Rebuilding a 4.0L Jeep Straight Six to 242HP - Engine Power S2, E14

today about

engine

power

a performance upgrade at the heart of

jeep

history the four-liter inline six-cylinder

engine

welcome to engine

power

today a new bill begins we call it project 242 now it's not a v8, is a 6-cylinder inline that had a high production This race that lasted 19 years has propelled millions of vehicles through trails, streets, deserts and mountains of several different countries, while establishing a standard of reliability that us made me want to build a modernized version using the latest performance parts built specifically for it, the super. The reliable 242-inch inline six-cylinder engines were first introduced in 1987 by Jeep owners.

I see these all-iron workhorses provided plenty of low-rpm torque for millions of Jeeps, from Cherokees to Grand Cherokees and from Comanches to Wranglers, that grunt went over one hundred and seventy-three horsepower. with 220 pound-feet and 87 up to one hundred and ninety horsepower and 235 pound-feet of torque in 2006 during its two decades of operation, Jeep produced more than five million for the leaders in its Kenosha Wisconsin Plan. It's always good to know the strengths and weaknesses of this 1987 block. It was the first year for the four-liter engine and was designed with seven main bearings to retain the long crankshaft.

They had a 3/8 80 bore with a 3/4 40 stroke, making the engine too square. Longevity was key and the inline design allowed for minimum cylinder, we are allowing these engines to run several hundred thousand miles. The only real weaknesses that emerged were lack of maintenance, such as running out of oil, letting them overheat, or just pure negligence. With a project name like 242, you may think we're talking about cubic inches, but it's actually the number of horsepower. We were more than a chase in the crankshaft. Now our goal is to generate one horsepower per cubic inch from this robust, reliable but somewhat anemic engine.

Now we are not petting it and we are not petting it. These are real world horsepower numbers based on an original short block. To make that happen, we're going to use these new Edelbrock Performer aluminum cylinder heads designed specifically for the 1987 to 2006 four-liter, one-hundred-and-forty-four. CC intake runner and a 77 CC exhaust runner on the valve side, the intakes are one nine ten and the exhaust is one five hundred, just like the originals, the combustion chamber is fifty five CC versus the heads original 57, but the most important part is at 500 thousand valves, lift this head, it comes out of the original head at 52 CFM to be able to use it, we have to assemble the short block now, we already checked all the clearances of our main bearings and recorded those numbers on our engine build sheet.

You can find on the om website that the clearances are very forgiving, unlike racing engines the clearances for this four liter range from 29 to 32 ten mils during machining. Our connecting rods and main journals were ground down to a size less than ten thousand, so a specific bearing is required to compensate for the smaller size. Trunnion Cut Light P Series main rods and rods will fill the saddles as our engines are always primed before starting. We're using our thirty break-in oil to lubricate the bearings before the cast crankshaft goes in. We want to see what works. weighs, compresses the scale at 57 pounds, this engine in its complete factory form weighs 483 pounds now, at any time, you can save weight while building the actual engine, this helps the entire vehicle run better and we have a lot of weight savings with the pieces we choose. up on the top end, put the crank on it and nice and flat is the way to do it.

You're not moving furniture. You're building an engine here, so take it easy. The seven main caps can be locked into place and adjusted from the center outwards. They are torqued to 70 foot pounds with CMD extreme pressure lubricant in the same center-out pattern the last measurement on the crank is to check the thrust clearance we have six thousandths not a bad start next a mix of new components and old to reach our goal We are back with project 242, now the camshaft for this engine was a pretty easy choice from Crane Cams and we want this engine to produce good torque at low revs and also have a good usable powerband , is now a hydraulic flat tappet piece that has a fairly aggressive profile for an inline 6 engine, but is necessary to complement the flow numbers that the Edelbrock cylinder head produces and take advantage of this flat tappet combo to heat up between the lobe of the cylinder head. cam and lifter face due to additional friction, so a lubricant with high ZD DP levels is necessary to prevent damage to the lobes during break-in, cam life is 50 mil in intake is 216 degrees, the exhaust is 228, the valve lift is 484 on the intake, 512 on the exhaust and the RPM range is 1,800 to 5,400 and like the crank, the cam must rotate freely without binding, the timing assembly only works in one direction so while we are here it is being installed, stock units are not known for failing and we picked one up at autozone Summit Racing was ours.

