Modified Mustangs & FordsHow To Engine
Budget FE Power! - Part 1 in a Two-Part Series
JGM Motorsports and Summit Racing Equipment Get Together to Build Performance into Ford's Venerable Big-Block
A Word About Bearings
There are a lot of misconceptions about bearings. That little tang on main and rod bearings isn't there to keep the bearing in place; it's a reference tool to ensure proper bearing positioning. Never use engine oil or assembly lube between bearing and rod, or bearing and block. Contact between bearing and rod, and bearing and block must be bone-dry for security purposes. Crush and crosshatch keep a bearing secure; so do dry contact surfaces. Be sure to use generous amounts of engine assembly lube (do not use a moly-based lube) on journals and bearings. Make sure the bearing is properly centered and secured. Check the oil hole alignment of the bearing where applicable.
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Blueprinting is the process of leaving no stone unturned in an engine build. Blueprinting means sweating details others tend to miss. It's one thing to call your build "balanced and blueprinted" and quite another to actually do it. When we degree a camshaft, we're examining the most important details of an engine build--rotating assembly and valve timing events.
Because there's no such thing as perfection in mass production, you must always believe in failure potential. Assume the worst and hope for the best. New parts right out of the box aren't perfect. Like the best of machine shops, there are going to be factory workers who are having bad days--inattentive to things they should be attentive to, apathetic, careless, sloppy, eager for lunchtime or beer-thirty. Are you willing to gamble hard-earned dollars and your engine to this kind of carelessness? We didn't think so.
When we degree an engine, we're checking two things if it's being performed properly. First, we're checking for true TDC (top dead center) on all eight cylinders. Reputable builders will check for true TDC on the No. 1 cylinder and see if it jibes with TDC on the harmonic balancer. Most of the time, it won't. When it doesn't, good builders will mark true TDC on the balancer--and degree the balancer for pinpoint timing. True TDC is dead-middle of the top-dead-center crank journal rollover when the piston dwells at the top of the bore.
Wise builders will find true TDC on all eight cylinders more for curiosity's sake than anything. The truth is, true TDC will vary with even the best 4340 steel crankshafts. In a perfect world, we would have identical TDC on all eight cylinders, but this isn't a perfect world. Factory machining tolerances vary enough that you're not going to have eight cylinders that smack TDC with identical consistency; however, it's always good to know exactly what you have before buttoning up.
Once you've established true TDC on the No. 1 cylinder, you're free to degree the camshaft. Degreeing a camshaft allows you to compare the cam card and camshaft. You're establishing valve-timing events and lift as they relate to crankshaft travel. If you're unhappy with valve-timing events, this is the time to make changes either with the existing cam or opting for another one.