Top End Tapping (1 Viewer)

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Nomis

Nomis

Joined
Feb 11, 2004
Threads
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Location
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I have a tapping sound coming from what sounds like the top end when the engine is under load. At first, I thought it was just the valves - even though I've checked and rechecked the valve clearances when the engine is hot. Next, I thought it was pinging but retarding the timing has no effect - neither does higher octane fuel.
The sound occurs when the engine is cold or warm, provide you accelerate so the engine is under load. Didn't hear any exhaust leaks using a hose as a stethoscope. 18in of vacuum at idle, rock solid. Other than this sound - the truck runs great.

Take a listen:

http://media.putfile.com/FJ40Sound



Any help is much appreciated.
 
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I had the same sound on mine and thought the timing was high(sounded just like valves when i got a load on it) or valves out of adjustment ,turned out to be a exhaust leak(in my case the gasket under the block off plate for the egr tube) Id have sworn it was valves. took me a week of after worktime to find it. sounded normal with no load on it.
 
I checked the EGR block off plate and didn't see any black soot on it so it looks like its sealing properly. I tried to listen for exhaust leaks at idle - but didn't hear anything. I will probably pull the carb off tonight so I can get a better look at the manifold.
 
Pulled the carb to get a better look at the manifolds - no exhaust leaks. Also pulled the spark plugs and looked at the tops of the pistons - no foreign no objects and plugs look good. I may take it in for a second opinion before I pull the head or the oil pan and check bearings. Fun stuff. . .
 
I listened to the clip, didn't hear what you're hearing I guess...
Usually, when I hear tapping, I get ready to adjust the valves but re-torque the manifolds and it goes away. And when somebody sez "I got no exhaust leaks" I call BS, but in a nice way. If you are SURE you got no exhaust leak, I might pull the rocker arm and check pushrods and lifters before I would pull the head. Then put the rocker arm back on and adjust valves again and see if there's any change...
 
76?

Air injection rail, or, if removed, air injection plugs.

REALLY can sound a LOT like a tappet noise, but only under load.

Best

Mark A.
 
Nomis said:
In the vid clip, its the high pitched metallic flutter that I'm referring to - you can hear it at secs 2-4 and 8-10.

FJ40 Sound - Putfile.com
Click to expand...

I don't hear it in 2-4, but I hear 'something' between 8-10 that sounds like a lite metal tapping, as if a piece of tin were contacting the rocker arm assembly at some point.

Are you going thru an RPM range during your test that could be picking up an RPM-sepcific vibration?

Can you isolate whether it is front, rear, or mid-engine.

It could be something as simple as a loose washer on a fastener, or the carb linkage. It DOESN'T sound like a tappet noise.

Best

Mark A.
 
I have had high end tapping noises on two of my 40's. Both times it was valves out of adjustment. once adjusted I could barely tell the engine was on it was so quiet. I think valves out of adjustment is prety common.
 
65swb45 said:
I don't hear it in 2-4, but I hear 'something' between 8-10 that sounds like a lite metal tapping, as if a piece of tin were contacting the rocker arm assembly at some point.

Are you going thru an RPM range during your test that could be picking up an RPM-sepcific vibration?

Can you isolate whether it is front, rear, or mid-engine.

It could be something as simple as a loose washer on a fastener, or the carb linkage. It DOESN'T sound like a tappet noise.

Best

Mark A.
Click to expand...

The sound is a little deeper than it sounds in the vid and a heck of a lot louder in person and is coming from the rear of the engine. I removed the EGR block off plate and resealed it as it did have a very tiny leak. I took it for a test drive - same noise.

The noise is not RPM specific - but is load specific. The greater the load - the greater the sound. If you run the RPM's up slowly, you won't hear it - even at high RPM. In the sound clip, the truck was at the same speed in fourth, I just floored the throttle which made the noise audible, when I backed off the throttle, the sound goes away. The best way I can think of to explain the sound is if you took your PCV valve and shook it up and down - you would hear that tapping noise.


Here's another clip - you can hear it pretty clear at 12 seconds. http://media.putfile.com/FJ40sound2
 
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Update

Running like a champ now - turns out there was quite a bit of carbon buildup - esp on the rear cylinders. I did a leak down test and it looked like the exhaust valve on #5 cylinder was sticking. I whacked it with a rubber mallet and it sealed - maybe the carbon wasn't helping. I think the carbon may have been causing pinging as well. I took care of the carbon by spraying some water down the carb at high idle (steam cleans it) - then used some sea foam spray and did the same. Double checked timing and threw in some fuel treatment and it runs great now. Glad I didn't have to pull the head to figure it out.

:beer:
 
nice

good fix that'll be a handy reference for others;)
 
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