Worlds Fastest Comanche Posted January 13, 2012 Share Posted January 13, 2012 Not yet, but hopefully soon. i was reading about a guy who has a H3 5 cylinder into a FJ80, and his gas mileage went from 10mpg to 16 mpg and way better performance. The GM 5 cylinder is a member of the Atlas engine family that includes a 4 cylinder, 5 cylinder and 6 cylinder. The 5 cylinder makes about 240 ft/lbs of torque from 1,000-5,000 rpm and is rated at 242 hp. So it seem like 50 hp more that the 4.0, but because the engine will rev to 6,000 rpm all is not what it seems. The 2000 and up 4.0 is rated at 235 ft/lbs of torque, so the performance for a daily driver is similar, although the 5 cylinder has an almost flat torque curve. What is not similar is the gas mileage. The atlas engines are modern 4 valve per cylinder double overhead cam engines with a cross flow head. The jeep inline 6 design was first used in a 1966 Rambler as a 199cid engine. Engine technology changed allot since 1966, and jeep did go with multiport fuel injection. What they could not change was the cylinder head construction. only 2 valves per cylinder and intake an exhaust on the same side of the motor. The Atlas engines have variable timing on the exhaust cam which allows for better emissions, gas mileage and the flat torque curve. So how hard would it be to put one in a Comanche? Well if you has a manual trans, easy. The Colorado and canyon trucks with manual transmissions came with an Aisin transmission, so if you get a engine out of a M/T truck and get the bell housing it will bolt to your trans. Motor Mounts, well the block has a square plate bolted to each side with an arm sticking out, here is a picture of the side of the block of a 6 cylinder with the mount removed, but the 5 cylinder has the bosses in the same location So yea you have to make some motor mounts. Computer: You can get it reprogrammed for $100 to work as a standalone wiring: Check the FAQ section of Vortec4200.com http://vortec4200.com/forum1/viewforum.php?f=7&sid=17bd36d55d644952a2a4b6e0b92ab05f for detailed instructions on how to rewire the PCM to break out the wires you will need for power, ground ignition, fuel pump, etc. The rest will take a little work, radiator hoses, fuel connection, etc. But probably could still be done in a weekend. The engines are available in boneyards for $500-$700. the gas savings alone will pay for this thing in less than a year. Another note, I have only been talking about the 5 cylinder, the 4200 is the 6 cylinder and is rated at around 300 hp. Problem is that it has a front sump oilpan and no manual transmission flywheel is commercially available. If people have some interest i can talk more about the 6 cylinder, but the 5 is really a great value and the best bang for the buck. more information can be found on http://www.vortec%204200.com I would really love to see sombody do this swap, if I can help, PM me. Thanks Link to comment Share on other sites More sharing options...
neohic Posted January 13, 2012 Share Posted January 13, 2012 :popcorn: :popcorn: :popcorn: :popcorn: Link to comment Share on other sites More sharing options...
HOrnbrod Posted January 13, 2012 Share Posted January 13, 2012 Interesting. Cooling is always one of the biggest considerations in the limited XJ/MJ available engine compartment real estate. The length of the 5-cyl vs. the 4.0 I would ASSUME is greater and would add problems. I've been fighting for years to keep my Hesco 4.6 stroker cool under all conditions as a D/D. It required a thicker alloy radiator, dual electric fans, and a cowl hood. No worries now, but it was tough to get there. I think it might be even more difficult with the longer block to meet these conditions w/o firewall mods - don't want to do that. Link to comment Share on other sites More sharing options...
Dirteatr717 Posted January 13, 2012 Share Posted January 13, 2012 That's odd :D ! I've driven my friends colorado before and got around 18 mpgs on a 3 hour drive. My truck with the 4.0,ax15, 33s and 3.07s gets between 16-20 depending on how heavy my foot is, its nice to have another motor to be able to swap in but I'll stick with a motor I like and know :smart: Link to comment Share on other sites More sharing options...
