With our short-block buttoned up and ready for combustion, it’s time to approach the cylinder head and induction system. While this may seem like a simple segment of engine assembly, it’s so easy to screw it up. All deck surfaces must be clean and free of imperfections. It’s a good idea to do a dry run with the cylinder heads and valvetrain, especially if you are running a high-lift camshaft. A dry-run includes bolting on the cylinder heads without the head gaskets and installing the valvetrain to check valveto- piston clearances.
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Checking valve-to-piston clearances involves placing a wad of modeling clay in the piston valve reliefs, bolting the head and valvetrain in place, and hand-cranking the engine two revolutions. Remove the cylinder head and see how deep the valve impressions are in the clay. You need at least .050 inch of clearance between the valve and piston. If you are running a high-lift camshaft and don’t perform this check, you risk valve-to-piston contact and severe engine damage. Even .050 inch clearance isn’t enough when you are running a high-lift hydraulic camshaft. At high revs, the valves can float, closing this gap in short order.
When it’s time to permanently install the cylinder heads, we suggest Fel-Pro’s Print-O-Seal head gaskets, which providea solid seal around the cylinder bores and coolant passages. When you are laying each head gasket in place, observe the coolant passages. Are they at the rear of the block? Each head gasket has passages at one end of the gasket. These coolant passages go at the rear of the block – always – with no exceptions. Installing the head gaskets backwards, with these passages at the front of the block, will cause overheating and serious engine damage. The word “FRONT” on these gaskets means exactly that – “FRONT.”
Make sure you have clean cylinder head bolts and threads. Lubricate the cylinder head bolts with engine oil before installation. Torque the head bolts from the center out, torquing them in onethird values for uniform seating. This ensures good cylinder head seating and sealing. When you are finished tightening the cylinder head bolts, recheck the torque again.
When you are installing the valvetrain, make sure all rocker arms have sufficient lubrication. Use engine assembly lube on the fulcrums and tips. Soak the lifters in engine oil, which fills them up with oil prior to engine start. This isn’t a mandatory step, but it is a good idea when you’re installing lifters.
With hydraulic lifters (flat-tappet and roller), adjust the rocker arms in time with the engine. Begin with number-1 cylinder and follow the firing order. Make sure you know the firing order. Most flattappet camshafts follow the old 221/260/ 289/302 firing order of 1-5-4-2-6-3-7-8. The roller cams go with the 351W firing order—which is 1-3-7-2-6-5-4-8. Make sure you know the correct firing order.
Step by Step: Assemble the Top End
Step-01: Install the Head Gaskets
Fel-Pro from Federal-Mogul is our gasket of choice. Installing the cylinder head gaskets is very critical because you can install these gaskets backwards. “FRONT” means FRONT with small block Ford head gaskets. Coolant passages must be positioned at the rear of the block for proper coolant flow. We suggest Fel-Pro Print-O-Seal head gaskets for best results.
Step-02: Install the Heads
Cylinder heads are installed next. Make sure the block dowels are installed first.
Step-03: Calibrate the Torque Wrench
Proper torque-wrench use is something we tend to overlook in our haste for a finished engine. First, never remove bolts with a torque wrench. Secondly, always zero the torque wrench after use. Following these rules helps keep your torque wrench calibrated.
Step-04: Torque the Head Bolts
Cylinder-head bolts are torqued in third values from the inside out. Begin at the two center head bolts and torque them to 50 ft-lbs, working your way outward to the ends of the head. Next, torque the head bolts to 60 ftlbs. Final torque is 65 to 72 ft-lbs. Double-check your torque readings.
Step-05: Lubricate the Lifter Bores
Engine oil is applied to the lifter bores to ensure smooth installation and initial operation.
Step-06: Install the Lifters
We’re using a flat-tappet hydraulic camshaft from Crane Cams. Lifter faces get a dressing of cam lube, then they’re installed as shown.
Step-07: Install the Pushrods
Pushrods are next. Lubricate each end of the pushrod with engine assembly lube for best results.
Step-08: Install the Rocker Arms
Installing the rocker arms involves lubricating the fulcrum with engine assembly lube and positioning the rocker in place. Check the rockerarm- to-valvestem relationship. The rocker needs to be centered squarely on the valvestem.
Step-09: Use Poly-Locs
We learned something valuable with the screw-in rockerarm studs that we installed during cylinder head build-up. Whenever you use stock rocker-arm lock nuts, you risk backing the screw-in studs out. If you do this, we suggest the use of aftermarket Poly- Loc rocker-arm nuts, which won’t cause the stud to back out.
Step-10: Adjust the Rocker Arms
Rocker-arm adjustment consists of running the rocker-arm nut down to where the rocker arm touches the valvestem, then giving it 1/2 turn. If you’re going to spin it high, give it 1/4 turn to allow for valve float. Small-blocks with mechanical lifters get .010-inch clearance on both the intake and exhaust valves.
