Hi all, I just got my Merc block and heads back from the machine shop. I was told they grinded the valve seats. Does this look right? I thought the usual three angle grind was 30- 45 - 60. I was told this is narrow grind at 45 degree for 1.5 valves. regardless of intake or exhaust.
I am not an expert on this subject. I suggest reading the thread below. It should answer your questions. I hope. https://www.jalopyjournal.com/forum/threads/flathead-valve-lapping.848894/
You might also trying posting on the Ford Barn. I went through a couple of flathead books I have, and one mentions them doing a 3-angle valve job (Tony Thacker & Mike Herman - H&H), and the other mentions a 30 or 40 degree angle being cut into the seat, and then a 2 or 3 seat angle is added. (Mike Bishop & Vern Tardel). I’m sure the experts will chime in.
Image 0471 appears to have a crack of some sort that runs behind the seat and down into the head. Not sure if that is a big deal or not on these engines.
What does the contact pattern on the valve look like? There may not be any room for top and bottom angles.
Three angle seat width is nothing new and here's why: Too wide, the seats and valve faces are subject to collection of carbon on the contact surfaces and can cause burning and early failure. Too narrow, the heat transfer to the water is hindered, causing burned valves. If I remember, the seat width is like 1/32" on these, per Ford specs. One thing I keep preaching about is the rust in the water p***ages. This rust is highly prone to flaking off and washing up into the radiator and plugging the tubes. It is especially bad about this after sitting dry for a period of time. Do yourself a favor and have the heads and block boiled out to eliminate this problem. Of special importance is getting all the **** out of the bottom of the water jackets on the block. I can see in your pictures that the rust in the jackets is in the early stages of flaking off in chunks. In addition, this rust buildup acts as an insulator and hinders the heat transfer to the water. It would be a shame to have constant overheating problems due to chunks of rust plugging the tops of the radiator tubes. Here's a tip to help prevent that: Never run straight water in these engines. Use 50/50 antifreeze and add a bottle of anti rust every year in a clean block. There is nothing you can do to fix Fords' metallurgy, though. Your valve job looks great, by the way.
Great point about rusty water jackets. My flathead had the jackets sandblasted as much as possible before machining and it runs at 180 down the interstate.
53kemper: Here's a good article of benefits of 3 angle valve job. John Maher Racing » The importance of the 3 angle valve job
Sure looks like the shop forgot to cut those valve seats. Stuck the new seats in and never came back. The Flathead valve lapping thread shows good valves.
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