How To: Increase Compression Chamber Pressure
 

I have a feeling my compression may be a little low on my car from wear put on by previous owner, with that said, what are some proven ways to increase combustion pressure? How well do products like Restore or other engine oil additives work in increasing the pressure permanently?
Second, if the problem is instead carbon on the top of valves, what are some proven ways to remove the carbon? I've heard of spraying water into the intake but how much and at what rate? Videos would really help in this process!
Thanks.
- Aaron

When I use to screw around with lawn mower engines as a kid we used glumps of wheel bearing grease to take up displacement in the head to bump the compression. I dont know if it worked, but it seems like a good idea. :eek:

Basically you need to make the room smaller or pack mo air in it. You can mill the head, deck the block or used force induction. :eek:

Rent, borrow, beg or buy a diagnostic vacuum gauge. Hook the gauge to a manifold port directly on the intake manifold and start the engine. Allow the engine to warm up and stabilize. The reading should be over 20" at a warm idle. If the needle isn't steady or the reading is low it could indicate a problem.

Here is a resource for you about reading a vacuum gauge.
Tips on Reading Gauges: Vacuum Gauges


If the vacuum gauge indicates a problem or you wish to further check the health of the engine the next step is to acquire a compression gauge and get an actual reading on all of the cylinders.

Hook up the gauge by removing all of your spark plugs . Install the gauge to each cylinder and hold the throttle wide open while cranking the engine over. You should be able to listen for a lumping as the cylinder with the gauge pushes air in to the gauge. Wait for 5 of those audio indications then stop cranking and check the gauge.

Write down the compression number for each cylinder and get a calculator out. Each cylinder should not be more than 10% away from the highest number. Low numbers for all cylinders typically indicate a worn out engine or incorrectly timed camshaft. If you have low numbers repeat the test on all cylinders but add a tablespoon of oil in each cylinder before installing the gauge. If the numbers rise a lot you most likely have worn out piston rings. If there isn't a significant rise in compression your issue is likely valve train related or blown head gasket.


Evaluating the health of an engine using tools you can use at home isn't very expensive but it will take research to understand what the numbers mean. The rule of thumb is even if the compression is lower... if the compression readings are within 10% of each other and the engine runs okay it means the engine is just tired and the only option is rebuild or replace.



As far as raising compression. Take this how you will. Surfacing the head will reduce the size of the combustion chamber which will increase the compression ratio. Using pistons with a different profile can also increase compression. Neither way is a fix for worn out piston rings. Once an engine is torn down to the point the piston leaves the cylinder the minimum is piston ring replacement and honing the cylinder. Expect the new rings to not last though. Cylinders over time will wear out and require them to be bored and honed. Though not by much boring a cylinder doesn't necessarily mean you are going for increased power it is to square up the cylinder again to make a good surface for the piston to travel in.

Razor gave you a lot of great advice, I just wanted to mention in addition to removing all of the plugs when doing the compression test, be sure to disable the EFI (pull the fuse) as a safety measure... It is also good practice to disconnect the ignition coil(s), as on some models, they can easily burn out.

I know how to check vacuum and use a compression tester. My question is for a simpler fix for these problems such as using Restore or other products that claim to fix compression problems. Also, how to remove carbon from the back of i/e valves by either putting something in the gas tank or spraying something directly into the throttle body. Thanks.

Great


Are there any products work to restore compression? Simple answer is no.

How do you remove carbon from the combustion chamber? There are many ways including the water trick you mentioned. Here is an example of it being done.
www.youtube.com/watch?v=UXetbuEFLvM

Many many many people use a product called seafoam. The instructions for use are on the can you just allow the engine to suck it through one of the vacuum lines.

I use a kit from 3M called the fuel system "tune-up" kit...
www.youtube.com/watch?v=RX5J5kZLTw4

If you have low compression and free up any carbon build up, you're only going to make your low compression worse. Chances are that carbon is helping keep compression up.

He poured a crap ton of water into that car! Wasn't expecting it to be that much. Thanks for the tips, if I end up doing any of this ill try to post any results.

A relevant post from a thread about catch cans early last year.

Cleaning out carbon (that may be causing your rings to stick) won't restore compression in every case, but it's cheap, it's easy and it worked for "BoB" (now retired).

