After two decades of production, the third-generation 5.7 Hemi V-8 has amassed a solid reputation as Chrysler's bread-and-butter workhorse and high-performance platform. In that time, the company name on the Hemi V-8 has changed several times (the Hemi is now a Stellantis product) but that hasn't dented the third-gen Hemi's destiny as the go-to heavy-lift reactor core for the Dodge, Ram, Jeep, and Chrysler nameplates. A continuous string of upgrades over the years has gradually improved performance and fuel economy, and now that many Hemis are reaching the end of their normal life expectancy, interest is high in repairing and refurbishing these future classics.
Like all high-volume mass-produced V-8 engines, the Hemi has its inevitable share of issues. As a self-professed Mopar fan, this author has owned four vehicles with third-generation Hemi V-8s, and the MDS-equipped 5.7 Hemi unit in question was from a 2011 Dodge Challenger R/T with a five-speed NAG1 automatic. In a previous story, we detailed the original cause of trouble on this MDS-equipped unit—a defect in the timing chain and chain guide/tensioner—and the Hemi's subsequent failure at 235,000 miles from an issue related to improper dealership repairs.
If your Dodge dealership is repairing your 5.7 Hemi engine in conditions like this, it's too late to run away.
The backstory to this 5.7 Hemi begins at 66,000 miles (2014), when the timing chain unexpectedly snapped at highway speed in "Eco" mode during four-cylinder operation. The defect was repaired at a Dodge dealership in Moreno Valley, California, under Customer Satisfaction Notification P01. At the time, many dealerships were back-logged with Hemi timing chain defect repairs and this dealership took one or more poorly-advised shortcuts which we'll talk about in a moment. These shortcuts eventually resulted in a failure of head gasket integrity around 235,000 miles, a testament to the forgiving design of the Hemi, but because the car is the author's wife's daily driver and not a weekend toy, it eventually forced the replacement of the engine with a new factory-fresh partial long-block.
The dealer-repaired Hemi finally came out at 235,000 miles and was replaced with a new partial long-block unit from Mopar. Items like the intake manifold, oil pan, timing cover, and valve covers were reused.
Our last story covered the disassembly and post-mortem autopsy of the seasoned third-gen Hemi V-8. After disassembling and inspecting the high-mileage Hemi at IMM Engines in Indio, California, we realized that the Hemi looked remarkably good inside and could be refurbished to near-new condition with most of its original parts, and, more importantly, that readers could benefit from the process. We could answer such questions as, can you rebuild a 5.7 Hemi yourself? How much of the work can you do on your own and how much must be farmed out to a machine shop? Is rebuilding a Hemi cost-effective? Is it worth having an engine shop rebuild a 5.7 Hemi or is it cheaper to buy a reman unit? Let's look at the key steps in rebuilding a used, high-mileage 5.7 Hemi!
After removing the Hemi's cylinder heads we discovered the telltale signs of a high-speed abrasive disc having been used by the dealership on the cylinder head to clean the surface. This shortcut is not a generally accepted method for any aluminum cylinder head that uses a precision MLS gasket, as the Hemi does. This was ultimately the reason this engine failed, not the original timing chain failure, which seems to have been correctly addressed on the factory side by the upgraded timing chain guide. We'll get back to this point in a moment.
The passenger side of the Hemi short-block is shown with the head gasket still in place. Note the discoloration toward the front (right side) where coolant gradually escaped, causing an overheated condition that gradually got worse over time. We attempted to fix the leak previously with K-Seal in an earlier story, but by then the problem was too severe.
"With an insignificant amount of wear and no problems with the rods and the pistons, there's not a reason not to use them as long as the cylinder bore is in as good a shape," says Brian Hafliger of IMM. These piston/rod assemblies have been relieved of their original rings and are being placed in IMM's hot tank for cleaning, a service IMM charges $60 for. If rebuilding a Hemi at home, Brian says you can soak them in a bucket of mineral spirits overnight then use a wire brush to clean them.
