the way the truck ran. Or, maybe I should say it didn't make enough difference to tell. Apparently Sea Foam won't cure bad valves and a flat cam. :nabble_smiley_cry:

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Sea Foam suggests using its product instead of water. The process is to get the engine warm, slowly pour the bottle into the intake on a running engine, and then shut it down and let it sit for X minutes. On my '82 Explorer, which was running very roughly, I chose to let it sit overnight.

The next morning I fired it up and the smoke started rolling. I hopped in and took off and did a better job fogging out the mosquitoes than the city does. Other vehicles held back at least a block. But after about a mile either it burned out or the catalytic converter kicked in as the smoke stopped abruptly.

However, it didn't make a bit of difference in the way the truck ran. Or, maybe I should say it didn't make enough difference to tell. Apparently Sea Foam won't cure bad valves and a flat cam. :nabble_smiley_cry:

Sea Foam is going to suggest their product whether it works better or not, they are in business to make money.

Steve, when I was doing this, there really weren't too many catalytic converters, most of what I was doing this to were big block Chrysler products that originally had Holley 4160s built to Chrysler specs and after either doing the TSB modification during a rebuild or replacing them with Carter AFB or AVS carbs, they were so carboned up they would hardly run. The alternative was to tell the owner to take it out on I-64 and go up to Williamsburg and back, not hard running but just a good highway run. These engines would glaze the plugs if you ran them hard after repairing them.

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Sea Foam is going to suggest their product whether it works better or not, they are in business to make money.

Steve, when I was doing this, there really weren't too many catalytic converters, most of what I was doing this to were big block Chrysler products that originally had Holley 4160s built to Chrysler specs and after either doing the TSB modification during a rebuild or replacing them with Carter AFB or AVS carbs, they were so carboned up they would hardly run. The alternative was to tell the owner to take it out on I-64 and go up to Williamsburg and back, not hard running but just a good highway run. These engines would glaze the plugs if you ran them hard after repairing them.

Yes, Sea Foam will recommend their stuff. But it is really good. I had a C6 that hadn't been used in years and it wasn't shifting properly. Stopped and bought a can of Sea Foam, got in the truck and laid the can on the seat and the tranny never missed a beat after that.

As for "big block" Chryslers and 4160's, in '68 the 335 HP 383's got that miserable carb and the 330 HP 383's got an AVS. In '69 it was exactly reversed, and my Bee was the 330 HP engine. Boy did I hate that carb. But, I will say that mine never had a chance to carbon up. :nabble_smiley_evil:

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Yes, Sea Foam will recommend their stuff. But it is really good. I had a C6 that hadn't been used in years and it wasn't shifting properly. Stopped and bought a can of Sea Foam, got in the truck and laid the can on the seat and the tranny never missed a beat after that.

As for "big block" Chryslers and 4160's, in '68 the 335 HP 383's got that miserable carb and the 330 HP 383's got an AVS. In '69 it was exactly reversed, and my Bee was the 330 HP engine. Boy did I hate that carb. But, I will say that mine never had a chance to carbon up. :nabble_smiley_evil:

Gary, neither did my Shelby, if it wasn't on the highway, we usually had an autocross on a Sunday afternoon, so it got run pretty hard, many time right up to the redline at 7000.

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Gary, neither did my Shelby, if it wasn't on the highway, we usually had an autocross on a Sunday afternoon, so it got run pretty hard, many time right up to the redline at 7000.

I was avoiding seafoam as I read that both that and atf coated the spark plugs and could impact spark. That and they cost money.

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