WO2013169261A1

WO2013169261A1 - Internal combustion engine ignition timing tool

Info

Publication number: WO2013169261A1
Application number: PCT/US2012/037438
Authority: WO
Inventors: Jeffrey L. SWINDELL
Original assignee: Swindell Jeffrey L
Priority date: 2012-05-11
Filing date: 2012-05-11
Publication date: 2013-11-14

Abstract

The internal combustion engine ignition timing tool includes a first embodiment having a closed configuration and a second embodiment having an open lower collar (118) and a closed cap (112) installable atop the collar (118). The closed caps or tops of both embodiments are configured to conform closely to the shape of the upper portion of the distributor rotor (R) in order to preclude relative rotation between the tool and rotor (R). Either of the embodiments is placed removably atop the distributor after removal of the distributor cap, and enables the mechanic to set timing accurately without additional equipment. The engine is turned to align the conventional external timing marks, and the distributor is rotated to allow the closely conforming lower portion of the cap to engage the shape of the rim of the distributor, thus assuring that the rotor (R) is precisely set within the distributor.

Description

INTERNAL COMBUSTION ENGINE IGNITION TIMING TOOL

TECHNICAL FIELD

The present invention relates generally to mechanical tools and the like, and more specifically to an internal combustion engine ignition timing tool that enables the ignition timing of an internal combustion engine to be set more quickly and accurately upon initial installation of the distributor prior to starting the engine and without the aid of a conventional timing light.

BACKGROUND ART

Although many spark ignition internal combustion engines now have essentially fixed initial ignition timing by using a crankshaft position sensor or the like, a large number of such engines still rely upon an ignition timing system wherein a rotor rotates within a distributor to distribute the spark impulse to the individual cylinders as the rotor revolves within the distributor. Such systems are mandatory in certain classes of racing vehicles. This basic principle is the same for mechanical points-type distributors in which a cam lobe(s) on the distributor shaft periodically opens and closes the breaker points, and for so-called

"breakerless" systems in which magnetism or light (visible or invisible spectrum) is used as the timing signal. The same basic timing principle is used with magneto ignition systems. The primary difference between the conventional distributor system and the magneto system is that the magneto also serves as an electrical generator to produce the electrical energy required for the ignition system.

Basic distributor and magneto ignition systems universally rely upon a distributor shaft that is geared to a rotary component of the engine, generally a camshaft or crankshaft. The distributor rotor is affixed to the end of the distributor shaft within the distributor housing. Due to the tolerances and gear lash inherent in such a mechanical system, as well as point wear in a mechanical point system, the distributor or magneto is always provided with some means for adjusting the timing of the ignition pulse to each cylinder. This is generally accomplished by allowing the distributor or magneto to be rotated slightly in its installation and locked into place when the timing has been set accurately. In the case of a magneto ignition system, this is known as "external timing," as opposed to internal magneto timing in which the timing of the rotary components for maximum efficiency in generating the required electrical energy ("e-gap") is accomplished. There are essentially two methods of setting the ignition timing with such an ignition system: The timing may be set with the engine operating (running), or with the engine stationary (shut down). In the case of an operating engine, the gear lash and play in the system is automatically taken up due to engine rotation driving the distributor or magneto. The mechanic may set the timing by using a timing light temporarily connected to the ignition lead to the designated number one cylinder, rotating the distributor or magneto to set the timing as required, and securing the distributor or magneto in place by means of the conventional clamp or other means provided.

However, in the case of a stationary engine, the mechanic must take into account any play and gear lash in the distributor or magneto drive system. This is particularly true in situations where the distributor or magneto has been removed from the engine, e.g., for engine rebuild or other major work, ignition system overhaul or replacement, etc. In such cases, the mechanic turns the engine over to position the timing marks so that the number one piston is at or near top dead center on its compression stroke, and adjusts the distributor or magneto to an initial position that appears to be at least close to the desired ideal timing. However, the mechanic must still set the timing using a timing light or audible signal, the timing light or signal being activated when the points (or other electromagnetic signal) first open. This method of timing using a timing light when the engine is stationary will still not provide the required degree of accuracy due to the gear lash and play in the distributor drive system. A knowledgeable mechanic will always turn the engine slightly in a direction opposite its normal direction of rotation, and then rotate the engine in the operating direction to the desired external timing mark on the crankshaft pulley or damper in order to remove gear lash and play when setting timing on a stationary engine. Checking timing after this procedure may reveal that the timing is still not optimal, and the process must be repeated while the engine is operating. Obviously, this is a tedious and time-consuming task.

