The skinny on upgrading the bumpstick in your 5.7L Hemi
By Jared Martin (Motohead)
So youíve done some upgrades to your Hemi Ram to squeeze a few more ponies out of the meanest small block to ever grace the streets: a cold air intake, cat back exhaust and maybe even a tuner. But you still want more, right? Well hold onto your torque wrench fellow gear head because Comp Cams has just released a line of camshafts for the 5.7 Hemi. ďDoesnít that require pulling the intake, heads, oil pan and oil pumpĒ, you say? Absolutely not! Sit back, pop a cold one, trash the DC Service Manual and/ or what you read on your AllData account and follow along as we outline the rather simple install. If you have the tools, the space and moderate mechanical ability your Hemi can be laying down 30+ more ponies for a dayís worth of work.
The first step once the engine has cooled is pulling of your intake/ CAI. Once this has been removed you can remove the coils and plug wires using a 10mm socket. Mark each coil and wire to ensure they go back on in the correct order. Lay the coils over the intake and tie-strap them out of your way if necessary.
The coil packs and plug wires are first removed in preparation to pull the head cover.
Next is removing the valve covers. Remove all the clips supporting the wiring harnesses running along each cylinder head. To keep them out of the way as you work on the heads, itís a good idea to tie-strap them to the headers. Also, pull the ground strap located on the third valve cover bolt at the top; there is one on each side. Take your time here so as not to damage the clip, simply work it back and forth while pulling up. It takes a bit of patience, but it will eventually work loose. Finally, take a deep 8mm socket and remove the ten valve cover bolts on each side.
With the valve covers off you can now remove the rocker arm shafts. Take a 10mm socket and remove the five bolts on each shaft. Do one shaft at a time and mark their location as you set them off to the side. Their location may not be critical upon reassembly (didnít bother to check), but I put them back exactly as I found them for good measure. Leave the pushrods in place as they will help you identify the lifters are suspended securely in the retainers later on.
Now itís time to change the springs. Remove one spark plug from each cylinder and thread the air fitting into the cylinder head. Pressurize the cylinder using an air compressor. Before taking off the springs, take several shop rags and cover the rest of the cylinder heads. This will keep the retainers out of all of the many oil passages and pushrod holes in the head should one get away from you (it will happen). Taking the overhead valve spring compressor, place the jaws as far down on the spring as possible. Make sure the compressor is aligned straight on the spring and seated evenly on the retainer. Hold the jaws in place as you begin to tighten the compressor to keep it in position. If the compressor becomes misaligned at any point while tightening it down, save yourself some frustration and loosen it up and start all over even if it appears to still be compressing the spring Ė you donít have a good bite on it and it will let go before you have a chance to grab the keepers. Do not replace the spark plugs after the springs are installed as it will be easier to time the engine (turn the crank) later.
The overhead valve spring tool makes installing the cam in the truck possible. Getting an even bite on the spring can be a challenge with the staggered jaws, but this little gem, overall, makes life much simpler.
Once you have compressed the spring, push down toward the head and remove the valve spring keepers with your magnet placing them in a magnetic dish. Discard the old spring and place the retainer and new spring in the compressor. Compress the new spring retainer and place over the valve. Next reinstall the keepers. The 5.7 Hemi uses double-groove keepers, which can be challenging to get into position and when combined with the beefy Comp springs, the degree of difficulty increases significantly. Compress the spring as much as possible to make this process easier. BE SURE to verify the keepers are sitting flush against the valve and that the retainer is sitting flat at the top of the valve. If the keepers are in a bind they will let go resulting in a dropped valve and catastrophic engine damage. Repeat this process for each cylinder and be sure to move the air line to the cylinder youíre working on (yeah, I know ďDuhĒ, but it is easy to get too wrapped up in the springs forgetting the obvious and the subtle clank of a valve hitting a piston is not a sound you ever want to hear).
The air fitting/ hose is threaded into the spark plug hole to pressurize the cylinders for the spring swap. For the Hemi head an extension hose is a must.
On the driverís side, we quickly noticed the brake booster laughing at us as we attempted to get the compressor on any one of the back springs. There may be a way to do it, but we didnít even give it a try and removed the booster instead. The time saved by not having to work around the booster outweighs the time needed to remove the booster and bleed the lines when the install is complete. To remove the booster, start by removing the two brake lines off of the master cylinder. Next, crawl under the dash and remove the four nuts off of the booster studs protruding through the block head (firewall). Slide the booster push rod off of the brake pedal and pull the booster from underneath the hood.
Pulling the brake booster/ master cylinder makes life much easier when swapping springs on the driverís side.
The difference between the Comp and OE springs is apparent at a glance. The meatier springs can withstand thousands of worry-free romping with the high-lift cam.
With the springs done, itís all downhill from here. First, we drain the radiator by removing the lower radiator hose and the cap on the overflow tank then pulled the upper radiator hose. Using a quick disconnect tool, we removed the two transmission cooler lines running to the right side of the radiator. Next, we unclipped the two power steering hoses from the shroud and remove them from the cooler and removed the two bolts on the core support attaching the shroud. Last, removing the top two radiator mounting bolts allowed us to slide the radiator straight up and out of the engine compartment. With the radiator removed, we effortlessly removed the shroud leaving the fan attached to the water pump. Remember to remove the wiring harness and line from the windshield washer reservoir.
