Burned Valves? Low Compression

[koukiVLAD]

I need your help guys. Basically I bought the motor from a guy (S14 SR20DET) a month ago and recently when I started pushing the car I discovered that I had noise over 5K rpms, then after 2 days my car started running rough and shaking (on 3 cylinders). I pop off the coils to check them, they are in good condition, take off the plugs and find that they're wrong plugs. So basically I was driving with the wrong plugs for 3 weeks and now my car running on 3 cylinders and making a noise (sounds like its in the head). Did compression test, 1,2,3 are 160PSI across the board, 4 is 60 psi. Now before you say its a bad ring, I do not get any blow by whatsoever, and my car shakes, if I had low comperssion my car would not shake like this, it shakes like when you plug off one of the injectors it starts to idle rough. My friend who worked on SR's said its a burned valve in cylinder 4 (or both of the valve i/e) and that they need replacing.


SHORT: Car runs on 3 cyl
I was DRIVING on WRONG PLUGS AND PUSHED IT HARD (no its not my fault)
Low compression
Makes a noise coming from the head
DOES NOT HAVE ANY SMOKE OR BLOWBY
Burned valve?

[S14_Kouki]

do a leak down test you could have a blow headgasket

[rc1honda]

I really don;t know what's worng, but is it possible that a valve was bent and broke off and fell into the #4 cyilinder causing the noise and the low compression? Do a leak down and pull the valve cover, find where the noise is coming from.

Could be the headgasket but that doesn't explain the noise. Also just cuz you not getting blowby doens't mean there is no damage to the piston, rings, or bottom end. Theres a leak somewhere in the #4 piston and i think you have to find out what the noise is to figure it out.

[fliprayzin240sx]

drop a cap full of oil into that cylinder and check the compression again. If the compression goes up, then its the rings. If it doesnt, then its something else...

[Bigsyke]

To be frank, it is your fault. Usually when you spend about 2 stacks on an engine, correctly anaylizing the composure of the engines blueprint is done before you drop the engine in.

How is the plug on that cylinder?

[koukiVLAD]

There is no leaks when I drive the car, no smoke, no nothing. The car's motor shakes. If this was the piston problem, why would the car shake? I had an Eagle Talon as my first car, and it had bad rings on #3 and #4 and low compression, and it didnt shake or do anything, it just blew a shitload of smoke and didnt pull hard.. but then again who knows :(

I added some oil into the 4th cylinder and checked the compression, it did not go up. It was 50psi and when added oil still was 50

When I pulled my plug out (when the problem occured) it was completely burned and really wet with oil/fuel.

Also when you unplug the 4th injector,and start the car, the noise is not present.

Regardless, I'm going to have to take off the head to see what is really happening, just wanted to know what it is so I know how much money I need.

[orion::S14]

Just because you had worn rings on your Eclipse, and it ran smooth...doesn't mean this will do the same.

AND, and burnt valve? That's an old hot-rod thing...valves nowadays are sodium filled, and have much better resistance to heat. Your valves are fine.

I will predict what you'll find:

You'll pull the head, and the valves will be fine.

BUT, the #4 piston will have heavy detonation damage. Edges worn away, maybe a hole in the piston. Or just your basic broken ring lands.

But that's just one mans opinion...having been there.

- Brian

[HYPNOTIK]

How were they the wrong spark plugs? The car obviously ran with them, what were they? Pull your valve cover and make sure all your rocker arms are still on, quick and easy thing to check.

[koukiVLAD]

How were they the wrong spark plugs? The car obviously ran with them, what were they? Pull your valve cover and make sure all your rocker arms are still on, quick and easy thing to check.

Rocker arms are fine I took the cover off, all valve springs are intact everything looks normal.

They plugs were wrong because they looked identical to my KA plugs. The car ran fine until I would push it 5K rpms +++ then it would make a ticking sound, I thought it was a loose bolt or something but just now I figured its because the engine was not getting enough spark thats why it made the sound (it also didnt pull hard after 6K+ rpm) Yes I know its retarded how I didnt check the plugs but trusted the guy before me who took me personally for a drive and it drove fine. (obviously he never pulled 6+K rpm) when test drove his motor.

Orion I think you're right about the piston.. I just now started to have this feeling, but I guess we'll find out soon when I pull the head and check everything, as far as the noise goes, I'm going to post a video of it and hopefully you guys can help me out (yes its probably the piston but to make sure). So the noise is basically rings rubbing against the cylinder wall or??? (then again a theory that maybe a piece of the valve landed on the piston and stuck in there therefore creating the noise. Video will be up in 2 minutes

[koukiVLAD]

YouTube - MOV02331 (http://www.youtube.com/watch?v=zvf7sI80az0)

video

[Rabboni]

Dude if i were you i would do a leak down test before you go any further. It will definitely tell you why there is low compression in that cylinder.

[huntington19]

listen for where the noise comes from when you do a leakdown test. if you hear air escaping when the oil cap is off then it's piston rings.

[koukiVLAD]

noise is from the head/piston... Anybody have any clues or you can't really predict what it is until you pull the head? I just need to know what could it be so I know how much money I need to fix it (if its just the valves or rings)

[rsibley22]

reguardless your going to have to pull the head sooner or later might as well be sooner