A better cylinder head

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Plechtan
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Re: A better cylinder head

Post by Plechtan »

I6FAN wrote:Plectan Wrote:

How about the HESCO combustion chamber[cc] is it like the stock, or is it custom (I know Lee says: Anyhthing you want, just $)? To me, the stock cc is okay, but not great. A LS style fast-burn cc would be a great improvement. My plan is to take an AHC and sink the valve seats ~.060-.100", and then re-carve the area around each the intake and exhaust so that each valve head sits down in a "miniture hemi". I don't know if the stock head could take that much though. That chamber design is essentially a LS style, fast-burn combustion chamber which is very popular. The June issue of Hot Rod features a 460 Ford Racing block based 429 Boss with Kaase heads that utilize this style cc, as the original used a "semi-hemi" (oval hemi with opposing quench pads). So my point is it must be a pretty good design.

The head is basically stock, including the combustion chmbers. 55 cc i think. You actualy want samller chambers if you can get them. Because the Hesco head is emissions compliant, they do not stray much from the stock piece. You can shave the hell out of it though, i took .050 off of mine and could probably take another .o50 without a problem. Every .007 you remove reduces te combustion chamber by about 1 cc.
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Re: A better cylinder head

Post by Plechtan »

Alex22 wrote:I pulled my jeep block out from under the bench today and put a 1133 (SB Ford) gasket down on top of it and the bolt holes on the Ford are about 3/8 further apart side to side but since the blocks have the same bore spacing so front to back they are close. The coolent passages on the left side of the block line up with holes in the gasket so they should match the Ford head. The passages on the right side of the block (lifter side) stick out further than the gasket and are in the wrong location. They would have to be relocated or set up for remote cooling lines, which looks possible. I will have to put a cylinder head on to take a look at pushrod geometry. A custom cam would be necessary since the Ford doesn't have the same intake/exhaust pattern.

If you are serious about this cylinder head it just might be possible, but not cheap.

Just remember that engines are only limited by division rules (cheating ability), wallets and/or fabrication skill.


Got Any pictures?
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Re: A better cylinder head

Post by Alex22 »

Plechtan wrote:
Got Any pictures?
I forgot the camera today, but I'm going to throw it in the jeep right now.


The Ford head:
The coolent passages aren't actually that far off. The triangular hole on the push rod side of the block overlap with the ford coolent holes when using the bolts that would be under the valve cover of the Ford head. The passages on the other side of the block would have to be drilled on the ford head, not a big deal. The distributor would line up between two of the Ford intake ports. The chambers line up pretty well on a stock jeep bore, with a 4 inch bore you could open the head up a bit wider. The rocker arm studs line up with the jeep's lifter holes but they are about an inch or so further away from the bore than where the push rods would be on a stock Jeep head. The block will have to be clearenced and possibly need to have the side extended in order to have enough room for the push rods to clear.

After work today I told my boss about this idea and he told me a fun little fact, The Chevy LS small block family uses a bore spacing of 4.400.
We just happen to have a few LS-1 heads in the shop as well so I bolted one of those on. Front to back the bolt center to center is good, but the left to right is off more than on the Ford head, but those holes can be moved around to make the head work. The LS-1 head has quite a few advantages over the Ford head. First off, its not a Ford product. :D Second is the price, an assembled pair of heads goes for 3 to 4 hundred bucks shipped on ebay, that knocks at least $1000 off of the cost of this project. The push rods will be closer to vertical on the LS head which means that the block shouldn't need to be modified as heavily for clearence. There is huge flow potential in the LS family of cylinder heads since the LS family small blocks share the same bore spacing. I will have to get some flow sheets for the CNC ported LS-1 head, I forgot to print one out before I left today.

Building a 4 banger as a proof of concept doesn't sound like a bad idea as long as it fits into the budget.

~Alex
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Re: A better cylinder head

Post by Plechtan »

so 4.4 vs 4.38 .020 difference. If you cut 2 v8 heads in half and centered them on cylinders 2 and 4 , then cylinder 1 and 3 would be +.020 towards the front of the block and cylinders 3 and 6 would be + .020 towards the rear of the block. Probably not the end of the world.

