williscr3

started doing this the other day. i heard a loud clicking or tapping sound so shut the truck off let it cool for about 4 hours at work. started it back up and it sounds almost like exhaust leak from header, but when it warms up it sounds like a metal tapping or clicking sound towards back of valve cover. pulled the valve cover off, chain and tensioner were replaced about 2 months ago so inspected chain first. its still tight no impact indication. i also used metal backed guides for chain. truck runs great no loss of power. vacuum gauge shows 21in. hg. and checked cylinder pressures, 1, 2, 4, were 180 psi, cylinder 3 was 178psi. its pretty loud tapping. mileage of truck shows 85k but could be a little more. i did check valves when i did chain 2 months ago all were good. maybe my problem? would it get louder as motor warms up? with the motor running i also picked up gently on the valve cover to see chain slap or rockers smacking valve cover no slack in chain and no rocker impact. i dont have oil pressure gauge on dash or in my garage so no clue other then the fact the idiot light isnt on. thanks.

williscr3

checked all the valves adjustment today. all were good. is it possible the head gasket is blown causing the sound between cylinders? can i rule it out being head gasket? i wouldnt have good vacuum while running right? i also wouldnt have 180psi between all cylinders right? is it possible a valve is hitting piston but then why only when warm? i dont understand why it becomes so loud only when warmed up. maybe i should check my oil pressure? not enough lube on valves causing noise? i just dont get it... the truck runs really good. when it warms up though it seems to idle rough while making the noise. valves were checked hot

williscr3

drove the truck till it warms up today soon as it started making noise i yanked all the plugs this time and did a 5 count with compression tester all 4 cylinders were 150psi BUT 4th cylinder spark plug had some ash on it. i thought it did last time but thought i grabbed some funk off head when pulling it out. it was dark outside. not sure what to think about this... the truck runs great it just makes a loud noise thats very very noticeable. i understand these motors make some noise but this seems excessive. im thinking about changing oil and filter again and putting lucas in it. i recorded a video if theres any interest

Rerunn

In the video it dies sound like an exhaust leak. But that's in the video. For giggles when it starts tapping pull plug wires one by one. If it goes away on one cylinder it could be a bad wrist pin. Hard to tell in video cause sounds gets distorted alot. Checking the oil pressure would be a good idea. Yotas have to have practically no pressure to kick a light. Check for rocker play side to side as well.

williscr3

yeah i kinda thought it really sounded like exhaust in video. if it was wrist pin wouldnt it do it right of the bat? this seems to come on as the engine warms up. you hear the typical valve train noise until it warms up then its that loud sound in video. either way ill give it a shot. i have the valve cover off now and plugs out im going to put camera in spark plug holes tomorrow to make sure no valve impact. how do i check for side to side play? when valves are closed rockers slide back and forth on the shaft is that normal? is it worth just changing the oil and filter? maybe substitute some lucas? thanks for the help, ill post results tomorrow.

Rerunn

Almost try and twist the rocket opposite of its normal movement. It's hard to explain in words.
I don't really like Lucas it's kinda become one of those mr. Fix it in a bottle.
Now I may get burned at the stake for this but I use STP oil treatment. I've actually assembled alot of engines with the stuff and had no problems. I became a firm believer in the stuff when I developed a main knock on starting up due to T-cover failure with cross contamination of oil and coolant. It was on sale so what the hale lol. Stuff is jam up!

williscr3

twisted the rockers today pushing top of rocker toward cab and bottom toward front of truck. it feels tight on all rockers. tried to use small camera to view in cylinder walls but camera didnt fit. was able to see tops of pistons barely and didnt look like any kind of impact. seems like rockers have a lot of lash play they really rock back and forth. im going to check valve lash again... for the 3rd time. they feel very loose at different spots.im pretty sure im folling the proper procedure for it. im not sure how to feel about this truck... im pressed for time. i daily drive it but have been driving camaro since this started which is ok but im in the middle of buying a house so i really need my truck right now. i dont have time to pull the head off and investigate whats going on. im not sure if its ok to drive or what.
i read worn valve guides could cause a chatter and worn valve guides could possibly allow oil into cylinder. i did have some ash deposit on the 4th cylinder but im pretty sure my 4th cylinder fuel injector is going bad its been clicking since i bought the truck. nervous about driving it... dont want it to cost me more money. theres no engines for sale in this area so its rebuild or new one. neither option fits my budget right now.

Rerunn

Hm.... what are you setting lash at?

williscr3

.008 and .012. one minute they look tight when doing it but now looking at them they flop back and forth making a nice gap. is it possible that the gap is opening up more when the motor warms up? when cold it sounds like exhaust leak when warmed up it sounds like valve chatter

Rerunn

They will appear loose unless setup for adjustment.
Man I hate noises lol

williscr3

ok adjusted valve lash again tonight. did a little on the tight side with cold engine 7 and 11. paid special attention to how tight the valve cover was and location of it. let motor warm up and sounds just like it used to. almost like a diesel. has a exhaust leak for sure around the manifold area but i can deal with that for now. going to change oil and add a little lucas just for peace of mind just a little not whole bottle. thanks for the help.

Rerunn

I'd fix that manifold leak first that could be adding to the sound or even be the origination of the noise.

williscr3

Sounds good ill try to swap it out this weekend if I have time. So far its reasonably quiet driving around neighborhood. I'm going to drive it to work tomorrow and see how it goes.