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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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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.
 

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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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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"??
 

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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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Discussion Starter #6
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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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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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 :)sphss
 

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steelcomp was here
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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 :)sphss
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.
 

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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.
Not at all if it's done right.
 

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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 .
 

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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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Discussion Starter #13
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:|err Now i've just got to figure out max c/r i can run with pump gas 91 or 94 octane
 

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come on wags a few "small" pits on a otherwise good seat is not the same as a wornout one :(:( :)coffee roger you will be fine .
 

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Discussion Starter #16
your right about the stains GN7. I think what there saying is it's like cancer in a 40yr old porus cast iron head. The valves from my d3ve heads are like brand new. One would be silly to put too much money into heads like this. If money was no object ,a guy would just get new aluminum heads. I'm just trying to do the best i can with a $6000ish boat. $60 for the c9,s ,$200 porting& polishing,valve grind & surface grind. I think they'll be fine.:)devil
 

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before i would install seats to get rid of the pits, i would just install oversized valves.

Not sure what stained means. If the metal is discolored, that just means smooth rust. But the metal is still oxidized.
x2:d
 

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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:|err Now i've just got to figure out max c/r i can run with pump gas 91 or 94 octane
Vacuum check them, if they pass, then the "pits" are superficial. If they fail, they need seats or bigger valves. This shouldn't be subject to someone's opinion.
 

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I,m in the process of prepping a pair of c9ve 460 heads. My guy thats doing the porting wants hardened seats installed.
Tell the guy porting the heads to quit making excuses, to quit nicking up your seats, and take better care while porting. :p

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 .
If you go with seats and they are properly installed into the iron heads, I don't see a problem. By the way, we usually sink seats about 0.020" further into the chamber and then lightly peen the chamber edge of the seat-cut over the seat itself...kinda overkill but we've never lost one.

In most cases I won't do seat replacement unless it is a necessary repair. That is to say, if the OEM pre-existing seats are serviceable then make use of them. If you are installing larger valves (and I sure hope you are) without installing seats, then the 45*'s will be outboard of where the current 45* seat, so that outer area is where you need to evaluating the pitting and whether the cut of the new seat will clean it up.

A one-gallon splash of AvGas in a full tank of pump gas will impregnate/lubricate the OEM iron seats with lead for a good ~25 hours of run time (ie 1 gal per 25 hours will minimize the possibility of your seats getting pounded in).

LO
 

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come on wags a few "small" pits on a otherwise good seat is not the same as a wornout one :(:( :)coffee roger you will be fine .
I know. I was just ball bustin'.

I am not afraid to install seats. If they tap in with a small hammer, that will be an issue. :D

I think GN hit the nail on th ehead. Install oversize valves.

I also agree it is not wise to sink tons of cash into stock heads. Good for the machinist, bad for the customer in the long run.
Wags
 
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