[CatnDoo]

Hi All

I seem to be getting differing answers to this question:

Are Factory Ram Air IV valves a one or two piece valve? In addition, what tells us its one way or the other?

Cat

[WDCreech]

Factory RA IV valves are two piece. I broke a couple before I switched to aftermarket.

[Formulas]

I kinda wonder if all the broken valves were in a near stock configuration or if 300lbs seat pressure was involved.. ??

[WDCreech]

.520" lift Crower hydraulic cam and springs back when I was still doing the street/strip thing.

[Tom Vaught]

Jim Brady broke a RA-IV valve (two piece) after a burn-out in the box as he was idling up to the starting line at Broadway Bob's track in Wisconsin.

The head came off, flipped over, and the engine stopped. Locked up. (Hint: if the engine stops suddenly, do not crank over the engine. Put a 15/16" socket on the crank and try to bar it over first.) By doing this, Jim was able to remove the head with no damage to it, replace the valves with one piece valves, and inspect the thick top (heavy) forged TRW piston. Piston was fine, rod was fine, bearing was fine. VERY LUCKY guy, Jim B!

So I will never run a RA-IV valve in any performance application based on that deal.

Tom V.

[gtofreek]

I also agree they are 2 piece. One way you can tell is to run a magnet down the stem. If it sticks to the stem, then suddenly doesn't stick anymore near the head, it is a 2 piece valve. Also 2 piece valves usually have a bulge in the stem where the head is friction welded to the stem. They make them 2 piece because that way they can use a very high heat alloy for the head, and combine it to a stem that can be a lot more wear resistant.

2 piece valves have no place in a performance engine. Had one destroy my 428.

[dataway]

Years ago had my 68 YS valves replaced with 69 ram air valves ... the exhausts had magnetic stems and SS heads ... so I assume two piece.

[steve25]

If your rebuilding a RA4 do use RA4 type tulip Intake valves as they really don't flow any better under dynamic conditions and only add weight to the valve train. If you don't belive me then ask yourself why Pontiac did not use a tulip type Intake in the 455SD, or why the aftermarket heads don't use them!

[PAUL K]

Originally Posted by steve25

If your rebuilding a RA4 do use RA4 type tulip Intake valves as they really don't flow any better under dynamic conditions and only add weight to the valve train. If you don't belive me then ask yourself why Pontiac did not use a tulip type Intake in the 455SD, or why the aftermarket heads don't use them!

Pontiac did use a tulip intake valve in the SD 455 engines. Visually it's almost identical to the RAIV valve but has a 45° valve face and it's shorter.

[Skip Fix]

Originally Posted by steve25

If your rebuilding a RA4 do use RA4 type tulip Intake valves as they really don't flow any better under dynamic conditions and only add weight to the valve train. If you don't belive me then ask yourself why Pontiac did not use a tulip type Intake in the 455SD, or why the aftermarket heads don't use them!

My RAIV heads and another set I flowed picked up 5% just using a flat D port style intake valve.

[Half-Inch Stud]

I've bough a couple sets of NOS RA IV valves, Gm boxed, number stamped up near the grooves. Magnet deal will reaveal the answer. They all stayed together for my S/Strip use.

A 71 455 HO didn't have such fortune when an exhhaust valve dropped head during an autocross event. So, those forensics (and some Other folks experiences) got me affording 1-piece valves.

Differing alloys get a weld... Friction-Weld?

New one piece valves are supposed to be the assurance of staying together.

[gtofreek]

Originally Posted by steve25

If your rebuilding a RA4 do use RA4 type tulip Intake valves as they really don't flow any better under dynamic conditions and only add weight to the valve train. If you don't belive me then ask yourself why Pontiac did not use a tulip type Intake in the 455SD, or why the aftermarket heads don't use them!

I believe you meant DO NOT USE. I have found the same thing, the tulip valves hurt flow. They flow better with the 12° flat valve, and even better with a 10° flat valve. I feel a lot of it has to do with the flat floor of the chamber.

[steve25]

Sorry , ment the round port HO heads.

[wovenweb]

Originally Posted by gtofreek

I believe you meant DO NOT USE. I have found the same thing, the tulip valves hurt flow. They flow better with the 12° flat valve, and even better with a 10° flat valve. I feel a lot of it has to do with the flat floor of the chamber.

Does this apply to the intake side only?

[1968GTO421]

Sounds like one piece after market valves are the way to go. But which is best (or are all pretty much the same)? There is Manley, Milodon, and Ferrea. Maybe others I'm unaware of.

[gtofreek]

I like the Ferrea valves the best. Their quality has been top notch. Ferrea's usually flow 5-10 CFM more also than some of the Manley valves because Manley uses a larger radius from the stem to head transition[3/8" compared to 5/16" for Ferrea]. The larger radius takes up space, thus reducing flow.

[gtofreek]

Originally Posted by wovenweb

Does this apply to the intake side only?

Intake side as IIRC, the exhaust side still uses a flat valve.

[gtofreek]

Also, I have seen Ferrea valves stems bent all the way around into a spring shape without breaking the head off. I have seen other brands of stainless steel valves break the heads off after being bent 45° or less. In all my years of using hundreds, if not thousands of Ferrea valves, I have only seen one break the head off. It was from thermal shock. I have seen a lot of other SS valves break heads off.

[Tom Vaught]

Originally Posted by gtofreek

I like the Ferrea valves the best. Their quality has been top notch. Ferrea's usually flow 5-10 CFM more also than some of the Manley valves because Manley uses a larger radius from the stem to head transition[3/8" compared to 5/16" for Ferrea]. The larger radius takes up space, thus reducing flow.

I have been buying the Ferrea Valves from the guys in Florida since 1997.
Good people and as was said, Quality of the parts is Top Notch.

Tom V.

[1968GTO421]

Originally Posted by gtofreek

I like the Ferrea valves the best. Their quality has been top notch. Ferrea's usually flow 5-10 CFM more also than some of the Manley valves because Manley uses a larger radius from the stem to head transition[3/8" compared to 5/16" for Ferrea]. The larger radius takes up space, thus reducing flow.

Thanks, Paul. Much appreciated.

https://www.ferrea.com/