# How much can i mill head down?

**URL:** https://forums.speedlife.net/t/how-much-can-i-mill-head-down/80603
**Category:** SON240sx Automotive
**Created:** [February 20, 2004, 3:11pm UTC](https://forums.speedlife.net/t/how-much-can-i-mill-head-down/80603 "2004-02-20T15:11:58Z")
**Posts on this page:** 4
**Page:** 1

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### Author: ![Sweet\_N\_SourSauce](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/sweet_n_soursauce/32/5490_2.png) [@Sweet\_N\_SourSauce](https://forums.speedlife.net/u/Sweet_N_SourSauce)
#### Post date: [February 20, 2004, 3:11pm UTC](https://forums.speedlife.net/t/how-much-can-i-mill-head-down/80603/1 "2004-02-20T15:11:58Z")

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Hey, anybody know how much i can mill a KAE head down? I was thinking that since i need to pull it and resurface the new one, why not bump the compression a bit. Any ideas will be helpful.

Thanks

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### Author: ![AnDrEw](https://avatars.discourse-cdn.com/v4/letter/a/f19dbf/32.png) [@AnDrEw](https://forums.speedlife.net/u/AnDrEw)
#### Post date: [February 20, 2004, 4:25pm UTC](https://forums.speedlife.net/t/how-much-can-i-mill-head-down/80603/2 "2004-02-20T16:25:24Z")

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good thread on milling head : [http://www.nissaninfiniticlub.net/forums/showthread.php?s=582b876e1d527e3419b5cb843412800d&threadid=20611&highlight=shaved+head](http://www.nissaninfiniticlub.net/forums/showthread.php?s=582b876e1d527e3419b5cb843412800d&threadid=20611&highlight=shaved+head)

I forget exact numbers, but I was going to take 1mm off and didn’t. You can take like 1.5mm I think comfortably I believe. Read that thread tho, someone said how much you can go before pistons hit the valves.

EDIT: 1mm shave will get you 9.25:1 compression, I think highest you can get is 11:1 from shaving.

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### Author: ![Sweet\_N\_SourSauce](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/sweet_n_soursauce/32/5490_2.png) [@Sweet\_N\_SourSauce](https://forums.speedlife.net/u/Sweet_N_SourSauce)
#### Post date: [February 20, 2004, 9:22pm UTC](https://forums.speedlife.net/t/how-much-can-i-mill-head-down/80603/3 "2004-02-20T21:22:36Z")

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Philip thanks! I was discussing with my mechanic about the engine type and we didn’t think it was an interferance engine, i guess i’ll just go by nissan specs then.

Thanks again

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### Author: ![AnDrEw](https://avatars.discourse-cdn.com/v4/letter/a/f19dbf/32.png) [@AnDrEw](https://forums.speedlife.net/u/AnDrEw)
#### Post date: [February 21, 2004, 6:25am UTC](https://forums.speedlife.net/t/how-much-can-i-mill-head-down/80603/4 "2004-02-21T06:25:32Z")

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> [@FrEaK](#):
>
> [quote=AnDrEw]EDIT: 1mm shave will get you 9.25:1 compression, I think highest you can get is 11:1 from shaving.

There is a chemical engineer with a SOHC honda running classified compression levels using a race mixture he himself designed… it’s said to be about 12:1[/quote]  
Your kiding me right?

Anyways, I didn’t read FSM, but there many people in states shaving the head to get higher compression on our engines. There is even a company that rebuilds them and bumps compression to 11:1 for you through shaving.

If your going to run higher compression, milling and pistons combo is a better method. If you just want to bump it a little like I was, I doubt the 1mm shave would hurt anything at all.

Your call, might as well experiment if your going to be droping another engine in anyways 😃

Anyway, hope everything works out ok.

Andrew.