4G32 Rocker gear advice?

[VGJONO]

once again i have a silly question, but pretty much after a fair few goes at doing my tappet spacing there is no stopping the tappet noise. it may get quieter but always comes back pretty quickly, ive got a hunch that the rocker shafts may be worn and its been sugested to replace them, but honestly i dont know if they are worn or if i am doing something really wrong, ive set them at the factory specs, and set them using some suggestions in an old post from geezer, my question is, if i have a noisy top end is it worth replacing the rockers or rocker shafts?

[geezer101]

I have seen rockers wear out badly (I mean badly) If you are not sure how bad they really are, back off one of the tappets completely then get a hold of the rocker while it is off lift. If you can twist it or jiggle it up and down from the rocker shaft it is fragged (you'll know right away if this is the case). The rockers wear out on the lower half of the rocker shaft hole as this is the surface that gets the vast majority of load on them. If you are setting them hot and are going by feel there should be no reason for them to go out of adjustment in a hurry.

[astronturbo77]

The head might have been bent like a bannana, then machined flat without the cam journals being line bored, as speaking real life experience with a saturn where I could quite literallly roxk the cam in the journals.. Either that or the rocker arms/shafts are crook

[Superscan811]

Another 2 things to check,
1.) Cam lobes and rocker slippers. Make sure they aren't wearing down and/or badly scored.
2.) The top of the valves aren't mushrooming or wearing a groove in them.


Cheers.

[VGJONO]

Cheers for the advice guys, definitely a few things i will be investigating tomorrow

[LukeAussie]

Hope you get to the bottom of this... how quickly do the tappets go out of spec after you fix them? And is is all of them, or specific ones in particular? I'm wondering whether there are issues with the locking threads too? If it's something like cam lobes or similar, you should notice the problems after a single revolution of the cam... hopefully it's an easy fix for you!

[MadMuz]

What oil are you using? If your engine is fairly old and worn, if you try and use light weight modern synthetic oils (like 5-20) old engines will rattle.... try thicker mineral oil like 20-50 or thicker and try adding thickening/clinging additive like motor honey, moreys or nulon to wring the last life out of the old girl I used to break rockers in my LC when I flogged it too much... ended up carrying spares in the glove box... lucky they were the same as colts If you have the tappet cover off, make sure there is oil making it up top.... no oil reaching the top is a death sentence for the valve train

[VGJONO]

Using Penrite 15-60 fully synthetic, and went out today and started it, seems to have stopped, tappet noise is there but not as bad as i thought it was yesterday, my theory is i was driving the car differently yesterday making it more noticeable, however i will still be checking over the rocker gear when i service it in 900k's as im still convinced something isnt right with it.

[MadMuz]

Next time you change your oil (or if the nose comes back) just get some 25-60 mineral oil and some nulon or oil additive that clings to things in the engine. New oils aren't designed for old engines, they are generally too thin and create the noises you are talking about. When your engine was new (last century) it was designed to run on mineral oil, not the watery new oils for modern high tech engines the synthetics are designed for.

The first number in the oil is how thick (thin) it is when cold and the second number is how thick (thin) it is when hot. So 5-30 weight is like water when it is cold and not much better when hot..... you need thick when cold and thicker when hot.... the additive will make the oil cling where it is needed.

If I were you, I would ditch that oil asap..... noise = damage.

just my opinion

[wheelbarrow]

Also it may pay to check the rocker gear is actually getting oil. Take out the dizzy if its a chain drive and using a flat screwdriver bit in a long extension and a drill you can run the oil pump.

[VGJONO]

so pulled a tappet adjuster from No.1 cylinder exhaust side to see what it was like, this here is new teritory for me but in comparison to the complete set i have in the shed (that seem pretty worn) these are worse, also seems to have some damage on the contact area, am i crazy or going in the right direction with this?




Cheers
VGJONO

[Sigmaproject]

Are you adjusting them in the right sequence ? I ran these on my GN head for about 10 years and only adjusted them twice. They only could get hammered if there was a lack of oil or badly adjusted.