With the 331 Chrysler Hemi receiving the go-ahead from Speed-O-Motive last month, it was back in my hands to start assembling the rotating assembly, heads, and valvetrain. Being a greenhorn to a full-on engine rebuild, I was slightly hesitant to jump right into the assembly, as I thought it would be quite a shame to ruin all the hard work the machine shop had done. I pushed it to the bottom of my "work pile," but thanks to outside pressures, namely magazine deadlines, I forced myself to tackle the assembly and present it as if I knew what I was doing.
Needless to say, I learned a lot along the way, with many thanks to those who had to suffer with my constant pestering. I can't say enough kind things about those involved, namely the crew at Speed-O-Motive, Egge, Hot Heads, and Mooneyes for dealing with my "newbie" questions. If there were ever any reluctance in getting your hands dirty building a vintage engine, sleep easy knowing there's a number of people in our industry who are not only knowledgeable enough to provide you with the know-how to tackle such a project, but that they're more than willing to explain things and walk you through some of those head-scratching problems you may come across.
Building a vintage engine can be shrouded by old-time voodoo secrets, ancient magic, and must-do speed tips, but be forewarned that a knowledgeable machine shop coupled with a competent parts supplier can take that ancient relic of Detroit's past and dumb it down to a tractor motor. The internal combustion engine is going on 100-plus years and while many great innovations have been made, it all boils down to a simple few points: Get the gas in the cylinder, make it explode, expel the burn, and create power to get you down the road. There have been leaps and bounds in technology, but the general idea has been the same since Henry Ford first took the Model T coast to coast.
That said, I was able to convince myself to act as the guinea pig for those who wanted to build a vintage engine and do it in the confines of their home shop. I've worked on the Mooneyes dragster and even moonlighted on a Bonneville race car that made it into the 200 MPH Club in 2004 (Todd Haas' SO-CAL Speed Shop-sponsored '34 roadster), but that hardly means I knew what I was doing. I was simply a bystander at the feet of bigger and better tuners, fabricators, and racers. But, I had the itch and that's all that matters.
With this 331ci Chrysler build, however, I was convinced that I could bring a down-home, do-it-yourself perspective to show that you don't need 40 years of experience to assemble a reliable, vintage powerplant. Armed with fellow staffer Ron Ceridono's priceless Chrysler Hemi Engine Manual and the support of the previously named aftermarket companies, assembling the early Hemi has been both a labor of love and a fruitful provider of frustration. But as it comes together, I've been exceptionally pleased with not only the fact that I did it, but that it will work and provide me with years of satisfaction as I'm driving the '52 Ford F-1 pickup in which it will eventually see life. Sure, a crate motor may have been the easy way out, but do you think Michelangelo would have ordered up templates to paint the Sistine Chapel over the Internet had he been given the opportunity 500 hundred years ago? I think not! Read on and stay tuned as we dress up the old goat with some contemporary pieces.
With the block, heads, and crank back from the machine shop, the first step was to give everything a thorough cleaning with warm water and dish-washing detergent. Extra care was taken to ensure any grit or debris from the machining process was removed. | 
Replacing the freeze plugs was the first step on our long list of reassembly. Hot Heads offers two options, both of which are removable if the need arises. Above is a brass assembly and below is a trick stainless kit. | 
Here are the two different styles installed to give you an idea of their aesthetics. I chose to use the stainless style for my motor. |
There's also a cam plug and two threaded plugs that need to be installed at the back of the block. The cam plug is installed just like a normal freeze plug; set it against the ridge of the block and dimple the center to expand it firmly in place. | 
I'm lazy and like to start with the easiest item first; therefore, I decided to drive in the bronze oil pump driveshaft bushing. A large drift and a hammer made the job a snap. | 
The main bearings for the 331 came from Egge Machine, who stocks everything for all three Chrysler Hemis-331, 354, and 392 ci. |
Since the motor was going back together for the first time since being machined, it's important to check all the clearances. This can be done by either measuring them with a snap gauge and an outside micrometer with the bearings installed and the main cap torqued to spec... | 
...or by installing the crank with all the mains torqued to spec and Plastigaging the surfaces. Main bearing clearances should be between 0.0005- and 0.0015-inch | 
The rear main bearings are block and cap specific-mix them up and you'll starve the rear main for oil. Also notice the locating ring for the rear main cap; this aligns the cap to prevent the oil pump driveshaft from rubbing against the block. |
Originally, the rear main cap featured a rope seal to prevent oil from leaking out into to the bellhousing. A seal from a 440 Mopar is now a common replacement. The rear main cap also has a provision to drain oil back to the pan between the bearing and the seal. | 
With the clearances checking out and the bearings bathed in a healthy dose of engine assembly lube, the mains were torqued to 85 ft-lb. Note the adapter on the rear main cap that accepts a high-volume small-block Mopar oil pump from Hot Heads. | 
