its a 91 Si CRX with 206,000 miles and the numbers are 200, 200, 195, 210
are these good?
thanks
Matt

 

yes, very good!

i forget what the spec is across the cylinder, but i think its like 25-30...

 

25-30 Psi??? cause if that is what you mean than that is way too low... please be more desctiptive...

 

well The reason I tested it was because there is oil on my plugs on the spark side so I thought I would do it and make sure it was good.
thanks
Later
MAtt
any suggestion about the plugs?

 

according to the onlin manual...

normal is 185psi.
min is 135psi.
max variation is 28psi.

 

its most likely the o-rings from your valve cover. replace them and you should be all set.

 

there should be no more than a 10% difference between the highest reading and the lowest. So you have a high reading of 210 and 10% of that is 21 so your lowest should be 189 (and your lowest is higher than that). Also you want at least 180psi or higher. While some radical cams will have enough overlap at cranking speed that these numbers will be lower, on a stock motor the higher the better. It sounds like you have a great high milage motor there

 

Yea the motor has been well tooken care of. I want to keep it that way too. I am going to take it in to the shop this week and have the valves and all adjusted.
thanks
later
Matt

 

You have some sort of build up in the engine, probably carbon. At those compression numbers your engine is going to start pinging unless you back off the ignition timing or run a higher octane gas. Running a little water through the intake manifold can help to break up some of the carbon build up. NOT A LOT OF WATER. WITH THE ENGINE RUNNING just disconnect a vacuum hose and feed a little water into the intake manifold, feather the throttle to keep the car from bogging. You'll see black smoke coming out the exhaust. If you do it long enough the smoke will turn white. You're getting things clean at this point. Retest the compression and it should be lower. You should also replace your PCV valve, it's behind carbon build up a lot of the time.

If you don't try and reduce the compression your engine will start to detonate and it will destroy your bottom end.


[Modified by Noahk, 2:09 PM 1/8/2003]

 

yes i agree, water has no place inside your engine.

 

Do not use ATF. Its a totally different procedure. The ATF trick is more for cleaning gunked up rings, not removing carbon from the combustion camber. Water works much better.

 

Water is an old trick. It works fine and does no damage to your engine. The water vapors work great to clean it out. It also helps if you're having a problem with hydro-carbons for smog.


[Modified by Noahk, 2:58 PM 1/8/2003]

 

Man haven't you guys ever heard of water injection??? I't really popular on high end drag race street motor's (I'm talking about v-8 running N/A and 14-15 to 1 compression). The water keeps the carbon out of the motor. You can use a squirt bottle (windex) and set it to spray. take off your air intake and using on hand to opperate the throttle spray water into the intake. Don't hose the **** out of it. Just a few squirts while feathering the throttle.

 

if it is carbon build up get some injector/engine cleaner it'll clean stuff right up.

 

waht kind of engine cleaner do you recommend I always run 93 octane Chevron Techron gas. Is there anything else I should do to extend engine life?
later
Thanks
MAtt

 

dont listen to the water thing
u DONT WANNA PUT WATER INTO UR ENGINE!!!
u ar ebetter going and getting a carburator choke cleaner can spray...
go and turn ur engine and spray it on ur intake.... that will clean any carbon buildups... thats the best stuff u can do ...


[Modified by JDM EF9, 10:10 PM 1/8/2003]

 

enough said!
http://www.geocities.com/MotorCity/D...ater_injection/

Water injection is a technology that is nearly as old as the car itself. However, like many automotive technologies, it has waxed and waned as fashion has dictated. Water injection has the ability to suppress detonation, allowing the use of higher cylinder pressures. It is easy to control and relatively simple to install. In times of tight emission controls, decreasing fuel octane and rising petrol costs, water injection is one of the best ways of controlling detonation. And it has another major advantage over taking other approaches - the 'fuel' is available at almost zero cost!

How it Works

Water injection is used to suppress detonation. Detonation occurs when the flame front does not burn progressively across the combustion chamber but instead explodes into action. This causes a massive and sharp increase in combustion pressures which can damage pistons, rings and even heads. Detonation can sometimes be heard as a 'tink, tink' sound coming from the engine. The piston and head shown here has suffered severely from detonation.


Water injection works in three ways. Firstly, when the water is injected into the intake system prior to the cylinder head, the small droplets absorb heat from the intake air. Water has a very high specific heat rating (it can absorb lots of energy while only slowly increasing in temperature) and so the intake air is initially cooled. Next, the small drops of water start to evaporate. Water has a very high latent heat of evaporation (its change of state absorbs a lot of heat) and so the intake air charge is cooled still further. Finally, when the remaining water droplets and water vapour reach the combustion chamber, steam is produced. This acts as an anti-detonant and also keeps the interior of the engine very clean, so preventing the build-up of carbon "hot spots".

Water injection was first experimented with in the 1930s. At the time it was discovered that detonation could initially be prevented by enriching the air/fuel ratio. As cylinder pressures rose still further and that approach ceased being effective, the injection of water into the intake air stream was found to prevent detonation. Interestingly, the detonation remained suppressed, even if the air/fuel ratio was then leaned-out. This occurred because the excess fuel was being used to cool the combustion process. When water replaced fuel in performing this function, less fuel was then required.

This has major implications for both emissions and fuel economy at high engine loads. In fact Saab on some of their recent turbocharged cars has used water injection at high loads in conjunction with leaner air/fuel ratios to reduce emissions output and improve fuel consumption. To put this another way, at high engine loads it is possible to reduce the amount of fuel being used, replacing it with water without sustaining any loss of power!





[Modified by SIRX, 9:35 PM 1/8/2003]

 

well dude i get ur point...
but look at the facts...
u talking to a guy that might have not idea what u meant...then he goes put a cup of water by accident down his intake and hydrolock it... u gotta tell him the facts and stuff...
his best bet its to stick to something that its already flamable and will not destroy the engine.... carburator cleaner will be his best bet unless he lets someone xperienced do it...

 

never thought of it that way. Yeah hydro'n a motor is death. You just came across in your previous post that it wouldn't work. I was just setting the record straight. Peace

 

well I am putting my car in teh shop next week for a valve assembly and adjustment. I will have my mechanic do it unless anyone has a link to a site with a how to.
thanks
MAtt