Just a note on the pushrod issue. On the jeep head the valves are angled towards the drivers side. this puts the top of the valve further away from the cam, so the rockers have to be very long. On the V8 heads, the head will be installed with the valves angled towards the passanger side . This moves the top of the valve towards the passanger side, so the rocker arm also has to move towards the passanger side. When they use to put SBC heads on the chevy 6 motors, they made a new lifter cover ( it is removalable on the chevys) and the pushrods were outside of the block.


Another point you missed, if you put to chevy heads together, you don't have to make a special cam.
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Re: A better cylinder head

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The LS family of engines uses the same Intake/exhaust pattern as the Ford (I E I E I E I E) over the old style to avoid hot spots in the heads. I would have to take a closer look at the head and block as well as the head gasket to decide where to make the slice. Using the LS head the push rods could probably be kept inside the block.

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Re: A better cylinder head

Post by Plechtan »

Looking at pictures of the head, it looks like the chevy head has 2 intake ports together, were the ford has 4 induivual ports. Am i looking at the SBC and not the LS motor?
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Re: A better cylinder head

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I checked the casting number on the cylinder head today and it is actually for a LS-6. The block that I am using for this mock up is a standard bore out of a 98 grand cherokee.

Here is the LS6 head on the block, it is being held in place by two bolts on the camshaft side of the block.
Image

You can see in this picture that the head needs to be shifted towards the cam side of the block in order to get the chambers to line up better.
Image

The LS6 head from the under side, it just clears the chamber on the push rod side and in the other picture it overhangs the deck so this head will need a large bore.
Image

The edge of the chamber may need to be welded up in order to get the correct alignment.

Here is a good picture to see how the push rod geometry would be with the LS6.
Image

There will be room for the distributor using the LS6 head as well.
Image

It looks like the coolent passages on the LS6 head will line up with the holes on the left side (intake/ex on a stock jeep head) of the block. The passages on the other side will have to be relocated in the cylinder head. Not a problem since welding aluminum isn't too hard.

Now onto the Ford head, this is a cracked 1966 289 ford casting. The head is bolted onto the block using the same row of bolt holes that the LS6 head was, the row on the camshaft side of the head.
Here you can see how much further the push rods are away from the bore.
Image

This picture will give you a good idea of what the push rod angles will be.
Image

The distributor is also is also between two intake ports using the ford head.
Image

The stock chamber lines up better on the jeep block, but it is not as good of a design as any modern head.
Image

A shot of the Ford chamber from the other side of the block.
Image

This is a bit harder to see, but when the head was on the block I shot dykem through the freeze plug holes to see where the coolent passages end up. If you look where the camera flash reflected back and ruined the picture you can see where one of the water holes is on the jeep head, and on the right side of the picture as well. The triangular black sharpee mark is where the coolent passage on the camshaft side of the block is.
Image

Here is a picture of the block, the black sharpee lines are where the coolent passage on the head would line up. The circle with the x in it on the right side of the block is where the oil drain back on the ford head would be, it can just be welded up since the oil will drain back around the push rods.
Image
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Re: A better cylinder head

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Here is a pic of what the finished product might resemble, using my sweet MS Paint skills. :lol:
Image
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Re: A better cylinder head

Post by 5-90 »

Plechtan wrote:My flow sheet would not do you an good, my head is not a catalog item. It has larger valves and the intake has been moved slightly towards the center of the chamber. The stock head is a good piece, and has plenty of meat for porting. but out of the box it will probably perform similar to a 0331 head.

Remember , more flow is not always better. it only becomes important if the head becomes the restriction point for getting more air into the engine. If you have too much flow, the engine will stumble down low.
I'd still be interested - although I'd also like to get a copy of your mod datasheet with the flow sheet. "There is no such thing as useless information" - and it's something I could still add to the Archives I maintain...

