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Good way to estimate how much to mill an intake? #1063429 08/26/11 01:39 PM 08/26/11 01:39 PM
Joined: Jan 2003 Posts: 15,439 Val-haul-ass... eventually B BradH OP Taking time off to work on my car
BradH OP Taking time off to work on my car B Joined: Jan 2003 Posts: 15,439 Val-haul-ass... eventually	What have you found to be a good way to estimate how much to mill an intake manifold? In some cases I've been able to use different thicknesses of gaskets to figure out how much should be cut, but this is a little different. The intake is uncut and will barely fit (i.e. allow the bolts to be installed) the block / head combination even w/o any gaskets 'tween the heads and intake. Looking down both the bolt holes and the manifold runners shows the intake is obviously shifted up too high. Given the cost to mill the intake, it will quickly become "cost ineffective" to guess-timate cutting off XXX, fitting it up again and sending it back again to the shop for another round of machining. So, any suggestions on coming up w/ a fairly accurate measurement for an initial (and hopefully only) cut is appreciated. - Brad

Re: Good way to estimate how much to mill an intake? [Re: BradH] #1063430 08/26/11 01:46 PM 08/26/11 01:46 PM
Joined: Nov 2003 Posts: 5,160 Texas dannysbee master
dannysbee master Joined: Nov 2003 Posts: 5,160 Texas	Sorry Brad I can't help you but now might be a good time to answer a question I have as well. Would it be better to cut the heads or the intake? You have to make two cuts on the intake so it should not be any more expensive to cut both heads. Getting old just means you were smarter than some and luckier than others.

Re: Good way to estimate how much to mill an intake? [Re: BradH] #1063431 08/26/11 01:50 PM 08/26/11 01:50 PM
Joined: Mar 2005 Posts: 1,581 N/E, Michigan RATTRAP pro stock
RATTRAP pro stock Joined: Mar 2005 Posts: 1,581 N/E, Michigan	It should be a simple right angle trig equation, u know the angle of the heads,now measure the distance it is off from the hole. now u have 1 leg of the triangle and a angle, u should be able to figure it out from there.as in the post below account for the gasket and crush

Re: Good way to estimate how much to mill an intake? [Re: BradH] #1063432 08/26/11 01:53 PM 08/26/11 01:53 PM
Joined: Jul 2010 Posts: 2,091 Delray beach, Florida P Performance Only top fuel
Performance Only top fuel P Joined: Jul 2010 Posts: 2,091 Delray beach, Florida	if you have half a bolt hole showing with no gaskets, shim it up until you are covering the bolt hole. you'll need to cut that amount plus 80%-85% of the thickness of the gasket you intend to run. machine shop owner and engine builder

Re: Good way to estimate how much to mill an intake? [Re: Performance Only] #1063433 08/26/11 02:19 PM 08/26/11 02:19 PM
Joined: Mar 2008 Posts: 553 Kentucky clovis mopar
clovis mopar Joined: Mar 2008 Posts: 553 Kentucky	Just went through the same. I could not get the intake between the heads. I wound up putting extra head gaskets on until I got the intake to fit. Once I knew the deck increase needed to make it fit, I calculated the intake cut. So in my case, it took two extra gaskets .040 (each), .080 total to make it fit without a gasket. I took the .080 x 1.23 to get .0984 or basically .100. I wanted to use a .060 intake gasket, so by the math I needed .160 total-I decided to just go .150. Since the heads had been milled and the intake side had never been cut, I cut the intake side of the head .050, and then I cut the intake itself .100. Everything fit perfectly with the gasket after the cut. All the bolts run in by hand. '75 Plymouth Duster Phase I 451 906/590/2-660 10.75/126 Phase II 451 Stage VI/590/1050 9.82/135 Phase III 383 906/Victor-Pump gas 11.30/119 "For by grace you have been saved through faith. And this is not your own doing; it is the gift of God,"

