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carbon build up


ORANGEZ

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I haven't used it on the Z yet as I haven't dropped in the turbo engine yet.

I have used it on 3 other cars and it seems to result in a smoother idle. Just watch where you use it. When used correctly it produces clouds of smoke from the tailpipe, looks like you blew a headgasket or are fogging for mosquitos...Lasts about 3 minutes.

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FYI... carbon buildup isn't the problem that it used to be. Since DOT required cleaning additives in fuel years ago caron buildup has pretty much been eliminated. You still get some varnish (a lot less then before) on some intake surfaces but that's not a big issue.

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  • 4 months later...

Heres the story on the motor. Rebuilt 1972 L24 motor that has been in garage for 10 years. Put into my 72 Datsun 240z. After being put in cars been dieseling every other time I start and drive car. Engine has been Seafoamed. Still diesels. What other items should I check?

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FYI... carbon buildup isn't the problem that it used to be. Since DOT required cleaning additives in fuel years ago caron buildup has pretty much been eliminated. You still get some varnish (a lot less then before) on some intake surfaces but that's not a big issue.

 

glad i cleaned all the carbon off every pipe, port, and valve on my z31t. I'm going to go for a drive-clean test to see if I pass when the heads are back on, even though I don't need too (which I don't :D)

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Dieseling has a lot of possible causes. In addition to the question of fuel octane and engine temp from loy I would ask what the plugs look like. Do some quick internet research on "how to read spark plugs" and see if you have one that shows overheating (the plug, not the engine) or any that show a lean condition.

Dieseling means that something in one or more cylinders is too hot and igniting the fuel mixture after the spark is gone. A too lean mixture or a vacuum leak are prime causes of this.

Reading the plus will help narrow down the issue if it is a lean condition (you will see all the plugs looking lean) or a vacuum leak (some of the plugs will show lean or overheated).

Good luck!

RD

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I used something like SeaFoam. It did shoot a bit of smoke for a while, stunk up my garage. Pretty fun experience. I got the stuff from a garage I worked at. I was called fireball or something. It had 3 parts, the can (same as SeaFoam), a spray bottle for the intake (probably the same as carb and choke cleaner), and then some fuel injector cleaner.

 

My turn to thread jack, kind of.

Is this same for turbo cars? I've heard mixed reviews, mostly between "Don't do it" and "it's ok but only keep your car at idle". I think anybody who's done this (the right way, through the brake booster vaccuum line) knows that you're car sounds like a race car from the rediculous idle that you have to induce or else you car just dies. So it would be impossible to just let it idle.

Any idea's?

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Ditto BJ Hines commentary on my bone stock 1974 260Z running on 91 octane California Premium...

 

Put in that 100 Octane ERC Fuel, runs fine, no dieseling after shutdown.

 

Petrol is not what it once was.

 

Go to autozone, put in the "NOS" octane booster (seriously!) and see what happens. It adds effectively $1 per gallon to the cost of my gas, but STOPPED the dieseling and spark knocking during driving that I was experiencing. Not that I use it every tank, I just keep a lighter foot, and kill it with the clutch at idle before shutdown.

 

I know what fixes it, but I'm not spending any money on it. It runs, I try to minimize the damage and just run the 91....

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My turn to thread jack, kind of.

Is this same for turbo cars? I've heard mixed reviews, mostly between "Don't do it" and "it's ok but only keep your car at idle". I think anybody who's done this (the right way, through the brake booster vaccuum line) knows that you're car sounds like a race car from the rediculous idle that you have to induce or else you car just dies. So it would be impossible to just let it idle.

Any idea's?

 

It works fine. You can rev it up a bit if you want to. and You can drip it in without throttle actuation. a 2.5+ engine being seafoamed probably won't die while seafoam is ingested. I know that the 87T I have doesn't die with a vacuum line straight into the bottle.

 

I wedged a 8mm socket in a vaccum line and dropped it in the bottle completely so it hit the bottom and stayed there while it sucked in completely. You have to shut the car off and let it sit for some time... 5 - 10 minutes. And then you turn it on and rev it. That's when it might stall a bit, on the restart. Be prepared for lots of smoke. Just Youtube it and see what you get. LOL

 

ONE THING I will say about it's performnace, is that after seafoaming a monht prior to taking the engine apart, I don't think I would do it again. As per Tony's Suggestion for cleaning heads when rebuilding them off the engine, using SimpleGreen took the varnishing right out. I would probably go trying a drippity drop Simple Green Max treatment instead of SeaFoam next time. SeaFoam most likely stripped the thin oil deposits left from my PCV in tight places of the intake manifold, and probably on the valve stems, but the entire intake was still covered in oil BEFORE and AFTER the seafoam, and the valve train was not cleaned.

 

In order to really use the PCV system to clean a valve train, I would use an oil additive instead. Pulling the fumes from the SeaFoam through the case vents didnt seem to do much for me...I'd rather use an oil additive prior to an oil change. I think GrumpyVette and Dr.Hunt have been suggesting B12 Chemtool. That's what I will do next time.

 

Again, SeaFoam did have my car idling 100RPM higher, which I think is where it was to be set to following a distributor alignment/Calibration, but I don't it's the end all and be all of engine cleaning. I would actually consider putting some SimpleGreenMax in the engine oil and have it run for 30 to 40 minutes, Then let it drain back to the pan before doing an oil change the next time I have to really clean this sucker. It's unbelievable what that stuff does. And the heat will effectivly steam up the substance when it's being passed through the engine.

 

Can't say enough about the Simple Green MAX. It's the only thing that completely wipes the oil and varnish that is semi-filmed up on everything right out.

 

I would contemplate using an old engine filter if it's laying around, and a old oxygen sensor before doing it though. And I don't think it will be damaging to any other components in the engine. Hopefully not.

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In order to really use the PCV system to clean a valve train, I would use an oil additive instead. Pulling the fumes from the SeaFoam through the case vents didnt seem to do much for me...I'd rather use an oil additive prior to an oil change. I think GrumpyVette and Dr.Hunt have been suggesting B12 Chemtool. That's what I will do next time.

Actually, SeaFoam is an oil additive. Read the bottle/can: it says to pour some into the crankcase, some in the fuel, and suck the rest into the intake.

 

I couldn't find a detachable hose that wouldn't kill it instantly, even with the throttle wedged to about 2k RPM, so I just dumped 2/3 of it into the gas (about 1/4 tank // ~5 gallons) and ran it empty. Haven't really noticed any differences, other than my oil coming out really nasty that change (ran it about 500 miles, which was probably too long) and some smelly exhaust. I also haven't taken the valve cover off since then, so I don't know what, if anything, it did in there.

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Sorry, I meant "different" oil additive. I forgot to mention that I did dump 1/3 of a second bottle into the royal purple I put (I figured it wouldn't be that much, so it would be ok to drive with).

 

The rest of the bottle I gave to a friend with a Micra 1.2. It's kinda hard to find a Micra doing a smoke show. LOL

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