Oil Leaks, Tuning Issues, and Proper Crankcase Ventilation

Oil Leaks, Tuning Issues, and Proper Crankcase Ventilation

By Gordon Young: Is improper control of blow-by gases in your crankcase causing problems in your engine?  If any of these questions below sound familiar, then read on. “Why does my engine leak oil?  I took care when fitting the gaskets and seals.” “Why do my valve covers persistently display oil around the breathers?” “Why does my car smell oily?” “Why can’t I perfect my idle tuning?” Imagine a small tailpipe constantly pumping combustion byproducts into your engine’s crankcase.  In effect, this is what is happening when your engine is running.  Blow-by gases entering the crankcase by leaking past the pistons and rings during the combustion process need proper evacuation.  If left unchecked, they cause numerous side effects, inducing engine problems that may seem unrelated. Side effect #1:  Crankcase pressure (“My engine leaks oil”) The job of the Positive Crankcase Ventilation (PCV) system is to remove blow-by gasses from the crankcase by vacuum and recirculate them via the intake manifold to be burned in the engine.  If the engine is producing blow-by gases faster than the PCV system can dispose of them, an increasing surplus becomes trapped in the crankcase, causing excess pressure and, inevitably,  oil leaks.  Even the most carefully sealed gaskets leak when confronted by rising internal crankcase pressure. A properly functioning PCV system will expel the gases from the crankcase faster than the engine produces them.  In addition, the low-level vacuum draws in fresh air to the crankcase from the crankcase breather. In 99% of normal driving conditions, this is how a properly functioning PCV system works. Obviously, the gasket’s job is made easier when the crankcase...
Vintage class winner: EMC attracts unexpected 600,000 views

Vintage class winner: EMC attracts unexpected 600,000 views

By Alfie Bilk: Jon Kaase has won this year’s Amsoil Engine Masters Challenge Vintage class with a 473ci 1958 MEL (Mercury-Edsel-Lincoln) engine. Exploring the classic turf in distinctive fashion, it was not the first time Kaase had arrived with an unorthodox relic endowed with bewildering technology. Held annually in early October at the University of Northwestern Ohio, his entry produced 770hp with torque never less than 630lb-ft during the entire scored rpm range of 3,700-6,200rpm. The engine’s peak torque was recorded at 715lb-ft. Earning a check in the sum of $13,700, it was Kaase’s seventh victory at the prestigious affair, which coincided a few days before his sixty-fifth birthday. This year’s Vintage rules specified factory cast iron cylinder heads and prohibited welding or the application of epoxy to the ports. Also, it was stipulated that the engine block must retain its original bore spacing and original block deck angle. A further constraint for Kaase was the fact that he had to return the MEL block to its owner, Royce Brechler, in a functioning condition. The origins that preceded the workings of a bright mind MEL engines had wedge-shaped combustion chambers formed between a flat cylinder head surface and an angle-milled block deck angle that was ten degrees off square with the bore axis. The piston crown determined the compression ratio and combustion chamber shape—a concept similar to Chevrolet’s 409, a design also introduced originally in 1958. Yet to each cylinder head deck, Kaase added four slugs of round bronze bar stock by counter-boring the heads to accept them. Measuring 4.600in diameter and 1.250in tall and protruding downwards, each set...
What is core shift and why is it detrimental?

What is core shift and why is it detrimental?

How a clever concept remedied misalignment in competition engine blocks – By Archie Bosman: No other engine deficiency would have irritated racers, particularly professional drag racers of the last century, like core shift. A bitter source of anguish, they would describe it in a way not easily forgotten. “We used mostly Hemi blocks,” commented “Mongoose” McEwen. “Often we would test fifteen-to-twenty blocks before finding one with consistent cylinder wall thickness. Keith Black had a method of measuring them, which typically demonstrated core-shift variations from around 0.090in or 0.100in to 0.040in. Consequently, if we raced those engines, the severity of the internal pressures usually split the cylinder walls.” As you can guess, the impediment of core shift didn’t debilitate just the racing Hemi; Funny Car racer “Wild Wilfred” Boutilier’s reject ratio with big-block Chevrolets was similar. So there they were pencil and pad in hand, slavishly enumerating cylinder wall thicknesses, one engine block at a time. The term core shift relates to the deviation of a foundry core during the casting process. That is to say, the core moves from its original position, perhaps as a result of inaccuracies in the machining process or the setting of the mold, and leads to alignment problems when the mold is closed. Mold temperatures or pressure differentials on opposing mold walls also cause deflections of the cores. Whatever the cause, the result is evidenced by undesirable variations in wall thickness, which affects the final shape and, thus, the mechanical performance of the part. The problem has now been resolved by substituting conventional foundry segmented cores with an evolutionary one-piece major core. Though its...
Hammerhead Hemi peaks 928hp: 427ci SB Ford

