By Rich Locasso
Originally published in Healey Highlights, Volume 5-8
Lightening the flywheel is an old hot rodders trick which decreases the mass of the engine components and increases acceleration. Dave Shelton of the Calgary Austin-Healey Club lowered the weight of his 3 litre flywheel from about 29 pounds to 20 pounds, and reported a very noticeable improvement in acceleration in first gear, some improvement in second gear, and nothing noticeable in third or fourth gears. He also said that he did not find and increase in engine roughness, either at idle or cruising speeds, and that it felt as smooth as stock. The flywheel and clutch assembly should be rebalanced after the flywheel is lightened.
For maximum acceleration performance the transmission and clutch must be in good repair. If you can grind the gears during quick shift flat out acceleration then the tranny synchros need replacing, and you will be losing time through a quarter mile. The Healey gearbox is a slow shifter to begin with, although the BJB box is superior to the earlier side lever type, and badly worn synchros can add 1 to 2 seconds to a quarter mile ET. Before overhauling my BT7 gearbox, the first to second shift under full acceleration took at least one second, maybe more, and I’d always “grind a pound”. In a drag, I’ve seen an otherwise equal sports car jump out two car lengths during this “snaaaaaaaaaap (grind) shift”. A rough clutch will make line starts difficult, and a worn clutch will rob power in third and fourth gears by slipping just a little bit before grabbing and transmitting ful lpower to the rear wheels.
The proper weight of oil is essential for optimum performance and longevity of the engine. If-too light an oil is used, the bearings and bushings of an engine will experience increased wear and under extreme stress conditions, a greater chance of failure. If a weight of oil is used that is too heavy, cylinder wall/piston friction increases and horsepower will be reduced. At one point before an engine overhaul on the Healey a few years ago, I was experiencing low oil pressure during hot summer days, so I tried 50 weight oil plus some STP. Oil pressure was up but power was down, so much so that the Healey didn’t have the snap it was capable of. I believe that Dave Ramstadre commended a good 30 weight for the Healey. A Healey engine in good original condition or overhauled is happy with a good 30 weight or 20/40 weight for summertime running.
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