The source of this omics timing cover is cast aluminum and has the timing markings built into it. ARP fasteners will tighten it. The balancer is made with professional products and will complement all other moving parts that allow this engine to run smoothly and the only way. to make it work is with the pistons and rods, these are as basic as the rods are cast, they have a press fit pin, they weigh 660 grams and have a center to center length of 6 125, the pistons are cast aluminum which have been heat treated and CNC machined now on the top they have a plate with a D-shaped cup and support a pack of rings 564 is 564 CH 3 sixteenths to seal the cylinders smeared with engine oil, we can place them using a ring compressor under the The caps are placed and by tightening them, we will put enough crust on the bearing, which will allow us to rotate it without damaging it.

Now our clearances are all within range, as are the principals. Once all six are in, we can torque the nuts to 33 foot-pounds. The heart of the engine is like yours in mind Its job is to pump fluids to all the vital elements to keep them running overtime Ours is a Melling standard volume M-80 that will do just that for our four liter one gasket and two The bolts secure it. The truck matches the idle oil pan we ordered from Summit Racing. It is corrosion resistant and is guaranteed to fit like all the crankcases installed here. The ARP bolts will hold it in with the same lubricant we put on the cam lobes for proper breakage on the hydraulic plane.

The tappet risers can now be fitted before installing the cylinder head. We want to make a weight comparison between the original cylinder head and the aluminum one. Could it be half of the original cylinder head? He weighs 66 pounds. Our new Edelbrock piece weighs 37 pounds for a 29 pound reduction in seal. attached to the deck is this Edelbrock MLS head gasket. Now there are no dowels on the AMC 400 or 4.2 liter engines to align the gasket and head, so here's a quick tip by cutting the head off a 1/2 inch bolt and putting in a small notch. the top for a flathead screwdriver bit will allow you to align both is an easy way to ensure proper alignment ARP fasteners are the only way to do it with ultra torque lubricant will hold them in three steps 35 70 and finally one hundred foot-pounds Lubricate the ball ends of the pushrods to protect them during initial startup anywhere there is high pressure, this should be done especially on the valve stem.

Harlen Sharp offers a roller rocker arm conversion for four-liter engines. They are a full roller pedestal mount with a 1.6 ratio. The whip is difficult to place because the elevator plungers are collapsed, so we are bringing it closer now everyone is tightening and when we get to the dyno room we will prime it and the real genius or madness of the ash collector will be the mother of invention that comes next. We go back to that and continue with the induction. Now we did some research and discovered that the '99-later Cherokee intake manifold has a larger plenum area and a smoother transition in the runners and that all equals better airflow for the fuel delivery we asked for.

This quick and easy self-learning EFI fuel injection system is designed specifically for 1972 to 1991 Jeep CJ and YJ engines. The adapter supplied from the intake to the throttle body will not work with the new Cherokee intake manifold, so let's go to do it. Some major surgery here in the plenum area and you will love it. Air and fuel supply are the keys to generating power and the less restriction you have on the intake side the more power potential you will have, we were going to have to modify this intake. Anyway accept the quick adapter, so why not go one step further using this aluminum adapter that we found in our parts cage and we are going to recess it into the plenum of the collector and that will give us better breathing potential ?

The process begins with grinding. Lower a couple of bosses that allow the adapter to sit flush in the plenum. Tracing the outside diameter of the adapter to the inlet happens now, the tighter the line the better the time to blow the chip using a carbide end mill and some trans fluid for the material. No need to leave, let the bird do the work and take your time After opening a path and fighting a bit, it's time to make a decision on the battlefield and switch to the air. It's a little more precise and a lot less complicated for now.

With the middle part finally out I'll fine tune it with a carbide and a flap roller, let's see how it fits or not, be very careful not to take too much off, check often and take your time, you want a good fit so the weld will work. go easier Oh bonanza, using our Miller TIG welder will poke it in a couple places and then burn it out using a filler rod. Now there are a couple of tight spots that are really hard to hit with the TIG, but it didn't slow us down now. clean it with a wire brush and let it cool meanwhile we are ready for our freshly painted valve cover.

Now the dual color crinkle plus gray gave this thing a killer look and on the inside Pat removed all the baffling to clean our taller rockers the Edelbrock head accepts late and early model valve covers we keep ours with the factory Hardware the water pump can work now it is a new unit we picked up from Autozone the water neck also came from their parts house which does not I don't turn on a thermostat on the dyno it has one built in as there is no accessory we are wearing. Electric motor gasket and water pump pulley is a universal kit that comes with spacers and many accessories The bracket attaches to two protrusions on the block It also acts as a locator that takes no tension due to the COG design Now it's time to Our modified induction and some rugged Ridge exhausts sent us this 304 stainless steel header that has been polished to a beautiful finish.