After a quick check of the bore diameter with a dial bore gauge to measure the bore wear (our bores were consistent at the OE 3.917 inch) IMM used a 280-grit ball hone on the Hemi's cylinders. With the original cross-hatch from the factory hone still in evidence, we didn't expect this block to need more extensive honing or boring on a machine, but bore diameter in several places (top, middle, bottom) should be checked for consistency (i.e. no "barreling" in the center along the thrust axis or ridges at the extremes). Brian says the hone and bores should be coated with a cutting fluid of solvent or oil, and the number of strokes with the hone limited to between eight and 15 strokes.
This visual before-and-after comparison of the same 5.7 Hemi bore shows how dramatic a difference this simple step can make in leveling most of the high and low spots on the bore. This improves cylinder sealing, which reduces emissions, improves fuel economy, and gives a slight imperceptible boost to power. If you're looking to do this on your own, IMM says a good resource for tools and information is Brush Research.
Reusing the stock cast press-fit hypereutectic pistons saved us a lot of money; they're fine for stock levels of horsepower and can cope with most modest levels of bolt-on power up to around 500 hp, such as an emission-legal blower, cam/head swap, or modest nitrous kit. After being hot-tanked, IMM cleaned the piston crowns with a wire wheel. This removes any caked-on carbon and allows for closer scrutiny of the crown and ring lands for cracks and other damage.
Here, IMM uses a long precision machinist's straight-edge to check the fire deck of the cylinder block for straightness using a .002- and .003-inch feeler gauge. IMM's Brian Hafliger says: "If a two-thousandths will go under but a three won't, that's acceptable." This must be checked on both banks in multiple places, both along the engine's length, and across and between all bores. Any dips or peaks beyond this tolerance will require a trip to the block decking machine. This high-mileage cast-iron Hemi block tested ok.
After disassembling and hot-tanking the 5.7 Hemi's cylinder heads they were inspected for cracks, then the combustion chambers were cleaned more thoroughly with a wire brush, taking care not to tag any critical machined surfaces like valve seats or the fire deck. This allows closer inspection for telltale cracks and it preps the surface for cutting the valve seats, which IMM did at a later stage. These heads had previously been rebuilt at a Dodge dealership under warranty and the quality of that prior work was highly suspect, so our guard was up. We'll detail our concerns in a moment.
Brian Hafliger of IMM put our 5.7 Hemi cylinder heads on a deck machine using a PCD cutter designed for MLS gasket surfaces. This was to square the cylinder head decks after the heads failed the "go/no-go" feeler-gauge test. The heads were inconsistent and far from flat across their surfaces and this resulted in a sealing failure that ultimately overheated the engine, precipitating an engine swap. If you've ever taken a shortcut to cleaning the cylinder head gasket surface on an engine that uses an MLS head gasket (take note, LS and Ford fanboys!) an engine rebuild may be in your future. Let's look at how bad the damage was.
In this photo taken after a single pass with the PCD cutter, you can see how low areas adjacent to the cylinder bore are still evident (yellow arrows). Brian Hafliger says: "This is not just the head being bent, it's where the dealership mechanics ran their abrasion discs, because they don't know any better. A lot of these guys don't go to school and learn this stuff, they just get hired and turn wrenches. It is what it is." You can still see the dealership's grinding witness marks along the top of the photo. If you absolutely must do it fast on the cheap, use a razor blade, not an abrasive wheel (you still might suffer a future head gasket failure, but at least your cylinder heads will be flat!). Both cylinder heads required a .007-inch cut to clear the damage inflicted by the Dodge dealership.
After being disassembled, hot-tanked, cleaned, wire-brushed, decked, and given a valve job, these heads check out and are read for reassembly. At this point, they are indistinguishable from new, bare heads.
If rebuilding the Hemi at home, one outsourced move you'll want to make is to have the crankshaft polished, a service IMM charges $45 for (IMM's pricing on common machine shop jobs you'll want outsourced can be found in the chart at the bottom). According to IMM's Brian Hafliger, "We're just making sure there are no raised edges on the journals anywhere. Giving it a real fine, super-slick finish allows for better start-up wear. The smoother and cleaner the journal surface is the less chance there is of bearing wear."
In preparation for assembling the 5.7 Hemi short-block the stock camshaft was inspected for wear on important surfaces like lobes and journals. The factory MDS hydraulic-roller camshaft is heat treated, allowing us to reuse it without much worry, but sometimes a failed lifter can do damage to the lobes, so it's important to inspect them before reusing. Here, IMM polishes the cam bearing journals by hand with a small piece of fine emery cloth before reinstalling the cam.
