Re: Seeking Comments on View of 1951 288 Head-off Valves and Piston Tops
Posted by kunzea On 2024/5/28 22:27:44
I went into the head because of several things.
The engine had a tapping sound that was inconsistent. The idle was rougher than it should be. It would curb idle just under 400 but just didn't sound right.
If I started it and operated it like I thought would be normal it had a really loud tap. With moderate acceleration the tap was pretty loud. The vacuum was about 17 with about a +/- just over a pound swing. If I took the compression right after an extended ride one of the cylinders was about 60 lbs. As it cooled off it came up to the others. If I cranked it and left it alone to warm up then drove with minimal acceleration it wouldn't tap too badly. On the other hand, once it started tapping it would persist pretty much for the whole trip.
I decided I had put it off long enough.
Here is a photo that represents all of the exhaust valves. The intake valves were not nearly as bad. Most of the valves were hard to pull out. I took a drill-bit-like wire brush and ran it through all of the valve guides. Most of them emitted carbon dust when running the brush. I have ordered a 11/32" reamer. In the interim I took a 11/32" drill bit and tested the clearance in some of the guides. It passed out the bottom on some but the others were obstructed.
BTW, I used a hand lapping tool on one of these cleaned exhaust valves then installed it with the spring and keepers. I filled the cavity around the valve with 30W oil. After about an hour and a half the oil was still there. The next morning it had drained. I have ordered a drill operated valve lapping tool to try to do a more thorough job.
Attach file:
IMG_20240528_215527.jpg (57.05 KB)
The engine had a tapping sound that was inconsistent. The idle was rougher than it should be. It would curb idle just under 400 but just didn't sound right.
If I started it and operated it like I thought would be normal it had a really loud tap. With moderate acceleration the tap was pretty loud. The vacuum was about 17 with about a +/- just over a pound swing. If I took the compression right after an extended ride one of the cylinders was about 60 lbs. As it cooled off it came up to the others. If I cranked it and left it alone to warm up then drove with minimal acceleration it wouldn't tap too badly. On the other hand, once it started tapping it would persist pretty much for the whole trip.
I decided I had put it off long enough.
Here is a photo that represents all of the exhaust valves. The intake valves were not nearly as bad. Most of the valves were hard to pull out. I took a drill-bit-like wire brush and ran it through all of the valve guides. Most of them emitted carbon dust when running the brush. I have ordered a 11/32" reamer. In the interim I took a 11/32" drill bit and tested the clearance in some of the guides. It passed out the bottom on some but the others were obstructed.
BTW, I used a hand lapping tool on one of these cleaned exhaust valves then installed it with the spring and keepers. I filled the cavity around the valve with 30W oil. After about an hour and a half the oil was still there. The next morning it had drained. I have ordered a drill operated valve lapping tool to try to do a more thorough job.
Attach file:
IMG_20240528_215527.jpg (57.05 KB)
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