How to Adjust valves

With the much appreciated help of all of you, I have traced my valves rattling to them needing adjusting. Well, I'm not sure how to do so on such a new model truck. Is it best left to a mechanic that knows about newer model engines, or can anyone with pretty good mechanical skills do it? If its possible for me to do so myself, can someone please point me in the right direction? I need to know what all is involved and what steps I need to take to get it done correctly.

pretty tricky the first time. you gotta do it on a hot/warm engine. you should get some new adjuster lock nuts because the ones on there get worn out quick if you adjust them much and then they loosen easy. basically, you crank by hand to get the engine to fully open valve on cylinder number one. Then, you loosen the lock nut and loosen the the adjust nut, then tighten the adjust nut till the rocker contacts the pushrod but it still will spin if you twist it but has no slack going up and down (you move it with your fingers). then you tighten it 1.5 turns more and move on to other valves that are open. once you've done all the open valves, you crank the engine by hand to another 60 degrees or so and do the open vavles and so on till you get them all. keep track of the ones you've done on paper. I read somewhere years ago you could get about 10 hp more by tightening them 2 full turns and that has always worked for me on chevy motors. until you've done it a few times, you can't be sure you are getting it right so its probably better to have it done by a pro.

juma

Any idea how much this will set me back?

Juma, I think you need to adjust the valves with the valves closed. The rest of your procedure is correct. The valves need to be closed, if they are open when you adjust them you risk there being too much play when the valve closes and the pressure on the rocker is released. At least that's how I've always done it on the small block chevys I've built.

huminski - would you recommend myself doing this, or a pro? Can it be any different than a Ford 302? all I've ever had is Ford's until this truck I have now.

Hydraulic lifter adjustment is pretty much generic, if you have adjusted them on a Ford you should be comfortable doing it on a chevy. I am not personally familiar with your skills but if you had success doing it in the past the new truck should not be a problem for you.

With the much appreciated help of all of you, I have traced my valves rattling to them needing adjusting. Well, I'm not sure how to do so on such a new model truck. Is it best left to a mechanic that knows about newer model engines, or can anyone with pretty good mechanical skills do it? If its possible for me to do so myself, can someone please point me in the right direction? I need to know what all is involved and what steps I need to take to get it done correctly.

you dont mention which engine, but for gen1 sbcs, put the taget cylinder on the cam base circle (tdc is best) and tighten the locknut slowly until twirling the pushrod gets difficult, then turn 1/2 to 1 turn more (I use 3/4) and you will have setthe proper lash

you also didnt say how you came to this conclusion, chevy hydraulic valvetrains just do not go out of adjustment...

How I came to this conclusion was that a few months back, I had my head gaskets replaced, one was leaking water into the oil. Ever since then,the valves have been rattling like hell, they never did it until I had that work done to it. I have been told that its very difficult to mess the timing up, but I don't know much about these new GM engines. It is a 5.3 w about 84K on it now. Do you suggest it might be something else? I know the Hypertech doesn't help any, but it was never this bad, even when it was installed before the heads were removed.

yes, I misstated that "valves open." I should have said closed. I was thinking about the rocker and the pushrod and it came out wrong.

If they had the head off, they had to adjust the valves when they put it back and it was probably cold. you gotta adjust them hot. also, that locknut can only be used once with reliability in my experience. once they wear a little going off and on they tend to loosen by themselves.

Its probably a 4 hour job at the dealer (4 hours times their rate). A service station mechanic may be able to do it for 100 bux, or maybe one of the chevy mechanics after hours.

juma

I am a close friend of the mechanic that worked on my truck, and asked him what the deal was. He said that he's not sure, but he could check the timing. I guess I need to demand they adjust the valves..thank God I still have the reciepts.

The Ford 302 has one set position for the rocker arms, they get torqued to a specific torque, and they are set, they are not adjustable. The Chevrolet Small Blocks need to have their valves fine tuned (Therefore producing more power) Juma's instructions are correct.

Before doing anything yourself, you must check the service manual for your engine. Not all hydraulic valves on GM engines are adjustable. I posted a reply to a thread on just that topic awhile ago. Depending on the studs that hold the rocker arm on a 4.3L engine, for instance, pressed in as opposed to threaded, made all the difference in regard to whether or not the valves were adjustable. Short answer is find out the procedure for your particular engine.