Big Power Jeep Straight Six Stroker Build on a Budget with Newcomer Racing

[Music] these days people act unimpressed unless an engine makes four-digit horsepower numbers but true fans of all American horsepower should be able to appreciate this build how about a straight six defensive build that bumps up the horsepower by well over 50% for right around five grand not too bad huh Keith's newcomer of Newcomer racing builds lots of variations of the Jeep straight-6 for off-roaders mud boggers and racers this particular build is a budget stroker but we're impressed with just how much power he's able to develop out of this meal without spending a ton of bucks the recipe for a budget stroker build is to start with a four liter block and make that with the crank and connecting rods from a Jeep 4.2 liter engine the four liter block is critical because it allows for a larger board in this case new comer has punched out the stock 3.875 inch diameter cylinder bores to three point nine zero five inches combined with a three point eight nine five inch stroke crank from the 4.2 liter engine that makes for a total displacement of 280 cubic inches or if you're into that European stuff four point five nine liters this particular block is known as a 449 casting and it's out of a 99 Cherokee the 4:49 is an NVH block which you can see on the side of the casting and that just means efforts have been made to reduce noise vibration and harshness for us however the benefit is the NVH blocks came with a block main girdle and more webbing internally that helps stiffen up the bottom end and handle additional horsepower remember this is a budget-friendly build so many of the parts use will be stock replacement level stuff here new comer has measured and installed the new main bearings and applies a thick coat of assembly Lube [Music] as we mentioned earlier this crank came out of an AMC 4.2 litre straight-six which is 258 cubic inches but it is important to note that this crank is the lightweight version found in 81 and up AMC's here's one of the heavy weight pre 81 cranks note that it is fully counterweighted between every journal and now compare it to the newer lightweight factory crank which has only four counterweights we're talking 37 total pounds versus approximately 65 and that makes the newer crank the obvious better choice for almost every naturally aspirated build the rotating assembly uses the same om connecting rods from a 4.2 liter engine all 4.2 rods are 5.8 75 inches long but they aren't all the same the connecting rods from 71 through 81 engines are generally considered stronger those are the blocks with a 707 number in the casting code 82 and up engines those were with casting code 352 are lighter weight and not as strong so they're to be avoided if possible newcomer has also upgraded these rods with high-strength ARP through bolts the Pistons meanwhile are all new sealed power hypereutectic castings they are definitely better than the stock slugs but still quite affordable a small dish helps keep the compression ratio pump gas friendly even with the added stroke they're also outfitted with a 1.5 1.5 3 millimeter ring package [Music] running the valvetrain is a bullet racing cams bump stick newcomer has spent a lot of time and money testing different combinations to squeeze the most bang for the buck out of this combo so we won't give away all of his camp specs but we can tell you that the hydraulic flat tappet cam has over 210 degrees of duration for both the intakes and exhaust at 50,000 s lifts and just under 500,000 scrub a lift the idea here is to maximize torque and build a healthy power band under the red line which newcomer says to be safe should be right around 5,000 rpm we aren't using the heaviest valve springs so a healthy coat of assembly Lube on the lobes is all that's needed and the cam is ready to go into place [Music] after the bullet camshaft the crank is laid into the saddles the main bearing sizes are the same between the four oh and the four - and normally it isn't necessary to clearance a 400 block for the extra stroke so the cranks should just drop right in the mains are torqued to a 100 pound feet with motor oil lubricating the threads one area where newcomer recommends splurging a little bit is with a timing chain this is a double roller from roll master they feature billet gears and not only don't really stretch but they also hold up much better to abuse and hardcore off-roading much better than a stock replacement [Music] after verifying the cam timing Newcomer finishes dropping in the other five pistons and rods No the rod bolts are torqued to 28 pound feet and with that the short block is basically complete next up are the hydraulic flat tappet lifters again with plenty of assembly Lube to protect them during the first fire up it can be tough to get the lifters all the way down into the block where they made up with the camshaft so Newcomer uses a magnet to help get each into its proper lifter bore stock replacement valve springs and retainers are used in the cylinder head new comer says they're good if you're building a stroker with relatively low redline to improve air flow new comer has pocket ported this head and back cut the valves but many more options are available for example he also has a cylinder head that's been completely worked over for a high horsepower turbo 6-cylinder bill coming up that's the ported head in the back and I asked newcomer to explain the differences this is like this is an H Oh head so be like a 7120 casting number this is a o6 3ov it'll be marked right in here basically this head started in 96 so this head would have been from like 91 to 95 this had been ninety six seven eight that's pretty much it this head would have dowels that would locate it on the block to the Doucet locate the head keep it from moving around but you can use this head you can use either head you want the dowels simply just sit in the open area if you decide you want to 70 120 on it but that head is about my exporters about as big as you're gonna get and we put a 205 55 LS valve eight millimeter in that one and this has got stock sized valve which would be like a 191 150 valve so as you can see it is quite a bit bigger so stop the stop which is the higher flowing head which is the better stop head these heads are actually