Thus, an internal combustion engine ignition timing tool solving the aforementioned problems is desired.

DISCLOSURE OF INVENTION

The internal combustion engine ignition timing tool is a closed timing tool cap that is removably placed upon the top of the distributor (or magneto) after the conventional distributor cap is removed. The timing tool cap may be indexed to the top of the distributor by a lower edge or skirt having a notch and key or other configuration congruent with the rim of the distributor. The timing tool cap also has a closed upper surface that extends over the installed rotor in the distributor. The upper surface of the timing tool cap has an internal configuration that conforms to the shape of the upper portion of the installed rotor. The clearance height of the general rotor clearance area inside the timing tool cap is higher than the height of the indexed skirt of the timing tool cap, and includes an additional clearance area for the central electrical contact finger (or button, etc.) atop the rotor. This allows the timing tool cap to be initially indexed to or seated upon the distributor rotor, and then indexed to or seated over the rim of the distributor as it is rotated beneath the timing tool and rotor that is rotationally locked with the timing tool.

The timing tool cap is used by initially turning the engine over in the direction of operation to align the external timing marks on the engine crankshaft pulley or damper with the corresponding marks on the engine case or block. The distributor and its shaft are then installed to the engine if this has not been accomplished previously, but the distributor is not locked into position at this point. The timing tool cap is then placed on the top of the distributor or magneto and rotor after removal of the distributor cap or magneto cap, and rotated as required to key to the top of the rotor. The conforming internal configuration of the interior of the closed upper surface of the timing tool cap with the rotor results in the cap seating atop the rotor and being rotationally locked therewith.

At this point, the timing tool cap is likely not yet seated properly on the distributor or magneto. As the rotor is essentially locked in place due to its gearing and shaft drive to the engine (with the exception of a slight amount of rotational freedom permitted by the gear lash or play in the system), the distributor must be rotated to complete the rotational alignment. The distributor is rotated to align its specific shape (screw lugs or bosses, grooves, wiring connectors, etc.) with the corresponding internal shape of the skirt of the timing tool cap. When the timing tool cap is rotationally aligned with the distributor, the cap will drop down the remainder of its axial travel over the distributor to lock the distributor, timing tool cap, and distributor rotor together rotationally. The distributor, the rotor, and the timing tool cap are then rotated as a unit in the opposite direction of normal engine rotation to remove any slack or gear lash or play in the system, and the distributor hold down clamp or other positional locking means is secured to lock the distributor in the desired rotational position. The timing tool cap is then lifted from the distributor, and the distributor cap is replaced to complete the task. The distributor system is now optimally timed and operable without the need for a timing light or other means of setting and/or verifying the ignition timing. In an alternative embodiment, the tool comprises an outer or lower collar that is removably placed on the distributor, and an upper closed cap that may be rotated relative to the outer collar. The outer or lower collar has a lower skirt that corresponds to the shape or configuration of the rim of the distributor, thus assuring that the collar is rotationally keyed or locked to the distributor when properly placed thereon. The upper cap has a closed upper surface having an internal surface configured to conform to the specific shape and configuration of the upper portion of the distributor rotor, as in the single-piece tool embodiment. This two-piece embodiment is used by first placing the outer or lower collar over the rim of the distributor and seating its specific shape and configuration in rotational registry with the distributor, as in the case of the first embodiment. The upper cap is rotated relative to the outer or lower collar to seat the cap properly over the rotor. The distributor may then be rotated to achieve the proper timing setting, as described further above with the single-piece tool.

