long_tall_texan

As the title states. Someone please enlighten me. In a separate thread regarding spark plugs, a couple comments about valves got me curious. My specific plans are very mild: Pulling my heads this week to have them "fixed" at a local shop that I trust. Milling the heads 0.030" while they are at it for a little free HP. Going back together with new bronze guides, stock cam, and Yella Terra roller rockers. No plans for any more radical cam in the foreseeable future.

So. Was planning to replace all exhaust valves with Ferrea F1597P solid SS valves. Some mentioned that may be a bad combo with the heavier roller rockers.

So.... Advice requested. Pros and cons of:

Ferrea F1597P solid SS valves
vs
Ferrea F2042P Hollow valves
vs
new OEM sodium filled valves

And... Will stock springs and retainers be OK, or other springs recommended due to rocker and/or valve changes?

Hib Halverson

Solid stem exhaust valves are heavier so, if you use them, you need higher tension exhaust valve springs or you need to reduce the engine's rev limit.

Think twice about milling the heads .030. As long as you can get gasoline with high enough octane a .030 mill will gain a small amount of power, but GM calibrates spark schedules for 93-oct. Milling .030 may push the octane needed to keep the engine out of detonation to 94 or 94.5. Of course, the engines knock sensors and EST will prevent detonation but it doesn't make a hell of a lot of sense to go up in CR then have knock retard all the time.

MTPZ06

Couple guys tested the YT rockers on a spintron a while back...pretty sure F2042p valves and PSI beehives were part of the combo that proved to be stable with stock cam up to OE redline. That won't be the case with solid. New OE valves are fine as well...I've just seen too much evidence over the years that the OE valves have quality issues. F2042p is simply an upgrade in my mind...

AzDave47

I went with a lightweight, stable valvetrain build. With CHE bronze guides I did Kateck TiMo intake valves ($$) and new OEM exhaust valves with PSI 1511 springs and Ti retainers. For your mild cam build and intended use, OEM Ti valves and OEM exhaust valves should be fine. I went with all new valves whereas some have the OEM Ti valves sent back to DelWest (?) for polishing and recoating. I did not want to reuse any valves that had operated in worn guides. At 46K miles, all exhaust valve guides and 6 of 8 intake valve guides were worn beyond GM spec.

I generally have access to 91 octane fuel, but had the heads milled .030 and the tune adjusted, figuring if I sell the car to a state where 93 is available, just a retune would be needed to get some cheap increase in power rather than opening up the engine.

Dan_the_C5_Man

They layman's version;

Solid ex. valve - non-starter.

Aftermarket hollow ex. valve - if it makes you sleep better at night, still requires an accurately machined guide.

Late model GM OEM ex. valve - perfectly fine when run in an accurately machined guide.

I had a choice to run the Ferrea or the OEM, I am running the OEM. And so long as my guides stay in spec, I do not fear a failure of that part (plenty of other crap will go first).

I also would not do bronze guides - I would only send my heads to AHP, let them install their PM guides. I will say plenty of folks do .030, BUT almost all those folks also have an aftermarket cam, which changes the DCR. I did "chicken out" and only went .020, I did NOT want to pull any timing (I am also keeping the stock cam and I do run 93).

MTPZ06

Link to thread that I mentioned in my previous post... https://www.corvetteforum.com/forums...ts-are-in.html

long_tall_texan

Yeah. I went searching and found it this morning.

Dirty Howie

You probably know this but the OEM is hollow and the only one that is sodium filled.


DH

Unreal

For your application hollow ferrera.

Solid valves are great for certain combos. I run solid valves in my 1200+hp car, that spins to 7300+. Valves are just one part of an equation and have different applications. It is about engineering a complete setup, from cam to lifters to pushrods to rockers to springs/retainers to valves. All of that needs to be matched.

I would run stock rockers and hollow valves, especially with a stock cam.

Michael_D

The combination of both the heavier valve, and roller tipped rockers is not a good idea. You'll need around 160 seat and 450 open load with that combination of parts, and that's just a WAG without any spin rig data to reference. Those loads on OE lifters is too much, plus the extra friction all that brings. And....with a stock camshaft. Just not a good match. Something has to give. Sometimes a great idea doesn't look so good after putting it to work.........

Josh B.

Tony Mamo installed Ferrea Hollow Stem SS intake valves in my MMS 265 heads along with solid SS exhaust valves. I have complete valve control up to 7600 rpm, solid roller, dual springs.

Like Unreal already mentioned, the valve is just one component of the valvetrain.

Something that Tony has mentioned to me "if the EV weighs the same as the IV, what difference does it make if they are non exotic materials? The valve spring has no idea if it's on an IV or an EV, weight is weight". Letting go of the Ti IVs sucked, and going to solid SS EVs seemed wrong, but all that matters in the end is if the valvetrain is under proper control.

Dirty Howie

I know Tony personally and he certainly knows what he is doing. Having said that I think this is the first time I have ever heard of this approach. Best of luck with your setup Josh. How do you know its stable at 7600 (dyno or spintron)?


DH

Josh B.

Thanks DH! Tony is great! I don't think Tony has used a spintron, but he would have to speak to that. I base my opinion on datalogs and dyno results that do not reflect valve float, in addition to regular valve lash maintenance that thus far has not shown any wacky stuff happening. Lash grew an insignificant .001" during the break in period. Of course, there "could" be some minor float that is hiding in there, but there are no symptoms and the valvetrain is very healthy. I have plenty of confidence to keep the hammer down and the tach needle high


Josh

grinder11

I know this thread is a year and a half old, but I just read it, and the LS7 debacle continues. As for OEM exhaust valves over Ferrea exhaust valves? I'd have to fall and bump my head-HARD-before I'd ever find fault with Ferrea valves!!! I bought an early set of AFR 225 heads back in 2005 that had upgraded Ferrea valves with REV valve springs, all installed by AFR when I bought the heads new. The installed height was set@1.700 (!!), NOT the spec'd 1.800". In other words, these valve springs were installed .100" TOO STIFF, which put a Hell of a lot of spring tension on the valves. I put 30,000+ miles on them before badly worn valve guides red flagged the problem. You didnt need to have a wiggle test done in order to see it. A WOBBLE test would be more accurate!! At the. 600 lift spec, I could bury a .060 TIR dial indicator. You didnt even need an indicator to see how worn the guides were. Those 30,000 miles included driving my C5 to California in the summer of 2006, when a record heat wave was pushing temps in Wyoming to 100 degrres+. The engine ran a coolant temp of 240°, hour after hour. But the valves, though the springs were shimmed WAY too stiff, never broke. The springs never broke, either. Enough said about the quality of Ferrea valves......

Dan_the_C5_Man

Sounds like you dodged a bullet. It's a shame there are so few competent shops.

grinder11

It didnt hurt matters, for sure, that the engine was assembled at Wheel to Wheel powertrain. But seeing as the heads were brand new, and assembled at AFR, I know I didnt check the installed height, and I'm sure W2W trusted AFR workmanship, too. The error was attributed to converting metric to SAE measurements. You shoulda seen my cam bearings!!!!