Worlds Fastest Comanche Posted January 13, 2012 Author Share Posted January 13, 2012 Interesting. Cooling is always one of the biggest considerations in the limited XJ/MJ available engine compartment real estate. The length of the 5-cyl vs. the 4.0 I would ASSUME is greater and would add problems. I've been fighting for years to keep my Hesco 4.6 stroker cool under all conditions as a D/D. It required a thicker alloy radiator, dual electric fans, and a cowl hood. No worries now, but it was tough to get there. I think it might be even more difficult with the longer block to meet these conditions w/o firewall mods - don't want to do that. The 5 cylinder is shorter than the 4.0, engine and is all aluminum and probably less then 400 lbs fully dressed. The 6 cylinder is another story. The 4.5-4.7 stroker will probably have the same or more torque than the 6 cylinder. The aluminum block helps keep the temps down. However if you have a blown motor and are looking at a $1,500 junkyard replacement or a $2,000-$3,000 stroker, this might be an interesting alternative Link to comment Share on other sites More sharing options...
HOrnbrod Posted January 13, 2012 Share Posted January 13, 2012 The 5 cylinder is shorter than the 4.0, engine and is all aluminum and probably less then 400 lbs fully dressed. The 6 cylinder is another story. The 4.5-4.7 stroker will probably have the same or more torque than the 6 cylinder. The aluminum block helps keep the temps down. However if you have a blown motor and are looking at a $1,500 junkyard replacement or a $2,000-$3,000 stroker, this might be an interesting alternative In that case, shorter length, less weight, alloy block, parts availability, an excellent alternative. :cheers: Link to comment Share on other sites More sharing options...
Incommando Posted January 13, 2012 Share Posted January 13, 2012 I understand that anything can be done but the why of most of it eludes me. I have seen several negative reviews of those engines. Despite the claimed numbers the 5 cyl has been considered fairly weak and longevity is an unsettled issue. Numerous head/overheating problems reported-at least with those old enough to have a few miles on them. GM's classic " (AB)use the customer to find and correct vehicle problems" may have taken care of many of the issues in the newer versions. I have read " all the power of a 4cyl with the mileage of a 6cyl" more than once. I get 17 city/24 Highway in a 3.7L/6spd KJ with a lift and 31" mud tires and an aggressive driving style . And it weighs at least 4,200 #'s, or about 1,200 pounds more than an MJ and 800 #'s more than a Canyon. The Colorado only weighs about 400 hundred pounds more than an MJ yet it's EPA figures are 15/20 for a 4wd!!! How is that impressive? I would almost doubt the Toyo swap guy's claims. :roll: An FJ80 and an H3 both weigh about the same but the H3 is estimated at 13/17 for EPA MPG so....another internet BS story? It is possible that he realized a performance increase as Toy's inline 6 is a poor performing, gas-guzzling turd. I am fairly certain my 225K mile '91 MJ gets around the 17/25 claimed MPG of a 5 cyl 2wd Colorado. Junkyard 4.0 around here is closer to $200-$400 dollars. $1,500 for a junkyard 4.0??? You can get a rebuilt longblock for about that. The "average" internet price for a used 5cyl is about $1,200 per Google. If you think you can buy the 5cyl fully dressed and with its electronics and adapt it to an MJ for between $300 and $1500 dollars I would like to see it. I think you are at least 75% below the actual cost of the swap for most people. If you want to do this swap for the "gee I did it factor" that is one thing but thinking you will recover the cost/time/aggravation on increased MPG in a reasonable amount of time ( if such a gain exists beyond the one Toyo dude's claims) is not realistic IMHO. Link to comment Share on other sites More sharing options...
