38 Flattie Valve Seat Problems

[Frank L.]

As some of you know I am part of a team that is currently restoring a Universal Carrier and we are running into a few problems with the engine....

After removing a few valves that were sticking (thanks for the tips BTW) and cleaning them up we noticed a problem with one of the exhaust valves....

Because it was stuck open for so long the valve seat has scaled and rusted nicely

My question is: How can a shadetree mechanic resurface the seat without messing up the engine?

We are thinking of taking an old valve from our spare engine and welding a valve stem to the top of it (ensuring that it is true of course) and use and old valve guide as a guide to keep the entire rig true in the bore. When that is set up, use lapping compound and a drill to turn the valve and slowly cut a new seat, ensuring that none of the compound makes it inside the engine.

Thoughts and comments please!

Regards

BTW....I am leaning toward getting an engine shop to do a proper job, if we can raise the funds.

[Geoff Winnington-Ball (RIP)]

Have no fear me lad, there are people here who know these things from past experience.

My two bits worth is that if you can raise the cash, have it done professionally. You will also need to have the block magnafluxed, as these flatheads are notrious for cracks, which you want fixed BEFORE you find out the hard way. Check it out in your local area... there are some engine places here and there who know these motors; call around and ask specifically whether they have anyone on the floor with practical experience with them.

Others will chime in later, I'm sure. A lot of Ford owners/restorers here.

Geoff

[Tony Smith]

If there's scale and pitting from rust, that's way beyond the capabilities of lapping compound. The valve seats will need to see a doctor, quick smart. Remachining will alter the depth of the valve pocket, so save up too for a set of adjustable lifters, as getting your machinist to do it the original way by grinding valve stems will cost you just as much in labour (and cost you too much goodwill with the machinist )

[Keith Webb]

Hi Frank
Tony is on the money about the valve grinding paste, and Geoff has a good point about the cracked blocks.
Back in the 70s, I worked for a parts place which received large numbers of these engines for reconditioning, and I must have pulled at least 70 of them down to send to the reconditioners.
Valve problems were fairly rare, although I did see some which had burnt valves, usually these had been genset engines.
Cracks were very common on the later 8BA engines, the ones with the distributor high up. It was the first thing I'd look for once the heads came off. Surprisingly hardly any Mercury engines had cracked blocks. Usually the worst thing to deal with was sheared head bolts on the 8BA and getting the studs out on the Mercury engines.
The engine shop dealt with any which were too difficult.
The adjustable lifters were like gold because they saved a lot of time grinding valve stems at the workshop.
As for valve seats, I recall occasionally seeing an engine with inserts - you can only grind the seat a certain amount before this is necessary. The other good thing a rebuild shop will do is to properly crack test and repair the block, and also resurface the block for the heads.
The only engines we couldn't do anything with and usually didn't even buy were those which had been in boats in salt water.
Hope this helps. There is a lot of knowledge out there on the subject and a lot of these engines are still being completely rebuilt, although it's an expensive business now.

[Frank L.]

Thanks guys for the info....

I'll have to look up a good engine shop and see what they are willing to do for a good cause.

If I can get my hands on a camera I'll post some picks and you can see what were up against.

I don't think the block is cracked. It ran on 3 cylinders when we first got it due to ignition and the stuck valves. It did leak at the water pumps though...mind you that is just a couple of gaskets.

Wondering if a valve insert kit would do the trick?

Regards

[cletrac (RIP)]

I'd try seating the valve deeper and using adjustable lifters.Inserts as a last resort, I've had them installed in OHV heads and found them rolling around in the truck box on the way home!If the engine isn't designed for them, there's not usually enough metal left to retain them properly.Your early thick-wall Ford would probably be ok. At least on a flattie a loose insert doesn't mix up with the piston, so you can limp home.