Saving the 4.0L

[Pookapotamus]

First off, this is strictly theoretical...... At least for now :rolleye0012: I have been thinking, I know, that's a bad thing, but I cant help it! Dead end job + over active imagination + abnormal mind + OCD = the insane ramblings of the Pookapotamus.

We all know the 4.0L is a great engine, but it is heavy and old school, there are performance upgrades out there ie. aluminum head, stroker etc... but with these mods the 4.0L is still a heavy cast iron block that is designed with tech from the 50's, carried over from the 40's, its a dinosaur compared to modern engines!

I have done some research on the weight of the 4.0L, Novak adapters lists the 4.0L at 515 lbs, a gen 1 small block chev is 550 lbs, not hard to figure out why the 350 swap is popular with much better HP and torque values!

There are no aluminum 4.0L out there, at least none that a quick google search reveled, but what if we could update the block? What would the weight savings be? Could we update the block with other features? So I fired up CAD and did some rough design work.
http://i264.photobucket.com/albums/ii191/pookapotamus/Block%20Rough_zps2119xhxf.png (http://s264.photobucket.com/user/pookapotamus/media/Block%20Rough_zps2119xhxf.png.html)
http://i264.photobucket.com/albums/ii191/pookapotamus/Block%20Rough1_zpslrvcngoz.png (http://s264.photobucket.com/user/pookapotamus/media/Block%20Rough1_zpslrvcngoz.png.html)

Yes I know this is extremely rough but it will do for a crude comparison between cast and aluminum. I get the cast block at around 130 lbs and the aluminum at 50 lbs so a weight savings of 80 lbs, that's not bad and I think it would be more once the block is accurately modeled, plus adding the aluminum head from Edlebrock saves another 30 lbs, bringing the weight of a dressed 4.0L to around 405 lbs. That's what an LS1 weighs, but still the LS1 is an easier option with tones more performance upgrades, unless you are a die hard I6 fan like me. What updates could we do to the block now that its aluminum and undergoing a redesign? Well firstly it will now have to be sleeved with steel, which means we can increase the bore easier, we can change water passages for better cooling, the design now has the outlet close to the inlet at the front providing more cooling to cylinder 1 than 6, oil passages can be upgraded, distributor can be deleted, sensors can be added, upgrade to a timing belt, etc. How far could we really take the 4.0L?

Ok ok! I know when I dream, I dream BIG! ,But how big am I really dreaming? The 4.0L block is a very basic block, I6 geometry is quite simple, compared to a V8, a CNC machine of today can easily carve this out of a billet of aluminum, all the major design work has been done when the block was originally designed, we are just using modern materials and machining techniques. So basically reverse engineer the cast block, produce a set of plans that the CNC can read (two things I am very proficient with) and find a shop that will do the machining. Is this actually possible? I get it, some of you might say "Pook you are crazy a full redesign to save 100 lbs", But why not? I mean really why not? what do you guys think? Any ideas to add? I got lots more! copyright infringement? I wonder what the JK would have been like with an updated aluminum 4.0L that possibly could have been the successor of the cast 4.0l?

Once again I think I have opened a can of worms that I can't possibly handle!
Pook

[4.3LXJ]

Yes I think you did open up a full case of worms. First, I moved your thread. No biggie. The fabrication section is reserved for actual fabrications that have adequate explanation.

But on to our request. First, you have no provisions for water jacket. That lets out full CNC and gets you into cast. Although I have seen a 220 hp Ford Model B four banger that bored out the inner cylinder into the water jacket and then had a second block cast around it. Held a local track record in a Dodge Dart for many years.

But back to your dilemma. You can use an aluminum cylinder without the sleeve. Subaru is a master of it. Al has to be hardened though. Not sure what alloy is used, but there are some alloys that don't expand with heat and one that actually shrinks. More surfing for you. Either way, the Al needs to be heat treated. Also consider four bolt mains. You know you want to. Also extending the outside of the block down and utilizing a cross bolted main adds strength and should allow you to shave a little off the block. A cast Al pan adds to strength too. All the high power GM engines have that now.