In this two-piece tool embodiment, since the upper portion of the tool is adjustable relative to the outer or lower portion, the two-part tool is not limited to use with only one specific distributor and engine configuration. In fact, the rotor may be oriented anywhere through 360° of rotation relative to the outer or lower portion of the tool and the

corresponding orientation of the distributor, thus allowing the mechanic to set the timing using any of the engine cylinders or ignition leads in the event that a cylinder other than the number-one cylinder is referenced (or if the number-one wire is relocated on the cap for some reason) for setting the timing. The relative rotation permitted between the lower and upper portions of the two-piece tool permits the mechanic to adjust the timing to allow for timing advance, rather than being restricted to setting according to initial advance when setting the ignition timing.

The timing tool cap, or the upper portion of the tool comprising the closed cap, may be manufactured of transparent or translucent materials to enable the mechanic to view the relationship between the interior of the closed cap and the electrical contact (button, finger, etc.) atop the rotor. Thus, when the timing tool cap is seated properly over the distributor housing, the electrical contact of the rotor will make contact with the interior of the timing tool to enable the mechanic to confirm that the electrical contact is at its proper height and that it will make proper electrical contact with the corresponding contact in the top of the distributor cap to provide electrical continuity for that portion of the ignition system.

These and other features of the present invention will become readily apparent upon further review of the following specification and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a perspective view of a first embodiment of an internal combustion engine ignition timing tool according to the present invention.

Fig. 2 is an environmental perspective view of the internal combustion engine ignition timing tool of Fig. 1, shown installed on a conventional internal combustion engine ignition distributor, the distributor cap having been removed from the distributor for placement of the timing tool thereover.

Fig. 3 is an exploded environmental perspective view of a second embodiment of an internal combustion engine ignition timing tool according to the present invention, shown in relation to a conventional distributor having the distributor cap removed.

Fig. 4 is an environmental top plan view of the ignition timing tool of Fig. 3, showing the fit of the upper cap portion of the tool over the distributor rotor.

Similar reference characters denote corresponding features consistently throughout the attached drawings. BEST MODES FOR CARRYING OUT THE INVENTION

The internal combustion engine ignition timing tool enables even the most novice mechanic to install a distributor or magneto and set the ignition timing accurately on a stationary (non-operating) engine without the need for further checking or verification of the timing by means of using a conventional timing light on the operating engine, unless desired by the mechanic as further confirmation. The ignition timing tool serves as a stop for the rotor in the distributor or magneto. Rotation of the distributor or magneto with the timing tool installed thereon opposite the direction of normal operation urges the rotor back to remove slack and gear lash in the system, thereby permitting the timing to be set accurately with no further steps required on the part of the mechanic.

Figs. 1 and 2 of the drawings illustrate a first embodiment of the internal combustion engine ignition timing tool or timing cap 10, comprising a unitary construction for removable installation atop a distributor housing D, shown in Fig. 2. The ignition tool 10 has a closed top 12, i.e., the top 12 is devoid of any holes or passages therethrough. The top 12 has an internally disposed, raised rotor clearance recess 14 formed therein and extending upwardly therefrom. The rotor clearance recess 14 is configured to fit closely about the rotor R of the distributor D, i.e., the recess 14 defines a rotor seat. As shown in Fig.2, e.g., the recess 14 has diametrically opposed indentations defined therein that conform to indentations in the rotor R that accommodate the heads of screws that secure the rotor to the distributor, and has radially spaced protrusions that conform to radially spaced ribs on the rotor R. Each ignition timing tool 10 will have a recess 14 formed in the top 12 having similar indentations, protrusions, bosses, or the like that are molded to seat on the rotor R of the particular distributor being serviced. The ignition timing tool or timing cap 10 is preferably vacuum- formed or otherwise molded or cast of a transparent or translucent plastic material, thus enabling innumerable different variations and configurations of the device to be formed easily to fit a wide variety of different distributor rotors R available. The rotor clearance recess 14 has a height 16 that allows the timing cap or tool 10 to slip down around the sides of the rotor R when the conforming shape of the rotor clearance recess 14 is aligned with the rotor R. It will be seen that the close fit of the sides of the clearance recess 14 about the rotor R seats the recess 14 on the rotor R, which results in the rotor R and the timing tool or timing cap 10 being rotationally fixed to one another when the tool or cap 10 is installed around the rotor R.

