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Cylinder Head Valves

G

Grayson

New CEG'er
Joined
Oct 11, 2007
Messages
10
Location
West Chester, OH
While considering adding forced induction to a naturally aspirated engine, I worry about the valve material. I definitely want to ensure that the valves can take the heat!

After searching the forums, it seems that nobody ever mentions replacing the valves when adding a blower or a turbo. Do the stock valves simply do the job?

What material are the stock valves made from?

AER supposedly replaces the stock valves with Manley pieces when assembling the Noble engines, but other than this, I haven't heard of anyone swapping out valves (other than to upgrade 2.5L valves to 3.0L versions).
 
It's mostly about exhaust gas temps. Safely tuned aftermarket forced induction setups typically have lower EGTs than a comparable OEM FI setup, and on top of that, an aftermarket FI setup will generally be expected to have a much shorter service life than the comparable OEM setup.

That said, your Lincoln 3.0L will have different valves than the taurus/escape/etc 3.0Ls we all use, because yours will have a DAMB valvetrain setup (Direct Acting Mechanical Bucket, instead of the RFF, Roller Finger-Follower in the "other" 3.0L engines) Yours will be more stable at high RPM, which will be a big benefit in your application.

All that said, the DAMB 3.0L valves are both stainless steel; The intake is a lower grade of stainless called "A-193" that should be just fine no matter what you do (it is good up to about 1000 deg F, and you would have to REALLY work to get it up there). The exhuast is a high nickel content stainless steel called 21-4-3, and is good for an OEM application to about 1500 deg F. (Note that these are valve temps, not EGTs, an EGT measured at the exhaust manifold is generally 50-60 deg. F higher than the EGT inside the port, which is the temp you have to assume the valve can reach) So, if you keep the EGTs below 1550 deg. F, you should get plenty of life out of your valves, and you should have no problem keeping them below that with a good safe air fuel ratio.

Also of note, is that both intake and exhaust valves on your engine are nitrided, which is a surface hardening process that leaves a black finish on the valves, and leaves a very hard and low friction surface on the whole valve. This results in better wear resistance and low friction on the stem and tip surfaces.
 
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Incredible post Rara. Geez. You even recalled that I was employing a DAMB motor.

Do you happen to know the source for your specification of the valve material? I'm very curious to know how you came to know the exact grades of stainless that were leveraged.

It sounds like the valves are equally as good as the valves that were installed in my 4G63 Mitsubishi Eclipse motor back when I used to race those vehicles.
 
He's working for a valve supplier to Ford now... so he's got lots of firsthand knowledge in that regard.
 
My company currently makes the DAMB valves, lol. We don't make the RFF 3.0L valves though :( It didn't stop me from trying to convince my boss to let me order up some hollow stem valves for my build up though . . . too bad he said no, lol. $200 per valve gets expensive really fast, lol.
 
btw, just as an aside, more and more NA applications are getting pretty high grade exhaust valve materials because of the high EGTs that result from trying to meet more and more stringent fuel economy and emissions requirements. This is a REALLY good thing for the homebuilt turbo guys.

Case in point, the 4.6L 3V V8 engines all currently get inconel based exhaust valves, as do the 6.8L 3V V10, the next step over inconel is a hollow stem valve filled with sodium for cooling.
 
My company currently makes the DAMB valves, lol
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Well, that certainly explains the excellent post! I feel like I just asked Payton Manning if he knows how to throw a football. :shocked: Thanks again for the great data - I'll definitely move forward with confidence in the valves.
 
Ain't that the truth Todras! In the never ending search for my next toy car (will be keeping the tour) I cruise around various boards and they don't hold a candle to this one.

The knowledge base is far superior and relevant. Seems everywhere else I have been 99% of the people posting fall into two groups. Those guys that just drop serious money to have some performance shop make a monster. And, the second group is pretty much a bunch of hacks. No real DIY people doing quality work.
 
haha the only reason we get quality DIY work is becuase everything we do is DIY work. its kind of nice. one of a kind most of the time.


and yeah this forum has great information and great detail on that information
 
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