Burls Posted January 13, 2012 Share Posted January 13, 2012 That's odd :D ! I've driven my friends colorado before and got around 18 mpgs on a 3 hour drive. My truck with the 4.0,ax15, 33s and 3.07s gets between 16-20 depending on how heavy my foot is, its nice to have another motor to be able to swap in but I'll stick with a motor I like and know :smart: Only 18mpg? I had an 04 reg cab z71 4x4 i5 with a slushbox and normally got 23-25mpg on all hwy trips. My 50/50 driving usually netted me 21-22 mpg. My moms crew cab was about 2-3 mpg lower due to the weight and possibly the gear ratio. I had 3.73s(seemed to be the perfect ratio) and my mom had 3.42s. It would definitely be interesting to see an atlas i5 in a mj. I'm sure it would move the comanche around with ease and have some decent mpg numbers. Link to comment Share on other sites More sharing options...
jimoshel Posted January 13, 2012 Share Posted January 13, 2012 Would like to try that. Somebody got a 5cyl Chevy they'll loan (give) me? Promise. I'll give it back when I'm thru with it. :D Link to comment Share on other sites More sharing options...
xjrev10 Posted January 13, 2012 Share Posted January 13, 2012 As a big fan of inline engines, I will be watching this. I know they put L6s in Trail Blazers but I don't know anything about them. Link to comment Share on other sites More sharing options...
johnj92131 Posted January 13, 2012 Share Posted January 13, 2012 The thing missing from these mpg numbers is at what road speed are we speaking of?? On a recent long trip I averaged 23 mpg at 55-60 mph with my AW4 4.0 1991 long bed. My around town mpg is 15/16, which is what the truck does most of the time. (average 3K miles per year over the last 6 years, so fuel cost is not a real issue). I use my VW Passat TDI for long trips and get 40 plus mpg, or about $.10 per mile traveled, compared to using the gas fueled Camry or Rodeo at something like 11 to 16 cents per mile. Remember, I am in California. Bottom line is that no engine conversion will pay off in less than 300K miles by my calculations. So do an engine conversion because you want to play with your toys. Don't claim you will save money. Hornbrod has a sweet Comanche, but he will never claim it is a cheap project (at least I don't think so). Remember, the difference between a man and a boy is the price of his toys. And our trucks are just our toys, for the most part. Link to comment Share on other sites More sharing options...
jimoshel Posted January 13, 2012 Share Posted January 13, 2012 Remember, the difference between a man and a boy is the price of his toys. And our trucks are just our toys, for the most part. El Jimbo's version. The difference between a man and a boy is the size of his GF's bo,,,, er,,chest adornments. :D Link to comment Share on other sites More sharing options...
Incommando Posted January 13, 2012 Share Posted January 13, 2012 36G (36DDD + a bit more) Do I be a man? Link to comment Share on other sites More sharing options...
mvusse Posted January 13, 2012 Share Posted January 13, 2012 Although I personally see no need to get rid of a good running 4.0 in a stock truck (mine got 24mpg on the highway when still stock if I kept my speed down to 60mph and had plenty of power), most of us like to modify, improve and/or personalize our rides. Some do it by lifting and fitting larger tires (typical), some due it by lowering their truck and trying to stuff large rims with rubber bands for tires inside the fenders (not my thing, but I can appreciate the engineering and fabricating to make it work), and some go for engine swaps. Out of those, the 4BT diesel is probably my favorite if anybody can figure out how to fit a twin turbo setup UNDER the hood without modifying said hood. If I ever do something like that I might go with a VW ot Mercedes diesel and go for mileage instead of power. A 5 cylinder Atlas would be somewhat unique as I don't know of anyone having done it in a Comanche, so why not. Good luck and have fun with your project, I will be watching for updates throughout the build. Link to comment Share on other sites More sharing options...
