US 3817234 A
A conventional distributor for an internal combustion engine is modified for automobile racing purposes by removing the vacuum spark advance unit and replacing it with an inexpensive manually adjustable unit having an identical mounting bracket, a horizontal adjusting screw mounted for rotation on said bracket and having an adjustable vertical pin mounted thereon, said screw being turned by a knob having means for indicating the amount of angular adjustment of the breaker plate.
Description (OCR text may contain errors)
Unlted States Patent 1191 1111 3,817,234 Jirousek June 18, 1974 [5 ADJUSTABLE DTSTRIBUTOR 3,242,274 3/1966 Sanden 200/31 A Inventor: om J o se C eveland. FOREIGN PATENTS OR APPLICATIONS 205,295 9/1939 Switzerland 123/1405 A As igneez Develco Manufacturing Great Britain Lakewood, Ohio  Filed: Mar. 14, 1973  Appl. No.: 341,237
 US. Cl.123/l46 .5 A, 123/117 R, 123/146.5 R, 200/31 DP 51 1111. c1. ..-F02p 5/00  Field of Search.. 123/146.5 R, 146.5 A, 117 R; 200/31R,31A,31DP
[5 6] References Cited UNITED STATES PATENTS 1,641,442 9/1927 Kroeger 200/19 R 2,018,892 10/1935 Kimball 123/117 R x 2,107,470 2/1938 Crawford et al. 200/19 R 2,944,122 7/1960 Thedick 200/31 R Primary Examinerl ,aurence M. Goodridge Assistant Examiner-Tony Argenbright 5 7] ABSTRACT A conventional distributor for an internal combustion engine is modified for automobile racing purposes by removing the vacuum spark advance unit and replacing it with an inexpensive manually adjustable unit having an identical mounting bracket, a horizontal adjusting screw mounted for rotation on said bracket and having an adjustable vertical pin mounted thereon, said screw being turned by a knob having means for indicating the amount of angular adjustment of the breaker plate.
6 Claims, 5 Drawing Figures I ADJUSTABLE DISTRIBUTOR The present invention relates to an accessory for the distributor of a racing car and more particularly to a very inexpensive manual adjusting device to replace the conventional vacuum unit.
Heretofore, it has been customary in racing cars to modify or adjust the centrifugal spark advance mechanism and to remove or disconnect the vacuum advance unit so that maximum power could be obtained from the engine. Ignition timing of the engine was adjusted in the conventional manner by loosening the distributor clamp nut, turning the distributor housing until the appropriate timing mark was properly located relative to the timing pointer on the engine, and retightening the nut. This adjustment couldsometimes take a considerable amount of time because the distributor moved in an unpredictable manner when the distributor clamp. nut was tightened.
Over the years many different adjusting devices have been proposed for manually adjusting the spark advance or the position of the distributor housing. Special distributors have been proposed which permitted adjustment of the timing without moving the distributor housing. However, special adjusting devices have rarely been used because of the substantial expense and inconvenience of installing the special equipment.
An object of the present invention is to provide a simple device for adjusting the ignition timing which can easily be applied to a standard distributor and which can be made at nominal cost.
Another object of the invention is to provide an inexpensive ignition adjusting device which can utilize the mounting plate of a standard vacuum advance unit.
A still further object of the invention is to provide a low-cost device for adjusting the ignition timing of a racing engine while the engine is in operation.
These and other objects, uses and advantages of the invention will become apparent to those skilled in the art from the following description and claims and from the drawings.
In the drawings:
FIG. 1 is a perspective view ofa distributor with parts omitted showing the adjusting device of the present invention mounted thereon;
FIG. 2 is .a fragmentary elevational view of the adjusting device with parts omitted and parts broken away and shown in section;
FIG. 3 is a bottom plan view of the adjusting device;
FIG. 4 is a foreshortened elevational view with parts in section showing a modified form of adjusting device mounted on the dashboard of the vehicle; and
FIG. 5 is a perspective elevational view of the indicator plate.
Referring more particularly to the drawings, in which like parts are identified by the same numerals throughout the several views, FIGS. 1 and 2 show the device of the present invention mounted on a conventional Delco-Remy distributor-timer A of the type used on General Motors automobiles and more specifically, a distributor used as original equipment on 1971 and 1972 Oldsmobiles, for example.
The distributor A is of standard construction and has a housing! with a flanged top portion forming a generally flat horizontal base plate 2 and with a vertical shank portion 3 forming a bearing for the distributor shaft 4. A drive gear (not shown) is rigidly mounted on 2 the bottom of the shaft 4 to be driven by the engine cam shaft, and a conventional centrifugal advance mechanism 5 is provided at the upper end portion of the shaft.
