MARINE PERFORMANCE PISTONS A look at how marine differs from automotive. Note the extra dome thickness of this marine piston example. It’s designed for long duration operation under load, especially with forced induction. (Illustration courtesy JE Pistons) Ever wonder if and how a marine-application piston differs from an automotive slug? Well, we did, so we [...]
SLEEVING TO SAVE OLD BLOCKS By John Catapang, Darton International Ductile iron is the primary material for cylinder sleeves. An option is cast iron. With a ductile iron sleeve in a cast iron block, the thinnest we recommend boring a sleeve is 0.060″. We have seen people go to 0.040″ sleeve wall thickness with success [...]
Thank you very much. The DOHC 2.4L head in this 2001 PT Cruiser spit the No. 1 spark plug without warning, taking the threads along for the ride. We suspect this resulted from poor thread quality coupled with a relatively low spark plug torque value. It appears that cylinder pressure worked its magic on the [...]
PRO-LEVEL SPARK PLUG THREAD REPAIR MADE EASY If you haven’t run into this problem yet, it’s very likely that you will in the near future. There seems to be a rash of spark plug thread failures in a variety of later-model aluminum heads. The most common is the 4.6L Ford head simply because some design [...]
SPECIAL FIRING ORDER CAMSHAFTS Tricks for smoother-running, longer crank bearing life, and maybe a few extra horses in the process. by Mike Mavrigian photos by author The cam on the left is a standard firing order bigblock Chevy. The cam on the right is a 4/7 swap cam. Notice that the second and fourth lobes [...]
WE BUILD A VINTAGE FE USING PERFORMANCE AFTERMARKET HEADS, INTAKE, ETC. by Mike Mavrigian all photos by author The “old” Ford 427 FE side oiler has regained its popularity among both racers and street rod/custom car builders, especially for Cobra replica builders. This blast from the past is back with a vengeance.The Ford 427 “side [...]
continued from Part 2 Considering the anticipated forces that a set of rod bolts will encounter during high-performance engine use, it doesn’t make sense to compromise by tightening with torque alone. Two examples of rod bolt stretch gauges. A variety of manufacturers offer these tools. The bottom anvil (stationary pointed pin) is adjustable to accommodate [...]
continued from Part 1 CYCLIC FATIGUE PROTECTION Whether measured by stretch or tightened by torque, rod bolts MUST be installed with the proper amount of preload (bolt stretch) in order to provide proper clamping force. If a rod bolt is installed without sufficient preload, every revolution of the crankshaft will cause a separation between the [...]
MEASURING CONNECTING ROD BOLT STRETCH Optimum bolt preload and clamping force is achieved by monitoring rod bolt stretch as opposed to applying torque value. by Mike Mavrigian photos by author Tightening connecting rod bolts while measuring bolt stretch provides a much more accurate method of achieving proper bolt preload and clamping force. Professional performance and [...]
VINTAGE ENGINE TECH Editor’s Note: This new column is dedicated to providing miscellaneous tidbits of info relative to ever-popular vintage engines that simply refuse to wander off into oblivion. These are the mills that remain dear to our hearts, and that find homes in an array of vehicle applications including nostalgia drags, street rods, old-school [...]
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