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#1
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Ram Air IV Valves - One or two piece valve
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 |
#2
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Factory RA IV valves are two piece. I broke a couple before I switched to aftermarket.
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Bill 64 GTO, tube chassis w/606" IA tall deck, PG & a pro geared Fab 9". 2750 lbs. 8.2550@164.17-1/4, 5.2901@131.97-1/8, 1.1981-60-ft. 8/10/08 |
#3
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I kinda wonder if all the broken valves were in a near stock configuration or if 300lbs seat pressure was involved.. ??
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#4
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.520" lift Crower hydraulic cam and springs back when I was still doing the street/strip thing.
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Bill 64 GTO, tube chassis w/606" IA tall deck, PG & a pro geared Fab 9". 2750 lbs. 8.2550@164.17-1/4, 5.2901@131.97-1/8, 1.1981-60-ft. 8/10/08 |
#5
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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.
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"Engineers do stuff for reasons" Tom Vaught Despite small distractions, there are those who will go Forward, Learning, Sharing Knowledge, Doing what they can to help others move forward. |
#6
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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.
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Paul Carter Carter Cryogenics www.cartercryo.com 520-409-7236 Koerner Racing Engines You killed it, We build it! 520-294-5758 64 GTO, under re-construction, 412 CID, also under construction. 87 S-10 Pickup, 321,000 miles 99Monte Carlo, 293,000 miles 86 Bronco, 218,000 miles |
#7
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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.
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#8
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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!
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#9
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Quote:
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. |
#10
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Quote:
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Skip Fix 1978 Trans Am original owner 10.99 @ 124 pump gas 455 E heads, NO Bird ever! 1981 Black SE Trans Am stockish 6X 400ci, turbo 301 on a stand 1965 GTO 4 barrel 3 speed project 2004 GTO Pulse Red stock motor computer tune 13.43@103.4 1964 Impala SS 409/470ci 600 HP stroker project 1979 Camaro IAII Edelbrock head 500" 695 HP 10.33@132 3595lbs |
#11
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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. |
#12
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Quote:
__________________
Paul Carter Carter Cryogenics www.cartercryo.com 520-409-7236 Koerner Racing Engines You killed it, We build it! 520-294-5758 64 GTO, under re-construction, 412 CID, also under construction. 87 S-10 Pickup, 321,000 miles 99Monte Carlo, 293,000 miles 86 Bronco, 218,000 miles |
#13
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Sorry , ment the round port HO heads.
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#14
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Does this apply to the intake side only?
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1971 Pontiac Trans Am Cameo White 1968 Firebird 400 coupe, Verdoro Green w/black vinyl top 1968 Firebird 400 convertible, Verdoro Green w/black top 1970 Buick Skylark Custom convertible(driver) Fire Red 1972 Buick GS 455 Stage 1 Royal Blue |
#15
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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.
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"No replacement for displacement!" GTOAA--https://www.gtoaa.org/ |
#16
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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.
__________________
Paul Carter Carter Cryogenics www.cartercryo.com 520-409-7236 Koerner Racing Engines You killed it, We build it! 520-294-5758 64 GTO, under re-construction, 412 CID, also under construction. 87 S-10 Pickup, 321,000 miles 99Monte Carlo, 293,000 miles 86 Bronco, 218,000 miles |
#17
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Intake side as IIRC, the exhaust side still uses a flat valve.
__________________
Paul Carter Carter Cryogenics www.cartercryo.com 520-409-7236 Koerner Racing Engines You killed it, We build it! 520-294-5758 64 GTO, under re-construction, 412 CID, also under construction. 87 S-10 Pickup, 321,000 miles 99Monte Carlo, 293,000 miles 86 Bronco, 218,000 miles |
#18
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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.
__________________
Paul Carter Carter Cryogenics www.cartercryo.com 520-409-7236 Koerner Racing Engines You killed it, We build it! 520-294-5758 64 GTO, under re-construction, 412 CID, also under construction. 87 S-10 Pickup, 321,000 miles 99Monte Carlo, 293,000 miles 86 Bronco, 218,000 miles |
#19
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Quote:
Good people and as was said, Quality of the parts is Top Notch. Tom V.
__________________
"Engineers do stuff for reasons" Tom Vaught Despite small distractions, there are those who will go Forward, Learning, Sharing Knowledge, Doing what they can to help others move forward. |
#20
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Quote:
https://www.ferrea.com/
__________________
"No replacement for displacement!" GTOAA--https://www.gtoaa.org/ |
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