Valve adjustment problems

[Phdintheory]

Okay, I've got a '91 with 285,556 miles. It's been running real loud with what appeared to be a dead cylinder.
I had determined it was a valve problem so I decided I'd give adjusting them a try. I've never done valves before so I read up on it until I figured I had a general understanding of what to do. That is until I started in...
First problem I had was trying to understand how you're supposed to be TDC one cylinder, but only if overlap is happening on another then you adjust the ones you...?
So what I figured is I'd just watch the cam lobes and when a set of them were pointing straight up I'd adjust them. Then move on to the next. By doing this it would give me a set of intake valves and a set of exhaust valves to adjust. I'd then go on to the next ones.
Got it all back together and now it's not running so hot. It's quieter which is good, but I've lost power and low end torque. Any ideas on what I've done wrong and what I can do to fix it?
Thank you

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[submitaweasel]

Oof. Sounds like you got in way over your head with this.

1. If you did not start at TDC on #1 the entire job could have messed up the valve timing for each subsequent step. Unfortunately, every step after the first one relies on the prior step having been completed.

2. You can get around this by adjusting only valves that are not under compression (by the valvetrain, cams, folowers, etc). Do you have any experience with feeler gauges? If not, we are off to a bad start.

3. Throughout the process, you should ensure that there is no mechanical load on the valves you are measuring. The reduction in sound implies you have tightened the clearances. The reduction in power is concerning.

4. Regarding the reduction in power, are all other maintenance items up to date? Being a 91 it must be a timing belt. If the timing belt is stretched or any of the related components are worn it could be the cause of your issues.

5. On-line diagnostics are not the way to fix problems. You may get away with it. However doing any fix above your head is asking for trouble. My best advice is to take it to somebody who is familiar with the engine to get a hands-on look at what is going on.

 

[Phdintheory]

Okay, I did start out on #1 TDC the first time I adjusted them but when I was done that time the whole thing sounded horrible. That's when I tightened them like I described. As I said, now it sounds better but I've lost some power.
Here's the deal though. The loss of power doesn't really concern me because it sounds more like it's supposed to. You see, for the last 6 months this car has sounded horrible. Loud and with an obvious miss. And it sounded like a sowing machine. Now I sounds more like it's supposed to. I think the loss of power is just a set or two of the valves that aren't correct.
So how do I adjust these things properly in order then?
Okay. #1tdc. Then which valves do you set? Then you rotate counter clockwise until #3 is TDC right? Okay, then which valves? Why does it matter? If they are set when the lobes are pointing straight up, why does it matter what order it takes for them to reach there?

Thank you for responding.

 

[BKK Jack]

The questions you are asking indicate that you really do not have the knowledge to do this job. If the adjusters are screw type, having it done professionally shouldn't be that expensive, and could potentially save you a really big bill from you maybe doing serious damage.

 

[Phdintheory]

I thought so. You CAN just go from one set to the next like I thought.

Please, instead of just trying to make someone feel like an idiot, next time actually do what you can to provide the assistance requested by the poster.
In this case I asked for advice on what I was doing wrong. From that video it appears as though I'm not getting consistent enough adjustments on my valves. Some are a bit tighter than the others etc.

 

[submitaweasel]

No one is trying to make you feel like an idiot (afaik). Following procedures is the easiest way to complete a job without experience. advising to see somebody with experience gives you the chance to learn from their experience.

FWIW If the tolerances are changing after adjustment, something may be deformed or worn beyond normal use.

I can add an anecdotal experience here: 3 techs worked on one Nissan frontier with a blown head gasket (that was repaired) at a company I previously worked for. The first 2 kept saying there was no issue, they measured the clearance. The third had enough experience to know something was wrong and found a bent valve.

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