Crankshaft end play is the movement of the shaft laterally in the block and is measured using a dial indicator. Acceptable end play is between 0.002- and 0.007-inch. |
Here's the small-block Mopar oil pump installed on the adapter. These are commonly available and provide more volume than the original Hemi item. | 
The pump registers on the main cap and requires another adapter to align the pump driveshaft with the block. | 
Moving onto the rest of the rotating assembly, the first thing to check was the piston ring end gap. The ring was installed into the bore an inch or two and the gap was measured using a feeler gauge. Ring gap minimum is 0.015-inch and shouldn't be more than 0.025-inch. If the gap is below tolerance, it needs to be filed using a ring jig tool. |
The ring end gap checked out so the compression and oil rings were installed on a new set of 0.040-over cast pistons from Egge Machine. A set of Grant rings will handle the compression chores in the 331. The expander-spacer oil ring is color-coded so it's easy to tell if it's installed correctly. The two colors should be visible and land directly above the wrist pin. Two steel rails hold it in place, with the gap on either side of the wrist pin (arrows). The gaps in the compression rings should be perpendicular to the wrist pin and on opposite sides of the piston. | 
New rod bolts are highly recommended, as the original units can stretch and not give an accurate torque reading. ARP fasteners are the best in the biz, so it was only natural that Hot Heads recommended them for our 331 build. | 
The rotating assembly for the 331 was completely balanced at Speed-O-Motive, and the stock rods were reamed with new bushings to accept the "palm push" fit, full-floating wrist pins. They're retained by a pair of snap rings that should be located with the opening vertically and not to the side where the reciprocating motion of the piston may cause them to move. The 0.020-inch-under rod bearings were also installed as a reference. |
A ring compressor was picked up from the local parts house and the well-lubricated piston was installed in the block with a few light blows from the handle of a dead blow mallet. Care was used to not hook the rings on the deck of the block. | 
With the pistons and rods installed, note the mark on the top of the pistons that point to the front of the block as the valve reliefs on the piston are relative to the intake and exhaust valves. The rods are torqued to 45-50 ft-lb. | 
Early Hemi head gaskets are top and bottom specific and should be coated with a copper sealant before installed. Permatex Copper Spray-A-Gasket works great, but don't get it on anything but the gaskets. |
With the heads in place on the stepped dowels provided by Hot Heads, new head bolts were lubricated prior to installation. Like the rod bolts, the original head bolts can also succumb to stress and stretch over time, resulting in faulty torque readings. New lubricated bolts will remedy this. | 
The heads are torqued to 85 ft-lb starting at the center pair and working out in an alternating pattern. | 
Returning to my old stomping ground, I coaxed Bill Jenks at Mooneyes to grind me a cam for the 331. Using a 354-style blank, Bill ground a 0.461-inch-lift, 280-degree solid lifter cam that will make the old Chrysler run like a watch with power to spare. A set of solid lifters from a 318 Chrysler was provided from Egge to fit the Hemi. |
Speed-O-Motive recommended using CMW Entech assembly lube for the entire assembly, including the cam and lifters. Rotella heavy-duty oil was used, as well, and will be run in the engine to help break in the assembly, as many modern motor oils lack the appropriate properties necessary for the old flat-tappet motors. | 
I made a cam installation tool by welding a bolt to a piece of tubing. Care must be taken when installing the cam to not nick the bearing surfaces. | 
This ring faces with the chamfer pointed toward the back of the block and supports the cam timing gear. |
A thrust plate bolts to the front of the block and controls fore and aft cam movement behind the timing chain assembly. The cam-retaining bolt and washer were indexed to fit over the keyway of the cam. Note the relationship of the dots (arrows) on the crank and cam timing gears. While some engine builders recommend degreeing the cam, Bill mentioned there's no chance in the lobes being off time since the cam was reground on a machine that registered everything off the key way. Fifty years of experience can't be wrong. | 
With the cam installed, the lifters and pushrods were dropped in and it was time to start adjusting the valves. The 331 is running adjustable pushrods from Hot Heads to set the valve lash. | 
A timely and frustrating dance to say the least, the valves need to be properly adjusted with the recommended 0.015-inch valve lash, measured here with a feeler gauge. |
With the head installed, torqued, and the number one cylinder valves adjusted, everything was pulled apart to measure piston-to-valve clearance. A tedious procedure, it's easier than finding out too late that the clearance isn't within the recommended 0.100-inch. Modeling clay was applied to the valve area of the piston and the depth measured with a caliper after the engine was turned over a few revolutions. | 
With the clearances checking out, the heads were reassembled and torqued, and the valves readjusted. | 
The intermediate driveshaft was the last piece of internal hardware to be installed before the engine really starts to take shape. This couples the oil pump with the cam and distributor. |
The assembled 331 is now ready for all the external components to be installed next month. See ya then! | | |