Worlds Fastest Comanche Posted January 14, 2012 Author Share Posted January 14, 2012 :hijack: See if we can get back on track, some people get 12 mpg with their 4.0 Comanches and some get 20 mpg. you can get a junkyard 4.0 for $250 or $1500 If you want a late model, low mileage engine, you probably will not get it for $250. I did some research of my own and a 2007 and up 5 cylinder Vortec 3700 does go in the $1,200- $1,500 range. Here is a link to a guy who paid $1,200 for a fully dressed 6 cylinder with 24 miles on it. http://www.vortec4200.com/forum1/viewtopic.php?f=10&t=786 That's 24 NOT 24,00. Using a Car-part.com search i did find 5 cylinder engines for $800-$900 some with less than 100,000 miles on them. So I am talking about a 2007 and up motor, a 4.0 would be a 2005 or earlier. The motor is lighter weight, more efficient, and has 50 more hp than a late model HO and about 60 more than the motors in the Comanche. It will also rev 1,000 rpm higher than a 4.0 allowing you to use lower gears and still be able to reach the same top speeds. Gas mileage: well throwing out the Magic Comanches that will consistently get 25mpg, I will pick a number that i think is a reasonable based on the Cherokees and Comanches i have personally owned. I will throw out the mileage from the Bonneville truck (4mpg) and say that my average mileage was about 16 mpg. If i drove 25,000 miles per year i would use 1,562.5 gallons of gas @ $3.50 per gallon that is $5,468.75 in fuel costs. If the 5 cylinder would give a 10% saving, that would be $546.00 I really think it would exceed 20%, a 20% saving is around $1,100 per year. 20% is only around 3 mpg. My wife's Trailbalzer with a 6 cylinder and is way heavier than a Comanche gets 18 mpg all day long around town. If the Colorado is rated at 19, there is your 3mpg ( and an increase of 50hp). Don't forget its an all aluminum engine that is much lighter, so less weight = more mpg ( ok somebody argue with that) Less weight also means less wear on front hubs suspension components etc. Is the 4.0 a great engine? Absolutely! The the Atlas motors are great too. If i could just pick any engine to put in a Comanche, it would be the 3.6L v6 Pentstar they are putting in the Grand Cherokee and the Wrangler. 286hp. The version in the charger is 305hp Problem is that you are talking big bucks. I have a grand Cherokee and with the Pentstar and i get 24 mpg driving 70mph. Great motor. But the idea was to do something on the cheap that somehow improves the vehicle. I think most people like to make changes to their truck, at minimum tires and wheels, probably a lift of some kind, maybe change the air cleaner to a better flowing one or put a header on it. change the bumper, etc. I think almost everybody wants more hp and better mpg, I say almost because i know somebody will come up with a reason that more hp and better mpg is a bad thing. Many of us buy a Comanche not because of what it is, but because we have vision of what we would like it to be. We see potential. to some extent that is how I am looking at the Atlas motors. I have built a 4.0 to a 5.0 and got 440 hp out of it naturally aspirated. It cost a ton of money and the bang for the buck was not there. The 5 cylinder installed is only the starting point. You have a fully programmable PCM ( EFI Live) A cross flow cylinder head that takes very well to a turbo. Probably another 75-100 hp easy. Then if we start talking E85, 450hp street truck. Seem like allot? A Cobalt from the factory with a 2L Ecotech produces 260 hp. 130hp per liter, so 3.7L x 130 hp = 481 hp and thats on pump gas! OK you can start your flaming now Link to comment Share on other sites More sharing options...
Worlds Fastest Comanche Posted January 14, 2012 Author Share Posted January 14, 2012 Here is a picture of the factory motor mount on the Atlas engine. The thing with the red cap is where the lower radiator hose attaches. This is a 6 cylinder, you can see the front sump pan that would not work in a jeep. the 5 cylinder has a rear sump. Link to comment Share on other sites More sharing options...
jimoshel Posted January 14, 2012 Share Posted January 14, 2012 How hard would it be to convert to a rear sump? Or even a remote sump?Obviously a custom fabricated pan but how about the oil pump and pick up? Link to comment Share on other sites More sharing options...
HOrnbrod Posted January 14, 2012 Share Posted January 14, 2012 Hornbrod has a sweet Comanche, but he will never claim it is a cheap project (at least I don't think so). Thanks John, and you are exactly correct. :( I think all these 23-25 MPG 4.0L guesstimates are just that - uncorrected speedo/odo readings after gear changes, bigger tires, etc. and those that post these ridiculous MPG claims are living in their own private dream world. My stroker is horrible around town (12-14) but super on the highway (21-23). But it requires 93 octane to get this MPG because of the CR. And everything's correct on my MPG, speedo gear, and GPS verified. The Hesco stroker is coming up on five years now, and I've never had an engine problem. The crate engine was not cheap, but it was a hell of a lot cheaper than they are now. IF I were considering modding another MJ for performance (I'm not, I'm happy :D ), the 5 banger Armstrong would be a damn good option should I ever do it again, and thanks to Peter for the facts. It beats the crap out of trying to cool a SBC block or similar, is mucho easier to install, and has good performance options. I too would love to see someone do this conversion. Link to comment Share on other sites More sharing options...