After applying small dabs of assembly lube to the cam lobes and journals, IMM reinstalls the OE cam back into the prepped block, which has been inspected, hot-tanked, and cleaned, including the oil passages. Before installing the cam, the cam bearings were inspected and deemed acceptable for reuse.
The 5.7 Hemi's four camshaft thrust plate bolts should be torqued to 106 in-lb.
IMM installs the standard-sized Clevite main bearings (part No. MS2220A std. ) in preparation for receiving the polished OE cast crankshaft. Note in this split-screen that the bearing halves on the block carry the oil through the groove in the bearing and that there's only one orientation for both the block and the main caps.
IMM's Brian Hafliger deftly lays the OE cast crankshaft into the 5.7 Hemi block after applying a small amount of assembly lube to all the main bearing surfaces. It should fit snugly without binding or excessive clearance. From here, the center main cap will be installed and the endplay checked (with thrust bearings in place) before the other main caps are installed. Endplay along the thrust axis should be checked with a dial indicator after the center main cap is installed and the bolts are snugged. Endplay should read between .004 and .010 inch (ours was .005 inch).
The Hemi block's center main bearing is home to the all-important thrust bearings, which in our 235,000-mile unit were good to reuse. On the left, you can see for illustration's sake (without the crankshaft in place) where these bearings ride. In practice, they are inserted after the crankshaft is placed into the block and before the main caps are torqued on.
The main caps are matched to their place in the block and numbers are etched into them for less confusion—mismatching the caps can result in engine failure. Main cap bolts are torqued first to 20 ft-lb in a spiral sequence starting in the center, then gone over again with an additional 90 degrees of twist. The cross bolts are then torqued to 21 ft-lb. If you're rebuilding the 5.7 Hemi at home, we highly recommend SA Design's "New Hemi Engines 2003-Present: How To Rebuild" book by Larry Shepard ($34.95).
With the cam in and the main bearings installed and torqued, it's time to install the timing chain and gears. An inspection of the OE timing gear and chain (replaced at 66,000 miles) showed little wear so it was reused. This split image shows how the crankshaft timing gear "dot" lines up with the single chain link having the rectangular icon facing outward (yellow arrow, at left). The right side shows how the cast-in slot mark on the camshaft gear (yellow arrow, right) lines up between the pair of timing chain links that have two consecutive rectangular icons.
The Hemi's updated timing chain guide is installed first. This is a nylon-lined aluminum piece that was originally developed for the 6.4-liter "Apache" Hemi (also known as the 392). The original 5.7-liter "Eagle" chain guide is a black plastic piece that shattered at 66,000 miles and was at the center of the silent recall under Customer Satisfaction Notification P01. The recall entailed replacing the chain guide with the stronger 392ci Apache unit shown; almost no guide wear was observed on this one after an interval of 169,000 miles.
In this throwback photo from the original dealership repair in 2014, you can see the original black plastic timing chain guide that was the subject of the original recall. It has shattered in two pieces after enduring excessive wear from repeated cycling of the MDS system. If rebuilding your 5.7 Hemi, make sure you use the updated nylon-lined aluminum chain guide from the 6.4-liter Apache Hemi, shown previously.
IMM's Brian Hafliger lines up the timing chain on the crank sprocket at the indicated sprocket tooth dot, then slides the camshaft sprocket over the end of the cam to engage the cam dowel pin at its correct clocking. As seen with the engine in right-side up orientation, the camshaft pin and the identifying slot on the cam gear should be at 12 o'clock and the crankshaft keyway should be at the 2 o'clock position when "lining up the dots."
The 5.7 Hemi's timing chain tensioner is made of two black plastic pieces on a hinge with an integral spring-loaded cylinder on one side. Use a thick piece of wire about the thickness of a coat hanger to lock the halves together before installation. Once the tensioner is installed and snugged, the pin can be pulled out to put tension on the timing chain.