A generally circumferential sidewall 18 depends from the periphery of the closed top

12. The sidewall has a lower skirt 20 that extends outwardly therefrom. The skirt 20 is configured to fit closely about the base or rim of the distributor D, i.e., the skirt defines a distributor rim seat that conforms precisely to the various bosses, receptacles, and other irregularities conventionally provided on such devices. The skirt 20 has a height 22 less than the height 16 of the rotor clearance recess 14 in the closed top portion 12 of the timing tool or cap 10. This results in the rotor clearance recess 14 of the timing tool or timing cap 10 dropping down only partially over the rotor R when the clearance recess 14 is in registry with the rotor R, if the skirt 20 is not in registry with the rim of the distributor D and is resting atop one or more of the irregularities along the distributor rim. However, this intermediate position of the tool 10 still captures the distributor rotor R within the tool 10, preventing relative rotation of the rotor and the timing tool or timing cap 10. Rotation of the distributor D relative to the tool 10 aligns the distributor D with the tool 10, allowing the skirt 20 of the timing cap or timing tool 10 to drop down over the rim of the distributor D to seat the tool 10 completely on the distributor D. The close fit of the skirt 20 of the timing cap or tool 10 to the rim or base of the distributor D precludes relative rotation between the timing tool 10 and the distributor D when the tool 10 is installed thereon. Thus, both the distributor rotor R and the distributor D are rotationally locked to one another when the timing cap or timing tool 10 is installed thereover. The rotor clearance recess area 14 of the closed top 12 of the timing cap or timing tool 10 also includes a raised rotor contact height gauge 24 therein, configured to conform closely to the conventional electrical contact extending from the top of the rotor R. These electrical contacts are generally in the form of an elongated strip or "finger" of electrically conductive metal, the rotor R rotating the contact finger due to engine rotation to distribute the electrical energy for ignition to each of the engine cylinders in turn. If this contact finger or the like is recessed due to wear, damage, or for whatever reason, it will not make proper electrical contact with the coil wire entering the center of the top of the distributor cap. The rotor contact height gauge 24 in the top of the timing cap or tool 10 enables the mechanic to determine easily whether the rotor contact finger is of sufficient height for proper contact. When the ignition timing tool or cap 10 is properly seated over the distributor D and the skirt 20 is seated properly over the rim of the distributor and the rotor electrical contact is at its proper height for good electrical continuity in the system, the rotor contact height gauge 24 will be in contact with the electrical contact atop the rotor R. The mechanic may determine this easily by noting the resistance to deflection of the thin, flexible plastic material of which the timing tool 10 is preferably manufactured, due to the underlying top of the rotor R in immediate contact with the inner surface of the tool 10. The tool 10, or at least its closed cap portion 12, is preferably formed of a transparent or translucent material to enable the mechanic to see the position of the top of the rotor R and its electrical contact immediately beneath the rotor contact height gauge portion 24 of the upper closed cap 12 of the timing tool or timing cap 10.

The ignition timing tool 10 is used substantially as illustrated in Fig. 2. Initially, the engine crankshaft is turned to position or align the conventional timing mark on the crankshaft pulley or damper with the stationary mark on the engine block or case, as required. The distributor (or magneto) and its drive shaft are then installed in the appropriate port or receptacle of the engine and aligned at least approximately with the desired optimal position, if this step has not been accomplished previously. The distributor base hold-down bracket (conventional component, not shown) is not tightened at this point in order to allow the distributor D to be rotated for adjustment, as described below. At this point the distributor cap is removed, if not done previously, and the ignition timing tool or timing cap 10 is placed over the rotor R of the distributor D in place of the distributor cap, and the rotor clearance recess 14 is aligned with the rotor R to key the rotor R rotationally with the timing tool 10.

At this point, the rotor clearance recess 14 is likely seated only partially over the distributor rotor R due to the lower skirt 20 of the timing cap or timing tool 10 resting atop the lower rim of the distributor D, due to misalignment of the irregularities of the skirt 20 with the corresponding irregularities of the lower rim of the distributor D. Accordingly, the distributor D is rotated beneath the timing tool or timing cap 10 until the skirt 20 of the timing tool or cap 10 is in registry with the base or rim of the distributor D. This allows the skirt 20 of the tool 10 to drop down over the rim of the distributor D, completing the placement of the tool 10 on the distributor D and the rotor R, thereby fixing the distributor D, the rotor R, and the tool 10 rotationally relative to one another. The height of the electrical contact on the top of the rotor R may also be verified at this point, in accordance with the discussion of the rotor contact height gauge 24 in the rotor clearance recess 14 of the closed top 12 of the ignition timing tool or timing cap 10 further above.