The mechanism 5 includes a flat horizontal weight plate 6 rigidly mounted on the shaft 4 for rotation therewith, a pair of hook-shaped governor weights 7 pivotally mounted on the plate 6, a cam assembly 8 with a sleeve portion 81 rotatably mounted on the shaft 4 having an integral polygonal breaker cam 9 with six or eight lobes corresponding to the number of engine cylinders to be fired and having a wing-shaped horizontal plate 10 integral with said sleeve portion for engaging the lever portions of the weights 7. The plates 6 and 10 have vertical posts 11 and 12, respectively, and tension springs 13 connected to said posts to move the weights radially inwardly. The weights are moved outwardly by centrifugal force and act as levers to turn the plate 10 and the cam 9 relative to shaft 4 in a direction to advance the spark. For example, in a conventional distributor, such weights may provide a spark advance of only a few degrees at 600 rpm while providing a maximum advance of 22 to 26 at 3,600 rpm. A conventional Weight cover and stop plate (not shown) may be mounted on the plate 6 to cover the unit 5 and to limit the outward movement of the weights. Such cover may carry the rotor (not shown). The plate 6 has a pair of mounting holes 45 for said cover and rotor.
A conventional circuit breaker assembly 14 is provided below the centrifugal advance mechanism 5 and has a flat horizontal breaker mounting plate 15 journaled for rotation on the distributor shaft 4. Said plate has a tab 33 and a series of holes for mounting a cam lubricator, a two-piece shield, a condenser 44 and a breaker contact set 61 which are conventional. The contact set is held in place on the plate by a screw 64. The shield is used to suppress radio interference and may be omitted. The breaker assembly 14 has a single set of contact points 61 which are opened and closed by the lobes of the cam 9. The pivoted breaker arm of said breaker contact set, which carries the movable contact point, has a conventional fibre rubbing block 65 which is engaged by the lobes of the cam 9 to effect the opening of said contact points.
The distributor A described above is conventional and details thereof are described, for example, in the 1971 or 1972 Oldsmobile Chassis Service Manual published by Oldsmobile Division of General Motors Corporation, which manual is incorporated herein by reference. The operation of this type of distributor will be apparent from Chambers U.S. Pat. No. 3,511,945 and the following patents of General Motors Corporation: Hartzell et al. U.S. Pat. No. 2,872,537, Coffin U.S. Pat. No. 3,036,166 and Sanden U.S. Pat. No. 3,242,274. As indicated in the patents to Coffin and Hartzell ct al, the conventional distributor is provided with a vacuum advance unit (not shown) having a spring-biased diaphragm connected to an L-shaped actuating rod. On the vacuum side of the diaphragm is a spring which is compressed when the diaphragm is moved by the vacuum. The vertical end portion of the actuating rod projects upwardly through a circular hole in the breaker plate. In the construction shown in FIG. 1, such circular hole is formed by the upturned portion 18 of the tab 33 which receives the vertical pin 19. A similar construction is shown in said U.S. Pat. No. 3,036,166.
idly mounted on an elongated metal bracket 21. The
bracket comprises a flat horizontal strip '22 of uniform thickness witha pair of slots 16 at one end, an upwardly .projecting rectangular tab 23 between said slots, and a pair of downwardly projecting rectangular tabs 24 on opposite sides of tab 23. The threetabs are flat and in alignment to provide flush vertical surfaces for engagement with the housing of unit 20. The strip 22 is symmetrical about its center line and has a wide portion 25 with a pair of laterally aligned circular mounting holes 26 and a narrow portion 27 of uniform width with a slightly elongated mounting hole 28 and a longitudinally elongated slot 29 of uniform width.
The bracket 21, which is drawn substantially to scale in FIG. 3, has an overall length ofabout 3 inches, a uniform thickness of about 0.09 inch, and a maximum width of about 1 /2 inches at the tabs, each of which are about /2 inchwide. The mounting holes'26 and 28 are 3/16 inch wide, and the slot 29 has a width of A inch and a length of /2 inch or so. The slot 29 may have a length sufficient to permit reciprocation of the pin 19 through a maximum stroke of 0.20 to 9.25 inch, but a J somewhat smaller stroke is usually adequate.
The bracket 21 is rigidly mounted on the distributor housing by a screw 31 in mounting hole 28 and a similar screw 32 in one of the holes 26. Said screws clamp the strip 22 against the flat lower face of the base plate 2 as shown in FIG. 2 to holdthe vacuum advance unit 20 in position on the housing. The clamping arrangement is similar to that shown in said U.S. Pat. No. 3,036,166.
