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View Full Version : Engine knock... Does this sound familiar?


01001010
03-05-2011, 05:55 PM
Ok, needing some help here guys...

I'm working on a 2.25 petrol engine with an interesting knock. I'm going to try to record a sound clip so you guys can hear. In the meantime, an explanation will have to do...

There is a knock that doesn't follow any pattern. With the valve cover off, I can hear that it's definitely coming from the valve-train...maybe the first 2 or 3 valves from front to back. I'll check clearances as soon as I can find my feeler blades.

EDIT: Nvm...file wasn't the correct type for YouTube
01001010
03-05-2011, 06:26 PM
Ok, here's the vid...

http://www.youtube.com/watch?v=C5QiTyNyxmc
SafeAirOne
03-05-2011, 06:37 PM
If the engine wasn't running so smoothly, I'd almost say it sounds like the "snap" of a leaky spark plug wire arcing to ground.

It seems like it's a one-click-per-two-revs noise, so that should narrow it down.
bkreutz
03-05-2011, 06:46 PM
Sounds like a valve sticking and then snapping closed, and I think I see a matching hesitation in the lowest rocker arm in that film clip. Just a guess on my part. (without being there myself, you can usually tell a sticking valve by looking for a fluctuating needle on a vacuum gauge.)
01001010
03-05-2011, 07:24 PM
Wow...thanks for the quick response guys.

AirOne... I know exactly what you are talking about but this definitely sounds like metal slapping metal.

bkreutz... That's the first thing I thought but it seems to sound louder on side opposite to the valves. This still remains high on the "Culprit List" though.
01001010
03-05-2011, 07:28 PM
Could there be a faulty tappet?
01001010
03-11-2011, 07:10 PM
Bump
SalemRover
03-11-2011, 07:53 PM
When you rev the engine around 7 seconds it seems to stop for a moment. Is the sound consistent at all rpms? Sounds like something valve train related. Does the exhaust have any clues through smoke, smell or backdraft (if an exhaust valve is sticking).

On an unrelated topic, is your name 01001010 the binary equivalent of the ascii number for the letter J? Just curious.

-Jason
I Leak Oil
03-12-2011, 05:34 AM
Could be a sticking valve. Could be a weak valve spring. Could be a worn rocker shaft bushing. Try turning the motor with a crank handle and have someone watch the suspect valves to see if you can pinpoint it.

My wife just asked me if I was watching a video of a steam engine. Told her it was a rover engine. She said "Oh, not much difference".....they just don't understand....
SafeAirOne
03-12-2011, 06:08 AM
Can you pinpoint the location of the noise using a short length of hose like a stethoscope? An even better alternative is to get a $10 mechanic's stethoscope (http://www.autozone.com/autozone/accessories/OEM-Mechanic-s-stethoscope?itemIdentifier=70131), which has a metal probe that you can place on different parts of the engine to pinpoint the source of an engine noise. Extremely effective! Watch out for the radiator fan when and if you do this.

Pinpointing the exact location that the noise is coming from is essential in diagnosis, Otherwise, "the engine is the problem" is probably the best anyone can do with any accuracy.
martindktm
03-12-2011, 10:32 AM
Could it be from the timing chain?
Terrys
03-12-2011, 06:00 PM
Sounds like a sticking valve to me.
01001010
03-12-2011, 09:54 PM
Terry!!! Good to see you're still on here man! I'm BACK!

Guys, I made some time to get dirty with Sasquatch today so I got started by taking the oil pan off and inspecting things from underneath. Everything looked fine until I found what looked like part of a shim on the oil pumps mesh screen.

With the Oil Pan off, I was removing the last little bit of oil when I started to come across tiny golden nuggets. I immediately knew...

Two hours later:
albersj51
03-12-2011, 10:40 PM
Pardon my ignorance, but what is it?
badvibes
03-12-2011, 11:20 PM
Pardon my ignorance, but what is it?

When you click on the pic and enlarge it look at the pic title in the lower left corner..... :thumb-up:

Jeff
albersj51
03-13-2011, 12:27 AM
When you click on the pic and enlarge it look at the pic title in the lower left corner..... :thumb-up:

Jeff

I did, but it doesn't show up on my phone. Oh well, ill look when I get home.
01001010
03-13-2011, 12:36 AM
On an unrelated topic, is your name 01001010 the binary equivalent of the ascii number for the letter J? Just curious.

-Jason

Correctomundo!
SalemRover
03-13-2011, 06:29 AM
Correctomundo!

Good to know the geek has not left me entirely. I have one of those tappets and it failed just like that, but only because I did not install the pushrod correctly. Mine was on a diesel engine so the clatter was different, glad you found it.

-J
I Leak Oil
03-13-2011, 07:51 AM
Bummer for sure. I'm surprised it's as intermittant as it is! ....and that it runs as seemingly smooth as it does.
01001010
03-13-2011, 08:10 AM
Salem, this is the second time I've had a 2.25 with a broken tappet. My first was a Diesel and it the damage was on the same exact location of the tappet. I never got to hear that engine run so now I know EXACTLY what a damaged tappet sounds like.

I leak... I hear ya. Thats why I was so baffled! My bro and law and I just stared at the engine running for about 20 mins.... just stared