It's still a good idea to get rid of excess carbon, as it can glow at high throttle settings and pre-ignite the combustion gases before the spark has a chance to.

Jim

Ive often thought about doing this, but what are the effects to the oxygen sensors with all that carbon blowing through the system? Would it be a good idea to remove them (not disconnect the wires) just for the cleaning and then replace them afterwards?

I would be more worried about clogging the catalytic converter before ruining an O2 sensor.

Would people advise to pour in water at a level just before stalling the vehicle?

I have tried this on a very tired engine. It may have helped but I duno. To get carbon off the valves I have hit the rockers on the valve side to knock them around a bit with a heavy rubber mallet. Made a noticeable increase in compression when doing leak-down type tests.

Oh, I thought you wanted to increase the compression ratio. To restore some lost compression from bad rings what we did back in the day was pour a qt of motor oil down the carb, much like the guy poured the can of water. It made a hell of a lot of smoke, but the resulting bath helped the rings as well as valves.

The compression test wet vs dry will tell you right away if its valves or rings thats the cause. :thumbup:

Take the engine apart and rebuild it.

Please do not pour motor oil in the air intake of your vehicle. I guarantee you will regret it.

...do some research on the Continental AVCR-1360 "Variable-Compression-Ratio" diesel engine that GM used in their XM1 Tank prototype, the experimental tank that lost out to the Chrysler/General Dynamics "Turbine" XM1-B during the Jimmy Carter presidential years.

...brief SAE info on the AVCR-1360: http://papers.sae.org/760051/

Be very wary about pouring liquids into a running engine as it can cause a hydrostatic lock and then it is game over.

I don't believe in most engine rebuild in a can snake oils because they simply cannot replace worn metal and tolerances and only serve as a short term band-aid. Sticky rings can usually be freed up with a couple short interval oil changes.

I do recommend Sea Foam added to a full tank of gasoline for safe carbon removal. When I first tried Sea Foam, I experimented with it on an air cooled Duetz diesel that had severe carbon build up and when I tore the engine down, the combustion chamber and valve stems were amazingly clean. I have had consistently good results with it in the commercial fleet that I maintain.

Yes, the excess *may* loosen things up for about two seconds, just before that *new* amount of excess oil begins to carbonize back up around the rings, and stick them better than they were before!

Jim.

how bad is your compression?

The best method of testing ring condition is with a leak down tester or a blowby meter. As the cylinder wall wears the ring end gaps open up by a factor of pi. Nothing that you pour out of a can is going to correct that condition. If you at all serious about gaining fuel economy put in a set of Total Seal gapless rings. With proper cylinder bore prep you can achieve near 100% seal. More power also.

I have found from experience that good ol mystery oil can cover the symptoms of low compression and a failing engine.

You will be stuck using it in every tank of fuel though (doesn't work at all in oil) and god only knows what damage you will be incuring in the mean time.

Please dear god do not use Seafoam or any of that additive crap. Like someone said earlier, the "carbon" could be holding something together you don't want unstuck.

Yes, that's right, IT CAN BREAK YOUR CAR. Read the reviews on amazon. I looked into it but for every 10 positive reviews (backed by unquantified results), there was one person who's car ran like sh*t afterwards.

Does anyone have some verifiable tests they can share aside from opinion? Might have to make an account over at B.O.G. if I can't get some more credible answers... arg!

Although I know very little about the maintenance and care of cars in general, I think we're going to need more information.

What are the quantifiable symptoms you're having?

Also, you have a car that's almost 30 years old (if we're discussing the integra listed on your profile). If you're getting a rough idle, that might just be how it is after 29 years. Older, asian cars will do that. (And honestly cars in general)

Credible answers come from compitent questions, and compitent effort...

Do a compression check. It will take a compitent person less time then you've spent reading the three pages of this thread.

If the engine your talking about is a b-series (guessing by the teg in your garage), it's likely rings or HG, as those are usually the first to go.

There is no perminent solution in a can.
There is no perminent solution in a can.
...
There is no perminent solution in a can.

I am an avid believer in seafoam and ZDDPlus for preventitive maintenance and recovery due to a lack of, but in no way will they fix worn rings, out of round cylinders, blown/warped head/gaskets etc.

Sounds mean, but very true. I've read all of your (Jackal) posts on this thread and I can't figure out what the hell the problem is!

