elusive Engine noise
 

The left side of my 1974 Porsche developed a sometimes more and than less ticking sound. I have driven 1000 miles like that.
I checked valve play and was ok. Timing chain OK. How can I determine that I have a loose valve seat? Without removing heads

thanks, harold

If compression /leakdown is good and consistent on all cyls, no smoke on startup or hot deceleration indication of worn valve guides, then I would suspect a little slop or wear in valve train... is there more noise hot than cold? Try a slightly higher viscosity oil to see if that changes anything, cushioning and quieting the slop, may come back when hot, indicating you are on the right track. Would not assume loose seat unless confirming indications of leak noise or compression. Hope some of these ideas help ..Gordon

exhaust leak?

How did you check the valve play?

Was the feeler gauge relatively new? Did you bend the blade so it wasn't cocked between the foot and valve top?

The ticking noise is more when engine is cold, and varies somewhat. I was thinking that I have a lubrication problem with one of the oil squirters to the camshaft????

thanks, harold

I'd still spend some time checking and rechecking your valve clearances before deciding on something major, perhaps get another owners ear on it as well. A valve that's even slightly off will tick... though usually when warm...

Its usually a sign of worn guides, especially on the 2.7's that run warm.

Are you running carbs?

what steve said.

Ok, I removed the exhaust manifolds and the ports where all carboned up and the tip of the gides oily. So even though the engine was running great with lots of power - the guides are the noise. Which is good because doing the heads is straight forward.

thanks, harold

No, I do not think I would assume that-- the oil is coming from the cylinders and being burned and deposited on the ports, and oil residue on ports and guides-- are the valves actually sloppy in the guides? are all cylinders the same ?? That would be unusual... any other thoughts, opinions?

will remove one exhaust valve cover, install the spring compressor and check the now free valve for play in the guide.
thanks, harold

You can try the process of lifting the valve off the seat and move the end of the stem back and forth or attempt to... I did this and noticed a fair amount of movement on one valve. Much later I did a complete top end rebuild and we found out one stem to guide clearance was huge. This was on a 3.2 with 45k miles (had the ticking sound) and I did the top end at 70k miles.. The ticking got slowly worse and worse. When I took the headers off I noticed a lot of oil/carbon build up.. this also pointed to lots of stem clearance, I guess. I also put in new rings and had the nic. cylinders "scrubbed/honed". I just recently took the headers off again to check things out and everything looks pretty clean and I don't have odd noises.
The original ticking started after the engine warmed up....like Steve said. Like you said if it is just top end issues then things can be fixed in a straight forward manner assuming all the parts are correct going back together. That's my 2 cents.
-h

You are going to rebuild the heads. If you choose to have it done by macine shop. There is one with excellent work in your back yard. Then get the motor to Mike at JB Racing in Taveres Florida.

Regards,