FORD VAN POINTERS.
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By R. T. Nicholson (Author of "The Book of the Ford').
HERE are a few miscellaneous facts and figures relating to the Ford. The details given may come in useful for reference at -odd times ; at any rate, there is hardly a single fact or figure amongst those following for which I have not been asked by some correspondent at some time: — 493,—Some Facts and Figures.
Frame Dimensions.—Truck: length of side mem. hers, 10 ft. 3 29-32 ins. Width of front cross member, 1 ft. 11 ins. Width of rear Cross member (to centre of bracket holes), 2 ft. 6 ins. Van : Length of side members, 8 ft. 4 ins. Width of front cross member, 1 ft. II ins. Width of rear cross member (to centre of bracket holes), 2 ft. 1"-k ins.
Wheel Base.—(By wheel base is meant the distance between hub-caps centres of front and back wheels on same side). Truck : 10 ft. 3 ins. Van :,8 ft. 4 ins.
Tread.—(Distance from one off-side wheel to opposite near-side wheel). 4 ft. 8 ins, for all models.
Road Clearance.—(Distance between the road and the lowest point of any part of the structure except wheels). About 10 ins.
Lubrication of Rear Axle—The rear axle housing should carry 1 lb. of grease. In the original assembling, or after dismantling for repairs, it is, of course, easy. to supply the exact amount required ; but after males of running it is impossible to tell exactly 'how much to add. The grease should lie about Gee-third up the differential bulge. If grease exudes from axle ends, the inference is that the lubrication has been overdone. Even when the felt washers at axleends are worn, there is little liability to escape of grease if supply is not excessive. The trouble begins when the grease lies so high that it , gets on to the axle shafts, and can then work along to the ends.
Lubrication of Universal Joint.--The housing
originally contained A lb. of grease. The supply should he dully maintained at all times. Over-lubrication has no. objectionable results, while under-lubrication spells trouble. . .
Front Wheel Spindle Threads.—Left-hand threads are cut on right-hand. spindle, and right-hand threads. on left-hand spindle. This is not due to "pure cussedness " . on the manufacturers' part. The object is to prevent the wheels from tending to slacken off when running : the arrangement in question tends, in fact, to make them run tight ; but this tightening tendency is prevented by the lock-nuts. The dims tion of the threads becomes important when it is a question of replacing cones and lock-nuts : an effort to force these on with a wrong turn " ehaws up the threads badly.
Springs Leaves (although this is not the the-poet's section 1)—The truck has -seven leaves in the front spring,' nine in the back spring. The van has the same number as the truck in front and one less (i.e., eight) in the back spring.
A Ford spring will take.a load of 2,000 lb. before flattening, and will recover itself after that.
Front Wheel Alignment.-1t is not generally known that the front wheels are " out of truth" in throe directions, and are meant to be so — (a) The tops of the wheels are 3 ins. (90 degrees) farther out than the bottoms. This is known as -" flare."
(b) The fronts of the wheels are from lc in. to in
farther in than the backs (51 degrees). We call this "gather."
(c) The front axle is tilted backwards 51 degrees. In this respect, the construction of the front wheels of the Ford is similar to that of the front wheel of a bicycle, the steering of which is much easier than it would be if the front forks ran in a straight line to the hub. With the bicycle, it makes "hands off" riding possible. With the Ford it tends to keep the front wheels running straight—to "castor."
(a) Camber is determined by the set of the spindle, and is unadjustable. (la) Gather is adjustable by the yoke on the tierod.
(c) Castor is determined by the spring perches, and is unadjustable.
Some Interesting and Useful Engine Facts.
Engine Dimensions.—Four cylinders, each having
3:I-in. bore and a 4-in, piston stroke, it is these dimensions that give us our horrible Treasury rating.
