replacing valve seat in situ

[GOSFAST]

Well, I think if you told Dave you know me, he would either do exactly what you wanted and no more or, just throw you out....LOL
And yes, most automotive machine shops can do a valve seat ring.

Hi Pete, to the latter part of your post, not really.

The shop would need one of three tools to get it done, first, a portable setup to install them from the deck surface, I don't know of a single shop in my area has this (there are 125 automotive machine shops in a 100 mile radius of us), second, a head machine capable of holding the Flathead block (most newer machines today are "dedicated" for heads only), or third, a CNC and the applicable tooling to use in conjunction with this type machine.

I'll place a shot below of one of our head machines, an older Winona PH-2000, that is capable holding the block. It was for this sole reason when we picked up a newer machine at a later date I decided to NOT sell the Winona. It was mine, I owned it, it owed me nothing, in hindsight it was very wise decision with the number of Flatheads we still do today!

On a side note I do agree with you, I would recommend against trying to do some type of "backyard" repair in this area. These blocks are getting harder to find every year!

Thanks, Gary in N.Y.

P.S. Here's a shot of the Winona showing one seat already machined for the insert and one showing we can also do the entire valve job on it as well! The third one shows us "pinning" the block for some SBC head dowels, same machine with our in-house fixture.

 

[Bored&Stroked]

You have to find an oldschool mechanic with a portable valveseat cutter that makes housecalls

Exactly! Because even if you find a seat and can get it correctly driven in, you still may need to reduce the overall height of the seat ring (lots of times they are too tall) . . . and at the very least you have to cut a new seat into this hardened dang ring - as it won't have one out of the box.

 

[Pete]

Gary, I have to stand by my statement as far as this area.
Most shops that have been around here for 40 or 50 years have portable seat tools.
They may have an inch of dust on them though....LOL
We have a Winona also and have free access to a Serdi.

 

[Ronnie]

Exactly! Because even if you find a seat and can get it correctly driven in, you still may need to reduce the overall height of the seat ring (lots of times they are too tall) . . . and at the very least you have to cut a new seat into this hardened dang ring - as it won't have one out of the box.

If you found a seat and correctly drove it in and then it is too tall you have just proven you installed the incorrect seat.Seats are sold strictly by size(id. od. and height) for old engines and someone had the wrong seat to install,measuring is key here.Why would anyone install an incorrect seat? A flathead seat is not special.This really isn't a job that the average flathead tinkerer should attempt by getting advice from some on an internet forum who have never installed a seat.

R

 

[GB SISSON]

You have to find an oldschool mechanic with a portable valveseat cutter that makes housecalls

A neighbor and friend was recently given a complete Sioux valve grinding setup by his father in law who was a die-hard flathead v8 guy. This neighbor who is 40 or so is strictly high performance chevy and said I could set up the whole works in my shop. It has the mandrels for the v8's and lots of stones. I was wondering if it has anything to cut the recess for os seats????

 

[flatheadmurre]

A neighbor and friend was recently given a complete Sioux valve grinding setup by his father in law who was a die-hard flathead v8 guy. This neighbor who is 40 or so is strictly high performance chevy and said I could set up the whole works in my shop. It has the mandrels for the v8's and lots of stones. I was wondering if it has anything to cut the recess for os seats????

A portable cutter has an arbor setup that just indexes on the pilot, the pilot itself aint strong enough to support a cutter.
But check around might be a portable cutter setup in the tooling
Next issue is to find an oversize cutter...i got tired of having a board full of them and never the right size, using indexable kwik way cutters now.

 

[flatheadmurre]

This is in the shop today i can do the 2 seats being replaced in the good,bad or
the ugly way if you want a backyard valve seat job
It had a monsun stuck in it took a thickwall sleeve to get it done.
Not gonna be a mint engine but will be a good driver and a another block saved.

 

[flatheadmurre]

Fasten your seat belts...here comes the bad and the ugly
And it can be done in the car !
Getting the seats out in any way you prefer, welding a washer or just pulling it out.
First seat had a nice round bore but measure loose...so i just installed an oversize seat and done !
Next seat wasnt to fun it took a scary big seat to find good metal.
But they are in there and the engine will continue its duty
And last pic just to prove i know the good way of doing to....

 

[Bored&Stroked]

Hey Flatheadmurre, what is that measuring device (looks like a barrel mic) in the center picture? Is that for setting up an adjustable cutter or something like that?

Big Seat: I must admit, that is the biggest/widest seat I've seen!

For those of you who didn't notice - see that he has specific pilots/mandrels that are designed specifically for the flathead (they index off off the valve guide bore). Some will go all the way down and also pickup the lifter bore - just depends on the manufacturer and setup. My machine shop has a special pilot they precision ground with a slight taper (so it tightens up) and they mount the block in a big milling machcine that has main-bore saddles - this is where they then use their cutters for seat work.

 

[flatheadmurre]

Yep you got it right its a setup fixture for the cutter.
Pilots are kwik way and they are the short type.

 

[GOSFAST]

With respect to the tooling in "Flatheads" photos that is very similar to what we use today for the inserts only. For the valve seat angles we use a different type of tooling, although in the photo below it shows both sets we own.

I do have the entire setup that came with the PH-2000 but I don't believe you can get the blades any more at least for cutting in the valve job. Haven't really tried since we now use different tooling anyway.

