A better cylinder head

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Re: A better cylinder head

Post by Alex22 »

The drawing is meant to show the misalignment of the bolt holes using a stock Jeep cylinder head as a reference. The common point for each of the head bolt patterns is the center line of the top right bolt hole in the picture. In the pictures I posted earlier it would be the intake side of the head and camshaft side of the engine block.
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Re: A better cylinder head

Post by Plechtan »

So if we used the center of the cylinder as a reference, then the pattern would of the v8 heads would be slightly wider than the jeep head, but the same from front to back of the block.


I guess it would be better to compare the head gaskets.
Last edited by Plechtan on May 5th, 2010, 6:57 am, edited 1 time in total.
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Re: A better cylinder head

Post by Plechtan »

Just a note on head flow numbers, on this thread about half way down, are the flow numkbers for a stock head, with big valves installed. http://www.jeepstrokers.com/forum/viewt ... oker+motor The exhaust flow seems to be better than my Hesco head but the intake is not as good.
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Re: A better cylinder head

Post by Plechtan »

I kind of like the idea of building a 4 banger to prove the concept. a 2.5 is basically a 4.0 with the 2 center cylinders removed. So putting a V8 head on that would be much cheaper than welding 2 together and putting them on a 4.0. The stroke on the 2.5 is only about 3.2" you could probably get it up to 3.4" using honda rods ( Stroker!) but that is still way shy of the 258 stroke of almost 3.9" You could probably get the stroke of the 4.0 out of it.

In doing research i found a company that is already making 4 cylinder blocks that you can bolt a v8 head on to. here is a linkhttp://www.kansasracingproducts.com/Kan ... lcome.html The engine is based off of the iron duke, so you could bolt one into a 4 banger jeep. The Cjs came with the Iron duke in 1982 and 1983 prior to the development of the Jeep 2.5 These blocks can be bored to 4.125" and a 3.5" stroker crank is available. This would give a displacement of slightly more than 3.0L Power would probably be equivelent to a stock 4.0 You could probably get the power up around 250-300 if you went crazy with performance parts. A 4.7 stroker would be way cheaper for a similar hp output, and would have way more torque down low.
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Re: A better cylinder head

Post by 5-90 »

Pete - I think you'll find that the Pontiac 151ci "Iron Duke" was used in the CJ-series 1980-1983.5, when it was replaced (almost-but-not-quite for 1984) by the 150ci AMC I4 (which was originally billed as the "2.46L" - nomenclature I still use to differentiate it. Pretty much /every/ vehicle manufacturer has put out a "2.5L" variant at some time - even now, I have a 2005 Suzuki Verona out in the driveway with a 2.5L I6 crammed in crosswise! Bought it for my wife, it had the following selling points:
- I could fit in it
- She could fit in it
- I'm a huge fan of the inline six (by pretty much anyone!)
- It's driven by a timing chain.)

Moreover, I do believe the very early 2.46L engine shared a common bellhousing pattern with the 151ci I4 and 173ci V6, which - I believe - carried it up to around 1987 or so.

Historical Note - the Pontiac 151ci I4 replaced the VW/Audi 121ci I4, IIRC. The VW/Audi engine was too "high-strung" to run well in a Jeep - and it was also underpowered for the heavier AMC pax cars. I believe the VW/Audi engine is the only non-GM engine that AMC used, after their acrimonious split with Packard as a V8 supplier...

Anyhow, I digress. Any chance you could interpret that handwritten note under the intake flow chart?

@Alex22 - That's what it had looked like, but I wanted to be sure. Rule Number One, and all that. Thank you for the clarification!
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Re: A better cylinder head

Post by Plechtan »

No idea on the notes on the flow paperwork.

The bell housing bolt pattern on the iron duke and the Jeep 2.5 is the "small GM" pattern shared by some of the gm v6 engines. I wonder if anybody ever swapped a Jeep engine into a Chevy?