Hammerhead Hemi peaks 928hp: 427ci SB Ford

By Freddie Heaney: The sound of the dyno approaching 8,000rpm was almost ear splitting. It was the first Friday of June and sitting in an open wooden-framed space at Charlie Pepper’s engine shop in Auburn, near Atlanta, Greg Brown’s innovative Hemi heads on a Man O’ War 427ci small-block Ford peaked at 928hp at 7,700rpm and generated a maximum torque figure of 674.0lb ft at 6,000rpm. Watch the video. When first tested in mild street form with around 9.5:1 compression ratio the combination yielded 602hp. Quite the accomplishment for unique and previously untested cylinder head designs. But it was not the main event nor might this be. Now, around six months later and using ported heads and intake manifold, higher compression ratio and bigger carburetor, but still employing the same stock-size valves (2.200-inch intake and 1.650-inch exhaust) the engine began the afternoon tests by generating peak power figures in the 850hp range. But with incremental timing and carburetion adjustments it eventually made its way up to a mighty 928 horsepower. Inevitable, I asked? “No, not at all, replied Brown. “Though we increased the flow in the ports from 382cfm / 260cfm to 435cfm / 290 (inlet and exhaust respectively), I would have been happy with peak horsepower numbers of around 850. Remember, ninety percent of all high performance wedge-style cylinder heads rarely exceed 800hp.” Of even greater significance, perhaps the 1250cfm Dominator-style carburetor had proved to be too small during the tests and will be replaced by another that’s capable of generating air flow of around 1450cfm. Was the 1250 carb an ill-advised choice perhaps? “No,” said Brown, “this...
Harmonic balancers: Free advice on selecting them

Harmonic balancers: Free advice on selecting them

By Archie Bosman:  It’s easy to underestimate the cost of a deficient harmonic balancer. But they can have a profound effect on the fortunes of the able race engine—a natural enemy of crank and bearings. With the engine running, camshafts and crankshafts vibrate torsionally (in twist) and, as the saying goes, for every action there’s a reaction. Camshafts are affected by the forces related to the opening and closing of the valves while crankshafts by the combustion events. Each time the cylinders fire, torque is imparted to the crank, causing deflections—twisting it as much as 2 degrees. All of this partially complicates the timing of the valve openings as well as the cam and ignition timing to say nothing of the oppressive conditions in which the crank operates. As a result of the vibrations and deflections in both shafts, a harmonic balancer or damper is connected to the crank to absorb them. Vibrations are at their highest when furthest from the flywheel. Hence dampers are mounted on the front of the crank. Yet, on historic and vintage race engines often there was no provision at the front of the crank to mount a damper. Consequently, they might use a custom elastomer or tunable pendulum damper at the rear of the crank near the clutch.   Resonance At certain engine speeds the torques imparted by the cylinders are in sync with the vibrations in the crankshaft, which results in a potentially destructive phenomenon known as resonance. This resonance can cause stress beyond what the crank can endure, resulting in crankshaft failure due to fatigue. Robert Bartlett of the noted historic...
Motown LS: Unfamiliar hybrid

Motown LS: Unfamiliar hybrid

By Sam Logan: What’s the motivation for adapting LS cylinder heads to a small-block Chevrolet engine? Why not just go out and buy a used LS-series? It’s a modern power unit; it’s bestowed with high flowing heads, it’s readily available and it’s affordable…all the benefits you could desire. Except there’s a catch—the inconvenient fact is there’s a ton of work required to get it installed properly, coupled to appreciable expenditures. If you are empowering any pre-1990s Muscle car with an LS-series engine it is usually not a simple swap. And it’s not just exploring engine and transmission mounting solutions and clutch actuation, but there are EFI and ignition considerations, a fuel system design as well as numerous cooling and engine accessories questions to resolve. The fact is that mounting a pair of LS-series cylinder heads on a small-block is a much more practical solution. Likely, the most interesting new engine for 2016 will be the Motown LS. Under the insightful command of Dick Boyer, the architect of the last year’s 454 Man O’ War Ford block, World Products committed to foundry tooling expenses for the production of such a hybrid. It is unique. Weighing 210lb and employing standard LS deck height, the Motown LS is a cast iron small-block that accepts LS-series cylinder heads. Boyer’s uncommon design made its first appearance in public at December’s PRI show. Available in two versions, a street-strip and a race variant, he had displayed the former although not yet tested. When tested the 427cu in engine generated just under 640hp at 6,400rpm. Not bad for a street-based engine. The drag race version uses...
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