valve seat ??
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valve seat ??

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    Senior Member rogerroost's Avatar
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    Default valve seat ??

    I,m in the process of prepping a pair of c9ve 460 heads. I'm starting with some pretty rough empty cores. my guy thats doing the porting wants hardend seats installed. The machinist doesn't recommend them on an engine that has any chance of seeing water in fear of them popping out. being wet headers with some cam,theres some risk.
    after the valve grind theres still some small pits & some rust stain on a couple of seats. the machinist say's there not pretty but they'll be fine.
    so the question is ,do I go with the guy doin the porting & get the hardend seats or do I not take the risk of them popping out ,like the machinist says and run the "not so pretty" freshly ground soft seats? the heads are 40 years old & this boat does have a budget .

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    steelcomp was here
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    Quote Originally Posted by rogerroost View Post
    I,m in the process of prepping a pair of c9ve 460 heads. I'm starting with some pretty rough empty cores. my guy thats doing the porting wants hardend seats installed. The machinist doesn't recommend them on an engine that has any chance of seeing water in fear of them popping out. being wet headers with some cam,theres some risk.
    after the valve grind theres still some small pits & some rust stain on a couple of seats. the machinist say's there not pretty but they'll be fine.
    so the question is ,do I go with the guy doin the porting & get the hardend seats or do I not take the risk of them popping out ,like the machinist says and run the "not so pretty" freshly ground soft seats? the heads are 40 years old & this boat does have a budget .
    You don't have to put hardened seats in to replace the seat. You can use a plain iron seat and there shouldn't be any issues with water.
    If the seats are pitted, IMO that's no bueno. You don;t want to go to all this trouble and expense only to put together a set of semi worn out heads.
    If God is your co-pilot, change seats!
    Acts 2:38, the perfect answer to the perfect question.

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    Senior Member lbhsbz's Avatar
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    Aluminum heads have seats in marine applications all the time, why can't an iron head?

    You could always pin the seats in....I'm not sure why this isn't done already.

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    steelcomp was here
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    Quote Originally Posted by lbhsbz View Post
    Aluminum heads have seats in marine applications all the time, why can't an iron head?

    You could always pin the seats in....I'm not sure why this isn't done already.
    If the seat is installed correctly there's no need...and what the heck is "pinned in"??
    If God is your co-pilot, change seats!
    Acts 2:38, the perfect answer to the perfect question.

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    Senior Member lbhsbz's Avatar
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    Drill a couple small holes as close to radially as you can get them in a non-sealing surface part of the seat and into the head, drive in pins so the seat can't fall out. After I dropped a seat years ago in a brand new type 4 motor I'd put together w/ new heads, and hearing plenty of others do the same, I pinned mine and they worked till I melted the pistons.

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    Senior Member rogerroost's Avatar
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    so dropping a seat is a concern? I would think fairly heavy damage to the valves & head.
    don't get me wrong ,the "not pretty" pitting in the seats aren't like holes.

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    Senior Member lbhsbz's Avatar
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    Quote Originally Posted by rogerroost View Post
    so dropping a seat is a concern? I would think fairly heavy damage to the valves & head.
    don't get me wrong ,the "not pretty" pitting in the seats aren't like holes.

    The only thing I've ever seen it be a concern in is aircooled engines. I wouldn't worry about it in a marine app, but steelcomp or some of the other gurus are better authorities than me.

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    Member kwilkinson's Avatar
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    Quote Originally Posted by lbhsbz View Post
    Aluminum heads have seats in marine applications all the time, why can't an iron head?
    My machinist told me the reason he doesn't like running seats on iron heads vs. seats in aluminum is because the aluminum heads he can press the seats in tighter where if he were to press seats in an iron head just as tight it risks cracking the head. Kind of made sense to me, but what do I know

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    steelcomp was here
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    Quote Originally Posted by kwilkinson View Post
    My machinist told me the reason he doesn't like running seats on iron heads vs. seats in aluminum is because the aluminum heads he can press the seats in tighter where if he were to press seats in an iron head just as tight it risks cracking the head. Kind of made sense to me, but what do I know
    Aluminum heads need more press because aluminum expands more than iron when it gets hot and as a result will lose some of it's press. The expansion rate of an iron seat in an iron head is the same, so the press fit is just enough to keep the seat in place and remains the same as the head heats up. You would never use the same amount of press in an iron head as you would aluminum.
    If God is your co-pilot, change seats!
    Acts 2:38, the perfect answer to the perfect question.

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    steelcomp was here
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    Quote Originally Posted by rogerroost View Post
    so dropping a seat is a concern? I would think fairly heavy damage to the valves & head.
    don't get me wrong ,the "not pretty" pitting in the seats aren't like holes.
    Not at all if it's done right.
    If God is your co-pilot, change seats!
    Acts 2:38, the perfect answer to the perfect question.

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    northern member Canuc's Avatar
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    we all like things to be perfect and on a high dollar or competition build , no question they should be . but since you are reconditioning 40 yr old heads on a budget , if your machinist is experienced and i'am sure he is or you wouldn't of gone to him i'd trust his judgement . hard to say without seeing them but some small pits and stain will be fine if they aren't more than 25% or so of the seat width .
    Quote Originally Posted by gn7 If your ran a cammer your odds of finishing WERE ZERO.

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    Senior Member wagspe208's Avatar
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    Hell, if a few small pits are no problem, then just run them. Why do a valve job at all.
    Your machinist should be your former machinist.
    Seats, when properly installed, don't fall out. The alum. more press fit is (as steelcomp said) due to expansion of alum.

    Wags

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    Senior Member rogerroost's Avatar
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    I took the heads back to the guy doing the porting today. He thought they looked ok,also said it was mostly staining. some more blending & polishing and I,m gonna run them Now i've just got to figure out max c/r i can run with pump gas 91 or 94 octane

  16. #14
    northern member Canuc's Avatar
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    come on wags a few "small" pits on a otherwise good seat is not the same as a wornout one roger you will be fine .
    Quote Originally Posted by gn7 If your ran a cammer your odds of finishing WERE ZERO.

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