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Intake Residue Question

oldkimmer said:
Talk to any machinest and see what they say. Of course we each have our own ways of doing things. Kim
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My machinist says cut the intake surface of the heads.... Think about it, why make an intake unusable with every other set of heads? So you do it and the parts get separated, now you have a set of heads floating around that won't seal to other intakes and an intake floating around that doesn't seal to most heads.... Brilliant!! Or you cut the intake side of the heads at the same time your cutting the head gasket surface and the heads can be bolted to any other block or intake with no issues.... Explain to me why you would want to do it the other way?
 
If a head is milled, the intake surface must also be milled to maintain the angle. If you mill an intake to match the heads, it is now dedicated ONLY to that engine with those heads.
 
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Road Grabber said:
That is a very good point. I remember the heads were surfaced but I don’t know if the shop removed material on the intake side when they did that.
I am changing heads and that could resolve the problem.
How would you “adjust” from there? Add gaskets?
Do you use paper intake gasket material for this test?
Click to expand...
I use a thin cork gasket material. The last gaskets I made was 1/16 gasket material. If the manifold ports are lower than the head ports a thicker gasket is needed and vice-versa. On thicker gaskets the floor and roof needs to be cut at an angle as the port face is not square with the port itself
 
Many years ago I had the heads milled .040 on my 1968 383 Magnum. I also had the intake surface milled on the heads, and it worked fine.
If you don't tell the machine shop to mill the intake surface, they probably won't do it. Then you may have fitment issues.
 
Mick56 said:
Many years ago I had the heads milled .040 on my 1968 383 Magnum. I also had the intake surface milled on the heads, and it worked fine.
If you don't tell the machine shop to mill the intake surface, they probably won't do it. Then you may have fitment issues.
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I am thinking that happened. The shop told the heads were cleaned up but most likely didn’t surface the intake side.
 
If an intake has been milled thicker gasket will allow it to fit. I've built motors with enough cut off the deck and/or heads that both the intake manifold and the intake side of the heads had to be cut. Sometime the head gets so thin there is nothing left to cut. Also if there has been a large deck cut on the block, it's a toss up. But in most cases cutting intake face of the head when cutting the head deck surface e makes the most sense.
Doug
 
dvw said:
If an intake has been milled thicker gasket will allow it to fit. I've built motors with enough cut off the deck and/or heads that both the intake manifold and the intake side of the heads had to be cut. Sometime the head gets so thin there is nothing left to cut. Also if there has been a large deck cut on the block, it's a toss up. But in most cases cutting intake face of the head when cutting the head deck surface e makes the most sense.
Doug
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Yes, if your cutting that much your gonna have to cut the intake too... But thats the exception not the rule... When your pushing the extremes for a race project you know some parts are gonna be useless when your done with them....

I agree, keeping the intake side cut on the head makes the most sense for the obvious reason of swap-ability of parts. But also from a machinists standpoint mounting a head for machining with it's two flat planes together is an easy task, mounting an intake to cut it is a bit more challenging, how do you hold it?
 
[QUOTE="1 Wild R/T, post: 911979649, member: mounting an intake to cut it is a bit more challenging, how do you hold it?[/QUOTE]
Mount it to a pivoting head plate. Then support the other side with jack's. Your correct time consuming to set up. I'm a rookie at matching. A couple of buddys set me up with their stuff.
Doug
 
dvw said:
[QUOTE="1 Wild R/T, post: 911979649, member: mounting an intake to cut it is a bit more challenging, how do you hold it?
Click to expand...
Mount it to a pivoting head plate. Then support the other side with jack's. Your correct time consuming to set up. I'm a rookie at matching. A couple of buddys set me up with their stuff.
Doug[/QUOTE]

Oh, I know how, just kinda pointing out it's not as easy or as solid as mounting a head...
 