All timing chain guide and tensioner bolts get torqued to 250 in-lb. The cam bolt gets torqued to 90 ft-lb. Once these are torqued, the retaining pin on the black plastic tensioner assembly can be pulled out. At this point, we turned our attention to final assembly of the 5.7-liter Eagle cylinder heads and IMM also took the time to paint the block an exciting Hemi orange.
If you're rebuilding your Hemi at home, chances are good you'll have your machine shop disassemble, clean, machine, and rebuild your heads, but if you do a stock rebuild yourself, the only new parts you'll need are the oil control seals, shown up front as Mahle part number SS46045A. At this juncture, IMM has already touched up the valve seats (45 degrees) and put a new cut on the valves (44.5 degrees).
IMM begins the Hemi cylinder head assembly by cleaning the valve guides of the 5.7 Hemi cylinder heads using a specialized nylon brush designed for this job.
The ends of the valve stems are dabbed with a touch of engine assembly lube and carefully inserted back into the valve guides, which are made of chilled iron on the Hemi.
Using an old half-inch deep drive socket as an installation tool, the positive-control oil seals are pushed onto the valves. A light touch is all that's needed here.
The Hemi cylinder heads are aluminum and require steel valve-pocket shims, which are the same for both intake and exhaust valves. These stock units are reinstalled before the valvesprings go back on.
IMM uses a pneumatic valvespring compressor tool (a life-saver when you're building as many engines as IMM does) but you can save some dough by using a manual valvespring compressor. Your goal is to avoid side-loading the valve stem on the valve guide when compressing the spring. You want to compress the spring just enough to admit the two wedge-shaped semi-circular keepers into the valve retainer.
This engine took standard-bore 3.917-inch rings but you should only order rings or pistons (if needed) after your block has been cleaned, inspected, and any honing or boring is completed. Before putting the rings in your pistons, verify the ring end-gap in the bore. Ring gap should be between 12 and 24-thousandths of an inch, but IMM likes to see them tighter, between 12 and 16 thousandths. We like the Mahle products for quality and consistency.
Our reuse of the stock press-fit rod/piston assemblies saved us a ton of money, only needing new rod bearings and rings after a thorough cleaning and inspection for cracks and other damage. The important thing here is to keep track of the rod caps, which must stay paired with their companion rods as they are the powdered-metal, cracked-cap type. Bearing shells only fit one way. Each piston pin and bearing shell should be oiled before installation.
You will need a ring compressor tool to install the piston/rod assembly in your Hemi's block; these are made in different size ranges and the one we used works for piston diameters between 3 ⅝ inches and 3 ⅞ inches. A set of ring compressors that can handle a variety of V-8 engines costs under $100. The trick is to lightly knock the piston to slide it into the bore without damaging the rings on the fire deck. If it stops going in, don't hit it harder and break the ring—remove it and figure out the hang-up before trying again.
After carefully guiding the big end of the rod down to the crank journal, making sure not to damage the journal, torque the rod caps to 15 ft-lb, then go another 90 degrees of twist.
The factory hydraulic roller lifters from our 235,000-mile Hemi proved to be in great shape, but you always want to check for two important things: lobe wear on each cam lobe and the wear on the lifter rollers. Additionally, check each roller for freedom of movement; you neither want to feel any snags nor any excessive looseness in the roller movement, which can indicate damaged needle bearings. The lifters along the top row are MDS lifters for MDS cylinders 1, 4, 6, and 7.
Before bolting on the cylinder heads, IMM laid out the Hemi's hydraulic roller lifters on the assembly table ahead of time, inserting them into the lifter trays (also called cassettes). Note the position of the MDS lifters (the ones with small lube holes in the side of the lifter body) relative to the non-MDS lifters. It's critical that the MDS lifters only go into cylinders 1, 4, 6, and 7, as noted in the layout.
Just as with the Chevy LS engine, the Hemi's lifters are captured below the fire deck by the cylinder heads and must be installed prior to bolting on the cylinder heads. The lifter bodies should be coated with assembly lube prior to installation. The 8mm retaining bolt in each lifter cassette gets torqued to the block at 9 ft-lb.
A little bit of this engine's history was documented before being covered up by the cylinder heads—note the two small indentations on either side of the number one piston. These were created in 2014 when the piston kissed the valves after the timing chain snapped. The dealership replaced the bent valves but the pistons were otherwise unaffected.