I tell ya, I'm getting to where I'm going to need about 150-250GB of online storage for my "Archives" section - that's just for the Jeep-related stuff! I'm tired of having to swap thumb drives...
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Re: A better cylinder head

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I will dig through my stuff, see if i can come up with the original Hesco sheet. I do remember that the original head barely flowed 150 cfm on the exhaust and the intake was 142 cfm@ .6 lift. After additional machine work the exhaust went up to about 165 cfm. We did a little more port work and went to a .7 lift to get the additional CFM.

Hey alex thanks for the pictures. It would be interisting to see a Jeep head gasket on the V8 head or vise versa. it would clearly show how much the bolts are off with the bores lined up.
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Hesco Head flow

Post by Plechtan »

Here is a the flow sheet from my head 2.02 intake, 1.570 exhaust. This is after hesco opened up the exhaust ports. A smaller valve probably would have flowed a little more.
headflow.jpg

head flow.pdf
Hesco Head.gif
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Last edited by Plechtan on May 6th, 2010, 2:42 pm, edited 1 time in total.
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Re: Hesco Head flow

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Plechtan wrote:Here is a the flow sheet from my head 2.02 intake, 1.570 exhaust. This is after hesco opened up the exhaust ports. A smaller valve probably would have flowed a little more.
Got it, thanks!

2.02/1.57 seems a bit interesting, with an E/I of ~65%. Flowed at 25" H2O (fairly standard,) but what's the word after "Used" in the remarks under intake?

I do understand the effects of "overflowing" a head at low RPM (the effect is similar to "overcarburetion" when selecting a mixer...) but, as I said, I'm just on an ongoing data gathering mission here.

Also, if you could explain the "scale value" and "% flow" rows - looks like that's what's used to calculated the actual CFM flow rate, but I'd like to be sure (Rule #1 - Thou Shalt Never Assume.)
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Re: A better cylinder head

Post by Plechtan »

Your questions might be better answered by someone who operates a flow bench on a regular bassis. I am not sure whhat the mean, i think they refer to flow bench settings.
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Re: Hesco Head flow

Post by Alex22 »

5-90 wrote:
Also, if you could explain the "scale value" and "% flow" rows - looks like that's what's used to calculated the actual CFM flow rate, but I'd like to be sure (Rule #1 - Thou Shalt Never Assume.)

Your assumption was correct. When using a flowbench that does not have a flowcom, or similar electronics, the flow has to be calculated by hand. For example, the Superflow 600 that I use has 6 holes in a plate. Each of those holes is called a range and the max flow in each range is tested for each bench when they are built. In order to get the most accurate flow data you need to be in the lowest flow range as possible. The inclined manometer has a scale on it that gives the percent of the flow range being used.



To find out how far off the head bolts are from a stock Jeep head I made some measurements to day with a pair of calipers then drew this up. More accurate than comparing head gaskets.
The Green circles are the jeep head bolt holes, Orange are the LS-3 and the Blue is the SB Ford head.
The Ford bolt hole center line is 0.310 wider than the jeep and the LS-3 is 0.4125 wider.
Image

There should be enough metal in the cylinder heads to move the bolts further towards the center.
One other way to make room for the wider head bolt spacing could be to move the head bolt holes in the block using a full thread insert that is offset outward from the stock bolt hole. Or if you really want to spend some money you could have ARP make you a custom set of head bolts out of their "Custom age 625+" material with a necked down shank diameter.
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Re: A better cylinder head

Post by Plechtan »

so in your drawing I assume that the holes to the left are the exhaust side and the holes on the right are the ones down the center of the head. ( for the v8 heads) and for the jeep the left side is the drivers side, and the right side is the passanger side.

Is the relationship to the cylinder bore correct for all three heads, or are the v8 heads shifted towards the drivers side? I would assume that on the Ford head the bolts are located 4.38" apart measuring front to back on the head ( exactly in between cylinders). but left to right, is the pattern centered on the cylinder or offset towards the exhaust side? Your drawing implies an offset.
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