If I deck the block .025-.030, and Mill .006 off heads, What about the intake?
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If I deck the block .025-.030, and Mill .006 off heads, What about the intake?
Piston will sit .025 in the hole as it is. I'm going to deck the block to bring the piston .005 (decked .030) out of the hole. Heads will also be milled ~.006. (total -.036)
What needs to happen to the intake to make sure that the ports line back up correctly, and that the bolts will still screw straight into the heads?
This will bring the heads in closer togother. Is there enough elongation in the bolt holes of the intake to compensate?
Since the intake will now sit a tad bit higher on the engine/heads, do I just drop the floors of the intake ports .036? Do I need to have the intake milled as well?
What needs to happen to the intake to make sure that the ports line back up correctly, and that the bolts will still screw straight into the heads?
This will bring the heads in closer togother. Is there enough elongation in the bolt holes of the intake to compensate?
Since the intake will now sit a tad bit higher on the engine/heads, do I just drop the floors of the intake ports .036? Do I need to have the intake milled as well?
Last edited by Dave88LX; Jun 12, 2003 at 09:46 PM.
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Originally posted by JordonMusser
put the intake on, and look down the runners with a mirror.. if they line up, you are golden. may have to enlonggate the holes a little.
put the intake on, and look down the runners with a mirror.. if they line up, you are golden. may have to enlonggate the holes a little.
What about sealing the bottom of the intake in the front and the back, that won't be sitting as low and tight to eachother anymore either...could that lead to leaks?
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WHelp?
Page#2
http://www.corral.net/forums/showthr...5&pagenumber=2
Talking to kim on corral.net, this is what he suggested:
Page#2
http://www.corral.net/forums/showthr...5&pagenumber=2
Talking to kim on corral.net, this is what he suggested:
The difference will determine the intake alignment issues, you should be able to match up bolt holes with a little hole elongating.
But if your not wanting to port the heads, then have the intake sides milled enough to seat it on the head.
Throw the end rail seals away. Use an appropriate amount of RTV. Let the RTV cure for 5 to 7 minutes, then set the intake.
But if your not wanting to port the heads, then have the intake sides milled enough to seat it on the head.
Throw the end rail seals away. Use an appropriate amount of RTV. Let the RTV cure for 5 to 7 minutes, then set the intake.
As for the ports on the head, I hate gasket matching. People **** up good parts with poor processes. The intake pleunum to bowl (the area in the head right behind the valve) should be a continuous taper. People get these huge assed intake gaskets, they cut out the area at the head/intake interface. If they really do a good job, they get the taper back about a 1/2"... this "swell" in the intake runner causes eddies, fuel fall out, basically ruins what might have been a decent flowing combination.
As for the floor, ideally you would raise the port roof, and add a little epoxy to the floor. You want to get as straight a shot to the valve as possible, thus stay away from the port floor.
But your not going to use epoxy... so You can knock the ridge on the intake runner down a little. A seamless match is not important. Back yard perfection leaves the intake about .005 to .010 smaller than the head port. It will not hurt flow, the big no-no is do not have any head, or gasket protruding into the intake path.
As for the floor, ideally you would raise the port roof, and add a little epoxy to the floor. You want to get as straight a shot to the valve as possible, thus stay away from the port floor.
But your not going to use epoxy... so You can knock the ridge on the intake runner down a little. A seamless match is not important. Back yard perfection leaves the intake about .005 to .010 smaller than the head port. It will not hurt flow, the big no-no is do not have any head, or gasket protruding into the intake path.
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From: Lousiana
Hey
This is some info I got out of HPBooks "How to rebuild small block chevy Lt1/lt-4 engines"
Anything more than 0.020 and milling the intake will be needed. Corrective cuts on both the (intake to head) mating surface and the (intake to block surface). It says you can take from the intake or the block, doesn't matter. Her are the formulas.
Combustion deck removal amount x 1.2 = material to remove from the intake port.
Combustion deck removal amount x 1.7 = material to remove from the intake manifold rails, front and rear.
So for .036 total cut. 0.04 off the intake port sides and 0.06 off the front on rear intake rails and you should be good. I would have all the cuts done on the intake and not on the block and heads.
