klack klack pause.....klack,klack pause

[Whiterabbit]

Rhythmic klack klack 5 to 7 second pause then klack klack at idle. I can't for the life of me figure out what is making that noise under the hood!
Any ideas??
78 MOD 109. 4cyl

[yorker]

Where under the hood? you need to use a screwdriver or mechanic's stethascope? 5-7 seconds is a long pause for an engine related click klack.

[Whiterabbit]

Yea, that's what's driving me nuts! too long a pause to be a tappet or rocker arm clearance issue or even a con rod. Best I can tel it's near the rear of the engine, up top.

[yorker]

how is it running? Is it skipping or stuttering by chance?

[jac04]

...too long a pause to be a tappet or rocker arm clearance issue ....

Not necessarily. I had the same exact symptoms on a 2.25 and it turned out to be one of the cam follower rollers. It had a flat spot on it. Things were nice & quiet until the flat spot hit the cam, then klacking until it rotated slightly.

[I Leak Oil]

Does it go away if you take the valve cover off?

[Whiterabbit]

Gonn'a pull the valve cover and check the clearances tomorrow. It might be a bad tappet. It speeds up when you come off idle but goes away when the motor is hot going down the road.
I'm running the truck hard to find issues that need addressed. All the U joints,transfer output seals, pinion seals, exhaust manifold leak,brake hoses,all the brake shoes and cyl.,rad hose,voltage stabilizer, fuel pump krapped out,electric pump in,etc,etc,bla,bla,blaa
I think the head gasket is letting go, oil and rad fluid disappearing now.
Been putting 100 miles a day on it back and forth to work.

[Alk-3]

I'm having the exact same issue and I've tried everything to get rid of it. I've gone so far as pulling the head to replace the valves thinking it was a sticky valve.. No dice. That procedure revealed that my head had a big crack in it, and I ended up getting a whole new turner head. Still the same noise. This week I replaced the rocker shaft and all the rockers, and still the same noise. I have just been thinking it might be the Tappet, or cam follower, so I'm interested to hear how you make out. I'm thinking about dumping some oil down each pushrods hole (maybe some Lucas oil stabilizer because its so thick?) and seeing if it makes a difference while the engine is going. Mine is loudest with the valve cover on, and the air cleaner attached. I think the sucking of the engine without the air cleaner drowns out the tapping noise, so it just seems quieter.
If its a flat cam roller, it's going to stay that way, because there is no way I'm pulling the head for a fourth time..