Hey there - Seattle50 again!
Here's a pic of cylinders 6 and 7. 6 (on the right) is the only cylinder with the valve seat area in this condition. Moisture must of had access to that area for 30 years somehow. All the spark plugs were in tight when I got it. The cylinder had a slight amount of corrosion that was fairly easy to remove but it was only present in the top 20 percent of the stroke. Ideally I'd take the block out and to the machine shop but could it be practical to grind the seats in place? I mean, they're in pretty rough shape. Thanks!

 

Yes a good valve man can grind the seat, but it's going to get grit all over everything. The problem, I don't know of anyone that can install a seat in a flathead in the state I live in.

 

You could try try lapping compound, although it would take forever to cut a clean seat. How does the valve's seat look? You have hardened seat inserts, a good thing. There are way to grind just those seats and keep the grindings contained, but it's a risk. BTW #6 is on the left...

 

By the look of the picture I think at least the exhaust side has inserts.It could be removed and changed.I would try to lap the other valve,it might clean up fairly well.

 

New inserts still need to be ground, unfortunately. If the engine still has original lifters (non-adjustable) that may be necessary to maintain valve clearance tho.

 

Thanks for clarifying.I wasn't sure about that.Dad and I just went halves on a old valve machine and seat grinder but have yet to try it.Although with the expence of rebuilding a flatty I think we may try it out on a simmiliar flatty with one set of rusty seats.Turns out the 49 pu I gave him has a cracked block.If a guy can keep it super clean and debri free. I think it would be worth a shot.

 

You can do what you just described, plug shop rags in all the holes, spread a light layer of grease around the area of that cyl to catch the grinding dust. If it still has the non adjustable lifers, you can grind the valve stem to get the right clearance. But if it had water in that cyl, the rings are going to be stuck in the grooves, and if you do get the valves to seat and run it, it won't be long till that piston comes apart.

 

All the rust in the cylinders means it was put up wet, and got rain down the intake to boot. Before doing anything else I'd have it checked for freeze cracks.

 

That's what I was thinking,a person could mask the rest of the engine as a precaution.The intake should port should wash out easy enough.And blow every thing out the exhaust.

 

I consulted with my Dad on this one . He said ad the White Rose garage he and his friend owned they ground and lapped the seats in frame all the time . just do as advised and cover everything up to keep out grit and then change the oil after about 200 miles . Your only other option is to pull it out , and if you're going to that much trouble then you might as well send it in and have new seats put in .

 

The cooling jackets look pretty muddy, and there's rust in the intake ports that will have to be removed or it will get sucked into the cylinder. I'd just yank it, have it vatted, check for cracks, then proceed after you know if it's good or not. No sense spending $50 on head gaskets, only to have it run hot and have poor compression.

 

Thanks Allan and all the commenters. I am in the process of ordering 45 and 30 degree stones with a guide. I am going to try and isolate the work as much as possible. Kind of like when they do a root canal on you (pleasant thought), if you been through that. The truck had 36K original miles but has just been sitting for a long time. It's a long road but this is where I'm starting.

 

I think it is worth a try.Alot of guys have unseized motors and run them as is.I have and old 57 Lincoln welder with a funny valve miss that won't adjust out.I am sure it is the same deal with rust on one exhaust seat.But I got got in a jam and had to use the old girl all last summer after it sat about 4 yrs not started.I wouldn't be to scared of trying it.

 

Both seats on a flathead are 45 deg.

 

Gee, shows ya how much I know! I was told there was a 2 degree deal on those but maybe they were thinking about another engine. To tell you the truth I didn't really notice a change in the bevel when I looked at them. Thanks Albque