Milling heads
#1
Senior Member
True Car Nut
Thread Starter
![Default](https://www.gmforum.com/images/icons/icon1.gif)
I may be getting a set of L36 heads, and I'd like to know how much they can be milled before piston/valve contact is an issue. Can it be done or do I need to pick up some pistons that are either dished or have valve reliefs?
#2
Senior Member
True Car Nut
Join Date: Sep 2004
Location: Farmington, Minnesota =MWBF '05 SURVIVOR= =CEBF '06 SURVIVOR= =August '06 COTM=
Posts: 9,130
Likes: 0
Received 0 Likes
on
0 Posts
![LakevilleSSEi is on a distinguished road](https://www.gmforum.com/images/reputation/reputation_pos.gif)
![Default](https://www.gmforum.com/images/icons/icon1.gif)
For safety I don't think that I would go past .010 with stock pistons. Probably should have a machine shop look into that one for you.
#3
Senior Member
True Car Nut
Join Date: Jun 2003
Location: Purgatory
Posts: 6,313
Likes: 0
Received 0 Likes
on
0 Posts
![PontiacDad is on a distinguished road](https://www.gmforum.com/images/reputation/reputation_pos.gif)
![Default](https://www.gmforum.com/images/icons/icon1.gif)
You want to make them flat or up your compression? You could use thinner head gaskets if your heads are already true, save a few bucks? 10 thou is not unheard of btw.
#4
Senior Member
True Car Nut
Join Date: Sep 2004
Location: Farmington, Minnesota =MWBF '05 SURVIVOR= =CEBF '06 SURVIVOR= =August '06 COTM=
Posts: 9,130
Likes: 0
Received 0 Likes
on
0 Posts
![LakevilleSSEi is on a distinguished road](https://www.gmforum.com/images/reputation/reputation_pos.gif)
![Default](https://www.gmforum.com/images/icons/icon1.gif)
Originally Posted by PontiacDad
10 thou is not unheard of btw.
I'd imagine that he'* milling the heads to up the compression. But chances are the engine that he'* getting the heads off of has been overheated pretty good....so he may need some milling just to flatten them out.
#5
Senior Member
True Car Nut
Thread Starter
![Default](https://www.gmforum.com/images/icons/icon1.gif)
You're right on both counts, Nate. The heads may be warped, but even if they're not I'd like to get 'em milled for more compression. Is this a question better suited for Todd or Scott?
#6
Senior Member
True Car Nut
Join Date: Sep 2004
Location: Farmington, Minnesota =MWBF '05 SURVIVOR= =CEBF '06 SURVIVOR= =August '06 COTM=
Posts: 9,130
Likes: 0
Received 0 Likes
on
0 Posts
![LakevilleSSEi is on a distinguished road](https://www.gmforum.com/images/reputation/reputation_pos.gif)
![Default](https://www.gmforum.com/images/icons/icon1.gif)
I'd figure that Todd would know for sure. I'd say 20 thou before you need different pistons.
#7
Senior Member
True Car Nut
![Default](https://www.gmforum.com/images/icons/icon1.gif)
Check this out:
http://www.zzperformance.com/latest_news1.php?id=48
I'm guessing you can probably mill the heads 40 over with stock thickness head gaskets but i know you can mill 30 over with .052" headgaskets.(someone on clubgp is running it now) You will need 7.0" pushrods to keep correct valvetrain geometry.
http://www.zzperformance.com/latest_news1.php?id=48
I'm guessing you can probably mill the heads 40 over with stock thickness head gaskets but i know you can mill 30 over with .052" headgaskets.(someone on clubgp is running it now) You will need 7.0" pushrods to keep correct valvetrain geometry.
#9
Senior Member
True Car Nut
Join Date: Sep 2004
Location: Farmington, Minnesota =MWBF '05 SURVIVOR= =CEBF '06 SURVIVOR= =August '06 COTM=
Posts: 9,130
Likes: 0
Received 0 Likes
on
0 Posts
![LakevilleSSEi is on a distinguished road](https://www.gmforum.com/images/reputation/reputation_pos.gif)
![Default](https://www.gmforum.com/images/icons/icon1.gif)
Originally Posted by opensourceguy
Just be careful if you start messing with rockers and cams. You could run into the valve smacking the piston then ![Wink](https://www.gmforum.com/gm/images/smilies/wink.gif)
-justin
![Wink](https://www.gmforum.com/gm/images/smilies/wink.gif)
-justin