How do you troubleshoot a ticking valve

[Kibokojoe]

My son's 91 735i m30 engine has had a ticking noise in the engine since we bought it almost two years ago. I have adjusted the valves 4 times now and it still ticks. I have inspected the cam, rocker arms and tops of the valves and can not see anything deformed, flat, cracked or broken. When I first opened the valve cover I did find that the front oil tube bolt had fallen out, so I am sure this has something to do with the problem. How can you troubleshoot a problem valve? Can you run the engine with the valve cover off while pressing on each rocker arm to determine the source of the tick? I am almost to the point of pulling the head and having it rebuilt but I don't want to go through this added expense if it is not the source of the problem.

[ArnZ!]

Haven't you asked this question before?

Try adjusting the rocker on the cam side using a 0.009" feeler gauge.

[whiskychaser]

Can you run the engine with the valve cover off while pressing on each rocker arm to determine the source of the tick?
Yes you can but I havent done it for about 40 years:D Cover up all you can to stop oil getting on it, especially the exhaust. And maybe wear some goggles?

[Ross]

The adjusting eccentrics are known to flat spot when starved for oil, as when an oil line's banjo bolt disappears.
Find the offending valve(s) as Whisky has suggested and carefully inspect the adjusting eccentrics.
M30s tend to be noisy, my experience is they run better when valve lash is on the loose side also.

[Kibokojoe]

I am going to replace all of the eccentrics and set them at 12 thousandths cold. Ordering them today.

[Robin-535im]

Did the Eccentrics help?

I had an errant tick that drove me crazy. I used a mechanic stethoscope to narrow it down to which valve it was but I still couldn't find WHAT was doing the ticking... until the rocker arm broke. There was a tiny crack that I couldn't see on the underside - it would be quiet for the first few miles after I adjusted it, then go noisy again, until one day it just broke.

[Kibokojoe]

I have looked and looked but sometimes you have to wait for something break before you find out what was wrong


Did the Eccentrics help?

I had an errant tick that drove me crazy. I used a mechanic stethoscope to narrow it down to which valve it was but I still couldn't find WHAT was doing the ticking... until the rocker arm broke. There was a tiny crack that I couldn't see on the underside - it would be quiet for the first few miles after I adjusted it, then go noisy again, until one day it just broke.

[Jeff N.]

So how's your valve adjusting technique? Is it possible you're just missing one? I do it all the time and finally had to get stupid anal about the whole thing.

Here's what I'll do to make sure I don't miss one.

- make a diagram and mark off the valves as you go.
- for each valve, set to your desired spec.
- after setting, test with the next size feeler gauge, if it slides in, it's not set right. Repeat until you can't slide in the next sized gauge.
- go to next valve, repeat until all are set.

After the first go-round, repeat and double check each valve by

- trying the next size up gauge. If it won't fit, try the correct gauge and it should just slide in. If OK, move on or otherwise, adjust again.

Since doing it like this, I've pretty much eliminated messing up one rocker (and getting the great big tick).

BTW, check your injectors - they can tick like crazy too.

[Kibokojoe]

Adjusting cams should be in tomorrow. I will make a diagram, sound like a good idea.

[Kibokojoe]

To finish this thread out. Installed the adjusting cams and the clicking went away. Not right away but after two days it cleared up.