[XJ Wheeler]

I love the 4.0 and am always glad to see someone finding new ways to improve it. I've never considered anything else in my xj. Maybe others but not this one. Turbo'd and stroked of course. :D

If you wanted to really make something special, and I'm not entirely sure it's possible (wish I had the knowledge to know), but dual cam and four valves...? Just imagine the sound.

Sent via messenger pigeon. I talk, he types.

[Pookapotamus]

also possibly considering a redesign on the oil pan, integrate some baffles and doors to keep the 4.0L lubed at any angle.

[Cheromaniac]

Hesco toyed with the idea of producing a 4.0L aluminum block for a long time but I believe they've abandoned that project due to low demand and the prohibitively high cost of each block. Aluminum has 55% of the weight of cast iron so with a bare cast iron block at 136lb and a bare cast iron head at 60lb, the total weight saving with aluminum head & block would have been near 90lb. My fully assembled bare long block without ancillaries weighs 360lb.
Unfortunately there's no easy way to completely redesign the existing engine and even if the block/head were made of aluminum, it would still have the shortcomings of the pushrod OHV design and a non-crossflow head.
At the end of the day you have two choices. Either make the best of the existing 52-year-old engine design while accepting its limitations, or swap in a more modern all-aluminum engine. The Chevy LS1 ticks all the boxes with its compactness (for a 5.7L engine), lightness, reliability, adaptability (to AX15 transmission), easy availability, low cost, and 300+hp.
The stock 4.0L oil pan can be modified with an extra baffle, and you could also add a "kick-out" to increase the sump capacity. These measures would prevent oil starvation and reduce oil temps. Otherwise the engine doesn't need any further upgrades for reliability.

[bluedragon436]

Think this would be awesome to see if you were able to make it happen and even more so nicely priced.. because like Dino said... if the cost is too high, no one would want to put that ind of money into it, just to save a (nice) little bit of weight...

[xjzaped]

I haven't looked in awhile but I thought the sizing of the Atlas 4.2 used on the Trailvoy platform was pretty close. Only thing I miss about my trail blazer, that 4.2.


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[Pookapotamus]

@ Dino, I agree with you 100% Everything you said in your post is totally correct! The 4.0L does not need a redesign, there are much better and viable options out there. And the LS1 does tick every box and would be a killer engine in an XJ! But... Its BORING, and its not "jeep"...at least to me. For me this is all about want. I don't want what everyone else has or has done, I do want an aluminum block 4.0L with a 4 bolt main full bearing cage and dual oil filters with a revamped cooling system and "Pook" carved into the side of it! why? Because when the Xj beside me has people drooling over the shiny LS1 producing 500 HP that is installed in it, Mine will still be unique, and I can say that I built mine, not just assembled it.

So basically its not you, its me:o and thanks for the criticism, I really do appreciate it, makes me try harder!

@ James, I don't know if this will ever happen, like I said this is all theoretical at the moment, I am a 3D mechanical designer and so far everything I have said that would be nice to have on an aluminum block is quite within the realm of my ability and the ability of a CNC machine, but like you and Dino have said the cost could be, and probably is very high! But that being said, with my skill set and my connections I would just be looking at the cost of machining, so maybe, just maybe, it might actually be possible to do a small production run.

@ Colin, I have looked into the atlas LL8, beautiful motor! and the fact that my neighbor has one for sale is very tempting! But to run that engine in the Xj would require an ECU swap or an aftermarket ECU as well as an tranny adapter, both are fairly easy, also considered the Toyota I6's, but again it does not keep it "jeep" to me.

Thanks for the input guys, I have tones of ideas, looks like i am going to have to pull my spare cast block out and start modeling.

[cantab27]

ell that's it then ..ya going to have to to it pook.....

[xjzaped]

@ Dino, I agree with you 100% Everything you said in your post is totally correct! The 4.0L does not need a redesign, there are much better and viable options out there. And the LS1 does tick every box and would be a killer engine in an XJ! But... Its BORING, and its not "jeep"...at least to me. For me this is all about want. I don't want what everyone else has or has done, I do want an aluminum block 4.0L with a 4 bolt main full bearing cage and dual oil filters with a revamped cooling system and "Pook" carved into the side of it! why? Because when the Xj beside me has people drooling over the shiny LS1 producing 500 HP that is installed in it, Mine will still be unique, and I can say that I built mine, not just assembled it.

