Making an intake work on heads that have been milled alot
08-28-2003, 11:34 AM
#1
Making an intake work on heads that have been milled alot Hey all,
jmX and I found that the two brass bolt locators on the underside of the intake (one on each left end of each bank) can interfere with the hole in the heads that they are supposed to sit in if the heads have been milled enough.
I the case of our heads/intake, the plastic that surrounds the other 8 bolts was not an issue. Just the two metal gold colored locators.
We dremmeled about 1mm off of the outside edge of the locator. Because we ere going to create lots of shavings, we stuffed the intake ports and did a very VERY thorough cleanup afterwards. That metal, whatever it is, is very hard stuff.
With the two metal locators "clearanced" we were able to (with a teenie bit of pressure) urge the intake flush onto the heads.
As to whether the approximately .050-.070 " it takes to mill the heads before you see this issue has caused the intake ports to seriously miss ligning up with the head ports, Im not sure yet. I suspect there is a very small (~.050") lip now near the injector. I'll mess with that at a later date.
I couldnt find this info on the board....so here it is.
chris
jmX and I found that the two brass bolt locators on the underside of the intake (one on each left end of each bank) can interfere with the hole in the heads that they are supposed to sit in if the heads have been milled enough.
I the case of our heads/intake, the plastic that surrounds the other 8 bolts was not an issue. Just the two metal gold colored locators.
We dremmeled about 1mm off of the outside edge of the locator. Because we ere going to create lots of shavings, we stuffed the intake ports and did a very VERY thorough cleanup afterwards. That metal, whatever it is, is very hard stuff.
With the two metal locators "clearanced" we were able to (with a teenie bit of pressure) urge the intake flush onto the heads.
As to whether the approximately .050-.070 " it takes to mill the heads before you see this issue has caused the intake ports to seriously miss ligning up with the head ports, Im not sure yet. I suspect there is a very small (~.050") lip now near the injector. I'll mess with that at a later date.
I couldnt find this info on the board....so here it is.
chris
08-28-2003, 12:17 PM
#2
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Re: Making an intake work on heads that have been milled alot yeh - i heard you are also supposed to take some material off the diameter of the alignment pins too...SDPC will sell you machined intake alighment pins if you ask...
...my heads were milled .055. i did not need to do any intake pin shaving, however ..some do, some don't at this milling depth...
my CR is 11.4 now.... the new heads eliminated the raspy-ness of my axhaust note - cool; right? i also get better mileage now...
...my heads were milled .055. i did not need to do any intake pin shaving, however ..some do, some don't at this milling depth...
my CR is 11.4 now.... the new heads eliminated the raspy-ness of my axhaust note - cool; right? i also get better mileage now...
07-20-2007, 09:47 PM
#6
I know this won't work for an LS1 but for general information. For a small block Chevy with 23 degree heads the formula is .0123" for every .010" of the head removed. So if the head was milled .050" with no other changes you would remove .0615" from the intake manifold.
The bottom portion of the intake manifold is .0173" for every .010" removed. So you would remove .0865" for a head that was milled .050". There are probably some formulas floating around for the LS1.
The bottom portion of the intake manifold is .0173" for every .010" removed. So you would remove .0865" for a head that was milled .050". There are probably some formulas floating around for the LS1.
