Would you mill an ecotec head? - Cobalt SS Network

ADVANCED Performance Modifications For advanced modification topics only.

Would you mill an ecotec head?

Old 06-30-2015, 03:25 AM
  #1  
Senior Member
Thread Starter
iTrader: (4)
 
Join Date: 09-07-11
Location: Las Cruces, NM
Posts: 3,256
Thanked 113 Times in 103 Posts
Would you mill an ecotec head?

****'s getting real here, and I'm wondering about milling my head for an increase in compression instead of having some one-off pistons made. This is a common option for SBC builds. I'm doing this very thing on my 307X build for my Nova. Is this a viable option for this car? Why or why not? Is clearance going to become an issue? Looking for serious answers here, so Sl0wbaltSS GTFO.
Jesse is offline  
Old 06-30-2015, 06:32 AM
  #2  
Moderator
Platinum Member
Moderator
iTrader: (1)
 
Slowbalt2000's Avatar
 
Join Date: 05-15-11
Location: Livonia, MI
Posts: 24,385
Thanked 302 Times in 277 Posts
Measure the ptv clearance first, determine how much you can take off, then do it.
Slowbalt2000 is offline  
Old 06-30-2015, 07:43 AM
  #3  
Senior Member
iTrader: (6)
 
Join Date: 07-19-10
Location: Denver, Colorado
Posts: 22,320
Thanked 373 Times in 330 Posts
Would you mill an ecotec head?

Pretty sure you can get away with some. The guy on the top of this whp list for NA 2.2 power shaved his head irrc, I just can't recall his user name
ECaulk is offline  
Old 06-30-2015, 12:32 PM
  #4  
Senior Member
Thread Starter
iTrader: (4)
 
Join Date: 09-07-11
Location: Las Cruces, NM
Posts: 3,256
Thanked 113 Times in 103 Posts
Originally Posted by Slowbalt2000 View Post
Measure the ptv clearance first, determine how much you can take off, then do it.
But... but... I'm lazy! I really need to get a second car. This one can't be down more than a day.

Originally Posted by ECaulk View Post
Pretty sure you can get away with some. The guy on the top of this whp list for NA 2.2 power shaved his head irrc, I just can't recall his user name
I'm glad you said that. I looked at his old FCOTM and it was shaved .020" with the stage 2 comp cams(whatever those are) so I'd probably assume a stock set of cams would be fine. Shaving .020" would reduce combustion chamber size by a theoretical ~1.7cc. Good enough for me. I also have the liberty of owning HP Tuners and being able to make changes. Previous guy had an 06 with trifecta(barf).

I'd reeeeeeeeally like to take that top spot on the dyno list.
Jesse is offline  
Old 06-30-2015, 12:52 PM
  #5  
Senior Member
iTrader: (6)
 
Join Date: 07-19-10
Location: Denver, Colorado
Posts: 22,320
Thanked 373 Times in 330 Posts
Originally Posted by supernovanator View Post
But... but... I'm lazy! I really need to get a second car. This one can't be down more than a day.



I'm glad you said that. I looked at his old FCOTM and it was shaved .020" with the stage 2 comp cams(whatever those are) so I'd probably assume a stock set of cams would be fine. Shaving .020" would reduce combustion chamber size by a theoretical ~1.7cc. Good enough for me. I also have the liberty of owning HP Tuners and being able to make changes. Previous guy had an 06 with trifecta(barf).

I'd reeeeeeeeally like to take that top spot on the dyno list.
He also lived near Vince back when Vince was actually responsive and involved with the cobalt community
ECaulk is offline  
Old 06-30-2015, 01:09 PM
  #6  
Senior Member
iTrader: (2)
 
Join Date: 07-04-10
Location: Carol Stream, IL
Posts: 3,283
Thanked 62 Times in 50 Posts
You will need to compensate with a thicker head gasket. The tolerences are very minimal
Omiotek is offline  
Old 06-30-2015, 01:35 PM
  #7  
Senior Member
Thread Starter
iTrader: (4)
 
Join Date: 09-07-11
Location: Las Cruces, NM
Posts: 3,256
Thanked 113 Times in 103 Posts
Originally Posted by Omiotek View Post
You will need to compensate with a thicker head gasket. The tolerences are very minimal
That would kinda defeat the purpose of milling it. I wish I could just drop a few hundred bucks on a spare engine to build but 07-08 are just impossible to find, and when you do they are crazy overpriced
Jesse is offline  
Old 06-30-2015, 01:56 PM
  #8  
Slobodan Milošević
iTrader: (8)
 
07blackg5's Avatar
 
Join Date: 11-05-07
Location: Serbia
Posts: 5,822
Thanked 195 Times in 161 Posts
i got my complete block and head for 400 bucks

