1967 122S
original B18
165,000 miles
never rebuilt

Did a cold valve adjustment this morning.

The Good:
All intakes were within +/-0.001

The Bad:
Cylinder 2 and 3 exhaust (valve #4 & #5) were at -0.004 and -0.005.

The Ugly:
Cylinder 1 exhaust (valve #1) was at ZERO GAP (I know, I know...)

Cylinder 4 exhaust (valve #8) was at -.004, BUT, valve #8 doesn't open nearly as much as the other 7 valves. I didn't do any accurate measuring, but I would guess that it's only opening about 50% as much as the others. Obviously, adjusting it 0.004" didn't change much in terms of how far the valve opens (i.e. the problem was ~the same before and after the adjustment).

So; it seems like a severely worn cam-lobe #8, correct?

Is it common for a single lobe to wear way more than the others?

Is this type of wear common at 165k miles?

What to do?

a) New cam
b) New cam & rebuilt head
c) With 165k miles, rather than dump cash into the B18 go for a completely rebuilt B20 (a long term goal of mine anyway)?

d) answer depends on results of compression test?

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in the meantime, should I adjust valve #8 any differently in light of the fact that it's not opening nearly as much as it should?

I was going to check all the valves again after a week of driving.

Thanks.

V

(btw- even with the state of valve #8, the engine runs much smoother after the adjustment).