Jeff D.
This is some info I got out of HPBooks "How to rebuild small block chevy Lt1/lt-4 engines"
Anything more than 0.020 and milling the intake will be needed. Corrective cuts on both the (intake to head) mating surface and the (intake to block surface). It says you can take from the intake or the block, doesn't matter. Her are the formulas.
Combustion deck removal amount x 1.2 = material to remove from the intake port.
Combustion deck removal amount x 1.7 = material to remove from the intake manifold rails, front and rear.
So for .036 total cut. 0.04 off the intake port sides and 0.06 off the front on rear intake rails and you should be good. I would have all the cuts done on the intake and not on the block and heads.
Jeff D.
Last edited by PoorMan; Jun 13, 2003 at 12:34 AM.
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Damn Jeff great info thanks!!!!
That's off each side I'm assuming...so with that math.
Ports: .030 x 1.2 = .036 (That's intriquing!!!)
Rails: .030 x 1.7 = .051
I'm wondering what would be best to take it from...Surfacing my heads is going to be $40 for the pair, I'm wondering how much to grab the 2 intake sides, maybe another $40? Any guidance on what that should cost? Same with the block...Wonder which is better to yank it from, or cheaper LOL
Mo' money mo' money
Cubic $...
I need to grab that book!!!!
<---Searching Amazon.com
That's off each side I'm assuming...so with that math.
Ports: .030 x 1.2 = .036 (That's intriquing!!!)
Rails: .030 x 1.7 = .051
I'm wondering what would be best to take it from...Surfacing my heads is going to be $40 for the pair, I'm wondering how much to grab the 2 intake sides, maybe another $40? Any guidance on what that should cost? Same with the block...Wonder which is better to yank it from, or cheaper LOL
Mo' money mo' money
Cubic $...
I need to grab that book!!!!
<---Searching Amazon.com
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From: Lousiana
Any reason you left off the 0.006 from the head mill? Maybe I missed something. Anyway, where to cut? The manifold. I would take all the material off the four sides of the same part. The intake manifold is also the cheapest part to replace if need be. Here is the ISBN# for that book btw. 1-55788-393-9
Jeff D.
Jeff D.
Thread Starter
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Joined: Oct 2002
Posts: 2,168
From: AACO, MD
Any reason you left off the 0.006 from the head mill? Maybe I missed something. Anyway, where to cut? The manifold. I would take all the material off the four sides of the same part. The intake manifold is also the cheapest part to replace if need be. Here is the ISBN# for that book btw. 1-55788-393-9
Yeah, because I messed up my math...good catch!!
Did we overlook the head gasket thickness as well? What's the stock thickness on that? .059" I think? EDIT! D'Oh!!! It's .049", I have to change this math...
The stock gasket is .049, and I will be going .039, so do I have to add another .010 to the .036 for the multiplication I think?
.030 off the block
.010 off the head gasket (from a .059 to a .039)
.006 off the head
-------
.046 shorter?
Ports: .046 x 1.2 = .0552
Rails: .046 x 1.7 = .0782
One point someone else made is that the heads and block are already 'tainted' while the intake is unmolested in that aspect...but I don't plan on selling the intake anyways so...
Last edited by Dave88LX; Jun 13, 2003 at 10:24 AM.
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From: Lousiana
Ya' know I always wondered if the advertised gasket thickness is the crush thickness or not. I am assuming their is one. Anyway, I would take those last numbers and round down to the nearest hundredth. That should be good. So, 0.07 rails and 0.05 intake port. The other guy has a good point if the block was NOT decked. If you corrective cut the intake port side of the heads, the cut will not be matched to the heads chamber cut alone. You need the decked block for it to work. Just thinking of future modding and sale of parts. The heads will work great on any other stock engine without the corrective intake cuts. So it will be easier to sale them if you deceide on it in the future. The intake isn't worth $150. They are on eBay. The heads aren't worth much more stock but are easier to sale if unmolested. Basically, you have two chioces, mate the intake to the block, or mate the heads to the block. I say number one.
Jeff D.
Jeff D.
Last edited by PoorMan; Jun 13, 2003 at 12:46 PM.
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