With the insert cutter setup you simply "mike" the insert then set the blades .004"/.005" under (for the desired press-fit) and machine away. The depth can also be taken from the actual insert but you can vary that dimension. On the "quill" on the machine there is tooling to preset the depths.

The blades we use today for the valve angles locate the seat, machine the top angle, and bottom angle all with single cut! Simple really, makes doing the valve jobs fairly easy.

Thanks, Gary in N.Y.

P.S. On a side note, the "head" of the PH-2000 is mfd where "Flathead" lives, you can see the "country-of-origin" on the machine's original label! Only the "head" was sourced out. It is an extremely versatile machine, very similar to a "Bridgeport" but with much more range. In the last photo you can see the cam-thrust-face (on a BBC) being machine for a "Torrington" bearing, same machine.

 

[Bored&Stroked]

The blades we use today for the valve angles locate the seat, machine the top angle, and bottom angle all with single cut! Simple really, makes doing the valve jobs fairly easy.

Nothing like the multi-angle carbide cutters - do a lot of work in a single operation. Do you still do a fine-compound lap afterwards?

 

[DjNeil]

Here is the offending valve.
I'm in the UK so this could be difficult.I'm ordering a valve,head gasket and inlet gasket.
I don't know what size the standard seat is or should I go oversize,can anyone help please.I will inspect for cracks.
What is the usual reason these come loose.I've had flatheads for 30 years and this has never happened before.It's done 20,000 miles since being a new 49 Mercury and i'm guessing lack of use could be the culprit

 

[flatheadmurre]

Std size is 1 3/8 x 1 5/8 x 7/32
If its been loose in there my wild guess is .010 oversize but you need to measure it and check for cracks before anything else.
If the seat is the problem i stick one in an envelope for you.

 

[DjNeil]

Thanks,that's great
i'll do that tomorrow
Neil

 

[DjNeil]

does the seat come as a band or are the angles already cut into it and just need finishing, normally with a cutter or in my case i've got three kids and lots of lapping paste.
A mate said today that i would be better simply taking out the lifters on the inlet and exhaust valve for that cylinder and the valves will be closed,removing the HT lead and running it on 7 cylinders until i can tear down the engine.i'm still up for peening a new seat in
any thoughts on the 7 cylinder option

 

[Bored&Stroked]

Once you install the seat, then you need to have a pilot for the guide bore and then new seats are either cut or ground into it. The seats are very hard - you won't be able to lap a seat into it, you'll just ruin a new valve. Since this kind of appears to be a big experiment on your end, seems like you should pull the engine, take it apart and bring the block to a shop that has the tools/equipment to just fix it. Yes - it is a pain in the rear, but why risk screwing up the engine? Just my thoughts.

If they have the 'portable equipment', might even be able to just do the block and not take it apart (tape everything off to keep the metal and grinding/grit out of everything else. Use a good shop-vac to suck the crap away from the block/bore as the work is being done. Might not be a big deal to fix it - with just a little time/effort/money involved. Just hate to see you hose up the engine for good.

The only problem with you buddies plan is that the valve that is having the problem won't seal off the chamber (as the seat is missing), so it will be sucking/blowing back into the intake manifold.

 

[Mart]

I replaced one once with the motor in the car. It was a fenderless car so it was like being on an engine stand. The new seat was a factory oversize piece and the supplier gave me the dimension to open the seat out to. I rigged up a flycutting type device and miraculously got the hole out to size. Chilled the seat in the freezer and warmed the block and got it in there. I think I did hammer it in. I peened the edge slightly for good measure. I can't remember doing anything out of the ordinary with the valve, I must have lapped it in ok. The seat must have popped out before, you could see an impression in the block where the seat had been hammered in while off ****.

It went on to run without problem at least as long as up until I sold it.

Mart.

 

[GOSFAST]

does the seat come as a band or are the angles already cut into it and just need finishing, normally with a cutter or in my case i've got three kids and lots of lapping paste.
A mate said today that i would be better simply taking out the lifters on the inlet and exhaust valve for that cylinder and the valves will be closed,removing the HT lead and running it on 7 cylinders until i can tear down the engine.i'm still up for peening a new seat in
any thoughts on the 7 cylinder option

You have a few "tough" choices ahead of you but I would add this, the insert could be "pre-machined" for the included valve angle/angles before the installation. It would still require some slight add'l attention afterwards.

We find ourselves machining seats all the time in a lathe. Not for the valve angles but for the radii on the back-side corners. We do this for the older "Fuelie" SBC castings, helps avoid hitting water when machining the castings. This would help some in getting the valve in correctly. You MAY only need a 45* angle machined, depends on the insert configuration, o.d. vs i.d.?

I would be more concerned about getting the correct press-fit in the block, this is really a somewhat "critical" dimension.

See the photo below showing the inserts and the "custom" blade for the machining!

Thanks, Gary in N.Y.

P.S. The procedure for installing the inserts below here does require a "matching" radius on the tooling for machining the heads, we use an .093" radius on the tool setup. This is ONLY referring to the back corners on the inserts. This back-side radius is actually good practice on ANY casting where there's a chance of hitting water!

 

[GB SISSON]

The guy who has the sioux valve grinding setup has Friday's off work, so maybe I'll go by there and see what's in the kit. What's it worth if I made him an offer on the set? Also, where can I buy the correct seats and some in oversize? I wouldn't mind having a few choices around here. Thanks. Edit: I have 4 nos ford valve seats coming from Bob Selzam in NJ. 2 standard size and 2 oversize.