As was said the valley would narrow if head/block mating area was milled. The only way the intake can be low is if the intake has been milled,or milled more, than the heads/block, unless some incredibly thick head gaskets were used & that doesn't seem likely. Any other Chr intakes around to compare? did you say the 2 bl intake isn't there? I have a number of intakes, but probably can't measure them accuratly enough for comparison.
Sorry George - I'm not convinced. The valley widens although you can argue not by much. The bolts holes get closer together. Maybe it's a terminology thing. In the pic - the thicker lines represent a starting point which includes a deck, valley and intake surface. If you look at the head section and imagine the exaggerated amount removed and then dropping the head straight down it seems clear that the intake surface has gotten further apart. What am I missing??
Nope valley narrows as the heads get closer together, that's why the intake gets milled when you mill the block/heads. Otherwise you'd have to add material to the intake if the heads moved away from each other inceasing the wigth of the valley.
If I understand your drawing, and notations thereto, your drawing and the conclusions you derive from it are in error. You are correct that the "head moves perpendicular to the block surface". But then you go on to show the manifold mating surface of the head dropping or lowering on a verticle line when the head moves closer to the block by quite alot. I submit it (the manifold mating surface of the head) would move toward the center of the car (narrowing the valley) at a much greater rate than it moves vertically..........thereby narrowing the valley. You could prove/disprove this pretty quickly using some paper/cardboard/wood cutouts simulating the real pieces of the engine as long as you maintain correct relationship angles of the surfaces involved and make a line or mark for the head locating dowel's position. Ray
Place your hands up in front of your face w/ finger tips pointed away from your face...then angle them as if they are the heads sitting on the engine blocks deck surface...Then drop your hands maintaining the same plane as if you milled the heads sitting on that same blocks deck surface.....and you will see what happens to the valley's new width and intake runners new position..........The heads on my last engine I had them shaved hard and I had to alter my intake as well.........Littleman
Sorry fellas, looks like I'm just gonna have to agree to disagree! In my earlier post I agreed that the BOLTS get closer together - no arguments there. However nothing has been said or illustrated to show the reasoning why the intake surface on the heads gets any closer together. Things do not work how we "want them to work" they work how they work! In this case it's easy to say the heads get closer together - heck we've all heard it a million times so it MUST BE TRUE - Right??? Nope - they get further apart - AND - the reason they get further apart is because the surface angle between the DECK SURFACE of the HEAD and the INTAKE SURFACE of the HEAD is LESS than 90 degrees. IF that surface was LARGER than 90 degrees then and ONLY then do those surfaces get closer together. IF that set of surfaces were 90 then there'd be NO CHANGE AT ALL. However in this arguement we're talking EARLY HEMIS & that surface is LESS than 90 degrees!!! I will stick to my original statements - 2 things happen: 1. The intake bolts get closer together. 2. The intake surface gets wider apart. I submit yet another sketch showing my reasoning. I encourage those saying I'm wrong to please sketch it up for me.
Hnstray, No where does my drawing show the head moving on a vertical line - it moves perpendicular or straight line towards the head - imagine it sliding down along the head bolts. As for the part where it "moves" the intake surface over -think about the LOWER (intake side) edge of the head - that corner "moves" to the RIGHT (in this illustration) as you remove material from the deck surface of the head. That exact point moves perpendicular to the head surface - THAT is why it is bigger. Put all your previous notions aside and just for a second pretend I might be right - follow the logic - think about the actual surfaces and their relative starting and finish points. I think it's all there. Better yet - cut out a piece of paper representing the head - sketch out the angles or just use the pic I provided. Move that piece of paper straight (perpendicular) to the deck surface - now tell me where the intake surface moved to. Remember when you make your cut out the Intake angle to the deck surface MUST be less than 90 degrees - I certainly exaggerated it to illustrate the point - your statement that it is a small amount is certianly true, but if I were deciding how much to cut off an intake - I would calculate all the variables to see what makes the most sense.
