goinbroke2
Well-known member
Turbo has a point on carburetion, I just didn't know how to word it.
So, you used intakes as larger replacement exh valves? COOL!!
I feel like I came into a conversation half way through and said something before I had all the facts.
In that case, yes I could see how the thinner intake could burn up because of less mass. Although the factories over compensate when it comes to reliability issues, I think they made the exh thicker(with more mass) for a reason. I have thought of this before but have never actually done it as I assumed the exh were different metal. (I'll go to bed tonight less stupid) Lol!!
My other plan was to use 8.2 L detroit diesel valves in a 460. The stem is the correct dia, but it is way too long. My plan was to use the lathe to cut new keeper slots, then cut the end off the valve at the right length. My concern which I couldn't find out for sure was whether the exh valves were sodium filled. As you are probably aware, sodium explodes on contact with oxygen, and some diesels have sodium filled exh valves.
Back to your situation. Since fuel distribution on a log intake is not the best, it's too bad you didn't have thermo couples (EGT sensors) in the primary pipes. This would of showed the exh temp regardless of timing/fuel/ etc. If the temp was good(even if it was rich or lean) and it burned up the valves then yes more mass was required. Otherwise you don't have conclusive proof that it was or wasn't any one thing or a combo of things unfortunately. I'm thinking though that this wasn't a distribution problem though.(or only a certain couple of cyl's would be hurt) And you said the total timing was 34? That should rule out late timing. Possibly a too lean situation? maybe. Stock angles used? then the only real reason I would guess at,and it's a guess would be the valve was too light.
Now that's not saying you can't use it, I'm saying that if/when using intakes in an exh application, you must be EXACT on your jetting and distribution/timing/etc. I would say they will work but you have no room for mistakes or no "safety net" per say.
Very interesting though, takes a pair to try something like that !
So, you used intakes as larger replacement exh valves? COOL!!
I feel like I came into a conversation half way through and said something before I had all the facts.
In that case, yes I could see how the thinner intake could burn up because of less mass. Although the factories over compensate when it comes to reliability issues, I think they made the exh thicker(with more mass) for a reason. I have thought of this before but have never actually done it as I assumed the exh were different metal. (I'll go to bed tonight less stupid) Lol!!
My other plan was to use 8.2 L detroit diesel valves in a 460. The stem is the correct dia, but it is way too long. My plan was to use the lathe to cut new keeper slots, then cut the end off the valve at the right length. My concern which I couldn't find out for sure was whether the exh valves were sodium filled. As you are probably aware, sodium explodes on contact with oxygen, and some diesels have sodium filled exh valves.
Back to your situation. Since fuel distribution on a log intake is not the best, it's too bad you didn't have thermo couples (EGT sensors) in the primary pipes. This would of showed the exh temp regardless of timing/fuel/ etc. If the temp was good(even if it was rich or lean) and it burned up the valves then yes more mass was required. Otherwise you don't have conclusive proof that it was or wasn't any one thing or a combo of things unfortunately. I'm thinking though that this wasn't a distribution problem though.(or only a certain couple of cyl's would be hurt) And you said the total timing was 34? That should rule out late timing. Possibly a too lean situation? maybe. Stock angles used? then the only real reason I would guess at,and it's a guess would be the valve was too light.
Now that's not saying you can't use it, I'm saying that if/when using intakes in an exh application, you must be EXACT on your jetting and distribution/timing/etc. I would say they will work but you have no room for mistakes or no "safety net" per say.
Very interesting though, takes a pair to try something like that !
. OO6. Excellent topic by the way,too 