Doing a little more research, the later version of the iron duke used a cross flow head. The engine was called a Tech 4. Here is a link

http://en.wikipedia.org/wiki/GM_Iron_Du ... ne#Tech_IV

The base tech 4 produced about 110 hp, so about 44hp/L. The later Jeep 4.0 HO Engines produced about 48 hp/L The Jeep 2.5 used in 91-95 produced about 130 hp or about 52hp/L . So the Jeep 2.5 seems to be the best output. But GM had a race version of the iron duke, with a stroker crank, 4.125 bore and of course the cross flow head. The 2.7L version produced 232 hp or about 86hp/L . A 4.0 at the same output level would produce 343 hp. A 3.2L was also available that produced 330 hp or about 103 hp/L so a 4.0 at the same level would produce 412hp. Race version would be a high compression ratio and probably use race fuel. Stil to go from 44hp/L to 103 hp/L is a tremendous improvment. The three main factors that allow this improved performance are the larger bore, the longer stroke and a much better flowing cylinder head. The new Pentstar engine that they will be putting in the Wranglers in 2011 is rated at 290 hp ( on regular gas) and it's 3.6L. so it's output is about 80hp/L. Why can't we get that?





It's very simple to prove. A gallon of gas contains a specific amount of enegry, to make a specific HP, you have to burn so many gallons /hr. to burn the fuel you need air. the more air (and fuel)you can get into (and out of) the engine, the more hp you can make. This is very simplistic, and many other factors will contribute to engine performance. but the basic assumption is sound. The quest for a better cylinder head will enable our strokers to perform much better. I wouldnt mind getting 320 hp out of a 4.0
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Re: A better cylinder head

Post by dwg86 »

I think a new cross flow head casting for the 4.0 is doable if some aftermarket company would be up to producing it. Keep the intake on the same side and move the exhaust to the passenger side. The problem I see is demand and pricing. Most people I see building strokers are building on a budget. So if a little porting on a stock head will get good enough flow numbers for low and mid range torque, where most stroker 4.0's are run, then why spend $2000.00 or more on an aluminum cross flow head. I would by one.
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Re: A better cylinder head

Post by lafrad »

I think a cross flow head would have to be with intake on passenger side. The dist, oil filter, and starter all would get cooked to a crisp from the exhaust. You also don't want the hot exhaust port running by the push-rod holes.

I'd be in for one also. very quickly.

Don't forget, its going to take a new intake and exhaust manifold too. I would really hate to see the process to get to a crossflow head, just to use the tiny little ports...
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Re: A better cylinder head

Post by Cheromaniac »

A non-crossflow head would be a non-starter on the 4.0 simply because you'd have to redesign the rest of the engine to make it work. It's not for nothing that Hesco stuck with the non-crossflow design for their aluminium head.
Sure, 300+hp from a N/A 4.0 would be nice but not with an engine design that dates back to the early 1960's. Then again, if you convert it to accept a 505 Performance roller cam, 300+hp might be possible after all.
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Re: A better cylinder head

Post by TurboTom »

A cross flow head is great ...Just be sure it has 24 valves and DOHC with belt drive.

Wonder what the bore spacing is on Chevys new 6.....That thing is flying with boost.
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Re: A better cylinder head

Post by Alex22 »

TurboTom wrote:A cross flow head is great ...Just be sure it has 24 valves and DOHC with belt drive.

Wonder what the bore spacing is on Chevys new 6.....That thing is flying with boost.
The 4.2 trail blazer engine has a bore spacing that is about 3/8 inch closer together. I compared the head gasket to my block today. Would have been cool if it worked.
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Re: A better cylinder head

Post by SilverXJ »

I'd be up for a cross flow head for $2000
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Re: A better cylinder head

Post by 5-90 »

A cross-draught head would have to be done with a driver's side exhaust and a pax-side intake, /or/ a redesigned block, /or/ you'd have to go with COP/DIS and perhaps a Hemi-type combusion chamber, with the spark plugs nearly vertical (hmm...)

Of course, if a cross-draught head is to be done, may as well do it with Hemi-style heads and design "mountain" pistons to fit as well.

I wouldn't want it to be OHC tho - too much work to get the timing up there. And, it would likely end up being a belt drive - which I absolutely farkin' /HATE/! Belts are for pants and accessories, but not for timing (unless you're going to strip the engine down every quarter or so.)

As long as we're doing the work, how about a full-on kit?
- Roller cam and lifters
- Rollerised rockers
- Raised valve cover rail, similar to the aluminum head done by Patriot and HESCO
- Enlarged pushrod bores, to pass the lifters without removing the head (like Patriot/HESCO)
- Choice of aluminum or iron (I don't care for half-and-half engines, and I'm still wondering if someone's redesigned a proper head gasket to go under the current aluminum head, so it won't "scrub out?"
- Modified timing cover to fit:
- A double roller or gear drive timing set (if gear drive, twin idler. Prefer a helical cut, but it doesn't need to be.)
- Replacement intake manifold

A new exhaust need not be designed - simply offer CNC exhaust port variations to fit whatever you're going to use (aftermarket header, late OBD-II split exhaust, RENIX, whatever.) The intake can be offered with two bolt patterns machined in, to fit the RENIX or HO throttle body (or have a throttle body that can be used with either pattern. Make it about a 65m/m bore or so. Maybe 68m/m - but I doubt we need to go larger than that as a general offering.)