about identical the next the version before would be a training said before this one and they were pretty much horrible and it's maybe in slight upgrade from a four to head and then the head next version up from this one would be like a high port exhaust the intake space the same but the exhaust was raised and a lot smaller for admissions yes this is going to be one of the next bills and it's as you can see it's it's big as you can see the pore size differs it's huge before you ported it they're pretty much identical okay yeah but for our naturally aspirated stroker build the cylinder head really doesn't need all that work it's got a bow blend a nice valve job back cut the vows and that's really about it for the head and everything up top is stock we're trying to go with low like a low spring rate so you get a long life out of cam not a lot of wear so we'll find out on the dyno if it likes it or not if it doesn't like it we'll have to up the spring rate so it doesn't float the valves or anything but as long as we can turn it to the red line which is 4900 if we can turn it to five and it doesn't float the valves I'm happy with it so the cylinder head drops into place with a standard composition gasket and the new head bolts are torqued to a hundred pound feet in stages [Music] the push rods were 5/16 in diameter with a 9 600 inch length new comer says if you're running a more aggressive camshaft with stronger Springs 3/8 inch diameter push rods may be necessary but to get them to fit without rubbing you have to slide the push rod holes in the cylinder head stock style rockers with a 1.6 to 1 ratio are used notice the straps used to help provide a little additional stabilization so this block came originally with a thrust washer to control your end play newer blocks have a thrust like a thrust plate the old ones have the cam button spring-loaded cam button and we just converted it and you'll just hook a time to cover up ever use the cam button off the front to set your employee because a lot of times the cams aren't easy to get with a thrust and those are easy to get for course so we just use that and convert it [Music] back on the bottom side of the engine this is the stamp steel om Mangalam with the mvh blocks it may not look like the beefiest thing in the world but every little bit helps right if you're running a stroker engine package make sure to recheck the clearance between the big end of the connecting rods and the girdle as the rods swing past you may need to add washers underneath the girdle to raise it up a little bit a little silicone and the corners helps ensure there will be no annoying oil leaks and a quality one-piece oil pan gasket is dropped in place before the stock oil pan is bolted down [Music] and now here we are at the diner with our stroker engine nearly complete an MSD ignition system provides the spark the plug wires are obviously too long but they're just a dyno set these are actually a used set of NASCAR Cup wires with ultra-low resistance hey here in North Carolina that stuff is practically everywhere both the intake and the exhaust are on the same side of the cylinder head and they actually share some of the same bolts for mounting thanks to large washers that overlap both the intake and the exhaust flanges Newcomer often fabricates headers for US custom high horsepower engines but because we're working on a budget here he says that these are some no-name eBay headers with a 3-inch collector the intake manifold is a cast aluminum aftermarket piece the newcomer is ported and modified to accept a highly style 4150 carb the customer will reuse his throttle body fuel injection system on this motor but for our testing we've bolted up a 950 CFM holley double pumper that's probably a bit too big for street use but on the dyno it'll do just fine newcomers found that a 1 inch spacer between either the throttle body or carburetor and the intake manifold also helps improve power so as you can see we've added one here [Music] and now we're ready to make some steam I'm always amazed to just have bluesy on the dyno the engine ran well and we were able to pull the 5200 rpm before the valves began to play so the stock valve springs actually did just a touch better than you come on originally expected overall the strokes are made excellent torque it never dipped below 300 pound feet from the beginning of the pullet 3,000 RPM all the way to 5200 peak torque was 329 and a half at 4,500 and for what many may consider a mild combo it pumped out an amazing 300 4.4 horsepower at 5100 RPM considering that in stock form the best the straight-6 could do was 190 horsepower this pump gas stroker is going to be quite the beast newcomer says you can also get this power with the OEM efi system but of course we're not talking about the older rinax engine management systems but it will require higher flowing 24 pound per hour injectors and a bigger fuel pump like a 225 walbro it isn't absolutely necessary but retuning the ECM is also recommended and of course we called this a budget build so we need to get to the numbers Newcomer says his bare long block like this goes for 3500 bucks which is quite a deal considering all the new parts and the fact that the block in the heads have been fully machined of course this is being filmed in 2019 so if you're watching this video and it's 2025 or something don't expect those numbers to be the same the complete engine varies with options but this one sold for right around 5,000 that includes internally balancing the rotating assembly bowl blending ported the intake accessories dyno time and shipping for all that torque and an additional 115 horsepower I consider that an awfully good bang for your buck [Music]

Channel: The Horsepower Monster

Views: 1,004,497

Keywords: Jeep engine, Jeep engine build, AMC engine build, jeep stroker 4.0, jeep stroker 4.2, 4.0 engine build, 4.2 engine build, Jeff Huneycutt, Horsepower Monster, off road engine, how to build an engine, budget jeep engine build, budget amc engine build, budget amc stroker engine, horsepower, stroker engine, Jeep cherokee engine, jeep wrangler engine, Keith Newcomer, Newcomer Racing, engine dyno, engine building tips, inline six, jeep cherokee, jeep xj, jeep cj engine

Id: WlHrqhwojf0

Length: 15min 59sec (959 seconds)

Published: Fri Aug 23 2019