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#31 |
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I thought the allowance of going to Honda/IRL rod journals in SS was stupid. This sounds like the rich racers putting the class out of reach for most people. NHRA must want to get the SS fields down to a pair of megabuck cars. Why bother to tech them at all? Just P&G one cylinder and wave it through. I would like to see fiberglass replacements for the aluminum front end cars as a cost savings. Cost saving measures would be nice rather than cost escalation.
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Mopar 2 Ya! |
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#32 | |
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#33 |
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We are all entitled to our opinions but in my opinion, all materials should be as per OEM in both stock and SS. That should include cylinder heads and any other items affecting performance. The only exceptions I would consider would be rods and cranks, replacing iron items with steel (of equal weight) does help reduce oil downs.
Jim Mantle V/SA 6632 |
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#34 |
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Brought to you by the same "group" that got worked over combustion chambers thru tech and then got them made "legal". Apparantly can't run legally with the fast stuff. By the way, this won't be the first time a engine has passed tech with titanium valves which were switched right in front of techs eyes. To prevent it, just check the guy with the shop towel wiping down the valves.
Oh, and for the record I am against allowing titanium. They are light, they are tough, but they are unforgiving as Jeff said. Also need replacement frequently if they are the high dollar ones. |
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#35 | |
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I recently held a 427 / 425 HP Ford intake valve from an old Hollman-Moody engine built in 1967 or so (the fishing boat engine I brought up on this forum). When disassembling the heads the head on an intake vale broke off. The dang thing was rifle drilled in the stem! Couldn't believe how light it was and it was a pretty large diameter valve. Now I know the exhaust are sodium filled on this engine but I didn't know they were doing this to intake valves back in the '60's. I'd have to say I'm with SS Engine guy and others on this. Based on my limited experience, I can't see the need. Sure it may be faster but I see no other benefit. Cost goes up, maintenance and replacement goes up and engine damage can be a real issue if one breaks. I lost two Stocker engines thanks to Mr. Schubeck, don't think I would want to go down this road.
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Jeff Lee 7494 D/S '70 AMX |
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#36 |
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This craziness has to stop.
At the end, it is not worth the extreme cost for marginal gains. First, unless they are Physical Vapor Deposition or Chromium Nitride coated, Titanium valves will wear at a faster rate than a SS valve. Although they have OEM applications such as the Corvette and many motorcycles makes, the valves they use are coated and they use valve seats with a higher Copper contents. Which means, if they are allowed, all seats will need to be replaced with a seat with a higher Copper contents. When NHRA allowed the use of Titanium valves on the 427 Fords, is due to the fact that at the time it was difficult to obtain hollow stem valves. Weight wise, the Titanium and hollow-stem valves are the same. Also, due to valve train dynamics, the RPM gains are not as much as many may believe. Today, you can buy good hollow stem SS valves from companies such as Ferrea. It also makes me wonder how many racers out there are using them. If the rule change is approved, I can see racers, later on, asking the valve stem size rule be deleted so they can run 7mm valve stems. |
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#37 | |
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If you went back to the stock spring pressure in stock an awful lot of cars would slow down a bunch. And a lot of camshafts would become short pool cues.
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Art Leong 2095 SS |
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#38 | |
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Which means, if they are allowed, all seats will need to be replaced with a seat with a higher Copper contents.
This is not true I have been using ti valves since 1969 they was on Ford cast iron heads with no seat inserts the seat were not even Induction hardened at that time (they were released by Ford then for use in Tran's Am Boss 302 and 351 C), we used the first as Intakes as there was no Ti for Exhaust, it would not work according to TRW who was the first to supply. I have run the intakes till the margin was thin and started to chip (small V shapped cracks) we then took these valves and turned them down and made exhaust with a much thicker margin and lasted another couple years. I WOULD NOT be in favor of the change! Just trying to set the record straight. Quote:
Last edited by BlueOval Ralph; 09-16-2010 at 10:05 AM. |
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#39 |
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If any one has the chance to buy New old stock the exhaust sodium filled pass on them as the sodium reacts to the steel and eats away from the inside out.
I recently held a 427 / 425 HP Ford intake valve from an old Hollman-Moody engine built in 1967 or so (the fishing boat engine I brought up on this forum). When disassembling the heads the head on an intake vale broke off. The dang thing was rifle drilled in the stem! Couldn't believe how light it was and it was a pretty large diameter valve. Now I know the exhaust are sodium filled on this engine but I didn't know they were doing this to intake valves back in the '60's. I'd have to say I'm with SS Engine guy and others on this. Based on my limited experience, I can't see the need. Sure it may be faster but I see no other benefit. Cost goes up, maintenance and replacement goes up and engine damage can be a real issue if one breaks. I lost two Stocker engines thanks to Mr. Schubeck, don't think I would want to go down this road.[/QUOTE] |
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#40 | |
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For longevity, it is a known fact that you should change the seat material when using Ti valves. Beryllium bronze seats, which is a Copper-based alloy is used for most applications because is softer and won't wear the Titanium as fast. You may have got away with the standard seat because in the earlier heads due to the availability of Lead in gasoline. Therefore, OEM's got away with softer seats in cylinder heads. According to an SAE paper that was written by Chevy engineers as realted to the developemnt of the 'Vette engine, they used a seat alloy called PMF-28. Here is a great informative article as regards to the use of Ti valves: http://www.enginebuildermag.com/Arti...lications.aspx |
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