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Original Message
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| RE: 428 cj Exhaust Manifolds |
| By kevin - 10/26/2001 9:40:06 AM; IP 209.240.222.130 |
| If you mean the Ford ligtweight valves I assume you have the 2.09 intake and 1.65 sodium exhaust, they are beautiful but beware. The powdered metalic sodium melts at 208 degrees farenheit and transfers heat more effectivly than a solid stem. This allows for a cooler running temperature of about 2-3 hundred degrees, which means lots more life. It also weighs only 79 grams as opposed to 137 grams for a stock Cobra Jet of the same size. This allows about 1,500 more RPM over the stockers with the same springs usually. The Intake of a stocker weighs 144 grams and I cant recall the Lightweight number, but the 2.19 Hi Riser weighs 97 grams so the 2.09 should be less. The sodium filed exhaust has popped the head off on many people for various reasons including, valve float, (all valves bounce on return to the seat above 7,000), the weld coming apart (they are a 2 piece design), and the sodium eating away at the metal from the inside. This last one is quite controversial to me as all FT truck engines have sodium exhausts and usually dont break them. There are many replacement stainless valves on the market but beware of the difference in quality, it varies. I myself have noticed that the majority of the race engines that had a broken sodium exhaust, seemed to do it on the end cylinder which in my opinion was due to shaft vibration on the nonsupported end of the shaft. I've been lucky to have never have one break but that is because I've always run end supports. When I did not once, I did have a valve spring break and only bent one. You can have them X-rayed to look for internal occlusions, but that could cost some bucks, or you can run them, or use them for paperweights, your choice. Good luck |
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