Wags391

92 Chevy S10 Blazer, 4.3L Z (TBI), 4x4, 216000 miles

Problem #1- So I've been trying to get the ticking from the rocker arms to go away for some time now on the driver's side of the engine. I have plenty of oil. I've tried the steps from the manual using the timing marks to align the shafts and then tightening certain rocker arms in the manual's stated sequence and I've tried the way of adjusting them when the truck is running. I always seem to get the ticking to go away when working on it, then it comes back the next day. I find that tightening the rockers to much blocks the flow of oil and too loose causing oil to spit out. Here are some flags and questions:
The rods at the rocker arm end are definitely worn from the years of use.
When I tighten the rockers too tight, the engine bogs down and almost dies, which I believe is normal because the lifters and valves have to "reset."
When adjusting the rockers with the car running, how tight should I turn the nut once the vertical lag (ticking) is gone?
Could the hydraulic lifters be worn out also, causing constant shifting so the ticking will never go away?
Would replacing the lifters, rods, and rockers fix my problem or is there a simpler way? Could I keep the original rockers?

Problem #2- Vacuum leak. I can't seem to find anything that would be a real problem except for the A/C "outside air" vent vacuum actuator. With the HVAC controls in any position, is never moves. When should it open and close? How can I test all the actuators and figure out which ones are bad? I'm definitely loosing vacuum because the Max A/C vent underneath the glove box only opens slightly, creating a whistle sound.

Thank you,

Wags

MT-2500

On adjusting rocker arms with engine running.
After gettiing the lash or ticking down no ticking just tighten the rocker down 1/2 t0 3/4 turn.
If ticking comes back check rocker arm and push rod for backing off.

If not you have a weak lifter.

How is oil pressure and oil filter and oil?

On heater controls check for good vacuumn from engine to heater contraols and check vacuumn ball for good vacuumn and bad vacuumn lines and fittings.

__________________
Remember proper testing gives us the answer to many problems.
MT

Wags391

How can I tell if it is backing off? Oil pressure and oil level, filter, oil is all good. I keep a tight change schedule and check level every gas fill up. I assume the vacuum off the check valve is what is feeding the HVAC system vacuum lines. I know vacuum to the engine is around 19 lbs. Slightly under par. The cruise control works with a slight leak when going up hills. It never downshifts to speed up while in cruise.

MT-2500

Re adjust and check for back off.
On vacuum check for good engine vacuum to heater controls.

__________________
Remember proper testing gives us the answer to many problems.
MT

Scrapper

if your pushrods are waren out i would get those and the rocker arms. and the vaccum hose going to blend door there could be a small hole in the line and if theres a t running there it may be bad or another vacuum on one of the vacuum lines there may be another vacuum hose leaking at t and not letting enough vacumm to open blend door.

Wags391

I'm assuming that if the ticking comes and goes, it's probably the lifters, right?

I'll have to get a vacuum tester again and test every place I can think of.

Wags391

It's been a couple of weeks, but I determined that the vacuum leak was from the outside air vacuum actuator for the A/C system. The rubber grommet had come out of its hole.

The ticking has still not gone away. No matter what I do, so what I need is some information on lifters, rods, and rocker arms. What are the specs on a stock S10 TBI for those parts? I'm looking at some aftermarket parts and I don't know the measurements for any of it. Or should I just go for the parts store replacement parts?? I figure if I'm going to be doing it, might as well use good parts. Suggestions?? Should I replace all three parts, or do you think the arms are good to reuse with new lifters and rods??

b1lk1

If I were personally going to go through that much trouble I would rebuild the entire top end including a valve job.

Otherwise, it is most likely weak lifters since the other hardware is mostly along for hte ride and usually does not wear out as easily.

__________________
1999 GMC Jimmy SLS (these trucks sure suck the life out of your wallet, LOL!)
Cold Air intake (eBay special with homemade heat sheild)/Throttle plate modded
2" Suspension lift (rear springs/front torsion crank)/1 1/4" rear wheel spacers

MT-2500

I would check rocker arms and push rods first.

If they are good you may have deeper problems or oi pressure problems or worn cam shaft or cam bearings.

Hav a look and see how bad it is.

Let us know what you find.

__________________
Remember proper testing gives us the answer to many problems.
MT

Wags391

I've been in there, and the only thing I can see is wear on the rods at the rocker arm end. Oil seems to be coming through fine on all cylinders. I took it all apart one day and cleaned everything to make sure the oil travel is good. It seems that no matter how much I adjust the rocker arm nuts down, the ticking comes back. So besides a worn camshaft and bearings, could it be just the lifters? Seeing how I can make the ticking stop, then it comes backs. As far as I can tell it's not the nut backing off. if doesn't get worse progressively. I tighten, then the next morning it ticks.

MT-2500

Yes could be weak lifter or cam lobe worn or lack of oil to lifter.
How is oil pressure?

__________________
Remember proper testing gives us the answer to many problems.
MT

b1lk1

If you are looking to get out of it as cheap as possible then I would change the lifters since they are the weak link in an older valvetrain. I am not suggesting that this is a wise course of action, but that would be where I started.

__________________
1999 GMC Jimmy SLS (these trucks sure suck the life out of your wallet, LOL!)
Cold Air intake (eBay special with homemade heat sheild)/Throttle plate modded
2" Suspension lift (rear springs/front torsion crank)/1 1/4" rear wheel spacers

534BC

Good chance that it is the camshaft and can adjust it like a manual to "get by" without replacing parts. Just .002 runout in the right spot can cause any lifter to pump up and then clatter.

But can we have exact details about temp,time,procedure for when it clatters the next day? does it EVER get quiet? does that cylinder run ok?

Wags391

Here is a normal course of driving and the sounds it makes:
Start up in the morning and ticking begins right away.
Ticking continues, getting faster and slower with engine revs.
Once warmed up, ticking isn't as bad, but is still there. It can be heard at stop lights, and is always present when moving from a stop. Once to a cruising speed, ticking is barely noticeable, if not gone. All temps, all times. All cylinders run fine during motion, but when idling, I do get some sputters here and there. Sometimes even a big dip in RPMs, almost causing the engine to die. It has died on a couple of occasions after a dip in RPMs. The car also dies sporadically, mostly after initial start up, and I have to restart and rev the engine to keep it going. Once warmed slightly, it doesn't die, but when going into motion, the car sputters and I have to give it some good gas to keep it going. It kind of the same thing as tightening the rockers too much causing the engine to sputter and eventually die.

534BC

I guess without seeing/hearing/checking it out I'm still going to lay money or a bad cam with some slight base circle variation.