Was driving my car the other day and it suddenly started making a loud clacking noise. After dropping the motor and pulling the rockers this is what I found. The oem adjusting screw head had no issues. The valve guide and seat is ok. The valve never hit the top of the piston. It just seemed to fall apart. Been running this motor for about 12 years without any issues. You can see the whole story by clicking the link below. Ray

https://youtu.be/epU1eCCDqhc

The remaining bit of that valve tip looks to be wasted as well. Look for wear on all the other tips; this one may just have been the first to fail noticeably.

Who made those? What kind of valve are they?

--DD

You did not say if they were new or used. Used, I would go with metal fatigue. New, would be bad forging.

Old age mostly,also if the valve is run with excessive clearance @ some stage or been used with worn adjusters this will happen.
The tip of the valve is hardened and they break that piece off where the hardening ends above the first collet groove,I once looked at type I that did this due to a weak (soft )valve spring.
Not a common issue however,I would serious check the rest and look closely @ the adjusters,any other valves you that are starting to distort or "mushroom'' will do the same thing over time.
Good luck sorting it.

This is a intake valve from a 2.0. It has the VW logo on it with a 039 part number. I found hairline cracks in another intake valve so all of them were replaced with new ones. Ray

Factory valve.

Run a magnet along a valve, you'll quickly figure out they are not 1 piece. They are 2-3 pieces that are spin (friction) welded together.
I agree that excessive clearance, pounding on the valve tip, likely fatigued the weld.

1st vid how the stems are put together
2nd vid how the tulip is forged, heated with friction.


https://www.youtube.com/watch?v=6E293CtK8ig



https://www.youtube.com/watch?v=dMt1tqDI1nM

The 2.0 intake valves are used and I agree it looks like metal fatigue. I pulled the heads and replaced all the valves with new ones.

Think that valve number is original ATE...someone correct me if wrong,as said just old = failure.

I had that happen to a type I. The valve head punched a hole in the piston and peened the spark plug in so tight I couldn't get it out and had to scrap the head. My introduction to overhauling vee dub engines. I used this. 1972!!

I took a closer look at the valve and you're right. It is also stamped with the ATE logo.

Man Elliot, you are so groovy! But in a good way.

I watched this being done in a factory and it's really something to watch. I got a tour from my brother in law that runs a forge press.

Funny, I was just watching a youtube video yesterday where they guy seems to have a similar problem. It wasn't fully off but it was significantly damaged at the tip

https://www.youtube.com/watch?v=epU1eCCDqhc

Back in the day a good friend of mine had a well worn copy of this book and he used it to keep his beetle on the road for very little money. It's a real hoot to read.

That's also the book I learned how to set the timing on my 914 from. Most places were good about giving the spec, and mentioning that you had to twist the distributor to get things to line up, but that book was the only place I ever found that explicitly stated where the clamp nut for the distributor body was.

--DD

That is my video on Youtube. It has 4 parts if you have time to watch them all. In part-4 I do some repairs to the heat exchanges. Ray

Nice videos, Ray! I was just checking them out and found them very informative. Jon

Thanks Jon, I've been restoring 914's for decades but this is the first time recording my work. Nice to know someone enjoyed it. Ray