INTERNAL ENGINE MODIFICATIONS Valvetrain |Heads | Strokers | Design | Assembly

243 milled 59cc...cr ? lq4

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Old Jun 10, 2010 | 02:12 PM
  #21  
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Originally Posted by Tootall
umha . . . that's a negative . . .

If you're getting your heads milled, the head side is the only side that gets milled.
Uhm, no your comment is a negative. For minor milling you can get away with just touching the deck surface of the heads. For severe milling such as being discussed here, you're going to run into issues with the intake manifold port alignment being proper. The only way to rectify it properly is to mill the intake port side of the head the same amount as the heads have been milled. This brings your geometry back to where it should be and your intake will fit as good as stock. Make sense?
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Old Jun 10, 2010 | 02:40 PM
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Originally Posted by fastrt
I cut .050" off my 862's. had a couple braket issues, but no big deal. had to bolt the intake down nice and slow, and in a circle pattern, then tq to spec. depending on the cc of a lq4 piston, it's either 10.75-10.8 to 1.
what were that bracket issues you had? and was there any real issues with the intake fitment you could tell, or did it fit good and you just were extra carefull with the bolting down?
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Old Jun 10, 2010 | 02:45 PM
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Originally Posted by hirdlej
Uhm, no your comment is a negative. For minor milling you can get away with just touching the deck surface of the heads. For severe milling such as being discussed here, you're going to run into issues with the intake manifold port alignment being proper. The only way to rectify it properly is to mill the intake port side of the head the same amount as the heads have been milled. This brings your geometry back to where it should be and your intake will fit as good as stock. Make sense?
what your saying makes sense, but im just not sure theirs going to be a "severe" miss port alignment with a .055 mill as long as the intake bolts line up decently..? anything much over that and im having my doubts, thats why i asked mostly..
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Old Jun 10, 2010 | 09:59 PM
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Originally Posted by hirdlej
For minor milling you can get away with just touching the deck surface of the heads. For severe milling such as being discussed here, you're going to run into issues with the intake manifold port alignment being proper. The only way to rectify it properly is to mill the intake port side of the head the same amount as the heads have been milled. This brings your geometry back to where it should be and your intake will fit as good as stock. Make sense?
This is the way that I've always understood it to be...
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Old Jun 11, 2010 | 12:45 AM
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Originally Posted by fastrt
I cut .050" off my 862's. had a couple braket issues, but no big deal. had to bolt the intake down nice and slow, and in a circle pattern, then tq to spec. depending on the cc of a lq4 piston, it's either 10.75-10.8 to 1.
thanks, and great info ppl keep it coming
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Old Jun 11, 2010 | 09:31 AM
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Are you guys cutting out the seats in these 862's and going to 2.0 valves?

Or are you studying under this guy? http://www.youtube.com/watch?v=Nlsf9AZbFEA

Last edited by MPFD; Jun 11, 2010 at 09:44 AM.
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Old Jun 11, 2010 | 10:33 AM
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Old Jun 11, 2010 | 11:47 AM
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Originally Posted by hirdlej
Uhm, no your comment is a negative. For minor milling you can get away with just touching the deck surface of the heads. For severe milling such as being discussed here, you're going to run into issues with the intake manifold port alignment being proper. The only way to rectify it properly is to mill the intake port side of the head the same amount as the heads have been milled. This brings your geometry back to where it should be and your intake will fit as good as stock. Make sense?
oha yeah it makes sense . . . but has anyone on here actually done that? I've only read about people suggesting it.

I have seen in person people getting away with .050 mill, with no issues. 50+ is when the intake starts to bolt down funny, then the valves will touch the bores (5.3 block), and then the holes on the alternator have to be elongated
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Old Jun 11, 2010 | 02:17 PM
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That's the problem, a lot of people don't do what they should. you should always check port alignment after milling a set of heads. You'd be surprised how much of a lip there is between where the intake manifold port and intake port of the head line up. This causes an obstruction of flow and turbulance. Next time one of you guys take your intake off your truck put some grease on your gaskets of your intake manifold then gently set it on your milled heads. Then remove the intake. You'll see the witness marks of the grease outlined around your intake ports. Now tell me how far it's off. Think of what you're missing out on by not having the intake side of your heads milled. That lip causes problems with smooth flow.
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Old Jun 11, 2010 | 02:31 PM
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I'll take this into consideration some day when I have my WCCH StageII 317's milled .035ish
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