Thread: Adjusting 350 rockers

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Hi, new here to register here.

I have lurked around the forums for quite a bit, but I ran into a bit of a pickle.

GM Goodwrench crate 350 nothing fancy...Got a slight tick really have to listen to hear it.

I am 90% sure its the rockers are loosening up engine only has 40k miles, used bradpen 10-40 oil changed every 2000 miles.

Long story short truck was weekend cruiser turned daily driver (69 Chevy).

Here are my concerns:

Would it hurt to pull the covers and adjust all the rockers just to be safe? I know its coming from the drivers side thanks to my cut off broom handle.

Do hydraulic Flat Tappets go out of adjustment after so long?

link removed

I have checked for exhaust leaks there are none (manifolds). It doesn't go away after engine warms up. My oil pressure is good 17-20 warm idle 35-40 cruising.

Just wanna make sure before I go out there to adjust rockers I am not wasting my time. Was also curious what else to look for before I go and try and adjust the rockers?


Was also going to make sure the method I was going to use to adjust the rockers is correct:

-Loosen rocker nut till slight clicking, tighten till clicking stops...Wait ten seconds make sure click doesn't come back
tighten 1/4 slowely, move onto next one?

I put the engine in myself, but this would be my first time attempting something like this.

Any advice would be awesome.

Welcome aboard Boger, good to have you here. It sounds like you've done you're homework so you should be fine. But it seems like there's a buncha ways to adjust chevy rockers, you description seems the most prevalent.

If it's really just a slight tick, consider leaving it alone?? Or has it become annoying?

Even for a flat tappet cam I would adjust the rockers static, without the engine running. TDC compression stroke on #1, back off the adjusting nut and let it "rest" for a bit for the lifter to relax, then run the nut down just finger tight to remove all lash from the pushrod, then set your lash the prescribed amount of pre-load. For a high performance engine I use 1/4 turn of pre-load, then tighten the set screw and give them a slight turn tighter to set the locks good. For a milder, more stock engine I'd lean to 1/2 turn of pre-load. Then turn the crank 90 degrees in direction of rotation and set the next one in your firing order. You can also do it by watching rocker action, rotating the engine until an exhaust valve just starts opening to adjust intakes one at a time; then rotate until each intake is fully open to adjust exhausts but I like the TDC method as it's straight forward.
If I were doing the old "loosen till it clicks, tighten till it's quiet method" (engine running) I'd want a set of old rocker covers with a slot cut above the adjusting nuts, as they tend to throw a lot of oil around as I recall. Haven't done one like that in about forty years myself.

Before you remove valve covers to chase a possible click, try shortong out the plugs one cylinder at a time to see if click goes away----could be loose/broken piston skirt or possible bearing / wrist pin starting to make noise--usually shorting out the spark the noise goes away---------

On adjusting the valves----you are going to spray some oil around so the cut out valve cover used to be common---also there were some clips to put on the ends of the rockers to stop the spray---

Roger, finger tight on the nut and set screw are aftermarket items--stock stuff will be self locking rocker nuts and they will be hard to turn. also a stud could be pulling out of head casting--

These are the clips that Jerry is talking about. Mr. Gasket 1015 Rocker Arm Oil Deflector Clips : Amazon.com : Automotive

I have a set. I would not do it without them anymore.

Originally Posted by jerry clayton

Before you remove valve covers to chase a possible click, try shortong out the plugs one cylinder at a time to see if click goes away----could be loose/broken piston skirt or possible bearing / wrist pin starting to make noise--usually shorting out the spark the noise goes away---------

On adjusting the valves----you are going to spray some oil around so the cut out valve cover used to be common---also there were some clips to put on the ends of the rockers to stop the spray---

Roger, finger tight on the nut and set screw are aftermarket items--stock stuff will be self locking rocker nuts and they will be hard to turn. also a stud could be pulling out of head casting--

old locking nuts do not have much holding power could be backing off if not poly lock nut s . like jerry said rocker stud could be backing out of the head cast quick check with a straight edge .or rocker is worn out and going in and out of lash the tips of rockers will get a spot that looks like this ) if real bad it will start cuting in to the rocker stud . if a stock steel shoe rocker the KD tool or someone made the wire clip ones. they work better then the tin stamped ones also check for a small hole in the header or gasket leak at ex side of the head

Originally Posted by pat mccarthy

old locking nuts do not have much holding power could be backing off if not poly lock nut s . like jerry said rocker stud could be backing out of the head cast quick check with a straight edge .or rocker is worn out and going in and out of lash the tips of rockers will get a spot that looks like this ) if real bad it will start cuting in to the rocker stud . if a stock steel shoe rocker the KD tool or someone made the wire clip ones. they work better then the tin stamped ones also check for a small hole in the header or gasket leak at ex side of the head

or a cracked flexplate.....

Well gentlemen, just a little update.

Broke out the broom handle, was listening all over the top of the engine, side of the block not a single sound. Went to the oil pan nice smooth sounds, no ticks. Went to check the where the manifold meets my exhaust system I heard a tick that was in line with the sound I am hearing. Not 100% sold that thats where its coming from but I have a set of headers that i've been putting off installing, going to try and do that wensday.

The noise I am hearing is coming from underneath the truck, no doubt in my mind. But I mean its a tick not a knock. I am probably going to go out there tomorrow and pull plugs just to make sure its not a wrist pin or a piston slap or something like that.

I did my previous listening with the engine cold so that may have to do with why I heard it twards the top of the engine.

" or a cracked flexplate.....

Today, 04:00 PM
pat mccarthy "

This also peaked my interest, everyonce in a while when I go to start the truck after its warm the starter seems to drag like it cant turn the engine over? Not sure if that would be related to the flexplate or not, I think I can also hop under there and check the flexplate while I am doing my pinion seal.

Thanks the responses, but I am pretty sure I just jumped the gun on this one and gave you guys false information.

Will also try and get a video of the sound and maybe someone will recognize it.

Originally Posted by techinspector1

or a cracked flexplate.....

yep last week a old 496 build solid roller the guy said he had added valve train noise went over looked at it. was the converter was loose from fly wheel most times the sound will not be as loud with it in gear. if fly wheel is cracked the sound is lower and center back of engine . loose really do not make the same sounds as a rocker . but more then one time i seen ex leak was the sound when a customer was thinking was a rocker

Had the same thing happen in my 496 Pat built. He said check
exhaust for leaks. Turned out to be a small pin hole in header
close to head. Fixed it and problem solved.