Step-11: Install Gasket Ports
Intake manifold gaskets rarely get the right gasket sealer treatment. We’re going to show you how to do it properly here. Intake ports get a thin application of regular old gasket shellac. If you are using Fel-Pro Print-O-Seal, leave the intake ports alone.
Step-12: Intake Gasket Coolant Passages
Coolant passages get silicone sealer for extra added measure. This keeps coolant where it belongs.
Step-13: Seat the Gaskets
Intake manifold gaskets are seated in place, taking extra care to ensure proper sealing.
Step-14: Trim Coolant Passages
Yes – we forgot to trim the coolant passages for our vintage 289 small-block. These gaskets are actually designed around the 351W coolant passage. We cut the passages as shown for the 289 – hopefully you’ll remember to do it before you start messing with the gasket sealer.
Step-15: Clean the Intake Rails
Intake rails are cleaned with a strong solvent to ensure good sealer adhesion.
Step-16: Use Silicone Instead
Gasket manufacturers all provide intake manifold end gaskets. However, we discourage their use. A bead of silicone gasket sealer works very well in preventing oil leakage. When the sealer cures, it expands, forming a tight seal along the ends of the intake manifold.
Step-17: Seat the Manifold
The factory cast-iron four-barrel intake manifold is installed, setting it down carefully to ensure proper port and bolthole alignment.
Step-18: Torque Down the Manifold
The intake manifold is torqued in crisscross fashion from one side to the other. Torque in third values, just like the cylinder heads. Begin with 15 ftlbs, then 20, and then 22 ft-lbs. Check your torque readings on all bolts.
Step-19: Clean the Mounting Surface
Roll the engine over and prepare for oil pan installation. First, clean up gasket mating surfaces with a razor blade as shown.
Step-20: Install the Oil Pump
Oil pump installation is handled first by putting the shaft in place and then installing the pump. Install the gasket between the pump and block. Then, Loctite the bolts. Make sure the crankshaft counterweight clears the pump.
Step-21: Check the Clearance
Close inspection of the oil pump and driveshaft is important to ensuring proper crankshaft counterweight- To-pump clearance.
Step-22: Install the Oil Pan Gasket
Oil pan gasket installation begins with silicone sealer at the unions located at both ends of the pan. Rubber end gaskets are installed first, taking care to seat them firmly in the timing cover and rear main cap. Use silicone sealer between the gasket and pan rails. There is no need to use sealer between the pan and gasket. There is also a one-piece pan gasket available from Fel-Pro.
Step-23: Seat the Pan
This reproduction steel oil pan from Virginia Classic Mustang is a perfect fit. The pan is seated in place, making sure all gasket segments remain in place.
Step-24: Hand-Tighten the Bolts
We have secured an AMK Engine Fastener Kit from Virginia Classic Mustang. These oil-pan bolts are hand tightened while the silicone sealer is soft and pliable.
Step-25: Torque the Bolts
Oil pan boils are run down with a speed handle prior to torquing. Tighten bolts in a crisscross fashion back and forth across the pan to 9 to 11 ft-lbs. After a sit period, check the torque again.
Step-26: Install the Valvecover Gaskets
Period-style Cobra valvecovers from Virginia Classic Mustang are installed next. Use gasket sealer between the gasket and valvecover.
Step-27: Install the Valvecovers
Finally, seat the valvecovers and tighten them down. There is no need for sealer between the gasket and cylinder head.
Step-28: Install the Carburetor
We’re going with original equipment on this relatively stock 289. This is the 480-cfm Autolite 4100 carburetor for the 289-4V engine, rebuilt and precision tuned by Pony Carburetors. You can step up to a 600-cfm version of this carburetor and gain more horsepower and torque.
Hand-crank the engine and follow the firing order. As each intake valve seats fully, adjust the valve lash by cranking the adjustment down until the rocker arm touches the valvestem, and tighten clockwise 1/2 turn. If you expect to spin the engine high, go with ¼ turn to minimize valve float.
If you are running a mechanical camshaft, valve clearances are typically .010 inch on both valves. See your camshaft manufacturer’s instructions for specifics. Not all of them are .010 inch. Sometimes, the cam manufacturer wants you to check the valve lash with the engine hot. This is important to remember because parts grow as they heat up. Things expand, which changes clearances.
When it’s time to bolt on the intake manifold, take extra care to remember proper sealing at the intake ports and cooling passages. This is an easy one to overlook in your haste for a completed engine. Use gasket shellac on the intake ports, just for extra measure. Silicone sealer works best around the cooling passages. Even though every gasket maker will provide you with end-rail gaskets, toss them in the trash. Apply a large bead of silicone sealer along those rails. As the sealer cures, it closes those gaps completely, providing a perfect seal, keeping the oil inside.
Written by George Reid and Republished with Permission of CarTech Inc
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