Shocks and Springs

REAR SHOCKS.

The stock lever shocks were used through 1998 and tube shocks were fitted during the 1999-2003 Major Upgrade.

These shocks have an extended length of 20 inches with a stroke of 7 inches (more than needed) and have ½ in. diameter spherical bearings at each end. Ten valving levels were available, indicated by numbers 0-9, and representing soft through stiff. The shocks are adjustable, but need to be dismantled to do so. The shocks were ordered with valving level 3 for both bump and rebound and purchased from QA1 Precision Products, PN 50730, (www.qa1.net).

They have been revalved and are now at level 2 for bump and rebound. They were serviced in Spring 2015 by Elite Shock Services in Elk River, MN. (www.eliteshockservices@yahoo.com).

For mounting, the upper end of the shock is inserted and bolted to a 1 ½ in. OD square tube bracket that is welded to a Rear Support of the Roll Bar Structure. That joint is also triangulated with a 1 ¼ in OD tube to the Main Roll Hoop. Step sleeves are used in the spherical bearing and a 3/8 in. AN bolt in double shear attaches the shock. The lower end attaches to a ½ in. diameter stud that is part of a custom bracket that bolts to the inside of the outer axle flange. The attached photo shows the set-up.

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FRONT SHOCKS.

The front shocks are the adjustable Koni units that are available for the Morgan with P/N 80-1021. They were replaced in 2013 after roughly 20 years (!)

FRONT SPRINGS

in 2014 I became aware of an on-line discussion on Morgan web sites regarding the interaction of the main and rebound springs. For about the first inch of bump travel, the spring rate is the SUM of the two springs, until the rebound spring is fully extended and free of the spindle. Then the rate is just that of the main spring. This causes a reduction in front roll stiffness, which during cornering could lead to sudden oversteer. Either I had not noticed this, or had adapted to it over many years of racing. Still, I wanted to explore it. The discussion referenced “what racers do”, which was to install a stiffer main spring and a shorter rebound spring that would barely touch the spindle at static ride height.

After some analysis, 225 lb/in main springs from QA1 were selected, with a free length of 10 in. and 1 7/8 in. ID. They were purchased through Summit with P/N HAL 10SM225. Spacers were fitted on the top of the main springs to adjust ride height. A shorter stiff spring (an Isky valve spring) was selected as the rebound spring, and barely touches the spindle at ride height. The set-up was run at a BIR test day in summer 2014, where I worked up to racing speed, and Morgan felt comfortable, with no surprises. It has since been run in competition at Watkins Glen, BIR and Road America with predictable responses during turn-in, powering out of 3rd gear turns, or in fast 4th gear sweepers.

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