Flathead Aftermarket Valves Heads-up?

[GOSFAST]

Just a tip for working with new valves!

When purchasing any new valves for the Flathead make absolutely certain you don't get ANY 2-pc valves. Many vendors have been "flooding" the market with these pieces.

These valves are welded together, "austentitic" heads w/steel stems. It makes for a real cost-savings for the mfr, not the best quality valves to choose however.

You can check them easily with a small magnet, from the tips to 3/4's way down the stems will be magnetic, the heads will not. I would strongly recommend using 100% stainless pieces on all these builds.

There's a reason I recommend avoiding them. The steel stems will be more likely to "hang" in the guides than their stainless counterparts. Any moisture build-up, short trips, long storage, etc, will begin to "attack" the steel more than the stainless. Even with the bronze guide option I would not use these 2-pc deals.

We had been using the Federal-Mogul valves for years and all was good until I sent a set of 16 out to a member here and he called me about this issue due to the fact I had warned him to avoid these valves. Before I sent him the new valves we had a discussion about the 2-pc ones and recommend he avoid them. I was unaware at the time Federal had made the change and took his back and got him the correct pieces. Haven't used the Federal line since then.

Thanks, Gary in N.Y.

P.S. Here's a shot of one valve starting to deteriorate along the stem. If you look closely it is quite noticeable. This is a 100% steel (magnetic) intake valve.

[cmbrucew]

Thank you Gary
This kind of information can save a lot of grief.
Bruce

[Joe Immler]

Who knew? Thanks, Gary. It just seems to be one thing after another with replacement parts.

[flatheadmurre]

There´s nothing wrong with a 2pcs design it´s just about cheap material as usual...
When it comes to the high performance turbo stuff you are bound to use multipiece valves and cast iron guides...so right stuff in the right place...and a shitty product is what it is no matter of design.

[JWL]

flatheadmurre is right. The 2 piece valve concept has been used very successfully for many years.

[GOSFAST]

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I think some here missed the point of the post, these are what we consider "cheap" valves, they cost under $1.50 to mfr.

I have no issue with the 2-pc concept but the ones we use (occasionally) cost around $40.00 ea and include "Inconel"! Our very high-end builds get Titanium (all 1-pc) with lash caps, more expensive still, average $100.00+ ea.

Thanks, Gary in N.Y.

P.S. The main point is about the stems being made with conventional steel (so to speak) you end up with the risk of corrosion in the guides. We have never experienced this corrosion with any stainless stems, period. You can see in the photo above the steel is already beginning to show the signs of deterioration.

[Ol' Ron]

I've always used the stock shevy valve in all my builds with the L-100 cam. These are a 2 piece valve. I shy away from the SS valves unless they have chrome stems, alittle pricey for a street engine, I also under cut the valves to aid flow. Had a special round 3/4" carbide that shapped the bottom of the valve in one pass. Probably a waste of time. But all the guides were knurled.. I know what Gary means here and what he does is far better than what I did. But I was just building strong street engines for a very reasonable price.

[Tim Ayers]

Originally Posted by Ol' Ron

I've always used the stock shevy valve in all my builds with the L-100 cam. These are a 2 piece valve. I shy away from the SS valves unless they have chrome stems, alittle pricey for a street engine, I also under cut the valves to aid flow. Had a special round 3/4" carbide that shapped the bottom of the valve in one pass. Probably a waste of time. But all the guides were knurled.. I know what Gary means here and what he does is far better than what I did. But I was just building strong street engines for a very reasonable price.

When using 1.5"ers, what's the consensus of using Chevy exhaust values for both intake and exhaust? Seems like you can get the SS undercut head, chrome stemmed, high flow valves for a reasonable price.

I don't have JWL's book with me right now, so he may answer this question in his book. I usually re-read it each summer and I'm about due for another pass.

[flatjack9]

I've always used the Chevy exhausts for both intake and exhaust. Seems to work well.

[Ol' Ron]

Me too. best way to run anL-100 cam or any other hight lift cam and adj lifters.