Hi Guys,

I can hear my valves knocking when the engine is running (hot or cold).. i think it's time for an adjustment
I've been searching for the correct feeler gauge measurement but was unlucky to find one - any idea what i need?

We're talking about k5 90'..
Also any tips on this procedure would be much appreciated

Thanks, Yarin.

 

Your truck would have come stock with hydraulic lifters. As such, the procedure for tightening the rocker arms is to first ensure that the valve in question is not opening or closing, but is fully closed. Loosen the adjusting nut, then tighten while spinning the push rod with your fingers. Tighten until you feel drag on the push rod then tighten another 3/4 turn.

As far as what valve to adjust when, here's some guidelines that'll help you get this done quickly and efficiently.

Turn the engine over by hand until the #1 cylinder is at TDC on the compression stroke (both valves closed). If the rockers move when your bringing the timing mark up, it is TDC on #6. When you have #1 at TDC on the compression stroke, you can adjust:

• exhaust valves on cylinders #1, #3, #4 & #8
• intake valves on cylinders #1, #2, #5 & #7

Now turn the engine one revolution until the timing mark lines up again. This will put the engine on TDC for #6. Now adjust:

• exhaust valves on cylinders #2, #5, #6 & #7
• intake valves on cylinders #3, #4, #6 & #8

This procedure should be done on an engine at or near operating temperature.

If this doesn't quiet down your valve train, you could be looking at a collapsed lifter, problem with a cam lobe, or a bent push rod. The push rods are easy enough to check before you go through the rocker arm tightening procedure by loosening up the rockers until you can pull the push rod, removing the push rod, and rolling them on a flat surface. They should roll nicely. If they don't, then they are bent. I always try to keep the push rod orientation (lifter side & rocker side) as well as the cylinder/valve location the same to keep the wear surfaces matched up and as such, I would only remove one push rod at a time.

Also worth a mention is that valve train issues are not typically described as a knock, rather a tick. Knock to me is an indication of deeper issues (crank/rod). My K5 has a rod and a main knock at the moment. It doesn't get driven enough to warrant pulling the motor for a full rebuild just yet though and I don't ever find pieces of bearing in my filter when I pull it apart after an oil change so I'm not all that worried about it.

Let us know how you make out.

 

Hi,

Thank you for the detailed response! i just got around to it today and your guidelines were spot on.
Oh and just to clarify - you're absolutely right, the word knocking was the wrong one to describe the noise i was hearing.. i think ticking is what i was hearing.
Anyway - I did the procedure along with my father which insisted that hydraulic lifters can be pushed down by hand and ours didn't but still - we went on with the entire process.

When we started the engine afterwards, #8 was knocking pretty bad.. it took me a few minutes to figure out the source of the noise. Eventually i tighten the #8 intake slowly, while the engine was running until the knock was gone and the engine seemed to be working 'round' (this is how we say it in my language, but you get the idea..)
However.. when i put the covers back on i expected to hear a reduced ticking sound but was disappointed.. i think the valves train is better adjusted than before but the ticking sound is still there..

Here's a video of the engine running at half way to working temp' right after i closed the covers.. i can clearly hear the ticking - what do you think?

Thanks, Yarin.

 

@swartlkk?

 

Sorry, can't hear anything amiss from your video. It's difficult to diagnose in such a way.

 

yeah.. i figured it's a long shot. Any general guidelines on what might be the persisting problem?
I'm starting to doubt i didn't set the TDC properly - do you have any tips on that maybe?

 

anyone..?