clacking sound when flooring it

[minisuper666]

I have an awful clacking sound under acceleration, particulary when I floor it . The sound dissapears at around 4K revs. Odd thing is, I get this sound in 1st, second, and 3rd gear. So, after 2 hours of using the search button, I come to 2 possible conclusions:

1.- Dephaser.- I don't really think it's the dephaser as I don't get the diesel sound on idle. Also, it seems to clear out at 4K revs. If it were the dephaser, it would clear out at 2K and be noisy on idle, correct?

2.-Bottom end.- Clanking does sound bottom-end-ish. The engine was ran with low oil (2 or 3 liters!!!!) about 3 month ago. Why i didnt get a check engine or STOP light for low oil level or pressure, I'll never know.

Now, the only thing that still makes me guess about the bottom end is that I only get the clacking when the engine is under a hard load. I can rev the engine on neutral to 7K and there's no clacking. Why???

Should I start looking for a second hand engine?

Merry Xmass to all !

 

[zeta]

Make sure nothing is obviously loose. Grab your engine when cold and give it a good wobble to see if it knocks on anything, check aux stuff too like alternator etc...

 

[minisuper666]

Well, it's not aux knocking. it sounds a lot like when a spark plug has worked itself loose and you hear that "clack clack clack" sound. Except it;s only under load. I checked the exhaust manifold for cracks but could not fin anything.


Also, I figured as revs go up oil pressure does too, so that would shut down the noise.

I'm looking at some pre owned engines now.

 

[VikkiB]

Hold the revs at 2000-2500 if it really clatters, it's big ends.

 

[minisuper666]

2000 to 4000 revs in neutral, I dont get any weird sound. I mean, it purrsssss. I'll rev it to 7.5K without clatter.

 

[Dan@SJM]

What fuel are you using? Super unleaded? (97ron)

 

[andy-reid]

your best bet before spending out is either try to record the noise let the masses hear it sometimes a description is nothing like the noise

 

[minisuper666]

I'm using 96 ron fuel (that's the highest grade available here)


andy,

I'll get a recoding (as soon as it stops raining).

 

[minisuper666]

Ill be damned!

As I started looking for the sound to record it, I ws greeted with a substantial oil pool near the dephaser solenoid. I took off the plenum, only to discover that the spark plug hole must have had around 15mm of oil in it. Took off the plug, and sure enough it was completely fouled---I'd been running on 3 cylinders.

I guess that explains the knock under load and loss of power.

Cleaned everything up and reinstalled plugs. Everything seems fine now.