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stugray |
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#1
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Advanced Member ![]() ![]() ![]() ![]() Group: Members Posts: 3,825 Joined: 17-September 09 From: Longmont, CO Member No.: 10,819 Region Association: None ![]() |
I was once told by one of the resident "experts" on this forum (who has not been around lately) that I should replace my sodium filled valves with stainless. However after visiting the local RSR racing mechaninc (who is machining my case and inspecting my heads), HE said that he goes out of his way to FIND sodium filled valves for race engines. He said that on Air-cooled engines, the sodium helps pull the heat from the heads.
Any comments or suggestions regarding sodium vs. stainless? I also heard that a simple change from two-angle to three-angle valve seats can increase flow by more than 20% with no other changes to the heads. Good news is that I should be re-assembling the engine without the deck height problems over thanksgiving weekend. Hope to have it running by Xmas. (IMG:style_emoticons/default/piratenanner.gif) Stu |
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HAM Inc |
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#2
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Senior Member ![]() ![]() ![]() Group: Members Posts: 846 Joined: 24-July 06 From: Watkinsville,GA Member No.: 6,499 Region Association: None ![]() |
Just to continue on the thread hijack, I attached a link to an article from my website about a Miata head that picked up 26% ex flow from just a seat cut. The page has a link to the flow data.
http://www.hamincgroup.com/blog/services/valve-seat-cutting |
bulitt |
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#3
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Achtzylinder ![]() ![]() ![]() ![]() Group: Members Posts: 4,188 Joined: 2-October 11 Member No.: 13,632 Region Association: South East States ![]() |
Just to continue on the thread hijack, I attached a link to an article from my website about a Miata head that picked up 26% ex flow from just a seat cut. The page has a link to the flow data. http://www.hamincgroup.com/blog/services/valve-seat-cutting That is unheard of, wow. Looks like his first pass is a straight cut into the throat so he is opening the seat to 89% of the valve dia. That make sense. Most local machine shops are just going to do a simple 60/45/30 when asked to perform a performance cut. So I guess when you ask for a "valve job" you really need to have a performance shop perform it vs. a rebuilder. Oh, I see this is your shop. So to get back on topic, what flow numbers have you seen from the porsche heads? And what work do you include in a "seat cut" ? For what Price? Your bench looks familiar...you do work for Jake? Impressive work Len! |
Mark Henry |
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#4
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that's what I do! ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() Group: Members Posts: 20,065 Joined: 27-December 02 From: Port Hope, Ontario Member No.: 26 Region Association: Canada ![]() |
Your bench looks familiar...you do work for Jake? Impressive work Len! Len does all of Jakes head work, but he is independent from Jake. I used a few sets of HAM heads, have a set on the bench right now, top notch work. Everybody thought the exhaust valves with a divot on Porsche heads were sodium filled but both factory paper work and destructive testing is showing that most SC and 3.2 valves are not sodium filled. |
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