FE Power Forums
FE Power Forums => FE Technical Forum => Topic started by: 482supersnake on September 20, 2023, 06:37:43 PM
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I'm finally assembling my 427 project and working on installing the intake manifold. It's a 427 SO block, Trick flow heads and a factory C6 PI intake. I set the intake on with some .060 thick intake gaskets and the valve cover rails sit way higher than the heads. I took the gaskets out and put the intake on and it sits perfectly flush with the heads now but it looks like the passenger side of the intake sits lower on the port than the drivers side. I'm guessing that the intake has been milled before.
So my question is, is there a thumb print on the intake face like heads have? I tried to take some measurements and it looks like the passenger side has been milled more than the drivers side. Or is there another way to check and see how much has been milled from the intake?
Scott
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Here is a drawing of a C6 and you could scale yours and compare.
(https://i.postimg.cc/9F020254/All-mixed-083.jpg)
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Thanks for the blueprint, unfortunately when I try and enlarge it to read the numbers it gets blurry and I can't read them.
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Bigger?
(https://i.postimg.cc/Wj619p57/All-mixed-083.jpg)
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A BHJ fixture can provide a reference for the machinist to measure and machine from. I don't own one, but Brent does, and one of the machine shops I use does, could talk to Brent about squaring your intake if you don't have someone local
Assuming decks are square and heads are the same, it has to be the intake's fault, and it's not uncommon to have to cut different amounts off each side.
You can maybe find a gasket that meets in the middle, but I would be concerned that the intake is not only tight, but crooked and thinner gaskets could fight you
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.......I'm guessing that the intake has been milled before.
If the intake had been milled it would sit lower not higher. Think I'd be looking harder for why it sits high. What's the gap between the intake and the valley rail? Do the TF heads have the same rail height as OE heads?
Thinner head gasket will have a minor affect in this direction but if the block and/or heads have been signifcantly decked, that will do it, but it would have to be a bunch.
Best,
Kelly
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This is not abnormal. As a matter of fact, I have to cut every intake on almost every build by the thickness of a gasket. It's also not abnormal for one side to sit differently than the other side.
If you have a borescope, you can check port alignment with the intake sitting on the heads with no gaskets. If the roofs of the ports line up, then I'd cut the intake flanges and bolt it on.
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This is not abnormal. As a matter of fact, I have to cut every intake on almost every build by the thickness of a gasket. It's also not abnormal for one side to sit differently than the other side. If you have a borescope, you can check port alignment with the intake sitting on the heads with no gaskets. If the roofs of the ports line up, then I'd cut the intake flanges and bolt it on.
Hmmmmm....seems pretty strange. Assuming the valve cover rails on TF heads are the same height as OE (are they?), then how did that OE intake ever fit anything? As a first order of business, I think I'd be checking how the mounting bolt holes line up with gasket installed and then the port roofs second. If the intake lands on the sides of the bolts before the intake seats...... that's no-good.
If the bolt holes and ports line up, you cut the VC rail height on the intake. If they don't, you cut the face of the intake until the holes line up, preferably with the intake holes sitting slightly high so they center when you pull the lid down. -Just me.
I suppose, if everything lined up great except the valve cover rail height, and you didn't want to cut your OE intake, and the valve cover rail height difference was relatively modest, you could just make up the height difference with a partial gasket under the full gasket. -Bring your gasket adhesive!
On other engines, milling a step in the intake face to accomodate the valve cover overlap is pretty common but FE intakes are unique with the shared valve cover rail feature.
Best,
Kelly
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This is not abnormal. As a matter of fact, I have to cut every intake on almost every build by the thickness of a gasket. It's also not abnormal for one side to sit differently than the other side. If you have a borescope, you can check port alignment with the intake sitting on the heads with no gaskets. If the roofs of the ports line up, then I'd cut the intake flanges and bolt it on.
Hmmmmm....seems pretty strange. Assuming the valve cover rails on TF heads are the same height as OE (are they?), then how did that OE intake ever fit anything? As a first order of business, I think I'd be checking how the mounting bolt holes line up with gasket installed and then the port roofs second. If the intake lands on the sides of the bolts before the intake seats...... that's no-good.
If the bolt holes and ports line up, you cut the VC rail height on the intake. If they don't, you cut the face of the intake until the holes line up, preferably with the intake holes sitting slightly high so they center when you pull the lid down. -Just me.
I suppose, if everything lined up great except the valve cover rail height, and you didn't want to cut your OE intake, and the valve cover rail height difference was relatively modest, you could just make up the height difference with a partial gasket under the full gasket. -Bring your gasket adhesive!
On other engines, milling a step in the intake face to accomodate the valve cover overlap is pretty common but FE intakes are unique with the shared valve cover rail feature.
Best,
Kelly
It's not abnormal because we normally have to cut the blocks to make sure they're straight and square and parallel to the crank. Factory FE block deck height is nominally 10.170". However, they're sometimes out .020" from front to back, side to side, etc., (even on aftermarket blocks that are new), so it makes the intake sit proud. It's not uncommon to end up at 10.145-10.150" even on brand new blocks due to manufacturing issues with them. It's certainly common to end up down there with factory blocks.
I've had situations where the valve cover rails just needed to be cut down, but it's been few and far between. It's most often cutting the intake flanges. Generally they will need at least clipped anyway, because they're not straight/flat after 50 years.