So basically its not you, its me:o and thanks for the criticism, I really do appreciate it, makes me try harder!

@ James, I don't know if this will ever happen, like I said this is all theoretical at the moment, I am a 3D mechanical designer and so far everything I have said that would be nice to have on an aluminum block is quite within the realm of my ability and the ability of a CNC machine, but like you and Dino have said the cost could be, and probably is very high! But that being said, with my skill set and my connections I would just be looking at the cost of machining, so maybe, just maybe, it might actually be possible to do a small production run.

@ Colin, I have looked into the atlas LL8, beautiful motor! and the fact that my neighbor has one for sale is very tempting! But to run that engine in the Xj would require an ECU swap or an aftermarket ECU as well as an tranny adapter, both are fairly easy, also considered the Toyota I6's, but again it does not keep it "jeep" to me.

Thanks for the input guys, I have tones of ideas, looks like i am going to have to pull my spare cast block out and start modeling.

Like Chrysler, I feel GM really made a mistake getting rid of the inline option. Ford did too but when you are too lazy to redesign your flagship pickup engine to meet California emissions regs you get the POS Essex 4.2. Which is oddly what I drove before acquiring my Trailblazer. Then I went back to full-sized for daily drivers with a 5.3.

[4.3LXJ]

Like Chrysler, I feel GM really made a mistake getting rid of the inline option. Ford did too but when you are too lazy to redesign your flagship pickup engine to meet California emissions regs you get the POS Essex 4.2. Which is oddly what I drove before acquiring my Trailblazer. Then I went back to full-sized for daily drivers with a 5.3.

I just read an article today that was on this subject. Chrysler spends more than any of the other car companies to be emissions legal. 5 billion a year. This is due to their larger engines, you know hemis etc. The problem with the straight six is that there is a difference in temperature between the front and back which affects emissions. This is why in 2000 the header was split and two sets of O2 sensors to split the zone in half. But still, emissions are so tight now that you cannot have a straight six that will pass. Just a sign of the times

[Cheromaniac]

The problem with the straight six is that there is a difference in temperature between the front and back which affects emissions. But still, emissions are so tight now that you cannot have a straight six that will pass. Just a sign of the times

That's not the problem with the straight six and even if it was, it would be easy enough to route an extra coolant pipe to the back of the cylinder head to rectify it.
It IS possible to meet tighter emissions regulations with a straight six. Just ask BMW. The REAL reason why straight sixes have gone out of favor is that they're long, tall, and difficult to package in an engine compartment that requires a low hood line to keep the aerodynamic drag coefficient as low as possible.
Even BMW cants its straight sixes at an angle but most manufacturers opt for a V6 configuration 'cause it's more compact, and it's easy to mount transversely if you prefer a front wheel drive set-up for its superior drivetrain efficiency.

[xjzaped]

I just read an article today that was on this subject. Chrysler spends more than any of the other car companies to be emissions legal. 5 billion a year. This is due to their larger engines, you know hemis etc. The problem with the straight six is that there is a difference in temperature between the front and back which affects emissions. This is why in 2000 the header was split and two sets of O2 sensors to split the zone in half. But still, emissions are so tight now that you cannot have a straight six that will pass. Just a sign of the times



I'll take your emissions guff and raise you the Atlas (which didn't go out of production until 2011). I'll also raise you pretty much every mid-tier BMW, Porsche, and Merc.

The engines are long and tall and in today's crossover-fication they only fit in full sized truck/suv platforms. Well, Ford is stuck in their ways of as much in the engine compartment as possible and pray the hood shuts…GM and Ram have consolidated engines as much as possible.

I'll also add, Cummins was the last of the trifecta to add DEF injection to their b series engines.


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[abebehrmann]

Sounds like one hell of a plan Pook. That all aluminum Jeep straight-6 sure would like nice in that XJ 6x6, just saying....

[Pookapotamus]

http://uploads.tapatalk-cdn.com/20160930/05dcb1a820dec529aa567d4dbb9e76bc.jpg
http://uploads.tapatalk-cdn.com/20160930/b526400c9dd0d512c3f8a56aecc0057e.jpg

This is what I am envisioning for the full bearing cage.