Since everyone just loves this seafoam, here are some reviews on amazon that say otherwise:

Amazon.com: Customer Reviews: Sea Foam Motor Tune - Up

Amazon.com: Customer Reviews: Sea Foam Motor Tune - Up

I know that MOST of them are positive, but is it really worth the risk of breaking your car?

I don't think you want credible answers I think you want to us to say something you want to hear. I was hoping I could save you time and money but you can only lead a horse to water. You can't make him drink.

Sorry I will not vouch for a product unless it actually works. Of the many many many products I have tried over the years not one will permanently help a worn out or hurt engine with low compression. I know this because I have owned vehicles with worn out engines and one that was very hurt (turned out to be a main bearing had spun)

Yes!... If you know what you are doing, and have a spare engine sitting on standby! :D

There are a variety of circumstances where MMO will make the apparent compression values improve.

Trouble is you want a liquid to fix a mechanical problem, at the very best it just covers up the problem, which MMO is very good at doing, if you have no plans of fixing the motor and just want it to run until you trash it MMO is for you, if rebuild is an option that really is the only way of actually fixing anything.

Sorry, you can ask a 100 times and get the same answer.

What you said:

What I read it as:

What you said:

What I read it as:

Competent*

Sheesh, didn't realize that I would get such backlash from "educated" members here on Ecomodder. I believe I checked the compression years ago and the numbers were a little lower than normal, I get slightly lower MPG than fellow owners of the same vehicle (avg 28-30mpg mixed), I burn a little oil maybe as much as 0.5qt every 5,000 miles.
Original question wasn't intended to be just for my particular vehicle, more of an across the board fix and seeing as I've heard of people using water and other liquids to remove carbon, thought I would ask here. Didn't post it on the other forum I'm a part of because maturity levels seem to be a lot lower there but I'm not sure this place is any better unfortunately:( If you don't have something nice to say, don't say it at all...
Again, some say it works and others say it doesn't meaning that there is some disagreement and one must make their own "opinion". All I'm asking is if someone knows for sure if it does or does not work and what the best method is for cleaning carbon out.

I've heard the water treatment as shown in the video on a previous page can help clean off carbon, but I don't know of anything that will PERMANENTLY improve your compression short of actual mechanical work on the engine.

One trick I used once when attempting to *slightly* improve compression was to install a thinner head gasket. We were unable to do before & after tests, since we changed heads too, though.

One of my cars had no compression at all in 2 cylinders, so the head is in the machine shop for a valve job at the moment. I wouldn't have done that if the compression was only slightly low, though - until it was time to do the whole engine (when it got worse).

I don't have to remind you that you are using the internet...right?


I have my opinion and they have theirs. Like I said my opinion was given to try to save you time and money. It really depends on the problem with your engine whether or not an engine cleaner would work. If for instance carbon build up is preventing your valves from sealing then yes a treatment could help you. However if the valves are too tight or the piston rings are worn out it isn't going to help.

There is some risk when using an engine cleaner. If you have a lot of carbon some larger pieces could break off and cause issues with the catalytic converter. The manufacturer of seafoam does warn not to use on high mileage vehicles.

Hope you get it sorted out.

Okay, now you're just whining. Sheesh is right.

And no one here claimed to be educated. And you put it in quotes to be an ass.

I literally laughed out loud at that.

It appears that you, yourself, do not subscribe to that philosophy. Why should we?

Now we're getting somewhere! Yes, "one must make their own opinion." Read the reviews on the products we have suggested, read what we said about these products, and then make your own opinion.

And we've answered that question. I've posted reviews on Seafoam earlier in this thread. Most are good, but that bad reviews are the ones that scare me. Hence my apprehension about using it.

There is no absolute truth. If you're going to use a product to clean carbon, I (along with other members) have recommended Seafoam and other various products.

P. S. This is the internet, but the same applies to real life. If you got 10 mechanics to look at your car (which I would actually recommend at this point, although the #10 might be a little high), you would probably get 10 different answers, and 10 different prices. (But don't let them charge you just for looking at it)

Honestly though, I think you just have an older car. These things happen to older cars just like they happen to older people - stuff just doesn't run as smooth as it used to.

so the question begs to be ask of those bad reviews of seafoam; did they use the 1/3 of a can(ie. directions) vs. the whole thing

to the original poster; are the cams timed properly?