When the above steps have been accomplished, the mechanic need only rotate the distributor D slightly in the direction opposite that of normal engine rotation to remove all gear backlash and play from the system. The rotation of the distributor D with the timing tool or cap 10 completely seated over the distributor rotor R and the base of the distributor D assures that all components, i.e., the distributor D and the rotor R, will rotate in unison due to the locking of their respective rotations by the tool 10. The mechanic may then tighten the distributor clamp to lock the distributor D rotationally, with assurance that the ignition timing is set optimally. The timing tool 10 is then removed from the distributor D, and the distributor cap is replaced atop the distributor to complete the task. Verification of accurate ignition timing may be accomplished conventionally by means of a timing light, but this step is not likely to be required nor to result in any need to change the timing as set using the ignition timing tool 10 as described above.

Figs. 3 and 4 illustrate an alternative embodiment of an internal combustion engine ignition timing tool, designated as ignition timing tool 110. The timing tool 110 is a two-part assembly comprising a closed upper and/or inner top portion 112 having a configuration substantially similar to the top portion 12 of the timing tool or timing cap 10 of Figs. 1 and 2, and an open lower and outer collar portion, discussed in detail further below. The upper and/or inner top portion 112 includes an internally disposed raised rotor clearance recess 114, which is configured to fit closely about the rotor R of the distributor D, as in the ignition timing tool embodiment 10 of Fig. 1. The upper and/or inner top portion 112 of the timing tool 110 is preferably vacuum-formed or otherwise molded or cast of a transparent or translucent plastic material, as in the case of the timing tool or timing cap 10 of Figs. 1 and 2.

The rotor clearance recess 114 has a height 116 that allows the timing tool 110 to slip down around the sides of the rotor R when the conforming shape of the rotor clearance recess 114 is aligned with the rotor R. It will be seen that the close fit of the sides of the clearance recess 114 about the rotor R results in the rotor R and the timing tool 110 being rotationally fixed to one another to rotate as a unit when the tool 110 is installed around the rotor R, as in the case of the ignition timing tool 10 of Figs. 1 and 2.

The rotor clearance recess area 114 of the upper or inner closed top portion 112 of the timing cap or timing tool 110 also includes a raised rotor contact height gauge 124 therein, analogous to the rotor contact height gauge 24 of the timing tool 10 of Figs. 1 and 2. The function of this rotor contact height gauge 124 is the same as described further above for the corresponding rotor contact height gauge 24 of the tool 10 of Figs. 1 and 2. Accordingly, the timing tool 110, or at least the upper/inner closed top portion 112 thereof, is preferably formed of a transparent or translucent material, as in the case of the top portion 12 of the tool 10 of Figs. 1 and 2.

Rather than having a unitary sidewall and skirt formed with the top portion of the timing tool 110, a separate collar 118 is provided. The collar 118 comprises a generally circular or annular sidewall having a distributor seating skirt 120 depending therefrom. The skirt is adapted or configured to conform closely to the base or rim of the distributor D. The skirt 120 has a height 122 less than the height 116 of the rotor clearance recess 114 of the upper or inner top portion 112. The function provided by these different heights 116 and 122 corresponds to that described further above for the first embodiment of the ignition timing tool 10. The precise operation of the timing tool 110 is described further below.