1800 miles on it haha
07blackg5 is offline  
Old 06-30-2015, 02:01 PM
  #9  
Senior Member
Thread Starter
iTrader: (4)
 
Join Date: 09-07-11
Location: Las Cruces, NM
Posts: 3,256
Thanked 113 Times in 103 Posts
Originally Posted by 07blackg5 View Post
i got my complete block and head for 400 bucks

1800 miles on it haha
There was one here with 236k miles for $850. I can't drop that much into a **** engine
Jesse is offline  
Old 06-30-2015, 02:06 PM
  #10  
Senior Member
 
Join Date: 04-23-12
Location: Texas
Posts: 2,215
Thanked 39 Times in 37 Posts
Originally Posted by supernovanator View Post
That would kinda defeat the purpose of milling it. I wish I could just drop a few hundred bucks on a spare engine to build but 07-08 are just impossible to find, and when you do they are crazy overpriced
that's what I was gonna say, why mill the head then compensate with a gasket?
Dipped_Cobalt is offline  
Old 06-30-2015, 03:07 PM
  #11  
Slobodan Milošević
iTrader: (8)
 
07blackg5's Avatar
 
Join Date: 11-05-07
Location: Serbia
Posts: 5,822
Thanked 195 Times in 161 Posts
Originally Posted by supernovanator View Post
There was one here with 236k miles for $850. I can't drop that much into a **** engine
oh wow. that's terrible
07blackg5 is offline  
Old 06-30-2015, 09:59 PM
  #12  
Moderator
Platinum Member
Moderator
iTrader: (1)
 
Slowbalt2000's Avatar
 
Join Date: 05-15-11
Location: Livonia, MI
Posts: 24,385
Thanked 302 Times in 277 Posts
dude look on car-part.com

i got a 42k mile le5 from a junkyard for less than $500 picked up
Slowbalt2000 is offline  
Old 06-30-2015, 09:59 PM
  #13  
Moderator
Platinum Member
Moderator
iTrader: (1)
 
Slowbalt2000's Avatar
 
Join Date: 05-15-11
Location: Livonia, MI
Posts: 24,385
Thanked 302 Times in 277 Posts
Originally Posted by supernovanator View Post
But... but... I'm lazy! I really need to get a second car. This one can't be down more than a day.



I'm glad you said that. I looked at his old FCOTM and it was shaved .020" with the stage 2 comp cams(whatever those are) so I'd probably assume a stock set of cams would be fine. Shaving .020" would reduce combustion chamber size by a theoretical ~1.7cc. Good enough for me. I also have the liberty of owning HP Tuners and being able to make changes. Previous guy had an 06 with trifecta(barf).

I'd reeeeeeeeally like to take that top spot on the dyno list.
swap to a manual that may give you a few hp hahaha
Slowbalt2000 is offline  
Old 06-30-2015, 10:06 PM
  #14  
Slobodan Milošević
iTrader: (8)
 
07blackg5's Avatar
 
Join Date: 11-05-07
Location: Serbia
Posts: 5,822
Thanked 195 Times in 161 Posts
Transmission delete. Weight reduction AND less drivetrain loss
07blackg5 is offline  
Old 06-30-2015, 10:18 PM
  #15  
Moderator
Platinum Member
Moderator
iTrader: (1)
 
Slowbalt2000's Avatar
 
Join Date: 05-15-11
Location: Livonia, MI
Posts: 24,385
Thanked 302 Times in 277 Posts
right lol
Slowbalt2000 is offline  
Old 06-30-2015, 10:20 PM
  #16  
Senior Member
Thread Starter
iTrader: (4)
 
Join Date: 09-07-11
Location: Las Cruces, NM
Posts: 3,256
Thanked 113 Times in 103 Posts
Originally Posted by Slowbalt2000 View Post
swap to a manual that may give you a few hp hahaha
Nah I like my auto. Hoping some rpf1's and light tires will free up a few HP.

Originally Posted by 07blackg5 View Post
Transmission delete. Weight reduction AND less drivetrain loss
Lol maybe you can convince Cobe or sl0wbaltSS of that.
Jesse is offline  
Old 06-30-2015, 10:35 PM
  #17  
Slobodan Milošević
iTrader: (8)
 
07blackg5's Avatar
 
Join Date: 11-05-07
Location: Serbia
Posts: 5,822
Thanked 195 Times in 161 Posts
Will 14s clear our front brakes? The 14x7 Rpf1 are like 8.6lbs or something
07blackg5 is offline  
Old 06-30-2015, 11:02 PM
  #18  
Senior Member
Thread Starter
iTrader: (4)
 
Join Date: 09-07-11
Location: Las Cruces, NM
Posts: 3,256
Thanked 113 Times in 103 Posts
Originally Posted by 07blackg5 View Post
Will 14s clear our front brakes? The 14x7 Rpf1 are like 8.6lbs or something
Idk. Was looking at the 15s. 9.9lbs and some 17lbs tires. My brake rotors are 10.8" I think? I'm sure 14s would clear I just don't want them.
Jesse is offline  
Old 06-30-2015, 11:02 PM
  #19  
Senior Member
iTrader: (2)
 
