Jim Smart
February 13, 2014

Reciprocating Parts Cont.

There has always been debate about the integrity of powdered-metal connecting rods common in Modular engines. In more than 22 years of Modular V-8 production from two engine plants, these rods have never been problematic when employed in stock or lightly modified engines. In short, you can hammer the daylights out of them and still have a reliable engine.

The supercharged 2003 4.6L Cobra DOHC engines had steel Manley rods and forged pistons for endurance—one exception is the 2000 Cobra DOHC with forged steel Carillo rods. If you stumble upon an '07-'11 Shelby GT500 donor or crate engine, it will also be fitted with Manley rods. Yet every other Modular including the 3V that arrived in 2004 has been factory fitted with powdered metal connecting rods. Another popular misconception according to author George Reid is that Modular engines all came with forged pistons, which has never been true. From the factory, all Modular engines (except the '03-'04 DOHC 4.6 Cobra), including the 3V and DOHC versions, had high silicon hypereutectic pistons. The beauty of hypereutectic versus forged is expansion properties. Forged pistons yield greater expansion, which calls for a loose cold fit. Cold knock until the engine warms up is often a side effect of the loose fit. The same can be said for hypereutectic pistons in that they tend to knock cold, but warm and expand more quickly than forged.

17. This is a Windsor PI head. Do you see the difference? The Windsor head doesn’t have a cam girdle like we see with the Romeo casting. This is also a PI (Performance Improved) head with smaller chambers, larger exhaust valves, and these modified teardrop intake ports for better flow.
18. Modular heads get virtually the same treatment as any other cylinder head. Because they are aluminum, the mill runs at a higher speed. Main thing to watch is how much material you remove, which affects chamber size.
19. These are the hydraulic followers/lifters, which fit into oil pressurized bores keeping the roller rockers against the cam lobes. No adjustment is required.
20. All of the 2V SOHC heads are omnidirectional meaning you may install them on either side. However, keep oil passages in mind when you do. Chain tension actuators install at the front end of each cylinder head. The end of the head facing your firewall must have oil gallery plugs where tensioners would go in front.
21. JGM Performance Engineering does a lot of Modular engines. Valve stems get Viton seals for longevity and exceptional oil control.
22. When it is time to hang timing chains, Ford makes it easy to find and align timing marks. Dark links connect with dots on each camshaft sprocket. Links down below match the crank sprocket. You’d have to work real hard to mess this up. This is the left cylinder head cam sprocket. The righthand cam sprocket works the same way with two dots and a dark link.
23. Two timing chain tensioners get oil pressure and apply tension to the chain guides. Any time you rebuild a Modular engine, install new chain guides and tensioners regardless of condition. Better safe than sorry.
24. Each cam should be degreed just like you would do with your conventional Ford V-8. Degreeing takes all of the doubt out of cam specifications by demonstrating exactly what you have for a camshaft as it relates to piston and valve timing events.
25. Modular engines have the best sealing in the history of Ford engine development. If installed properly and checked for proper fit, they will last the life of your engine. Here, Fel-Pro gaskets are being used. If you are building a BOSS50 block, you will need Cometic cylinder head gaskets due to the larger bore size.
26. Cylinder head gaskets get a dab of Permatex’s The Right Stuff in the corners to head off any oil weepage that could occur here from oil drain back.
27. The Modular has a separate bolt-on cast-aluminum rear main seal cover with a one-piece seal making rear main seal replacement easy should you ever have to do it. Because the SOHC Modular engine is virtually leak free when properly assembled, you should never have to worry about this. The seal lip and spring go toward the engine. Pack the seal lip with engine assembly lube to prevent spring loss during installation. If you lose the spring, it will leak.
28. SOHC intake manifolds are limited to the truck/sport utility tall cast aluminum/plastic combo piece (doesnt fit under a Mustang hood), and this plastic passenger car intake manifold common to the Mustang GT, Crown Victoria, Grand Marquis, and E-Series vans. 2001 Bullitt Mustangs were equipped with a unique cast aluminum piece, and a number of aftermarket aluminum manifolds are now available.

Crankshaft/Balancer Identification

There are two basic crankshaft types used in all Modular engines—six- and eight-hole nodular iron. The eight-hole cranks are Windsor or high-performance Romeo, according to George Reid. Reid adds that since 1991, when production began, there have been a few basic cranks used in all Modular engines. All are nodular iron. Sean Hyland of Sean Hyland Motorsports, who builds and races a lot of Modular engines annually, told Reid he's never seen anyone break these crankshafts. The nodular iron crank is good for up to 500 horsepower. Given a choice between six-hole and eight-hole, choose the eight-hole flange. There are two crankshaft weights available—heavy and lightweight. The quickest way to identify is the balancing holes in the counterweights. Heavy cranks were made for heavier connecting rods, which first entered service in 1996.

There is the steel eight-hole M-6303-D46 DOHC/Cobra crank you can drop right into the SOHC block. Some minor block modifications may have to be made to prevent block and counterweight interference. If you're building a 5.4L SOHC, there is a steel crank available, M-6303-M54, with an eight-hole flange.

Another closely related issue is the harmonic balancer. There are three basic types for the Modular engine—six-rib for 4.6L, wider six-rib for Cobra/DOHC, and the eight-rib for 5.4L engines. There are also aftermarket balancers for the Modular engine, which tend to follow the six- and eight-rib rule.

Torque To Yield?

Torque to yield is a long-practiced concept designed to prevent over tightening. These fasteners are easily identified by a slight bevel or taper below the bolt head.

Their use calls for tightening them to Ford's specification, then tightening them the suggested additional number of rotational degrees. Torque to yield fasteners are a one-time use fastener—use them once and throw them away. Not all Modular engine fasteners are torque to yield, but cylinder head bolts surely are.