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Discussion Starter · #1 ·
How much work is it to install +1mm valves in a D16Y7 head? Does it require new seats? Do they even have seats? Or is it just a simple oversize hone and open up the ports?
 

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I don't know the answer to your question, but it does beg the question why not a Z6 or Y8 head?
 

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Discussion Starter · #3 ·
Because I own a Y7, and it's already ported, and I already have a big cam for it, and I prefer non-VTEC! I don't need a low-lift cam profile, I want it big all the time!
 

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You have to machine the seats to accommodate the new valves, and open up the ports as well.
This is a precision job requiring precision tools and knowledge, so get a shop knowing how, to do it.
The valve job is important in the quest for horsepower, so don't skimp on it.
 

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Discussion Starter · #5 ·
I have asked a shop, and they asked me if I knew if the seats would need to be replaced. Anyone know?
 

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i wouldn't do it...was going to get 1mm oversize myself but decided against ..it can actually choke up the motor if everything is not right..more valve shrouding for starters...money better spent getting a performance valve job instead
 

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I am interested in that too. Do you have to replace the valve seats with 1mm oversize or just to bore the valve seals for 1mm and cut the new angels.

Thanks!
 

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Replace valve seats? No... The valve seats are a part of the head...
Bore valve seals? The valve stem is still the same thickness...

I don't quite get what you guys are asking about here...
I think you should take a look at what it actually looks like, before asking questions like this.
 

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I know that the valve seats are the part of the head but I saw that it can be changed. With bore the valve seats, I meant that you enlarge the iner diameter whitch is now for example 26mm.... and after it will be 27mm.
 

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Discussion Starter · #10 ·
I haven't looked at the seats (my head is on the car!). Are the seats removable, or just part of the head?
 

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1996 Civic Type DX
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Yes, the valve seats have to be replaced. They are seperate from the head casting.

I wouldn't go oversized unless you are big bore. Shrouding.
 

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I have +1mm Ferrea Valves, my valve seals are stock and I have no problems with the setup
 

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I ment to go with 78mm bore.... So it is good to raplace the valve seals.

The valve seats are just the metal rings which are pressed into the head. They must be bored out and then you can press the new one.

But thanks for the info eg4, so the stock seals works for you, but how did you do the angel job? Is it OK? How high you rev your engine?
 

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An local engine shop(germany) did the valve job. They said its no problem with the Honda valve seals. I rev to 7500rpm and had no problem, till an valve spring was broken. But the engine is running soon again. Only one valve was damaged
 

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I can belive it. Me to! I have the dartons sleeves, but mow I must fine someone to install them for me . I am from Europe (Slovenia). :p
 

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I have also some parts for my head Crower cam (stage 3), crower springs and retainers, now I am looking to by ferrea valves +1mm. And then build my head.
 

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You can use the stock seats, but theres no point in going oversized if you can't do a good valve job (which is why you put new seats in).

Valve seals are not a problem. Just replace them when you do the build.
 
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