The Stovebolt Site Forums The Shop Area Engine Shop how do you install valve seats?

Hello.

Im working on a 216, 1941.

I was wondering how you install exhaust valve seats, but after looking on You Tube it looks like the other option is to cut the valve seats a little bit...? How do you do that and keep the same angle for the valve?

It looks like most of my intake seats are in decent shape and can be lapped, but I have a few exhaust valve seats that look pretty bad-pitted and what not.

Im trying to do this without taking it to a shop-at least for this first rebuild. If its possible, I would appreciate any experienced wisdom.

Thanks,
Judson

My intakes and exhaust seats were pretty pitted. In an attempt to "get by" until a rebuild was necessary I just lapped them with coarse lapping compound & my drill motor at low speed. I spent quite a bit of time with it & managed to get most of the pits out. It served me well for quite a while. I finally got the engine rebuilt with a professional valve job (no seat replacement was necessary) a few years later. Good luck with it.

if you can't lap them as suggested, just take it to a shop. Unless you already own the cutters and valve grinding machine,it is much easier that way. Unless of course you plan on doing a lot of this type of work, then just go ahead and invest in the tooling. But if you are just doing one or two, just go to the shop. I don't know the condition of the rest of the head, or the rest of the engine for that matter. That should decide a lot of it for you.

Depending on what you are going to do with the engine and vehicle,it is probably cheaper in the long run to get them ground at a machine shop.

I would also be concerned with the valve itself. If the seat is used up where it needs grinding the valve face should be resurfaced. Then the issue of how wide the actual contact between the valve and seat is. And where the contact is on the valve, more than likely the seat will need to be back cut.
Probably best to have a machine shop handle it. It's more that just shining up a couple surfaces.

The larger 235 intake valves can be reduced to a slight oversize (vs. the 216 head OD), and the seat completely refreshed without replacing the seats.
For the exhaust, use V8 1.60".
Typically, going up +1/32" to 3/32" will do it. Narrow the seats from inside as normal.

So why do shops install new seats instead?
It requires actual engineering (not common in the last 30 years), and someone has to pay for those machines.

To regrind or cut the seat face requires valve seat cutters, they use a mandrel that fits into the valve guide to keep it aligned with the seat. The cutters come in different angles and sizes for various seats.

John

Is there room in the 216 head to use the larger 235 intake valves?? I know the book I was reading said you could use the 235 PG intakes in the 1937-40 216 head but not the 41 and up. What is the difference between these heads??

JOhn

Thanks, all! This is very helpful. Im going to go ahead and lap the seat and valves, and on the valves that are really bad-just buy new valves. The nice thing is that I can purchase these from Napa. Ill keep u posted. Thanks!