It is customary, when modifying an engine for drag racing, to employ a new cam shaft and stiffer valve springs and to modify the distributor by removing or.
disconnecting the vacuum advance unit (20) and by employing new springs (13) on the centrifugal advance unit to obtain the spark-advance curve'desired for maximum power and accelerationj The initial timing'is adjusted by loosening the distributor base'clamp (not shown), whichholds the distributor housing in place on the engine block, and turning the distributor until the pointer is properly located relative to the timing mark on the crankshaft pulley (or flywheel). A timing light may be used when making this adjustment, and the adjustment can be time-consuming because the housing usually moves slightly away from the adjusted position when the base clamp is tightened.
The present invention makes it possible to make the desired adjustment quickly and easily, without loosening the distributor base clamp, by use of a simple adjusting device B which can be made at nominal cost and which can use the same mounting bracket (21) that is used for the vacuum unit (20). j The adjusting device B of the present invention which isdrawn substantially to scale in FIGS. 2 and 3,
stop portion 39, which may be cold formed to minimize cost. A removable molded plastic adjusting knob 40 is rigidly mounted on the cylindrical end portion 35, which fits tightly in the cylindrical bore 48 and is held in place by the set screw 47 or other suitable means. A cylindrical vertical metal pin 34 is mounted on the threaded end portion 36 at the opposite end of the rod. The pin 34 has an external diameter of about 141 inch and an overall length of about inch and has an internally threaded lateral hole to receive the screw portion 36 and an integral reduced end portion 19 with an external diameter of about 0.15 inch and an axial length of about A inch. The end portion 19 projects through the hole in the breaker plate at 18 to provide a connection between rod30 and the breaker plate, whereby said screw holds the plate in a fixed adjusted position.
rod 39 and perpendicular to said rod and to the strip' 22. The plate 41 has a central circular hole 58 with a diameter substantially equal to that of the rod 30 and substantially less than that of the stop portion 39 to re- I ceive said rod and hold it in position while permitting rotation thereof.
A helical compression spring 37 is mounted on the rod 30 and is compressed between the plate 41 and the flat vertical face of the dial to hold the flat annular vertical face of the stop portion 39 against the flat inner face of theplate 41 as shown in FIG. 3, whereby the adjusted position of the pin 34 is fixed relative to the bracket 21. The spring 37 yields sufficiently to permit easy adjustment of the knob 40 but is sufficiently strong to maintain the rod in a fixed position perpendicular to the plate 41 and to prevent accidental or unwanted rotation of the rod.
The flat outer surface of the circular indicator plate 41 has regularly circumferentially spaced radial lines 42 and the black knob 40 has a white line or pointer 43 and a white circular dot 61, whereby the elements 41, 42 and 61 provide means for indicating the amount of angular adjustment of the breaker plate 15. The slot 29 permits the pin 34 to'reciprocate, in response to rotation of the rod 30, a distance corresponding to an angular movement of the breaker plate 15 of about 15.
Thus, it is relatively easy to adjust the breaker plate 5 or more in either direction.
If desired, the adjusting unit B may be modified to permit adjustments from the dashboard of the vehicle. FIG. 4 illustrates schematically one way of making such adjustment using a conventional flexible drive cable 54 having a conventional flexible sheath 55 extending almost the full length of the cable. As shown in the figure, one knob 40 is rigidly mounted on each end portion of the drive cable 53 for rotation in unison therewith. Each knob has a cylindrical metal bushing 48 extending therethrough of a size to receive the end portion 35 of rod 30 and the end portions 53 and 62 of cable 54. A radial set screw 47 extends through the bushing 48 to grip the end portion 35 and a similar set screw 52 extends through the bushing to grip the end portion 53 of the cable, whereby a rigid driving connection can be provided between cable 54 and rod 30.
An indicator plate 50 is provided with radial lines 42 identical to those of the circular plate 41 and with a central hole 58 of a size to receive the end portion 62 of the cable 54. The width of the plate 50 may be equal to the diameter of plate 41. The plate has a rectangular horizontal flange 59 with a pair of holes 57 to receive sheet metal mounting screws 56 which rigidly fasten the plate 50 to the dashboard 51 of the automobile at a suitable location near the drivers seat, such as near the steering column.
The knob 40 used in association with indicator plate 50 may be the same as the black knob used with plate 41. The white line 43 and white dot 60 of the knob can thus be used with the regularly spaced radial lines 42 of the plate 50 to indicate the amount of adjustment of rod 30. It will be understood, of course, that the circular plate 41 can be omitted when the arrangement of FIG. 4 is employed.
It is preferable to mount the spring 37 on the end portion 62 and to tighten the set screw 47 on said end portion to compress thespring'so that the knob 40 cannot turn accidentally, but this is not essential.
While the optional equipment of FIG. 5 is advantageous for quick adjustments or for adjustments while the engine is running or while'the car is moving, it does involve more cost. The unit B of FIG. 3 is a popular item without such optional equipment because of its exceptionally low cost of manufacture and the ease of installation. It will be noted that only two screws 31 and 32 are needed to mount the unit B in place and that this can easily be done in less than a minute. Also the method of assembly is self evident and requires no installation instructions.
