need advice on noise

[ekurty]

just adjusted valves to what i feel is the correct drag on the feeler gauge and it got a rattling noise out of the top end that I had, but now it seems to almost have a diesel sound to it. Is this normal sounding for the m20? Im open to all input, as I know my experience is limited.

[Kvasi]

No its not supposed to sound like that.. Dont remember the english name on them, but the round fellas you turn to adjust valves sometimes gets flat on one side, and then the valve smacks them out of position. Find out what aera the rattling comes and check. Its a cheap and easy fix, if thats the problem.

[ekurty]

Ill order new eccentrics and bolts to try and get a more accurate clearance adjustment. Iwas just glad that the rattling noise that comes between 2-3k is gone. Hopefully she will hold a week till the new eccentrics get here.

[paperplane94]

what did you adjust it too?
Where did you place the feeler gauge?
Was it an angled feeler gauge?

[BergerNJ]

eeeeek I wouldn't run that until I had it repaired and adjusted properly....

You had the knowledge and sense to know and post asking about it and how bad it was....if you can don't run it until its fixed.


Replacing the eccentrics may not be necessary...I would go back and readjust just to make sure

[5Toes]

My car does this to. Doing a valve adjustment tomorrow I think. However, how can one tell if the eccentric is flat spotted or whatever?

[ekurty]

adjusted to .010 and placed gauge between top of valve and eccentric. i tried .008 beforea to see if it ran any better, and it seemed to run quieter and smoothly idlin/low rpm, but would get a nasty rattle around 2.5/3k. i bent my feeler to get it in there squarely. To tell if the eccentric is flat, loosen it and spin it around to see where it contacts the valve.

[ekurty]

http://youtu.be/T7XJkYnFgAE

this is after replacing the eccentrics nuts and bolts. still getting rattling noise at certain rpms

[thowes24]

I'm having a very similar issue... To me it sounds like a broken rocker arm but all of mine are in tact... I have no clue what it is.

[paperplane94]

Maybe its bottom-end problems.

Obtain a stethoscope and listen around.

[Thizzelle]

this is exactly what is happening to my engine, same sound around 3k rpm. did a valve adjustment and still there. All rockers where inspected and look good. Next i'm gonna change the oil pan gasket and while I'm there going to check for a loose rod bearing, but that's not happening for a month.

[ekurty]

so i took it to a shop ive heard good things about and they tell me the noise is the piston slapping the head cause of a rod bearing... does this seem like a probable guess??? a few others ive talked to say this is very unlikely

[jlevie]

A bad rod bearing can make a noise that sounds something like a loose valve. The difference is in where the noise is the loudest.

[ekurty]

Would a bad rod bearing give it enough to wobble to really hit the head? I would think it would be a catastrophic failure at that point if so. I've put at close to 2k miles since I noticed the sound and it hasn't got much worse

[jlevie]

A bad rod bearing isn't going to allow the piston to hit the head. Well I guess it could, but the rod would come through the side of the block before that.

A mistimed cam can allow the valves to kiss the pistons or if the head has been off and one, or both of the locating dowels, are missing a piston can kiss the head. If neither of those apply and the valves are properly adjusted worn valve guides become the likely cause of noise.