The lower and outer collar portion 118 of the timing tool 110 includes a circular or annular inner receptacle 126 adapted to fit closely about the circular diameter 128 of the upper and inner closed top portion 112 of the tool 110. An inwardly projecting flange 130 is disposed below the receptacle 126 for supporting the top portion 112 of the tool 110, the flange 130 supporting the rim of the top portion of the tool 110 when the top portion 112 is placed within the collar portion 118. This configuration leaves the top portion 112 free to rotate within the receptacle 126 of the lower collar portion 118. The lower collar portion 118 includes means for securing the top portion 112 therein, to prevent its rotation within the lower collar 118. A pair of threaded studs 132 extend upward from the lower collar 118. Corresponding threaded nuts 134 and washers 136 are used to grip or clamp the edges of the upper or inner top portion 112 within the lower collar portion 118. Tightening the nuts 134 locks the top portion 112 within the collar portion 118 to prevent relative rotation therebetween. The two part timing tool 110 is used in a manner generally similar to that described further above for the single piece timing tool 10. However, there are some differences, as described below. Initially, the engine crankshaft is turned to position or align the

conventional timing mark on the crankshaft pulley or damper with the stationary mark on the engine block or case as required, as with the timing tool 10 of Figs. 1 and 2. The distributor (or magneto) and its drive shaft are then installed in the appropriate port or receptacle of the engine and aligned at least approximately with the desired optimal position, if this step has not been accomplished previously. The distributor base hold-down bracket (conventional component, not shown) is not tightened at this point in order to allow the distributor D to be rotated for adjustment, as described below. At this point the distributor cap is removed, if not done previously, and the collar 118 of the timing tool 110 is placed over the rotor R of the distributor D in place of the distributor cap, and the skirt 120 is keyed or aligned closely with the distributor D, e.g., with the wiring clearance notch 138 fitting over the corresponding grommet G or the like of the distributor D, to thereby lock the collar 118 rotationally with the distributor D. The closed upper or inner top component 112 is then placed within the inner receptacle 126 of the collar 118, and rotated to align the rotor clearance recess to conform with the rotor R to lock the upper top component 112 rotationally to the rotor R.

At this point, the ignition timing is ready for setting and adjustment as required. It will be seen that unlike the ignition timing tool 10 of Figs. 1 and 2, the rotor clearance recess of the upper top component 112 is fully seated over the rotor R at this point, as the top component 112 is free to rotate relative to the collar 118, and thus may be rotated for alignment with the rotor R. Accordingly, the distributor D and the collar 118 rotationally affixed thereto are rotated beneath the upper closed top portion 112 and the rotor R that is rotationally captured therein until the distributor D is aligned rotationally with the predetermined position for proper ignition, as required. The top 112 is then secured immovably to the lower and outer collar 118 by tightening the nuts 134 or by other means in order to lock the top 112 rotationally with the collar 118. This also results in the top 112 being seated at its lowest position within the collar 118, placing the top closely against the underlying distributor rotor R. The height of the electrical contact on the top of the rotor R may also be verified at this point, in accordance with the discussion of the rotor contact height gauge 24 in the rotor clearance recess 14 of the closed top 12 of the timing tool or timing cap 10 further above. The top 112 is preferably formed of a transparent or translucent material to provide for this function, although the collar 118 may be formed of opaque metal or other material. When the above steps have been accomplished, the mechanic need only rotate the distributor D slightly in the direction opposite that of normal engine rotation to remove all gear backlash and play from the system. The rotation of the distributor D with the timing tool or cap 110 completely seated over the distributor rotor R and the base of the distributor D assures that all components, i.e., the distributor D and its rotor R, will rotate in unison due to the locking of their respective rotations by the rotationally locked top portion 112 and collar 118 of the tool 110. The mechanic may then tighten the distributor clamp to lock the distributor D rotationally with assurance that the ignition timing is set optimally. The timing tool 110 is then removed from the distributor D and the distributor cap is replaced atop the distributor to complete the task. Verification of accurate ignition timing may be

accomplished conventionally by means of a timing light, as with the timing tool 10 of Figs. 1 and 2, but this step is not likely to be required nor to result in any need to change the timing set using the ignition timing tool 110 as described above.