The heads on my hemi were milled to up the compression. The normal deal is to mill the manifold to make it fit. I did this on engines in the past.If you do not, then the manifold is too wide. It looks like your manifold was milled to fit milled heads.
To clarify my predicament... I've tried two manifolds. Both had the same casting number. Both fit my engine the same way...pretty much the exact same gap. I think it's unlikely that two manifolds were machined exactly to the same specs....so I'm leaning toward the issue being with my heads. What I don't get is that if I follow the drawing above, if my heads were milled on the deck side, then I would think my bolt holes would move down toward the valley cover...thus I would expect them to be off toward the bottom of the manifold holes. But the head holes are higher than the manifold holes. If the manifold flange on the head was milled at some point, would that cause what I see?
If the manifold flange on the head was milled at some point, would that cause what I see?[/QUOTE] Yes
Think I figured out the answer to my question. Found a diagram of a hemi here. In the top picture, I drew some lines that followed the manifold mounting surface. The white space between the manifold & head is an exaggeration of milling on the manifold flange on the head. Then in the lower picture, I moved the manifold straight down. The red lines represent the bolts...before I moved the manifold down, they were a solid line. So the manifold flange on the heads must have been milled at some point ( wasn't during my rebuild ).
Ok, that could account for the problem. But, if this engine was in an aircraft tug and it presumably was running with these heads, what sort of manifold could have been used to accomplish that? If this had been some sort of hot rodded engine, vs the tug, I would think ANYTHING was possible..........you may well be correct in your ***essment but it still leaves some questions unanswered. Dang It! Ray
I believe the original manifold was a 1 barrel setup. Never saw it though...seller said he didn't keep it because it wasn't going to be any good for a car. Engine was together when I bought it, so I'm sure it was running with the heads I have.
Pretty much what I said, if the heads were milled on the intake side no manifold will fit properly. Multiple gaskets &/or the 331/354 to 392 spacers will have to be used.
I believe you should still consider the dowel pins in the block. What are the signs and indicators of using large dowel heads on a small dowel block? What are the consequences if the heads are not in alignment on the block? I had forgotten all about dowel pin/year model until reading here. Tom S. in Tn.
HemiRambler has it 100% correct up until this point. The intake bolt holes mover inward by the amount that the heads were milled. The second consequence of milling the heads is that intake mating surface moves down by some fraction of the amount the head was milled, as George indicated in his drawing. (I can't figure out the actual amount without some engineering drawings for the engine.) This happens because the dowel pins physically locate the position of the head on the block. This will make it appear that the \/ shape has gotten wider. It hasn't really, the \/ shape has moved down by some fraction of the amount the heads were milled. The final result is that the intake manifold is now too small to properly fill the gap. If this were a SBC, the intake manifold would be hanging up on the front and rear edges of the valley. IMHO, One way to correct the problem is: 1. Use the thickest intake manifold gaskets available to make up for the missing material in the heads and, 2. Drill the intake manifold holes slightly bigger to make up for the mismatch in the holes. Just be carefull not to hit water. Another possible way it to have a great machine shop relocate the dowel pins to the correct head position to ensure that the manifold fits correctly BTW, Just draw this out on a piece of paper. Make sure you show both sides and it will make sense. Good Luck.....Dave....
This just SOOOOOO wrong I can't believe TWO people can make the same claim .............no disrespect intended....but both you and HemiRambler are mistaken.........there's no more tactful way to say it. Read or re-read post #70 above. Ray
I had a set of heads that unknown to me were milled 30 thousands, my intake bolts didn't line up well first off. Second the engine would run good for about a month then develope an internal va***e leak. The intake would seal good on the top edge near the valve covers but not at the bottom close to the valley. It took a while to figgure this out but hope that sheds some light on the direction things move around when the heads are milled.
Found a picture of the block with the heads removed. Not sure if you can tell what type of dowels I have in there.
