My spare cylinder head is at the machine shop getting ported and polished in preparation for my stage 2 build. The machinist convinced me to shave down the head a few thousands of an inch or gain a higher compression ratio. This is good also, but I think the head needed it anyway because I dont want the HG to blow and it had some nasty grooves in it. Any info on how much of a good/bad idea that was?

95 Eclipse GS: 10.5:1, Crower 2's and MSII
186 WHP - 150 WTQ
14.697 @ 93.85 MPH......Gone, but not forgotten
99 420A Avenger: Given to my sister
99 GS OZ: Sold
03 Evo 8: Family Car with balls

My DOHC swapped Neon was like that.

I had it milled .030 which should have netted a 10.3ish CR.

EDIT: I just searched the info I used on Neons.org, ended up finding something better:

milling .060 = one compression point, .030, half a point, .015 = 1/4 point
So that would be like from 9.6 to 1........... milled .015 around 9.8 to 1 or just a little bit over, between 9.8 and 9.9 to 1 compression going by the cylinder bore size.

-Eddy Fierro

You'll be okay, if there were some heavy gouges in the mating surface it was probably a good idea to get this done. Just keep an eye on things when you get ready to set the timing on the motor. Rule of thumb would be to find TDC and remark your cam gears, they shouldn't be off by much but you'll want to take this into account.

I contributed to the Wiki.

Ok cool thanks guys. I was thinking if the cam gears are off too far that it bothers me I could just get adjustable cam gears. Ill probably post up what he milled when I get it back.

95 Eclipse GS: 10.5:1, Crower 2's and MSII
186 WHP - 150 WTQ
14.697 @ 93.85 MPH......Gone, but not forgotten
99 420A Avenger: Given to my sister
99 GS OZ: Sold
03 Evo 8: Family Car with balls

I just picked up the head and it looks awesome. Although he told me he only milled it about 8-10 thousandths.

95 Eclipse GS: 10.5:1, Crower 2's and MSII
186 WHP - 150 WTQ
14.697 @ 93.85 MPH......Gone, but not forgotten
99 420A Avenger: Given to my sister
99 GS OZ: Sold
03 Evo 8: Family Car with balls

looks purdy, although I'm surprised that the intake ports look more polished than the exhaust. I was always told that you want things slightly rougher in the intake to prevent fuel from sticking to the walls and puddling. Whereas the exhaust should be polished to prevent carbom buildup.

I could be wrong.

Erik P.
Official 2GNT thread Hijacker
Some say that he's driven over more Covenant than he's shot, and that his grenades aren't where you'd expect them to be...
All we know is, He's not The Stig... But he is The Stig's Spartan cousin!

Im not sure. All I know is this guy has a top fuel dragster and is pretty much he best machinist in my city. Everyone who does any kind of work brings it to him, so I trust his decisions. It goes on this weekend and Ill let you know the results.

95 Eclipse GS: 10.5:1, Crower 2's and MSII
186 WHP - 150 WTQ
14.697 @ 93.85 MPH......Gone, but not forgotten
99 420A Avenger: Given to my sister
99 GS OZ: Sold
03 Evo 8: Family Car with balls

Not sure, his name is Carl West. He has a shop up here in Ashtabula. I would ask around to see where to take stuff up by you. I just asked around and everyone said he was the best in town so I took it to him.

95 Eclipse GS: 10.5:1, Crower 2's and MSII
186 WHP - 150 WTQ
14.697 @ 93.85 MPH......Gone, but not forgotten
99 420A Avenger: Given to my sister
99 GS OZ: Sold
03 Evo 8: Family Car with balls

What you will find with .008-.010" is about a 1/2 tooth off on the cam gears. That is about 2* on my Fidanza cam gears.

My Blog

I had my head shaved .080 and block .011 with wiseco 10.5:1 and love it. Getting 225 across the board with 1500 miles on fresh rebuild. However, I also went to OBX adjustable cam gears, which makes timing EASY

Captain Caveman

96 RS Turbo 11.414 @ 119.62 MSNS, Crower 2 NA cams, BW366, 10.5 comp, UDP, 60mm TB, W/A intercooler, 3.55 tranny 567.9whp 430tq
97 RS NA 13.188 @ 103.87 MSnS powered 12.5 comp, Crower 3's and 219.4whp with 175tq
98 RS DD 12.5 comp on stock ECU, LTH, Crower 2's, Koni, GC, Hypercoil, DG hats
99 OZ 5sp Stocker 15.856 @ 85.97
99 GS stocker auto 17.7@77mph!

wiki home page:http://www.2gnt.com/index.php?d=bullettdsm

Lol. Its a high comp all motor build. Had the shaving and honing done by Benny Cranes in Abilene, TX. Guy has been doing it for over 25 years and told me that he could take 8 thousandths off the head and 11 thousandths off the block VERY MOST. He also mentioned before I left that I had no room for error in timing or I would introduce the pistons the the valves.

so you had 0.008 taken off, not 0.080.

0.080 is eighty thousandths and not likely that you had that removed.

---

2012 2500HD LML

Classic power of ten error And the valves?

"Tutto fa brodo."

Todd Scungio
98 RS
15.173 @ 90.70 MPH

And also a 2011 Ralliart

Originally posted by VX100
Classic power of ten error And the valves?

Captain Caveman

96 RS Turbo 11.414 @ 119.62 MSNS, Crower 2 NA cams, BW366, 10.5 comp, UDP, 60mm TB, W/A intercooler, 3.55 tranny 567.9whp 430tq
97 RS NA 13.188 @ 103.87 MSnS powered 12.5 comp, Crower 3's and 219.4whp with 175tq
98 RS DD 12.5 comp on stock ECU, LTH, Crower 2's, Koni, GC, Hypercoil, DG hats
99 OZ 5sp Stocker 15.856 @ 85.97
99 GS stocker auto 17.7@77mph!

wiki home page:http://www.2gnt.com/index.php?d=bullettdsm

I see. Yes, my mistake for being off on the numbers. But that IS what I had taken off and the car is still running like a champ

How high can you get away with in terms of milling the head on a 420a n/a motor to get a higher compression ratio, and what ratio it can be at and still use 91 and 93 octane and not crunch valves.