In conclusion, the internal combustion engine ignition timing tool greatly facilitates the setting of ignition timing in such an engine, eliminating previously required tedious and likely repetitive steps in the process. The tool may be applied to a wide variety of ignition systems, including distributors and magnetos in automobiles and other land vehicles, aircraft, boats, and stationary power plants, such as generators and the like. At least the top or cap of the device in either of its embodiments is preferably formed of a transparent or translucent material (plastic, etc.). However, the device, in either of its embodiments, may be constructed of any of several solid or rigid materials, including various metals (aluminum, various grades of steel, etc.), any of a wide number of different plastics, and/or even composites, such as glass or carbon fiber in an epoxy or polyester resin matrix. The first embodiment of Figs. 1 and 2 is limited in its versatility due to its lack of adjustability, but will serve the home mechanic well for use in tuning a specific engine. The second embodiment of Figs. 3 and 4, with its wide adjustability and versatility, will find greater favor among professional mechanics who have need for a tool that may be used on a wide variety of different distributor and magneto ignition systems, the limiting factor being only the diameter of the distributor or magneto unit and the cap attachment means that is also used to attach the tool to the distributor or magneto. Accordingly, a small number of such ignition timing tools will cover a wide variety of different ignition systems and will greatly assist the professional mechanic in his work. It is to be understood that the present invention is not limited to the embodiments described above, but encompasses any and all embodiments within the scope of the following claims.

Claims

CLAIMS I claim:

1. An ignition timing tool for use with an internal combustion engine having a distributor having a body, a rim, and a distributor rotor, the tool comprising a timing cap having:

a closed top defining a periphery, the top having an internally disposed, raised rotor clearance recess, the recess defining a rotor seat configured to conform closely with the rotor so that the cap and the rotor are constrained to rotate together when the timing cap is placed over the distributor rotor, the recess having a height;

a sidewall extending from the periphery of the closed top, the sidewall having a lower skirt extending therefrom, the skirt defining a distributor rim seat configured to conform closely with the rim of the distributor, the skirt having a height less than the height of the rotor clearance recess.

2. A method of timing ignition of an internal combustion engine using the apparatus of claim 1 , the engine having a distributor including a distributor cap and rotor, the engine further having timing marks thereon, the method comprising the steps of:

(a) aligning the timing marks on the engine;

(b) rotating the distributor to a position corresponding with ignition for a predetermined engine cylinder;

(c) removing the distributor cap from the distributor;

(d) seating the timing cap atop the rotor so that the rotor clearance recess conforms closely with the rotor;

(e) rotating the distributor beneath the timing cap and rotor, thereby engaging the skirt of the timing cap with the rim of the distributor and rotationally locking the timing cap, the rotor, and the distributor in registry with one another;

(f) removing gear lash and play from the distributor system by rotating the timing cap, the rotor and distributor being rotationally secured therein, opposite the direction of normal rotor rotation until any gear lash is removed from the system;

(g) securing the distributor immovably to the engine;

(h) removing the timing cap from the distributor; and

(i) reinstalling the distributor cap on the distributor.

3. The ignition timing tool according to claim 1, further comprising a raised rotor contact height gauge disposed in the rotor clearance recess of the closed top.

4. A method of checking ignition of an internal combustion engine using the apparatus of claim 3, the engine having a distributor including a distributor cap and rotor, the rotor further having an electrical contact thereon, the method comprising the steps of:

(a) removing the distributor cap from the distributor;

(b) seating the timing cap atop the rotor so that the rotor clearance recess conforms closely with the rotor;

(c) rotating the distributor beneath the timing cap and rotor, thereby engaging the skirt of the timing cap with the rim of the distributor and rotationally locking the timing cap, the rotor, and the distributor in registry with one another;

(d) confirming that the electrical contact of the rotor contacts the inner surface of the rotor contact height gauge;

(e) removing the timing cap from the distributor; and

(f) reinstalling the distributor cap on the distributor.

5. The ignition timing tool according to claim 1, wherein the sidewall comprises a collar removably secured to the closed top.

6. A method of timing the ignition of an internal combustion engine using the apparatus of claim 5, the engine having a distributor including a distributor cap and rotor, the engine further having timing marks thereon, the method comprising the steps of:

(a) aligning the timing marks on the engine;

(c) removing the distributor cap from the distributor;

(d) seating the collar on the distributor so that the skirt of the collar conforms closely with the distributor;

(e) seating the closed top atop the rotor and with the collar so that the rotor clearance recess conforms closely with the rotor;

(f) rotating the distributor and collar beneath the closed top and rotor to a predetermined rotational position;

(g) securing the closed top immovably to the collar;

(h) removing gear lash and play from the distributor system by rotating the closed top and collar, the rotor and distributor being rotationally secured therein, opposite the direction of normal rotor rotation until any gear lash is removed from the system; (i) securing the distributor immovably to the engine;

(j) removing the closed top and collar from the distributor; and

(k) reinstalling the distributor cap on the distributor.

