Stainless Steel Valves???
 

How can I tell if my valves have been replaced with newer stainless steel style? I just removed the head and attached a magnet to the valve. The magnet sticks to the valve but I don't know if it's because it's a low grade stainless or an old style steel valve. Is there a way to check? Any comments or concerns would be appreciated.

Skeeter in South Jersey

Re: Stainless Steel Valves???
 

The original valves sit low in the block. This is called the kerf and the original style have an almost knife edge kerf. Originals also sometimes have 2 holes for the old style lapping tool. If a magnet sticks you probably don't have stainless.

Re: Stainless Steel Valves???
 

If the edge of the valve looks to be less than 1/16 thick they are probably the original type, if the edge looks to be thicker than 1/16 they are probably "modern" type.

There are also some original type valves ford made in the 30s that are stainless ---I don't remember testing with a magnet, but they never rust.

Re: Stainless Steel Valves???
 

The Ford and other manufacturer's exhaust valves made for A and B engines during the 1930's and 1940's are generally all non-magnetic, but may not be stainless steel. Some were made of an alloy called stellite.

Re: Stainless Steel Valves???
 

Original valves, to 1948, had mushroom stems, visible with the side cover off.

Re: Stainless Steel Valves???
 

Llitehi,
justa note.
You mentioned stellite in the production of ex. Valves. Stellite is used in the production of 50 cal machine gun barrels. It extends about hlaf way down the barrel to reduce wear.i am not sure if it is maganetic or not, but it does a good job.



Al

Re: Stainless Steel Valves???
 

i don't remember which ones are which but either my exhaust valves or my intake valves say FoMoCo the other is plane with the two holes both low profile with a knife like edge. I think these are original? never checked to see if they were magnetic. Do they sound origional?

Re: Stainless Steel Valves???
 

Any reason for needing to know?

Re: Stainless Steel Valves???
 

I think stellite was used in the seats, not the valves. In blocks with inserted seats, they are usually stellite.
Terry

Re: Stainless Steel Valves???
 

It is only partially true that a magnet will stick to a lower grade of stainless.

Stainless steels, like all steels, come in various alloys. Stainless alloys fall into three classes based on crystalline structure; Austenitic, Martenistic, and Ferritic. Each class has many different alloys within it. Of the three classes only Austenitic alloys are non-magnetic. Most automotive valves are made using a Martensitic alloy and are therefore magnetic. While it is true some of the cheaper alloys fall into this class, i.e. the type used for automotive exhaust systems, there are many other alloys within this class that are by no means "cheap" yet are still magnetic. In short: Using a magnet to test for alloy is probably not the best way.

If the valves are serviceable use-em.

Tom in SoCal

Re: Stainless Steel Valves???
 

Valves shouldn't have a knife edge as that can run hot and cause preignition, especially on the exhaust. Either replace those valves or at least grind away the knife edge.

Re: Stainless Steel Valves???
 

Sharp edges on the head of the valves is an indication that the valves have been ground, many times and not necessarily an indication that they are original!!! Like Tom says, they can cause preigmition and will burn quickly. It is best to never use a valve with ground sharp edges on any engine... I would avoid valves that are magnetic because they will burn in a few thousand miles and causer a low speed miss or worse ...

Re: Stainless Steel Valves???
 

I found a full set ot stainless valves with Ford script on the head for my Flat V8.

Re: Stainless Steel Valves???
 

I didn't know that it was ok to grind away a little of the knife edge. I guess reducing the diameter a little won't hurt anything

Re: Stainless Steel Valves???
 

I'd rather replace the valves, but I'd rather grind off the knife edge than run with it, as long as the proper seating location can still be had on the valve head. You want the correct width seat (contact area) and it should be near the center of the valve face. I like to save old valves in case they can be made to fit antique stationary engines, etc.