The primaries measure an inch and a half and will complement our 4 liter power potential. They are installed at the same time since they share several of the same fasteners. Squeezing the AR peas will compress the gasket for a good seal. An MSD Pro Billet distributor designed for street performance is dropping. It has mechanical and vacuum advance to maintain stable timing at each rpm. We locked it down for the dyno III races. The diamond spark plugs will ignite the air/fuel mixture and the pre-terminated eight point five millimeter superconducting wires on MSDS will supply them with voltage to the engine.

At this stage of assembly we need to place it on the docking board which makes it simple. The task for us is our Condell overhead crane and our Slanket engine, there's the test bed, next in our quest for horsepower per cubic inch. We're back and we're very close to hearing the beats of Project 242 come to life on the testbed. The elevators are there. Yeah, while Pat's real ash on the valves, here come the gaskets and throttle bracket, which are covered by this efi throttle body that houses the fuel rails for the injectors and some sensors. The harness is pre-labeled, making it self-explanatory with the three power cables attached.

Along with weatherproof ECU and computerhandheld, we can fill the cell with 87 octane fuel. The ignition moment is encouraging. We will start this session at 28 degrees applying a light load at multiple throttle positions. We are simulating a vehicle driving down. the road the best we can now the injection needs to see this for its adaptive learning process we will do the first pole from 2,500 to 4,000 to see if the injection system and our highly modified manifold move together 220 foot-pounds of torque 133 um power , I'm thinking that it's not the injection of our madness that did this, but let's see what multiple magic does or can have, there is a serious problem here, well, it's not the injection's fault, no, not at all, unfortunately, sometimes things don't work out. work as planned, concrete example of our highly modified manifold, injection system works perfect, starts at idle, does everything it's supposed to do, what's the big problem is that our modifications to the manifold have changed the characteristics so much which doesn't like to run on this setup, so what we're going to do is go old school, we'll put a carburetor on it and try to make some noise with it and see what happens. is our tried and true 750 CFM dining unit last seen in Little Black and Blue.

It sits on a one inch HVH spacer and the quick adapter we don't know how it will act on this engine due to its size. but we know it's a great car, it could be good for us. Wow, look at that torque, 273 pound-feet, 213 horsepower, Donny, yeah, let's spend some time here, since with any engine we'll do our normal tuning procedure and advance the timing in small increments. to find your torque threshold, which ended up at 34 degrees, man, go right through it to 28 to 83, right threshold, that threshold is fine, so we went back to 33 and did a substantial jet change for our last attempt, our last chance was raised. ready, I hope something good happens, okay, come on, it's clean, boy, dog, clean, pull, yeah, a horse for Q, it's not like that on the hill.

Wow, I feel so much better now we got it, but we didn't get it, but we got it. with 286 torque which is extremely impressive see 177 which is a gain of 66 horsepower.220 and 66 in torque, the 66 LS dual swaps aren't slowing down and neither are the companies behind them, that's why Doug's is offering these one in seven eights long tubes that fit 67 to 69 and 68 to 70 Camaros for Novas that are getting an LS Transplant, the tubes are CNC bent for better flow and fit and are made of steel 16 gauge for longer life, they even have their metal ceramic coating, they are designed to decrease back pressure and increase power at high rpm and they even come with everything. to install them like Oh, two extensions, gasket and the rest of the hardware, the fair price is 650 dollars.

It is blue and has an ACME screw and will help you install engines and transmissions. This is the articulated motor lift plate with maximum pivot reaching angles up to 35 degrees. It now accepts most two and four barrel carburetor patterns and if you have a late model EFI engine, don't worry, they make several adapters to cover you. Now this is made from a quarter inch thick steel plate and all the hardware hardened. Plus the blue powder coat finish makes it look great now that with the weight of the motor hanging off, all you have to do is adjust the Acme screw to change the angle for easy installation.

The price, as you see it here, is one hundred and fifty-nine dollars at Summit. Racing since 2007, all vehicles produced in the US are required to have a tire pressure monitoring system or tpms, which is located on the wheel inside the tire, so it's in a pretty tough environment and , like all sensors, can fail and that can really attack. your wallet, which is why Rock Auto offers Sridhar TPMS sensors that are a one-for-one replacement for the ones coming off your vehicle's assembly line. The cost varies depending on what trip you have, so log on to Rock Auto comm to get your low price.

Well, that's all for us and we hope that if you learned something today, you're not afraid to experiment a little, after all, that's how this industry was created, see you next time.