While it is usually preferred to provide an attractive knob 40 and indicator plate 41, it will be apparent that these may be extremely inexpensive. The plate 41 is preferably made of steel or sheet metal but may be molded of a synthetic resin or provided with a molded cover layer. Because the bracket 21 can be original equipment removed from the original vacuum unit 20, elements of the unit B which must be manufactured are essentially the pin 34, the adjusting rod 30, the knob 40, the spring 37, and the (optional) indicator plate 41. The cost of these is, of course, extremely low.
It will be understood that, in accordance with the provisions of thepatent laws,'variations and modifications of the specific devices shown herein may be made without departing from the spirit of the invention.
Having described my invention, 1 claim:
1. in a timer distributor (A) for an internal combustion engine having a distributor housing (1) with a horizontal plate (2) and a vertical shank portion (3), a vertical shaft (4) journaled for rotation in said shank, a centrifugal advance mechanism (5) including a horizontal weight plate (6) rigidly mounted on said shaft and a pair of hook-shaped governor weights (7) pivotally mounted on said plate, a cam assembly (8) mounted to turn on said shaft and having a polygonal cam (9) and an integral wing-shaped plate (10), spring means (13) providing a yielding connection between said last-named plate and said weights to resist outward movement of the weights, said weights (7) providing means for turning said cam relative to said vertical shaft in response to centrifugal force, and a circuit breaker assembly (14) having a horizontal breaker plate (15) rotatably mounted on said shaft (4) for carrying a condenser (44) and a set of breaker points (61 said breaker plate having a tab (33) with an upturned portion (18) forming a circular hole, the combination which comprises an elongated mounting bracket (21) having a flat horizontal strip (22) and integral vertical tabs (23 and 24) extending upwardly and downwardly from said strip, said strip having a mounting hole (28) at its outer end and a laterally extending portion (25) with a mounting hole (26), said mounting holes providing means for rigidly mounting said bracket on said base plate, a flat vertical indicator plate (41) rigidly mounted on said tabs and having a central hole (58) and regularly spaced lines (42) extending radially from said hole to indicate degrees of rotation, an adjusting rod (30) having a threaded portion (36) at its inner end and a mounting portion (35) at its outer end having a cold-formed enlarged stop portion (39) with a vertical face engaging said indicator plate at the margin of said central hole (58), said mounting portion (35 projecting through said central hole, a removable indicator knob (40) having means (47,48) for rigidly mounting said knob on said mounting portion 35) and having indicator means (43,60) showing the angular position of the knob relative to said indicator plate, a helical spring (37) compressed between said knob and said indicator plate for yieldably resisting rotation of said adjusting rod (30), a vertical pin (19) carried by said rod for engaging the upturned marginal portion (18) of said circular hole to provide a driving connection between said pin and said breaker plate, said pin (19) having an enlarged lower end portion (34) with a lateral hole to receive the threaded inner portion (36) of the adjusting rod, said lateral hole having threads fitting the threads of said inner end portion to provide means for advancing the pin to response to rotation of said adjusting rod, the strip (22) of said bracket (21) having a narrow slot (29) to receive the pin (19) and guide it in the direction of said adjusting rod, said slot having a length sufficient to permit 10 to 20 degrees of angular adjustment of said breaker plate (15).
2. The combination according to claim 1 in which a flexible driving cable (54) is rigidly connected to said adusting rod (30).
3. The combination according to claim 1 in which the means for mounting said knob (40) on said mounting portion (35) comprises a metal sleeve bushing (48) of a size to receive said mounting portion of said rod and a radial set screw (47) extending through said knob and said bushing and engaging said-mounting portion.
4. The combination according to claim 3 in which said bushing (48) extends axially through said knob (40) and has means (52) for rigidly attaching said bushing to one end portion (53) of a long flexible cable 54 having a long flexible sheath (55) and in which an indicator plate is provided having a flange means (59) for mounting theplate on the vehicle dashboard and having a circular hole (58) for receiving the other end portion (62) of said flexible cable, and an indicator knob (40) is rigidly mounted on said other end portion (62), said flexible cable (54) having a length to extend from the distributor of the engine to the dashboard and providing a driving connection between said lastnamed knob and said adjusting rod (30), whereby the spark advance may be adjusted by the driver while he is operating the automobile.
5. The combination according to claim 1 in which said adjusting rod (30) includes a flexible driving means (54) extending from the distributor of the engine to the dashboard to permit manual spark adjustment during operation of the automobile.
' s with a width of 1 t0 2 inches and a series of integral vertical tabs (23 and 24) welded to said indicator plate