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[Pookapotamus]

Well, I have a rough model of the block, but it is obvious that I am going to have to get my spare block cleaned so I can handle it more, and move it to my computer work station and get very accurate in-depth measurements. I have also discarded the idea of trying to reproduce a cast block into aluminum then modify, all I really need is the key features, enough to use the standard internals and externals, the parts in between don't matter. so my next steps are to clean the cast block, then fire up the lathe and make a set of threaded locators to use in obtaining all the accurate dimensions that I need. Also have to spec out a material (A319-T6 or A356-T6 or maybe something else?) to use and import that into cad software, still have not located a machinist capable of handling this project either.

Also need to decide on metric or imperial bolt standards, and want to change the main bearings to studs instead of the cap bolts that I have in there, Need to research cutting heads to get the profiles I want for a CNC'd block, lots of design research to do yet! And of course lots of work on the 3D model to improve functionality and ease of design, fun stuff!

This is actually taking shape a lot easier than I originally thought! And this is turning into a real fun project!

http://i264.photobucket.com/albums/ii191/pookapotamus/Block_zpszg5mcdtf.png (http://s264.photobucket.com/user/pookapotamus/media/Block_zpszg5mcdtf.png.html)
http://i264.photobucket.com/albums/ii191/pookapotamus/Skellington_zpss4f89rnk.png (http://s264.photobucket.com/user/pookapotamus/media/Skellington_zpss4f89rnk.png.html)

[Pookapotamus]

About 3 hours work and I have a thinner block, full webbing on the internals and a front cover!

http://i264.photobucket.com/albums/ii191/pookapotamus/Block2_zpsqpksdwwy.png (http://s264.photobucket.com/user/pookapotamus/media/Block2_zpsqpksdwwy.png.html)

I have also noticed that a stock 4.0L with Keith Black pistons and 4.2L crank like I have, has the piston skirt protrude out of the bottom of the cylinder bore by around 1" ( stock is roughly the same, longer skirt but smaller stroke on the crank). This effectively leaves only about 2" of piston in the bore, witch can allow the piston to rock at BDC. What this translates to is when the piston is in the bore ie. TDC it can rock .2 deg from center, so .4 deg total rock. When it only has 2" left in the bore at BDC it can rock .3 deg a total of .6 deg total rock. this will be about the same if you use the ICON forged pistons with stock 4.0L rods.

Big fat hairy deal, right?

Well maybe at idle, but at 5000 rpm that piston is traveling kinda fast, if we can control the rock at BDC we can lessen the stress, noise and vibration of that piston rocking. And this thread is about improving the design of the stock block, so by lengthening the cylinder walls so that the skirt does not protrude out of the bore I can gain a few bonuses, such as reduce rock at BDC and get more volume in the coolant chambers around the pistons, and thankfully this is easy with a sleeved aluminum block, and there is the room around the crank so that it does not contact the sleeve while rotating.

Yes I know I am splitting hairs, too bad! Go build your own block! :smiley-taunt002:

[4.3LXJ]

I agree Pook. Gotta keep as much of the piston in the hole as you can. I don't think 2" is enough

[Pookapotamus]

http://i264.photobucket.com/albums/ii191/pookapotamus/Water%20Neck_zpsertjvqla.png (http://s264.photobucket.com/user/pookapotamus/media/Water%20Neck_zpsertjvqla.png.html)

here you can see the new planned water passage in the rear of the block, a quick 90 into an electric pump and we have much better cooling through the block, will also be redesigning the passages from head to block to allow even flow from front to back, hopefully cool down some of the hot spots and bring down rear temps. Would have to pipe from the back to the front, or possible run the passage up to the front, yes more under hood piping, but to me that's a small price to pay for an more evenly cooled block.

[4.3LXJ]

I like it. A needed improvement

[Pookapotamus]

I like it. A needed improvement

enough to swap back to one Steve??:rolleye0012:

[4.3LXJ]

Nah, too late. The V6 is getting worn out though. Looking at stuff that starts with LS :D

First step, upgrade axles. In progress as I type

[denverd1]

4 bolt mains?? [emoji106] [emoji106] [emoji41]

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