Join Date: 07-04-10
Location: Carol Stream, IL
Posts: 3,283
Thanked 62 Times in 50 Posts
Originally Posted by Havok_Cobalt View Post
that's what I was gonna say, why mill the head then compensate with a gasket?
the point is you cannot deck the head a lot without compensating because the tolerences are already close. GM even specifies this. The heads are so cheap they are pretty much throw aways. You will run into issues with the timing chain and clearances else ware.

so you wont be decking it enough to gain any compression.
Omiotek is offline  
Old 07-01-2015, 01:46 AM
  #20  
Moderator
Platinum Member
Moderator
iTrader: (1)
 
Slowbalt2000's Avatar
 
Join Date: 05-15-11
Location: Livonia, MI
Posts: 24,385
Thanked 302 Times in 277 Posts
Like i said, measure it and do what you can. The tensioner should be able to compensate for .020 of difference...

I say at least measure it out and try it. I could maybe put a test motor together to see what stock ptv clearance is.
Slowbalt2000 is offline  
Old 07-01-2015, 03:03 AM
  #21  
Senior Member
Thread Starter
iTrader: (4)
 
Join Date: 09-07-11
Location: Las Cruces, NM
Posts: 3,256
Thanked 113 Times in 103 Posts
Originally Posted by Slowbalt2000 View Post
Like i said, measure it and do what you can. The tensioner should be able to compensate for .020 of difference...

I say at least measure it out and try it. I could maybe put a test motor together to see what stock ptv clearance is.
I'd feel bad for asking you to go through the trouble. My main concern is that I haven't done a cam change in this car before. SBC you can check PTV clearance easily by holding the piston TDC and rotating the cam. This engine is interference-style though and I can't do that.

Honestly though, I think I'm overthinking this. If you can buy cams that offer .05" more lift than stock then a stock cam should be just fine with a .02" shave. Plus it's been done before, with a larger than stock(comp stage 2 whatever the eff that is) cam. Sure, the 07+ cam is different but there's no way it's bigger than the 06-prior aftermarket cams.
Jesse is offline  
Old 07-01-2015, 04:02 AM
  #22  
Moderator
Platinum Member
Moderator
iTrader: (1)
 
Slowbalt2000's Avatar
 
Join Date: 05-15-11
Location: Livonia, MI
Posts: 24,385
Thanked 302 Times in 277 Posts
The 07 cams are actually the worst of all ecotec cams but thinking that just because aftermarket cams have higher lift doesnt mean they dont have a different ramp rate or duration. Still a good idea to measure it. But youll probably be fine.


My "test" motor is blown up in my garage so it wouldnt be super hard to do i just have to put it together.
Slowbalt2000 is offline  
Old 07-01-2015, 02:59 PM
  #23  
Senior Member
Thread Starter
iTrader: (4)
 
Join Date: 09-07-11
Location: Las Cruces, NM
Posts: 3,256
Thanked 113 Times in 103 Posts
Originally Posted by Slowbalt2000 View Post
The 07 cams are actually the worst of all ecotec cams but thinking that just because aftermarket cams have higher lift doesnt mean they dont have a different ramp rate or duration. Still a good idea to measure it. But youll probably be fine.


My "test" motor is blown up in my garage so it wouldnt be super hard to do i just have to put it together.
I emailed NWAE_Cobalt so we'll see what happens. Also made a mistake by forgetting the diameter of the combustion chambers. A .020" shave would reduce combustion chambers by 3cc, not 1.6cc which would put me close to 10.45:1. Maybe even tempted to go .030" which would get me to 10.7:1
Jesse is offline  
Old 07-01-2015, 08:15 PM
  #24  
Moderator
Platinum Member
Moderator
iTrader: (1)
 
Slowbalt2000's Avatar
 
Join Date: 05-15-11
Location: Livonia, MI
Posts: 24,385
Thanked 302 Times in 277 Posts
I guess we'll see
Slowbalt2000 is offline  
Old 07-01-2015, 11:45 PM
  #25  
Senior Member
Thread Starter
iTrader: (4)
 
Join Date: 09-07-11
Location: Las Cruces, NM
Posts: 3,256
Thanked 113 Times in 103 Posts
Well 07blackG5 just has to go and give me a great ******* offer on a set of stage 2 LSJ cams modded for the 07-08 L61... Maybe a spare bottom end is the way to go after all.
Jesse is offline  

Thread Tools
Search this Thread
Quick Reply: Would you mill an ecotec head?


Contact Us Archive Advertising Cookie Policy Privacy Statement Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.