With the radiator and shroud out of the way, we could start pulling accessories. The obvious first step is removing the drive belt by pulling up on the tensioner and sliding the belt off the alternator pulley. The A/C compressor has two bolts facing forward that attach the compressor to the accessory bracket. On the backside of the compressor, remove the bolt connecting the compressor to the block. With the compressor free, tie strap it up and out of the way. The A/C lines do not need to be removed; however, pay careful attention verifying the lines are not kinked and are not supporting the weight of the compressor once you have strapped it out of the way. Remove the nut and eyelet terminal on the back of the alternator and the bolt and nuts on the support bracket. Next, remove the bolt and stud to remove the alternator and remove both idler pulleys and the belt tensioner. Removing the three bolts attaching the power steering pump to the cylinder head, which can be accessed through the holes in the p/s pulley. Do not remove the p/s lines from the pump. Set the pump to the side, or suspend it out of the way with tie straps ensuring the lines are not in a bind and/ or supporting the weight of the pump.
With the radiator, shroud, trans cooler, and power steering cooler out of the way pulling the accessories is a breeze. The mighty Hemi sits so far back, thereís enough room to step inside the engine bay to work and even grab a seat on the bumper when you need a rest.
With the accessories and idlers removed, the engine timing cover, water pump, fan and clutch can be pulled as an assembly. Remove all the bolts around the perimeter of the cover, leaving the water pump bolts in place. Remove the three bolts attaching the timing cover to the oil pan. Next, using a three-jaw puller, remove the crank pulley then remove the timing cover and reinstall the crank bolt back into the crankshaft. With the timing chain still in place, rotate the engine to where the marker on the cam exciter ring is pointed at 12 oíclock and the timing mark on the crank is pointed at 2 oíclock. This will make it easier to time the engine once the new cam is in place.
Remove the cam bolt using an impact and pull the cam gears/timing tone ring and cam chain then reinstall the cam bolt back into the camshaft. Remove the three bolts attaching the cam plate to the block. The oil pan will be exposed at this point, so itís a good idea to cover it with shop towels to avoid dropping any foreign items into the pan.
At first glance, it appears the oil pump must be removed to remove the cam plate, which would also require pulling the oil pan to remove the oil pick-up. However, it can easily be pulled by removing three bolts.
Take a minute to verify each lifter is seated on the camshaft by pushing down on each pushrod. Rotate the camshaft several revolutions watching for the pushrods to lift up into the retainers. Remove the camshaft by pulling the cam bolt using it for leverage to keep the cam straight as it passes through the cam bearing journals. Once the cam is out, remove the cam gear dowel pin and insert into the new cam. BE CAREFUL not to gouge or damage the dowel in anyway. Lube the new camshaft with assembly lube or engine oil and slide it back into the block, once again using the bolt to keep the camshaft square with the block. The cam bearings ARE NOT serviceable so take you time and use caution when pulling/ installing the cam.
Install the cam gear/ timing tone ring with the arrow pointing straight-up at 12 oíclock and verify the timing mark is still in the 2 oíclock position. Replace the timing cover (gasket IS reusable) and torque the bolts to 250 in/lbs. Mount the crank pulley using the install tool (Dodge p/n 8513A or equivalent). DO NOT attempt to tap or hammer it on as it may damage the crank shaft. Install the new crank bolt (Mopar p/n 6506340AA) and torque to 129 ft/lbs.
Using the cam bolt for leverage, slide the cam bolt out of the block as straight and evenly as possibly so as not to damage the cam bearings. Note the heads, intake and oil pan still attached to the block.
Reinstall the accessories in the reverse order they were pulled. Double-check the routing of the power steering and A/C lines ensuring they are not bound. Place the shroud/ washer bottle over the fan/ clutch. With the shroud resting on the fan you can slide the radiator into the alignment tabs located on bottom of the core support. Install the four bolts connecting the shroud/ radiator to the core support. Snap the trans cooler lines into place and attach the power steering cooler lines to the cooler. Connect the upper and lower radiator hoses.
Moving back to the heads, push the pushrods down to set the lifters on the cam. Then, reinstall the rocker arm shafts and torque the bolts to 195 in/lbs. Take your time here and remember your threading into aluminum. Back the bolts off as far as possible and set the shaft into the journals on the heads. Align the pushrods with the rocker tips and thread the shaft down evenly. The exhaust shafts take some patience and may require another set of hands. Double check the shaft is seated in each journal and the pushrods are seated in the rockers before moving on.
Install the valve covers, coil packs, and plug wires. Fill the cooling system through the overflow bottle with the Mopar coolant or an equivalent. At this time, itís a good idea to bleed the brakes as itís easy to forget once the Hemi returns to life. Reconnect the battery cable.
The truck WILL NOT want to run when you first start it. Once you get it running, apply slight throttle pressure to get the engine between 1500 and 2000 RPM while the computer learns to adjust to the new hardware. Release the throttle pressure after a couple minutes and it should continue to run even though it will be searching for an idle. If possible, once the truck is able to stay running, take it out on the road. DO NOT do this if you donít have an area free of traffic in which you can drive the truck. The truck will die periodically throughout the road test leaving you without vacuum to assist the brakes and steering.
The final verdict: We took the Hemi Ram back over to our friends at Slaterís Automotive for the final numbers. All pulls, before and after, were made with the transmission in second gear with the torque converter unlocked. The truck would most likely produce greater numbers with the converter locked in third gear; however, we wanted to see as much of the power band as possible, which canít be done in third gear below 75 mph as it will kick down into second gear. On the first pull, the Hemi laid down 299 for an increase of 23 hp over the baseline. The Comp Cams XE268 makes solid power throughout the RPM band, but it really comes to life from 4000 through 6200 RPM. To take full advantage of the power, a hand-held tuner is recommended which will allow the factory rev limiter to be extended from 5800 to 6300 RPM. A few more pulls were made using the Hypertech Power Programmer. The custom tuning and the ability to extend the rev limiter 500 RPM netted us an additional 11 peak horsepower for a total of 34 horsepower. Not bad for a dayís work.