You can sometimes get away with reusing MLS head gaskets if they are new and in good shape, but we weren't taking any chances with gaskets this old so we ordered a new set from Mahle. These are labeled left and right and have callouts for the top side which should be placed face-up. This is the last chance you'll have to inspect and clean the deck surfaces of the block and heads.
You'll want to start with a fresh set of head bolts when you rebuild a Hemi. Many newer engines with MLS gaskets use torque-to-yield head bolts (they get torqued to a specific torque spec then rotated an additional amount) which stretch out and lose their elasticity, and thus their clamping force. The Hemi uses 10 long 12mm bolts and five shorter 8mm bolts per side.
The ten long 12mm bolts correspond to the fire deck, the five smaller 8mm bolts to the top between the intake runners. Remember to coat the bottoms of the bolt heads and threads with a small dab of assembly lube before torquing. The long bolts are torqued first to 25 ft-lb in a spiral sequence followed by the shorter 8mm bolts, which are taken to 15 ft-lb. Now go back to the 12mm bolts and re-torque them to 40 ft-lbs, following that up with a re-torque of the 8mm top-row bolts to 15 ft-lbs (again). You're not done yet! Go back to the longer 12mm bolts and tighten each one (in sequence) another 90 degrees. Lastly, hit the top row of 8mm bolts one more time at 25 ft-lbs.
We're reusing the stock pushrods which checked out straight with a simple roll test on the countertop, but if you're using an aftermarket cam you'll definitely want to use a pushrod length checker to calculate your custom pushrod length. If you're staying stock, the only thing you'll need to remember is that the exhaust pushrods are the longer ones. Before installing the rocker arm assemblies, dab a touch of assembly lube on the pushrod tips for lubrication upon initial start-up.
The OE rocker arm shaft assemblies on the 5.7 Hemi are extremely stable and can handle a significant amount of abuse relative to traditional pedestal-mount rocker arms. These OE rocker assemblies are reused here and only need the hold-down bolts to be given a smear of assembly lube before being reinstalled. Hold-down bolts are torqued to 195 in-lb in a spiral sequence. It's a bit of a chore to get all the pushrods nested into their respective rocker cups at once, but the shafts can only be tightened once all the pushrods are properly captured. Note that the intake rocker arms all have the letter "I" cast into them. Ideally, this operation should happen with the number one piston about 20 degrees after top dead center (all pistons are below the deck).
Our rebuild of the stock Hemi ends here with reinstallation of the factory oil pump and OE attaching bolts, which get torqued to 11 lb-ft. We've deliberately left out coverage of replacing the rear main seal and housing (Mopar part No. 53021337AB). At the time of the story, these were unavailable from any outlet, but we managed to find one used on eBay for under $30. IMM says despite the seals being serviceable, they almost always leak afterwards. For leak-free operation, the rear main seal and housing should be always replaced as a unit and not serviced.
The remainder of components to build a complete long-block aren't shown (intake, throttle body, valve covers, timing cover, oil pan, etc.) because they were reused in Mrs. Hunkins' 2011 Challenger R/T. What you're seeing is the equivalent level of assembly provided in a new partial long-block or reman unit. The total cost to get to this stage was $1,173.92, which doesn't include the tax or shipping on parts or the engine assembly itself. IMM says the cost for engine assembly varies depending on how much additional work is required but could potentially run into the thousands of dollars (you may have to ask yourself how much you love your specific Hemi versus a random 5.7 Hemi!). A check on the prices of stock rebuilt 5.7 Hemi engines here suggest that a similar unit to ours can be had starting around $2,400, but won't come with the same satisfaction of rebuilding it yourself.
A lot of folks search the web for a Hemi rebuild kit without success because there is no company that offers everything you need in one box. This is likely because your engine's wear will be unique. Some people may need rings and pistons in an overbore size and other engines like ours will call for a standard set with the pistons being reused. Likewise, bearing sizes may need to be oversized based on the recommendation of your machine shop. With that bit of explanation, here is the list of the components we used, with part numbers, prices, and links to the parts at Summit Racing.
*Labor total for IMM Engines does not include overall engine assembly