If the block wasn't milled, there would have been no reason to pull the dowels. As far as the right ons, thay should be a reasonably snug fit to the gasket.
belyea_david, In regards to the bold wording...Why does the intake now bottom out on the valley? It does so because it now sits LOWER than heads than it once did. To FIX it it will need to sit EVEN lower yet until the bolt holes line up. Lets for the sake of arguement say that the head was a perfectly square cross section - meaning that the intake sealing surface and the head deck surface are 90 degrees to one another. What happens now when you mill the head? Well the intake in this case sits exactly where it did poriginally - problem the bolt holes are still off and the intake manifold needs cut. The intake doesn't raise or lower it stays the same - it's the darned intake bolt holes that "moved" closer together & the main reason why you have to remove material off the intake. Repeat the firedrill for a normal head with an angle less than 90 degrees. In this case let's exaggerate it and make it 45 degrees and also let's exaggerate the amount of material removed and make it 2 inches! The intake manifold now sits WAY WAY LOWer than it did before - for the same reaosn that your previous example of a SBC needs the valley sel surface cut. Try the model with the computer - try the cardboard - exaggerate the angles to illustrate the point.
Just an observation, and probably not of any real value to your mystery, but based on these photos, your block appears to be a Poly block. If this engine was originally a 354 Poly motor, maybe that is a clue?? Or maybe not... Maybe Industrial and truck engines had the oblong push rod holes.
Picture worth a thousand words perhaps? I greatly exaggerated the amount of material removed to make the illustration more clear.
I'm not an engine machinist, but I was under the premise that the blocks and heads were machined at at slight taper and then the intake surface was cut back to factory specs. IDK but was told That's done to retain the features of interchangeable parts . Also corrects all the nonsense that Danbabb is dealing with. I do have a couple hemis here and I got I got great grades in math. Think about this: Vertical center line = zero degrees Blocks head surface = 45* For reference perpendicular line = 90 Intake surface 120* Opposite head intake surface 240* Cylinder head angle is 75* or 1/5 of 360 Intake manifold is 120* or 1/3 of 360 block from head surface to head surface is 90* of 1/4 of 360. Divide this circle into those pieces 90* 75*120*75* Now remove some even amount from both side of 90* representative of decking the block Remove some even amount from only the lower side of both 75* pieces representative of milling the heads . Now put the 120* piece un touched back in . What happens is the angles mate perfectly but the piece is now TOO BIG.none of the holes line up Why? The degrees remained the same on all pieces but the radius got smaller thus making the original arc section or 120* over size to fit into the altered circle. This don't solve the problem for the Guy. Now remove as above but keep pieces in alignment representative of dowel pins, put the 120* manifold back in. What happens? The manifold or arc section of 120* is Too Short. Why because the arc section of 90* block was cut, both 75* or 150* heads were cut and the radius stayed the same because of the dowels . There is still 240 degrees but the arc section is smaller thus the intake would need to be bigger or have a larger arc section or radius of 120* to complete the circle. IE add something equal to the amount cut off. On the other hand, remove a wedge shape from the pieces , and its easy to see how this could cause problems very similar to those pictured here. A little bit off and now the circle is eggshaped and not one but two manifolds don't fit. Added to the problem are an ancient rebuild on an industrial tug motor. Think about what was going on in that rebuilders mind.
Just a thought, are your new head gaskets much thicker than the originals. Like a very thick multi layer composite? That would move the heads apart and increase the manifold gap. What type of head gasket is used? I think some of the factory head gaskets were just a thin metal almost like shim stock.
From PAW: http://www.earlyhemiengineparts.com/showpage.cfm?catid=1775 OP's block As scooter pointed out...the pushrod holes seem different....
1955 to 1958 Chrysler Poly 301, 331, 354 Sure looks like a windosr head gasket like this one, in the photo above. Wonder what that indistrial data plate visible in the second photo indicates about the block ? My $$ say there is a mis match a**** the combination of parts used. I'd take the heads off and study carefully. There are ways to make all the different combinations to work together, just have to be aware of the differences. Tom S.
HemiRambler - Thank you for the diagram - I cut out similar models with paper and scissors and I stand humbly corrected. Thank You, Dave....
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