I still can't help but wonder who's doing the casting for Patriot and HESCO. I still have my file copy of the old mailing list discussion, compleat with my summary notes, and /identical/ to the copy I'd dropped off for Russ Flagle at Indy Cylinder Heads. I picked him to give it to because he was already doing AMC heads (and Edelbrock isn't as interested - their mainstay is SBChevvy, with SBDomestics and BBV8 taking a high second. Following in the tradition of Vic Sr.) I don't want money - I just want to know if I actually have earned a place - however small - in the history of the AMC performance aftermarket...
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Re: A better cylinder head

Post by Plechtan »

Bigger, faster, larger, more powerfull. This is what everybody wants. With cheap aftermarket cranks available, it will not be long before 4" stroker cranks are common. Most of the 05 and 06 blocks can be bored to 4" without a problem. Maybe bigger! So you end up with a 5.0L engine with a head that was made for a 4.0L engine. You need to get at least 20% more air through it , 30 percent would probably be whare you wanted it.
I think a reasonable market does exist for a head, and if it flowed 30% better you could probably get your $2,000 for it.

I have been looking at the Jeep head and aftermarker V8 heads. it seems like the best solution to get more air through the standard jeep head design would ne to move the manifold mounting surface towards to passanger side of the car by about 1.5" The intake and exhaust runners would be almost gone. The new location for the manifolds would be almost directly on top of the drivers side head bolts. If you look at the exhaust side of most V8 heads, you will see that the runners are very short, and the head bolts are below the ports. Doing this on the jeep head would remove the bulge in the runners between the intake ports and make the runners very short. it will still be tough to fit everything on the same side of the head.
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Re: A better cylinder head

Post by Alex22 »

Plechtan wrote:So if we used the center of the cylinder as a reference, then the pattern would of the v8 heads would be slightly wider than the jeep head, but the same from front to back of the block.

I guess it would be better to compare the head gaskets.
No head gaskets at the moment but this should do. All 3 bolt patterns are centered on the cylinder bore.
Image
Cheromaniac wrote: Sure, 300+hp from a N/A 4.0 would be nice but not with an engine design that dates back to the early 1960's. Then again, if you convert it to accept a 505 Performance roller cam, 300+hp might be possible after all.
At work we build SB Ford 302s that make mid 500' for horsepower and SB Chevy 302s that make closer to 600 hp naturally aspirated. Those engine designs date back to the 60's as well. It is a V8 vs a L6 and some displacement so I don't expect to see those numbers by any means, but 300HP should be reachable.
Plechtan wrote: I have been looking at the Jeep head and aftermarker V8 heads. it seems like the best solution to get more air through the standard jeep head design would ne to move the manifold mounting surface towards to passanger side of the car by about 1.5" The intake and exhaust runners would be almost gone. The new location for the manifolds would be almost directly on top of the drivers side head bolts. If you look at the exhaust side of most V8 heads, you will see that the runners are very short, and the head bolts are below the ports. Doing this on the jeep head would remove the bulge in the runners between the intake ports and make the runners very short. it will still be tough to fit everything on the same side of the head.
Interesting idea. The coolant passages would have to be moved, new thermostat housing and who knows what else will come up on the build. One other way around the head bolt choke could be to weld an aluminum sleeve into the head bolt hole and use a stronger stud head stud material such as ARP Custom age 625+ or some other high strength fastener such as tool steel. If the stud has a higher tensile strength then its area can be reduced giving you more room for a wider port.

A custom camshaft would still need to be made because of the intake/exhaust pattern. Pete what did you use for a cam core?
SilverXJ, I saw that you mentioned the pressed on lobe design for a cam in another thread. That would be a good solution to 2 problems at the same time. The one problem that I can see with that cam design is that the pressed lobe camshafts that are used in the ford modular engines (4.6 and 5.4) have been known to shift while the engine is running. I am not sure what caused the cams to shift, forced induction, stiffer springs or maybe just a bad batch. Maybe this cam style is worth some more investigation.
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