Head and rockers.
 

I have been meaning to replace the valve cover gaskets as well as the pcv valves. While driving in 4 th gear and only under a load such as a hill i have been hearing a rattling coming from the engine. I pulled the driver valve cover to adjust the vavles and it doesnt look to clean. I also noticed that the rocker closest to the firewall i believe its an exaust valve moves left and right on the shaft? How bad is this and whats your opinions on the pics? Any way to safely clean without removing the head.i have yet to remove passanger valve covers.

Re: Head and rockers.
 

Its hard to see what's in there, but does it look like just thick oil? Or does it look like slime? If its slime-like it might be water in the oil. that's bad (head gasket maybe?).

If its just thick oil in globs it could be sludge from the PO not changing the oil. You can use a sludge remover and give it two treatments and it should clean a lot of it up. I used this stuff on the wifes car. Worked pretty good.

http://www.auto-rx.com/

Re: Head and rockers.
 

Some sludge, but I've seen some much, much worse. I have carefully cleaned up my rocker assemblies with brake cleaner or lacquer thinner while trying to avoid any sludge going down into the motor. Yours really doesn't look that bad. The rocker arms should have some side play. Not sure how much would be excessive. Check your rocker pads and valve stems for any unusual wear patterns.
The throttle return spring on yours is still a nice yellow, so it appears your engine could have relatively low mileage.

Re: Head and rockers.
 

I think your rocker assemblies look very clean...compared to most I've seen in these motors, unless they were rebuilt recently.
I suspect yours has had the top end, or at least the rockers assemblies redone recently.
Some side play is normal and therefore to be expected. You might want to compare to the other side when you get that cover off.
Are the valves adjust ep properly? A loose valve adjustment can make a significant racket.
Rod J
Issaquah, WA

Re: Head and rockers.
 

The "rattling" you hear is probably detonation.

Has nothing to do with the valve adjustment. Excessive lugging, fuel octane, or timing are the likely culprits if the engine isn't running to hot.

Re: Head and rockers.
 

Its only in fourth gear and only at the top end lije around 55... it sounds like a metalic similar to a spray paint can

Re: Head and rockers.
 

No rebuilds that i am aware of. She sat in a field for a while. How long is unknown to me as i bought her from the guy that "saved "her

Re: Head and rockers.
 

I would not worry about the sludge, a lot of old engines ran on non detergent oil. You can add a quart of automatic trans. fluid to your oil, and clean alot, but I have had engines when all the sludge comes loose, it clogging oil sump screen, and causing oil pressure drop on the highway.

Re: Head and rockers.
 

What's the initial timing set at?

Mine knocks in the morning and it is not even the engine...it's the clutch fork bearing. I can feel it when I push the clutch in. haha

Re: Head and rockers.
 

No idea on the timing. Dont own a light yet and have never done it. Maybe its timw to invest and learn hahaha

Re: Head and rockers.
 

I just learned this on my last wrestling match with Cecilia :)

you won't use it every day, but it's a good investment. You can use the same light for all kinds of engines too. Not just trucks. Biggest problem with using a timing light is not getting the wires in the fan blade when it's running. Ask me how I know :poke:

Your noise could also not be the motor at all. Maybe something rattling in the front or on the frame as the wind picks up. Can you do the same thing when you're sitting still and at the same RPMs?

Re: Head and rockers.
 

When cruising at around 55 there is no noise. When i try to accelerate to pull a hill or speed up even slightly the noise begins. Now i hear it when i rev it up to a high rpm in neutral. It sounds like its coming from the passanger side of the engine...ya know the side i have yet to pull the valve covers off of haha. I guess i might know more when i do remove the cover. Oh and does anyone have a know part number for the pcv valves that are under the valve covers?

Re: Head and rockers.
 

This table of known part numbers is very handy. http://6066gmcguy.com/partnumbers.html

Re: Head and rockers.
 

Sounds like detonation to me. Normally that will happen under load when the timing is to advanced and the mixture is to lean and or there is not enough octane. I'd get one of those cheaper lights and just see, Or just retard the timing a bit and see if it goes away.

Re: Head and rockers.
 

How old and what grade of gas are you running? At first you described the conditions for detonation. You could try some drygas as you may have gotten some bad gas. If it persists not only set you timing, pull the plugs read them and check the gaps for erosion.

Re: Head and rockers.
 

No one is giving you an answer. You have two different deals. Its pretty simple.