(The " 4 " in the folio-wing calculations represents the number of cylinders, not the length of the piston stroke. The latter factor is not allowed to enter into the computation : it would be far fairer if it did, because, actually, the length of the piston stroke makes all the difference to engine power. The Ford has a relatively short stroke, whereas most engines— to develop good power—have a relatively long stroke. That is why the poor little Ford is taxed so heavily as compared with motors that develop much greater horse-power in actual practiee):— ._ The divisor of 2.5 shown above is an arbitrary figure, which took account of piston stroke, 1,000 feet per minute being presumed. This divisor was, at one time, supposed to give true results. It is now known that the calculation is altogether wide of the mark.
Pistons.—The piston is smaller at top than at bottom by about 100th of an inch (diameter). This difference is made to allow for expansion of top ot MI piston through excessive heatthere encountered Diameters:—
At bottom (skirt), 3.748-3.749 ins. At middle ring, 3.743-3.745 ins.
At top, 3.738-3.740 ins.
Piston displacement. iii all four cylinders jointly,
is 176.715 cub. ins.
Piston Rings.—The two middle rings are provided for retention of compression. The bottom ring is provided to prevent oil from finding its way too liberally upwards, and so fouling the combustion chamber.
Width of piston-ring gaps should be as follows, the rings being compressed as far as possible in position in their grooves:— Bottom, .008 in. ; middle, .005 in. ; top, .003 in.
In fitting -new piston rings note that the word " Ford " should lie towards top of piston.
Gaps in rings should be evenly spaced out (120 de grecs apart vertically) to prevent a "straight through " way for escape of gases of combustion. Piston clearance in its cylinder should be .004 in. when piston and cylinder are new, or after reboring, and should not exceed .006 in. 'when Worn.
-Pistons rise approximately 5-16 in. above flat of cylinder casting.
Engine compression should be 60 lb. to the square inch.
Order of Firing.-1, 2, 4, 3.
Valves.—Valve head at top is 1 15-32 ins. in-diameter ; at bottom it is about 1 9-32 ins. Angle of face is 45 degrees to centre of stem ; head is 3-16 in. thick; stem diameter is about .311 in.
Valve springs should have a tension of about 20 lb,• when in working position on valve.
Valve clearance should be from .022 in. to .032 in. when engine is cold—i.e ; there should be a gap of (approximately) from 1-32 in. to 1-45 in. between top of push rod (tappet) and !bottom of valve .stem. Heat, of course, tends to reduce it when engine is running. Valve lift should be 7-32 in. Wear of cams tends to reduce it—and engine efficiency. Timing Gears.—Old-style large gear has 42 teeth, small gear 21 teeth. New-style gears (1920 onwards) are spiral, and give much quieter running. In either ease the camshaft turns at one-half the rate of the crankshaft, the gear ratios determining this.
Engine Timing.—Exhaust valve should open when piston is short of bottom centre (on down stroke) by
5-16 in., and should close at top centre. Inlet valve should open when piston has passed top centre by 1-16 in., and should close when piston has passed bottom centre by 9-16 in. Crankshaft end play should not exceed .004 in., as, if it did, the .gap between magnets and stator coils would be variable and sometimes excessive, or might Cause the magnets to collide with the stator coils. Heat expansion tends to lessen the play of .004 in., but. this expansion acts forward, and does not affect the gap in question. Rear bearing is thus set to give .004 in. end-play, centre and front bearings having from .031 in. to .062 in. clearance (allowing both for expansion and lubrication).
Thermo-siphon Circulation.—Circ.ulation does not begin until the water is ra issd to 180 degrees Fahrenheit. Greatest engine efficiency is _gained at about 190 degrees.
The radiator has 95 tubes, 4-in. diameter, 17i ins. long ; 87 fins give a radiating surface of 54.63 sq. ft., the radiating surface of the tubes being 8.94 sq. ft., total radiating surface being thus 63.57 sq. ft. in all. The whole circulating system holds approximately three gallons of water, of which nearly two gallons are in the radiator proper. The tubes alone hold nearly half gallon. And yet she sometimes boils!
The present radiator is 24 ins, higher than the old one, has 13 more fins, and•1.176 more sq. ins, radiation surface ; but the present cooling system contains apint less water, and the radiator proper holds half pint less.
LI have a few more of these miscellaneous facts and figures which I will incorporate in a later contrib ution.—a. T. N.]