Jim Smart
April 27, 2010

Tech | Engine Building
We Wrap Up Our Edelbrock/MCE Engines 427w Raptor

We began our Edelbrock/MCE Engines 427W Raptor stroker project with elements important to making power in the March 2010 issue. This month, we're going to wrap up our project with important points to releasing power wasted inside your engine. They don't always involve cam specifications, carburetor sizing, and cylinder head flow numbers. Marvin McAfee of MCE Engines in Los Angeles, California, stresses you must go looking for trapped power inside an engine.

Marvin's strategy for power includes internal friction reduction, reducing windage, improving oil return flow (scavenging), playing with valve timing, making finite adjustments to valve lash, and making modifications to induction and exhaust. He likes to get clearances to where they aren't too small yet they're not too large either. He wants liberal oil flow across bearing journals, yet he seeks a healthy oil wedge to keep moving parts happy. He likes his engines to have loose tolerances to free up trapped power, yet he likes things snug for durability.

Put your hands on the crankshaft in one of Marvin's blocks and give it a twist while it's on the stand. Rotary motion in Marvin's engines is buttery smooth-easy to turn, yet comfortably snug. Slide a timing gear onto the crank and feel unequalled smoothness because everything with Marvin is zero fit void of resistance. Put your mallet away because you won't need it.

Marvin's engine blueprinting regiment is a strict discipline he follows with every engine he builds-extreme attention to detail that begins with the teardown and close forensics analysis. This comes of Marvin's extensive racing background coupled with a career in aviation. Failure analysis is his specialty. If an engine failed, Marvin wants to know why. Engine failure can lead to engine failure again if you miss something important to its foundation, Marvin will tell you. A crank or rod that isn't true; a block with misaligned main saddles; a warped deck, cracked castings; fasteners that should be replaced; and a host of other things we haven't thought of. Marvin will tell you it isn't always the obvious, but the unobvious, that leads to engine failure.

Marvin blueprints every oil pump, checking rotor clearances in every way imaginable. He likes a nice, smooth slide fit along with proper spring pressure when he checks the pressure relief valve. Marvin wants at least 10 pounds of oil pressure for every 1,000 rpm along with volume with the engine hot. Raising pressure to increase volume will cost you power.

When Marvin gets parts back from his machinist, he goes over everything with a fine-tooth comb, measuring all dimensions and inspecting machine work in great detail. Screw-in oil galley plugs are installed where press-in plugs existed. All oil galleys and water jackets are chased thoroughly to rid debris. Brass core plugs (also known as Welsh plugs) are installed with an industrial adhesive. Internal surfaces are coated with GE Glyptal to improve oil return flow. Ragged edges, known as stress risers, or radiuses are chamfered to prevent cracking. Components are checked for proper fit again and again during pre-assembly (mock-up) and assembly.

The Edelbrock Glidden/Victor Pro-Port Cylinder Head
The Edelbrock Glidden/Victor CNC Small-Block Ford cylinder head is a replication of the head Billy Glidden designed and used for record drag racing numbers in NMRA competition. The Glidden/Victor casting was born to make the most of the 289/302/351W Ford V-8s. Because these castings come from Edelbrock's own foundry and machining processes, you know you're getting the best American quality possible. MCE Engines has prepared these head castings, massaging in significant improvements to improve durability. No additional port work has been performed though. Marvin opted for Manley hollow-stem stainless steel valves for his Edelbrock Glidden/Victor heads because they power the winners. And as we all know, everyone loves a winner.

"One sales/technical representative at a prominent cylinder head manufacturer said we'd be lucky to reach 500 horsepower with the cam we had chosen," Marvin tells us. "Achieving 600 horsepower is a no brainer. A more aggressive camshaft will get you there with this engine package. But 600 horsepower isn't what we're seeking here. Our goal is 550/550 on torque and horsepower-a nice compromise in our quest for both road racing and durability." Marvin went on to say, "I can't say enough about both Manley Performance and Edelbrock. These guys give you from mild street performance all the way to extreme duty, and they do it so well."

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