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I just ordered a inexpensive bore scope that should be here tomorrow so I can check the inside port alignment. I'll do some more checking in the meantime. I'm not sure how much the machine shop took of the decks of the block but I wouldn't think it was a lot. The intake bolts thread in fine with or without the gaskets. Local shop wants a couple hundred dollars to cut the flanges so I only want to do it once.
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I will echo what I said earlier and what Brent said, it's very common.
As far as how did the old builds work? Well they didn't always, or often people accepted pulling down the intake until the end 4 lined up, and if it all sealed, we pressed on. I can't imagine me in my youth test fitting an iron intake under the hood of a F350 and removing it after to have it cut, nor did the average machine shop have the ability to do it profitably. I'll even add that we had all kinds of tricks in the old days to find intake leaks, thank God I haven't had to deal with that in forever....It's common though for mismatch and I allow for machining in every build quote. Sometimes you can swap a gasket to get there, sometimes you can't. Sometimes they are crooked in every direction :o
I'd likely shim all 4 corners with feeler gauges until you get it where you want, then see what it tells you. Remember a 50+ yr old intake may not only fit poorly, it's likely not flat either
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No one has asked how much clearance between the bottom of the intake and the china wall. When cutting the sides, you move the distributor hole if they are not centered. That should be your first measurement. Drop the distributor in place and then measure the side clearances without the gaskets. Joe-JDC
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No one has asked how much clearance between the bottom of the intake and the china wall.
See third sentance of post #5. I just call them valley rails instead of China wall.
Brett builds engines for a living and I build them for fun so if he says it's not uncommon on an OE block, then I believe it, but if any block of mine were out of square .025" I wouldn't be building on that block because if the deck is out that far, where's everything else at dimensionally? I guess I'm fortunate that all my builds in the last 20 years have been on aftermarket blocks that needed to be finish machined anyway.
Besides, if we're only talking .020" in the extreme, the OP's opening post says "it (the intake) sits way higher than the heads".....not sure what that means to you but it would be something >>.020" to me. I wouldn't sweat .020" of mismatch on something as benign as a valve cover gasket, but the position of bolt holes and ports would likely follow. Sort of depends on how you value the intake, but I'd also think twice before cutting an intake to match (and potentially every other intake you might ever fit to that engine) unless it was truly the culprit responsible for the mismatch. Some of my lids have a lot of work into them and I value them highly.....thus my remark, I think I'd be looking for why it's way too high in the first place. -Different strokes for different folks I guess.
Best,
Kelly
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No one has asked how much clearance between the bottom of the intake and the china wall.
See third sentance of post #5. I just call them valley rails instead of China wall.
Brett builds engines for a living and I build them for fun so if he says it's not uncommon on an OE block, then I believe it, but if any block of mine were out of square .025" I wouldn't be building on that block because if the deck is out that far, where's everything else at dimensionally? I guess I'm fortunate that all my builds in the last 20 years have been on aftermarket blocks that needed to be finish machined anyway.
Besides, if we're only talking .020" in the extreme, the OP's opening post says "it (the intake) sits way higher than the heads".....not sure what that means to you but it would be something >>.020" to me. I wouldn't sweat .020" of mismatch on something as benign as a valve cover gasket, but the position of bolt holes and ports would likely follow. Sort of depends on how you value the intake, but I'd also think twice before cutting an intake to match (and potentially every other intake you might ever fit to that engine) unless it was truly the culprit responsible for the mismatch. Some of my lids have a lot of work into them and I value them highly.....thus my remark, I think I'd be looking for why it's way too high in the first place. -Different strokes for different folks I guess.
Best,
Kelly
Had to cut a brand new BBM block to 10.145" once because the decks were that out of whack.
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I guess some folks have a chip in their shoulder when questioned. I have just completed over 1130 pairs of cylinder heads and intake manifolds for folks around the world. I have worked with just about every Ford head and intake manifold ever cast, from Y's to Boss 429s and everything in between. When working with the C6AE-H/F Ford intakes, nearly every one of them sit proud if the heads have been milled. For any restoration/race engine/show car engine it would be better to mill the face of the head and leave the intake manifold alone. That way the engine could have several different intake manifolds tried without having to cut any of them to fit. JMO, but I would still center the distributor first and then measure everywhere before cutting that manifold. Joe-JDC
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I admit to regret for milling a rare vintage manifold to fit with milled heads, when I should have milled the intake face on the heads.
But like many, I was young and knew everything.
Now I am older and know far less... But it is frustrating trying to pry experienced knowledge out of people sometimes.
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Seems to be a camp for each side, but I’ve never cut a head before, I always cut the intakes.
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I had a chance to run a bore scope down the runners earlier today and as I thought without a gasket the drivers side sat perfect and the passenger side was a little low. The distributor sits pretty centered in the hole. The end rails have about .135 of clearance. Since the intake has been previously cut I'll have .060 taken of the drivers side and .040 off the passenger side.
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Had to cut a brand new BBM block to 10.145" once because the decks were that out of whack.
What was out of whack? BBM machined the block with a taper? How much?
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Had to cut a brand new BBM block to 10.145" once because the decks were that out of whack.
What was out of whack? BBM machined the block with a taper? How much?
The low spot was on the intake side of the deck if I remember right, been a few years back. It was off about .020". Had another block that needed a sleeve because of a porous spot. Had yet another that was porous to the outside of the block leading from an oil gallery. Nothing like priming the pump and watching oil appear on the outside of the block. Good times.