Valve clearance / Shims less than 0,060

[SENC]

Thanks 2cams. Will post follow-up this weekend.

[steveh]

Henry,
Looking at your pictures , i think retainers 3 and 4 are contacting under the followers.
You could engineers blue to confirm with the assembly built

[alan.barker]

Please have you tried new Collets and Collet Retainers yet as i suggested.
With new Collets they will not be worn on the outside Dia and therefore push the Collet Retainers to a lower level.
This can stop the contact between inside of Follower and Collet retainer.
new Collets cost peanuts and a quick.
This solved the same problem on a +2 i had many years ago.
Alan

[rgh0]

Lots of discussion but the issues are clear I believe.... I may be wrong as relying on photos without all the needed measurements but..........

Issues
1. Recessed valves
2. Valve tips ground off to get acceptable shim thickness
3. Down to minimum shim thickness and still no clearance on No 4 Ex
4. Follower hitting retainer on No 4 Ex due to ground tip and thin shim
5. Maybe other issues as a result of follower hitting retainer with worn retainers and collets and valve stems making it all worse

Answer
6, Pull head and start from scratch to set up the valve train right

cheers
Rohan

[StressCraxx]

Lots of discussion but the issues are clear I believe.... I may be wrong as relying on photos without all the needed measurements but..........

Issues
1. Recessed valves
2. Valve tips ground off to get acceptable shim thickness
3. Down to minimum shim thickness and still no clearance on No 4 Ex
4. Follower hitting retainer on No 4 Ex due to ground tip and thin shim
5. Maybe other issues as a result of follower hitting retainer with worn retainers and collets and valve stems making it all worse

Answer
6, Pull head and start from scratch to set up the valve train right

cheers
Rohan

My thoughts exactly. If the issues aren't corrected there will be tears.

[SENC]

Please have you tried new Collets and Collet Retainers yet as i suggested.
With new Collets they will not be worn on the outside Dia and therefore push the Collet Retainers to a lower level.
This can stop the contact between inside of Follower and Collet retainer.
new Collets cost peanuts and a quick.
This solved the same problem on a +2 i had many years ago.
Alan

I have not, yet - I don't have an extra set and am actively working on my discipline to not order bits pre-dx!

Thanks @steveh, Rohan, and @stresscraxx. I appreciate the additional eyes and input. I'm pretty well resolved to take the head off for full review and measurement, etc. in order to identify and resolve root cause (and will surely ask more questions as I do), but as part of my "education" I really appreciate the insights and want to grab some measurements and make some more observations in current state. Hopefully I'll learn a few more things along the way that may help me better dx such issues in the future.

Question for you all - I resurrected an old thread on a similar topic to avoid creating a new one - should I continue posting updates, pictures, observations, and questions to this thread or at this point would it be better to start anew?

[SENC]

I had a piece of 1" aluminum long enough to bridge 3 valves, so milled some flats at the halfway point and some through slots for a caliper - that worked a charm for getting a common reference point, and at 1" it sat just on the bearings. Thanks to all of you for the idea.

The valve tips measured at 0.95" down from that point (likely not perfectly at the center of the tunnel so doesn't perfectly match Rohan's 0.92" reference measurement, but common across the 3 and I was looking for relative measurements anyway).

As several of you commented, the height of the valve tip above the collet appears too short. I measured the difference at 0.05", half of the 0.1" Rohan quoted. A quick measurement of my top hat shim proved Alistair's conjecture correct - it's recess is 0.075", so in my test it was resting on the collet.

So, it appears my collets and retainers are riding high, so next step will be head off to gain more measurements and try to determine root cause and the fix. It will be May before I can get to that due to other commitments, t will report back once inside.

Thanks again.