claymore

Not really a DIY but some general facts to think about before using these products.

There have been several posts on "internal engine cleaners", combustion chamber cleaners, sea breeze, or whatever you want to call these products.

To the guys that don't want to read the whole thing... they are a waste of time and money on MOST modern cars.

OK for everybody else here is WHY I feel that way.

It is a subject that is "One of those" where there is a lot of anecdotal "it feels much better" posts but a dearth of evidence.

The first reason is Why use them... if we were talking about 20-25 years ago when every car used leaded gasoline for fuel they MIGHT have help a bit. But since the removal of lead additives from fuel sold at gas stations there is little or no use for them.

See in the old days of leaded fuel the build up on valves and inside combustion chambers came mainly from lead additive residue and since it is not added to fuel now there is only VERY MINOR incomplete combustion residue (there is never ever Complete combustion there is always residue) that might coat the valves, tops of the pistons, and combustion chamber in a modern engine using UN-leaded fuel.

Think about the path of the air/fuel mixture inside the engine for a minute. Air comes in the TB and through the manifold and just before the combustion chamber the correct amount of fuel is added by the injectors.

The mixture then passes the intake valve and this is the only time that any "build up" of deposits could occur on the back of the intake valve. Since there is no longer any lead in the fuel the chances of any significant build up of ANYTHING is NEGLIGIBLE in other words "not a chance in hell". Anything that tried to stick in that area is quickly washed away by the next batch of mixture passing through the same area washing away any deposits that might have been TRYING to stick there.

In the old days the lead in the fuel reacted to the heat of the intake valves heated by the heat radiating from the combustion chamber and over time turned into a hard carbon like substances that were impervious to fuel. The result of this was that the residue STUCK to the under side of the valves a small amount at a time. But since there is no longer any lead there is only minor residue.

Inside the combustion chamber the lead wasn't completely burned so there was build up of large deposits inside the combustion chamber. But again no lead way less deposits.

Then on the way out the residue gasses pass by the heated exhaust valve and you would get some of the lead residue built up on the exhaust valve but again no lead tiny amounts of deposits.

Anyone that has removed a head from an engine with no problems can attest to the fact that inside modern engines using un-leaded fuel there is hardly any deposits on the backside of valves anymore the rest of you will have to take our word for it.

All that is good an well... no lead no deposits BUT there is another reason NOT TO USE THEM.

It's called thermal blocking..... anybody that is a competent drag racer knows that HEAT, inside the combustion chamber, makes power.

The crud from incomplete combustion inside the combustion chamber, on the tops of the pistons, and on the head of the valves effectively BLOCKS THE HEAT FROM RADIATING OUT OF THE COMBUSTION CHAMBER and that is a very good thing.

Pro teams PAY good money to get the tops of their pistons and valves coated with super duper new coatings (if allowed by the rules in their class) that your crud is doing for FREE why would you ever want to remove it??

I know there is somebody out there that cant wait to say "what about the crud blocking or interfering with the mixtures travel inside the combustion chamber"? If you had ever taken the head off an engine you would have seen the crud is NOT spread evenly across the piston tops. Why is that?

It's because the mixture moves through the combustion chamber better or more efficiently through different parts of the chamber and guess what any residue is washed away in the fast moving areas and the deposits end up in the normally slower less efficient areas so they don't have any effect on the faster moving parts of the combustion chamber so why remove them?

So the bottom line is using products that claim to remove deposits in an internal combustion engine running on modern un-leaded fuel is not going to do anything because there are no large deposits to remove for one and any residue coating the valve head, top of the pistons, and combustion chamber IS A GOOD THING NOT A BAD THING.

If you are concerned with your "dirty engine" the very same thing can be accomplished for free with nothing needed but your foot. Any unwanted deposits can be removed or not allowed to build up in the first place simply by flooring you car and taking it to red line a couple times a month it's really that easy.

You could get large deposits IF you have a 150,000 mile beater engine that is burning oil and cleaners won't help them for more that a day or two at best.

This is NOT a post against Fuel Injector cleaners they are a subject to be discussed another time.

manxman

To add to claymore's good warning, the Honda Fit Service Manual warns you NOT to use spray-in throttle body cleaners because they will dissolve and flush away the permanent lubricant that is used on the pivots of the 'butterfly" that controls throttle position and air flow.

scottkiller

good info to know..can i ask some question??
when we wipe our finger at the exhaust tips, then u will find your finger is blacked.. therefore i believe there is something inside the combustion camber that produce those "black dust". Since there is no lead contain inside the fuel.. what is the cause of the "black dust"??

claymore

CARBON it's a byproduct of any combustion

Rickdogg

how do u clean it off cause i got alot

claymore

Clean what off what?

scottkiller

that is what i thinking.. since there is carbon deposited at the exhaust tips.. i believe there should be carbon deposit inside to engine block which require to "flush" out right? Pls correct me if i was wrong.

manxman

Your catalytic converter completes the combustion cycle by burning unburned fuel and other elements left in the exhaust stream when the exhaust leaves the cylinders. The carbon that you see in the exhaust pipe tip may only be the residue of chemicals being burned in the cat, and have nothing to do with carbon build-up in the combustion chambers.

If you had any serious carbon build-up in your cylinders, you would have noticeable knock or ping on hard acceleration- sounds like marbles or ball bearings bouncing around under the valve cover. The knock is caused by carbon on the piston heads and cylinder heads shrinking the space inside the combustion chamber, and increasing the compression ratio because of the smaller space. Ping and knock are also called "detonation" because the air/fuel charge in the cylinders ignites prematurely in an explosion instead of burning evenly and completely.

claymore

If you are worried about the black inside your exhaust tip just wash it off. Most of the time it will wash right off but will ruin your sponge turning it black. Or on stubborn spots you can try some scothbrite.

IT'S NORMAL like manxman said. If you are concerned take your car on a high speed run to clean out the carbon deposits. Or every couple of days start from stop and floor it up to redline (WATCH OUT FOR POLICE) in first gear.