Lifters / Valve adjustment question

[c10stepside79]

My truck has that tell-tale clacking sound that means something is amiss with the valves or lifters, what I'm curious about is what exactly is it that's making the noise?  Is it the push rod hitting the lifter, or the rocker arm rattling? 

I'm really just trying to determine what parts are being worn down and how important it is to get this fixed.  Can this go on for longer periods with no major damage or is it something that should be addressed asap?

[bd]

I suggest you begin by checking your oil level, oil condition (When was it last serviced?), and then oil pressure using a manual gauge.  Is there a lot of caked sludge under the valve cover?  If the pushrods and rockers are worn, you may have a lubrication issue that could turn catastrophic. 

Does the motor misfire?  Or, does it pop back with rapid throttle opening?  Either could indicate a flat cam lobe.  You could also have a rocker stud pulling loose, or broken valve spring.  The lifters could be worn out - but then I would wonder about the cam.  You might just need to adjust the valves... but, if they're loose, there's a cause for it that should be diagnosed.  It is not something that I would recommend putting off.  No one can definitely answer your question on consequences or urgency of repair without a proper diagnosis, so that's where you need to start.   

[Fairlane514]

I agree with bd, try changing your oil if its old and see if that doesn't help.  Then you will have tear down the valve train of that doesn't cure it. Collapsed lifter, worn cam lobe etc, all makes sense to me.

[c10stepside79]

The oil is new: It was changed it right after buying the truck, 5W 30, and about three weeks ago on the advice of a buddy who thought it might help quite the lifters, I changed it again using 20W 50.  The engine doesn't misfire, I'm not sure about "pop back" but I don't think so.  The truck runs well, just noisily.

I definitely agree a good diagnosis is whats needed, so I guess the next cheapest/easiest step would be to pull the valve covers and try adjusting the valves? 
I've been thinking about replacing the valve covers and cutting out the tops of the old ones to use while doing the adjustment.  This will be by far the largest mechanical undertaking I've ever taken on so any advice would be most appreciated. 

[starkey]

Was the noise audible when using 5w-30? Why the switch to 20w-50? That oil is pretty thick, and will have a hard time pumping up the lifters, unless the engine was built with very loose tolerances or bearings are wore out.

I would drain that 20w-50 out and put some 10w-30 back in and adjust the rocker arms till they are quiet.

pull a valve cover, crank the engine up and see if you are getting any oil through the pushrods. If there is oil coming through start adjusting them. If there isn't any oil coming through, you've got bigger problems.

I've adjusted the rockers on many a engine by doing this:

1. pull the valve cover off one side
2. start the engine
3. starting with the closest rocker arm, loosen the nut just until it clacks, then tighten 1/4 turn. If you go to far, you will hear the engine miss, so just back it off a bit.
4. repeat for all rockers.

Stark

[c10stepside79]

Thanks!  And yes the noise was there before the 5W 30 went in, it was there after, and it's still there with the 20W 50.

[starkey]

No problem. Regardless, I wouldn't run 20w-50 in it unless there is severe bearing wear and you have no choice but to run it till she blows.

[Fairlane514]

Another quick check.........SOMETIMES an exhaust leak can sound like a lifter knocking.  If you have headers or even manifolds, check for loose bolts or gaskets gone bad.

[starkey]

Totally agree Fairlane.

[bd]

Another quick check.........SOMETIMES an exhaust leak can sound like a lifter knocking.  If you have headers or even manifolds, check for loose bolts or gaskets gone bad.

If this ^^^^ is okay, verify your oil pressure before tear-down.  Keep all of your parts in order by cylinder.

...I wouldn't run 20w-50 in it unless there is severe bearing wear and you have no choice but to run it till she blows.

That's kind of a dramatic way of saying you don't like 20/50   

[c10stepside79]

Another quick check.........SOMETIMES an exhaust leak can sound like a lifter knocking.  If you have headers or even manifolds, check for loose bolts or gaskets gone bad.

The exhaust manifolds do look rusted, pitted, and generally burnt.  After reading your post, I did some research and I can see this as a real possibility.  In the morning, I plan on holding a screwdriver against my ear and the valve cover.  If the knocking isn't louder over any one valve, I'll start checking the exhaust.  Thanks.

[starkey]

...I wouldn't run 20w-50 in it unless there is severe bearing wear and you have no choice but to run it till she blows.

That's kind of a dramatic way of saying you don't like 20/50   
[/quote]

It's not that I don't like 20/50, its just that I wouldn't pour a quart on a burning crackhouse. 

just kiddin... every weight of oil has its purpose, and for a stock 350, I don't believe 20/50 is the ticket.

[Fairlane514]

You shouldn't need 20W50 unless you have a situation like loose bearings and you need more oil pressure. It takes longer for 20W50 to get through the engine at start up, and its harder on oil pumps and distributor gears. Could even rob a few hp.

[c10stepside79]

Apparently, getting your head close to the valve covers while the engine is running is not as simple as I thought, so the screwdriver thing didn't go so well.  And looking at the exhaust manifold, I don't see anything that would indicate an obvious leak.

But there is an interesting new development: The ticking sound continues after the engine is shut off.  It is much slower and quieter, but it can definitely still be heard for about 20-30 seconds.  The more time that passes, the slower and quieter the ticking becomes.  With the engine off the sound is clearer; it sounds metallic, like if you were very gently tapping your fingernail on the hood.   

Any thoughts?

[Fairlane514]

Sounds like you are describing some kind of metal expanding from heat.   Do you have a catalytic converter?