MTFCA Forum

Is it pretty obvious when your T has had seat inserts installed? Below are a few pictures of my valve seats. Seems to be an excessive amount of concentric circles around most of the valves. Are these inserts? If so, are all inserts hardened?

Interesting variety of sizes used. If memory serves, there are or were 3 harnesses. 1) cast iron. (soft.) 2) hardened. Normal for unleaded fuels & 3) real hard (for propane)

Yes Ryan, those are aftermarket inserts of some kind. The valves in both my 1924 and 1925 engines have seats machined directly into the cast iron of the block.

For a T engine, any “hard” seat is fine. Yes, there are different alloys and hardness available... but the low operating temperatures of the T engine do not require anything different/better than the original iron. The major contributor to valve seat recession, is the low operating temperature of the original carbon steel exhaust valves. Swap out the valves for a nice set of stainless steel valves, and valve seat wear becomes a thing of the past... with or without hard seats

Ok, so I have new SS Valves to replace the 2-piece valves that were in it. Should I do anything with these hardened seats? What is the best tool to freshen them up in the car? Neways?

If the seats leave a fairly decent pattern on the new valves as-is should I avoid messing with the seats altogether?

MN_Ford_Fan wrote: ↑

Sun Jan 23, 2022 5:37 pm

Ok, so I have new SS Valves to replace the 2-piece valves that were in it. Should I do anything with these hardened seats? What is the best tool to freshen them up in the car? Neways?

If the seats leave a fairly decent pattern on the new valves as-is should I avoid messing with the seats altogether?

Use a little lapping compound to confirm seat width, full contact & position on the new valve faces.

So this is a little unexpected. I am in process of installing the new valves from Langs. The hardened seats look so good I decided to just lap each valve lightly as I go to confirm seat engagement. I have four done and two have had .015" of clearance right out of the package. One I had to grind off .003" and the 4th one I had to sort the remaining unopened valves to find one that had less than .020" of clearance. I have 4 left to do yet.

Is it common for the valves to be so close right out of the package? I was expecting to have to remove much more material.

MN_Ford_Fan wrote: ↑

Wed Jan 26, 2022 6:35 pm

So this is a little unexpected. I am in process of installing the new valves from Langs. The hardened seats look so good I decided to just lap each valve lightly as I go to confirm seat engagement. I have four done and two have had .015" of clearance right out of the package. One I had to grind off .003" and the 4th one I had to sort the remaining unopened valves to find one that had less than .020" of clearance. I have 4 left to do yet.

Is it common for the valves to be so close right out of the package? I was expecting to have to remove much more material.

Not at all. You got lucky.
Murphy must be laid up with the covid.

speedytinc wrote: ↑

Wed Jan 26, 2022 6:41 pm

Not at all. You got lucky.
Murphy must be laid up with the covid.

Well it's making me nervous that I'm messing it up, lol. Plus I spent like 4 hours setting up a perpendicular grinding base at my bench grinder and I'm anxious to put it to use!

As I finish the last 4, If I come across another one that is too short, what is the biggest gap I dare use as-is?

MN_Ford_Fan wrote: ↑

Wed Jan 26, 2022 6:49 pm

speedytinc wrote: ↑

Wed Jan 26, 2022 6:41 pm

Not at all. You got lucky.
Murphy must be laid up with the covid.

Well it's making me nervous that I'm messing it up, lol. Plus I spent like 4 hours setting up a perpendicular grinding base at my bench grinder and I'm anxious to put it to use!

As I finish the last 4, If I come across another one that is too short, what is the biggest gap I dare use as-is?

I use adjustable lifters typically set @ .010". Ideally they would all be @ your target.015. If you had a few @ .025-.030, you dont need to loose any sleep.
I assume this is not a hi performance motor. I also assume grinding the seats lower is not a good option for you. (thats how its done)

speedytinc wrote: ↑

Wed Jan 26, 2022 7:03 pm

I assume this is not a hi performance motor. I also assume grinding the seats lower is not a good option for you. (thats how its done)

You are correct, it's not meant to be high-performance. Just want a solid runner that I can depend on. Grinding the seats is not a great option simply because I don't have the proper tools or knowledge at this point. But we'll see this weekend when I get to the last 4. Hopefully none are more than .020" gap.

There is more to a valve job than just stem clearance and good valve face contact. Valve seat width can make a big difference in how well a valve seals, and in turn how well an engine runs. Specifically, how well an engine starts. Check that the valve face contact width is 3/32”, and is comfortably located on the face of the valve with about 1/16”-3/32” of valve face exposed above the seat contact.

Too much seat width can cause a valve to seal poorly due to insufficient spring pressure. This can cause an otherwise good running motor to have a hard starting problem, especially in a hand cranked engine