Loud tap/ping noise

[el salsero]

Sorry if this is sounds redundant. I checked a few other posts to see if have a similar problem, and although I did, the circumstances are different, anyway let me explain.

1990 4x4 22re over 100,000 miles. Engine ran fine before I changed the timing chain guides, only pinging was the chain rattling against the head. Buttoned her back up. Truck ran strong for another 500 miles or so, then while the truck was on the fwy, it was an effort to hold 65 mph, and finally over-heated. Towed it back to the house.

One of the hoses near the firewall had a broken rusted bracket which was leaking anti-freeze, changed that. Gave the engine a once over...the #4 spark plug wire came unfastened at the tip. Also, doubting my work, I checked the torque on the header bolts, each one was about 10 lbs. over torqued. I backed off the torque bolts in the proper order very slowly to the correct lbs. Also fixed the #4 plug wire. Fired her up, now there is a loud pinging coming from the #4 piston area in the valve cover. I thought it was a valve. I checked the clearances, fine, still have a loud ping.

It's not a bang, or a knock, a very loud ping that is not intermittent. Maybe a valve is warped? I thought of pulling the header again to check it out, however before I take on that task again what ideas would any of you have? Thanks very much in advance.

[KimMG]

Did you replace the valve cover gasket and all the other little rubber parts when you had the valve cover off the last time? The rockers can hit the valve cover if the gasket is compressed too much. What does the #4 spark plug look like? Is it firing correctly? Have you done a compression check on the motor? Overheating of my Datsun motor caused a valve seat to fall out of the head causing a knocking noise.

[KimMG]

PM from el salsero-Hey thanks for responding!

Checked the distributor wires, they are hooked up correctly.

The sparkplug from the #4 cylinder looked burnt and black.

el salsero-Private messages are not always good because they limit the amount of help you can get.

A burned and black spark plug means something is not firing correctly.
Were you able to do a compression check? Are you getting spark to the #4 cylinder? Are you getting any smoke from the tail pipe when your truck is running? Have you checked to make sure your distributer cap is not cracked? Did you fix or replace the #4 wire?

[el salsero]

Originally Posted by KimMG

PM from el salsero-Hey thanks for responding!

Checked the distributor wires, they are hooked up correctly.

The sparkplug from the #4 cylinder looked burnt and black.

el salsero-Private messages are not always good because they limit the amount of help you can get.

A burned and black spark plug means something is not firing correctly.
Were you able to do a compression check? Are you getting spark to the #4 cylinder? Are you getting any smoke from the tail pipe when your truck is running? Have you checked to make sure your distributer cap is not cracked? Did you fix or replace the #4 wire?

No smoke coming from the exhaust, seems to be exhausting normally, checked the dist cap, not cracked. I have yet to do a compression check and/or replace the wire. I'm going to pull the head and see whats going on inside. I want to make an mp3 recording so you can hear.

[KimMG]

Don't pull the head yet. Try trading the spark plug wire. Try the number 4 wire on cylinder #1 and the #1 wire on cylinder #4. Never known anyone to be able to fix a spark plug wire (not saying it can't be done). A bad wire will cause the symptoms you describe.

[el salsero]

Originally Posted by KimMG

Don't pull the head yet. Try trading the spark plug wire. Try the number 4 wire on cylinder #1 and the #1 wire on cylinder #4. Never known anyone to be able to fix a spark plug wire (not saying it can't be done). A bad wire will cause the symptoms you describe.

Spark plug wires are fine. Tested each one. It's definitely something tapping very loudly from the #4. Imagine doing a drum roll on the valve cover, thats what it sounds like.

[KimMG]

Did you find out what the noise was?

[el salsero]

I had a buddy come over and use a stethescope and place it on the back part of the valve cover, he hears the same thing, just lots of tapping. So I'm going to take some time and pull the header off to see whats going on inside. Maybe there's a piece of metal banging around in there. I'll keep you posted.