Re: Good way to estimate how much to mill an intake? [Re: Performance Only] #1063434 08/26/11 02:38 PM 08/26/11 02:38 PM
Joined: Oct 2003 Posts: 7,506 Az Crizila master
Crizila master Joined: Oct 2003 Posts: 7,506 Az	Quote: if you have half a bolt hole showing with no gaskets, shim it up until you are covering the bolt hole. you'll need to cut that amount plus 80%-85% of the thickness of the gasket you intend to run. Do you mean shim up the manifold until the bolt hole in the head is centered on the manifold bolt hole? Fastest 300

Re: Good way to estimate how much to mill an intake? [Re: Crizila] #1063435 08/26/11 04:21 PM 08/26/11 04:21 PM
Joined: Jul 2010 Posts: 2,091 Delray beach, Florida P Performance Only top fuel
Performance Only top fuel P Joined: Jul 2010 Posts: 2,091 Delray beach, Florida	Quote: Quote: if you have half a bolt hole showing with no gaskets, shim it up until you are covering the bolt hole. you'll need to cut that amount plus 80%-85% of the thickness of the gasket you intend to run. Do you mean shim up the manifold until the bolt hole in the head is centered on the manifold bolt hole? no, the problem is that his manifold sits to high. by how much he didn't really say. but if half of the bolt hole in the head is all that shows, he can raise the intake with shims or gaskets until it's raised an equal amount. then use that thickness to decide how much to cut so the manifold sits down lower afterwards. machine shop owner and engine builder

Re: Good way to estimate how much to mill an intake? [Re: Performance Only] #1063436 08/26/11 04:39 PM 08/26/11 04:39 PM
Joined: Oct 2003 Posts: 1,170 Westbury, NY B bumps440 super gas
bumps440 super gas B Joined: Oct 2003 Posts: 1,170 Westbury, NY	IMO it is always better to cut the cylinder heads. that way the manifold remains universal and can be used on any other head and engine combination. if you cut the manifold you are limiting it to be used ONLY with that engine. For every .010 taken off the deck surface .012 needs to be removed from the manifold surface.

Re: Good way to estimate how much to mill an intake? [Re: BradH] #1063437 08/26/11 05:57 PM 08/26/11 05:57 PM
Joined: Jan 2003 Posts: 15,439 Val-haul-ass... eventually B BradH OP Taking time off to work on my car
BradH OP Taking time off to work on my car B Joined: Jan 2003 Posts: 15,439 Val-haul-ass... eventually	Thanks for the input.

Re: Good way to estimate how much to mill an intake? [Re: BradH] #1063438 08/26/11 06:18 PM 08/26/11 06:18 PM
Joined: Nov 2009 Posts: 2,177 ill D dennismopar73 top fuel
dennismopar73 top fuel D Joined: Nov 2009 Posts: 2,177 ill	idono, i put intake on dry, then take feeler gauge front to back, side to side, top to bottom, then go to my machinist, he cuts it i put it on, done

Re: Good way to estimate how much to mill an intake? [Re: Performance Only] #1063439 08/26/11 06:41 PM 08/26/11 06:41 PM
Joined: Oct 2003 Posts: 7,506 Az Crizila master
Crizila master Joined: Oct 2003 Posts: 7,506 Az	Quote: Quote: Quote: if you have half a bolt hole showing with no gaskets, shim it up until you are covering the bolt hole. you'll need to cut that amount plus 80%-85% of the thickness of the gasket you intend to run. Do you mean shim up the manifold until the bolt hole in the head is centered on the manifold bolt hole? no, the problem is that his manifold sits to high. by how much he didn't really say. but if half of the bolt hole in the head is all that shows, he can raise the intake with shims or gaskets until it's raised an equal amount. then use that thickness to decide how much to cut so the manifold sits down lower afterwards. Got it. Thanks. I was looking at it backwords. Fastest 300

Re: Good way to estimate how much to mill an intake? [Re: bumps440] #1063440 08/26/11 08:23 PM 08/26/11 08:23 PM
Joined: Oct 2007 Posts: 4,206 New York polyspheric master
polyspheric master Joined: Oct 2007 Posts: 4,206 New York	For every .010 taken off the deck surface .012 needs to be removed from the manifold surface. Depends on which engine... Read more in my article here: http://victorylibrary.com/mopar/intake-mill.htm Boffin Emeritus

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