Stainless/regular valve difference

[Ronbo]

I'm not sure where to ask this but, how do you tell the difference between the two when they are "used"? I bought a used head with supposed stainless valves but the machine shop (questionable) said they are not and sold me a replacement valve like you would get at Advance. The valve has a very pronounced divet, almost like a hole, in the middle. The valves in the head are more like what I'm familiar with, a slight divet in the middle. I have a stainless replacement but it is not the correct size, needs to be cut down (diameter) to fit, and the shop said no one does that. The stainless valve "looks" like the valves currently in the head but I'm not experienced with this sort of work. Usually, I go with the buy it new and bolt it on approach. This head was damaged in shipment and I want to get it right before I sell it to someone else.


Ron

 

[Falcon Ranch]

Remember that a magnet will not stick to stainless steel...so if the magnet sticks, you got suckered.

 

['68falconohio]

There are stainless steels that are magnetic also, unfortunately I don't know what type of stainless steel is used for valves though.

 

[Ronbo]

Thanks for the replies guys. Its not so much "getting suckered" as it is getting it right for the next guy I'm going to eventually sell the head and I want it straight.

Ron

 

[AzCoupe]

Ron, give this a try.

First, 300 series stainless steel contains Chromium and Nickel which makes it non-magnetic. 400 series stainless steel contains just Chromium, which makes this type magnetic.
However, neither series of stainless should rust or show signs of red oxide.

Hence, test first to see if they are magnetic. If they aren't, then you have stainless steel valves for sure. If they are magnetic, try putting a blot of water on one and leaving it over night. If any signs of rust or red oxide occurs, they are carbon steel. If not, they're stainless.

 

['68falconohio]

Ron, give this a try.

First, 300 series stainless steel contains Chromium and Nickel which makes it non-magnetic. 400 series stainless steel contains just Chromium, which makes this type magnetic.
However, neither series of stainless should rust or show signs of red oxide.

Hence, test first to see if they are magnetic. If they aren't, then you have stainless steel valves for sure. If they are magnetic, try putting a blot of water on one and leaving it over night. If any signs of rust or red oxide occurs, they are carbon steel. If not, they're stainless.

AzCoupe,
What grade of stainless steel are valves usually made from? When I read Ron's post, I got on Manley's site to try to see what series they're stainless valves were made from but could only find their trademark names.

Thanks,
Stephen

 

[Ronbo]

Interesting enough, the two stainless replacement valves: non-magnetic, the two bent valves from the head: magnetic, and the replacement valve the shop gave me because they couldn't/wouldn't cut the stainless exhaust valve down: non-magnetic? Thats odd as they said it is just a plain replacement valve. Up next water torture....err...test

Mike,
When I figure out what I have going on I'll be sending an order for valve seals.

 

[Ronbo]

Shoot, overnight, the valve the shop gave me has no rust on it and the valve that was in the head originally is rusted big time. A drop of water on the face of each. Why are people so darned dishonest? The human race in general ticks me off sometimes.

Ron

PS to add to the confusion, the shop's standart, non-stainless replacement valve, is in fact stainless???? Bah!!

 

[65ShelbyClone]

EV8 seems to be one of the more common stainless steels used for high performance engine valves.....