1 Wild R/T said:
Though the years I've seen dozens of big block Mopars that sucked oil into the intake ports... They run fine, they just use a little oil... Three bond solves it... Period... Your welcome to thrown hundreds if not thousands of dollars at a machinist to try to correct it but a stamped steel bathtub isn't the best way to seal an intake.... And yes some folks use paper gaskets & other folks use a valley pan & separate gaskets... Well I use three bond.. Been doing it a very long time & it works... I won't be changing... And I'll continue to recommend it to others... I've never had someone actually try it & come back & tell me it didn't cure their problem...
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....I'd say you're 100 correct on the sealer sir....if applied by an expert like yourself. Many folks apply far too much, and the overhang of squeezed off extra could get pulled into the motor....
 
I think that most people that say "...just machine the intake...." don't fully understand what it really takes to do that right. Just because someone takes your money to mill your intake it does not mean they actully have the right equipment and that they will do it well. Milling the intake side of the head, easy peasy.

For all cylinder heads that I have done in the last 40 years, they all get at least 0.060" removed off the intake side, and maybe more, and use two paper gaskets on each side of the pan. Never use a sealant and never have a leak. I do use a little grease around the ports for quick and clean intake swaps on the dyno or at the track.
 
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BSB67 said:
I think that most people that say "...just machine the intake...." don't fully understand what it really takes to do that right. Just because someone takes your money to mill your intake it does not mean they actully have the right equipment and that they will do it well. Milling the intake side of the head, easy peasy.

For all cylinder heads that I have done in the last 40 years, they all get at least 0.060" removed off the intake side, and maybe more, and use two paper gaskets on each side of the pan. Never use a sealant and never have a leak. I do use a little grease around the ports for quick and clean intake swaps on the dyno or at the track.
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I had used two paper gaskets from the Felpro 6pack set. They are two thin gaskets. They worked great on my 6pack aluminum manifold but they must have been too much for the 383.
How do I check the fit of the gaskets to see if the ports line up and determine what thickness gaskets to use? Sorry if I didn’t pick that up somewhere else.. Do I use a new valley pan gasket for a test fit?
How do I know just steel, one gasket, two gasket, one thick , two thin…
I’d like to do this once….
Thank you
 
And then there's Edelbrock. I have four of them out in the stash from different years of production, and the angles and thickness of the sealing rails are/were all over the place from the factory, top to bottom, side to side, and front to back. Some fit 'okay' and some fit like ****, regardless of the block/head combo. So sometimes you end up needing to mill the manifold as well to get a precise fit.
Just like neat little snowflakes, every one's different...
 
If you would test fit the manifold, without any gaskets, with some grease applied on the faces you could leave a "print" on the cylinder heads flanges.
In a good fitment case they should show that the manifold sits a little low, adding the valley pan and a single gasket on the manifold side will narrow the V-angle in raise the installation height of the manifold.

Other option is install the manifold as normal and perform a pressure test on the intake and use soapy water to detect any air leaks.
Just have to loosen the valve train/rocker shafts to ensure all valves are closed and apply approx..5 psi on the manifold with a block off plate on the carb flange.

Tighten the manifold bolt in stages and work from the center to the outer bolts.
 
Wietse said:
If you would test fit the manifold, without any gaskets, with some grease applied on the faces you could leave a "print" on the cylinder heads flanges.
In a good fitment case they should show that the manifold sits a little low, adding the valley pan and a single gasket on the manifold side will narrow the V-angle in raise the installation height of the manifold.

Other option is install the manifold as normal and perform a pressure test on the intake and use soapy water to detect any air leaks.
Just have to loosen the valve train/rocker shafts to ensure all valves are closed and apply approx..5 psi on the manifold with a block off plate on the carb flange.

Tighten the manifold bolt in stages and work from the center to the outer bolts.
Click to expand...

Thank you. Really appreciate that reply. I like the carb plate idea. I have to scout out some material.
Would this require using a fresh gasket after the test? Leaving no stone unturned here…
 
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