Worlds Fastest Comanche Posted January 14, 2012 Author Share Posted January 14, 2012 The 6 cylinder would totally blow away a 4.0 A stroker is a different story. The 6 cylinder is rated at 291hp, but a stroker would probably beat it a little in the peack torque department. On the other hand, because of the flat torque curve of the vortec, you would have more torque available at lower RPMs. As for the oilpan, well here is one solution. I guess all you need is a citoff wheel, some aluminum diamond plate and a tig welder Here is a link to a thread on the Colorodo 4x4 forum that talks about this conversion. http://colorado4x4.org/vbb/showthread.php?t=155422 I think the 6 cylinder would be a great way to go, but the costs associated with the oilpan and a Manual transmission flywheel seemed a little high to comapre with a stock engine replacement. There is a guy who makes an oilpan and he wants about $700.00 for it. Self racing sells a flywheel but it is $500. So those two items alone are $1,200.00 Here is a thread and it shows how to stretch and relocate the stock pickup tube and screen. http://www.vortec4200.com/forum1/viewtopic.php?f=10&t=780 Link to comment Share on other sites More sharing options...
Incommando Posted January 14, 2012 Share Posted January 14, 2012 Can't wait to see all of these 5 cyl swaps :wrench: and the methods used to to increase the mileage so much over the factory applications' numbers cited from credible sources. And I hope for a careful calculation of the total cost of the swap vs. the numbers of miles driven @ X provable MPG to see the length of the cost recovery (if any) in the real world. Even if the swapper values their time at $0 I like to see the total amount of time of the swap vs. an engine R&R. Should be interesting to see how this would go vs. an r&r using the 84,000 mile '99 4.0 available locally right now for $300. Link to comment Share on other sites More sharing options...
Sir Sam Posted January 14, 2012 Share Posted January 14, 2012 I think all these 23-25 MPG 4.0L guesstimates are just that - uncorrected speedo/odo readings after gear changes, Not in my XJ at least, those are very attainable numbers for me on the highway. Link to comment Share on other sites More sharing options...
terrawombat Posted January 14, 2012 Share Posted January 14, 2012 Not in my XJ at least, those are very attainable numbers for me on the highway. Driving at 60MPH, down a hill, with the tires inflated to 60PSI? Even the 70K mile '98XJ I had wouldn't ever go over 21MPG on the highway no matter what speed I cruised at. Link to comment Share on other sites More sharing options...
Thunderbear Posted January 14, 2012 Share Posted January 14, 2012 Here is a picture of the factory motor mount on the Atlas engine. The thing with the red cap is where the lower radiator hose attaches. This is a 6 cylinder, you can see the front sump pan that would not work in a jeep. the 5 cylinder has a rear sump. What jackass decided putting the axle through the sump was a viable plan? Unfreakingbelievable. I would like to see this swap, as well. Link to comment Share on other sites More sharing options...
Incommando Posted January 15, 2012 Share Posted January 15, 2012 I think all these 23-25 MPG 4.0L guesstimates are just that - uncorrected speedo/odo readings after gear changes, Not in my XJ at least, those are very attainable numbers for me on the highway. A pure highway tank gets me 24 in my much heavier KJ albeit with a different engine. Adding taller tires without a gear change ( probably the most common scenario) would cause an uncorrected MPG figure to be lower than it really is, yes? 23 highway in a fly weight MJ? Very believable. Link to comment Share on other sites More sharing options...
HOrnbrod Posted January 15, 2012 Share Posted January 15, 2012 Yes, on a pure highway tank full, I get right at 23 MPG w. the stroker. Some were posting over 20 MPG averages which I can not believe. Link to comment Share on other sites More sharing options...
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