7. The ignition timing tool according to claim 1, wherein the timing cap is formed of transparent material.

8. An ignition timing tool for use with an internal combustion engine having a distributor having a body, a rim, and a distributor rotor, the tool comprising a timing cap having:

a raised rotor contact height gauge disposed within the closed top; and

a sidewall extending from the periphery of the closed top.

9. A method of timing the ignition of an internal combustion engine using the apparatus of claim 8, the engine having a distributor having a body, a distributor cap and a distributor rotor, the engine further having timing marks thereon, the method comprising the steps of:

(a) removing the distributor cap from the distributor;

(c) confirming that the electrical contact of the rotor contacts the inner surface of the rotor contact height gauge;

(d) removing the timing cap from the distributor; and

(e) reinstalling the distributor cap on the distributor.

10. The ignition timing tool according to claim 8, further comprising a lower skirt extending from the sidewall, the skirt being adapted to conform closely with the rim of the distributor housing, the skirt having a height less than the rotor clearance recess, the lower skirt defining a distributor rim seat configured to conform closely with the rim of the distributor.

11. A method of timing the ignition of an internal combustion engine using the apparatus of claim 10, the engine having a distributor including a distributor cap and rotor, the engine further having timing marks thereon, the method comprising the steps of:

(a) aligning the timing marks on the engine; (b) rotating the distributor to a position corresponding with ignition for a predetermined engine cylinder;

(c) removing the distributor cap from the distributor;

(e) rotating the distributor beneath the timing cap and rotor, thereby seating the skirt of the timing cap on the rim of the distributor and rotationally locking the timing cap, the rotor, and the distributor in registry with one another;

(f) removing gear lash and play from the distributor system by rotating the timing cap, with the rotor and distributor rotationally secured therein, opposite the direction of normal rotor rotation until any gear lash is removed from the system;

(g) securing the distributor immovably to the engine;

(h) removing the timing cap from the distributor; and

(i) reinstalling the distributor cap on the distributor.

12. The ignition timing tool according to claim 8, wherein the sidewall comprises a collar removably secured to the closed top, the collar having a skirt extending therefrom, the skirt being adapted to conform closely with the rim of the distributor, the skirt having a height less than the height of the rotor clearance recess, the lower skirt defining a distributor rim seat configured to conform closely with the rim of the distributor.

13. A method of timing the ignition of an internal combustion engine using the apparatus of claim 12, the engine having a distributor including a distributor cap and rotor, the engine further having timing marks thereon, the method comprising the steps of:

(a) aligning the timing marks on the engine;

(c) removing the distributor cap from the distributor;

(e) seating the closed top atop the rotor and with the collar, the rotor clearance recess conforming closely with the rotor;

(f) rotating the distributor and collar beneath the closed top and rotor to a predetermined rotational position as desired;

(g) securing the closed top immovably to the collar; (h) removing gear lash and play from the distributor system by rotating the closed top and collar, the rotor and distributor being rotationally secured therein, opposite the direction of normal rotor rotation until any gear lash is removed from the system;

(i) securing the distributor immovably to the engine;

(j) removing the closed top and collar from the distributor; and

(k) reinstalling the distributor cap on the distributor.

14. The ignition timing tool according to claim 8, wherein the timing cap is formed of transparent material.

15. An ignition timing tool for use with an internal combustion engine having a distributor having a body, a rim, and a distributor rotor, the tool comprising a timing cap having:

a closed top defining a periphery, the top having an internally disposed, raised rotor clearance recess, the recess defining a rotor seat configured to conform closely with the rotor so that the cap and the rotor are constrained to rotate together when the timing cap is placed over the distributor rotor, the recess having a height; and

a collar having a generally circular sidewall removably secured to the closed top, the collar having a skirt extending therefrom, the skirt defining a distributor rim seat configured to conform closely with the rim of the distributor, the skirt having a height less than the height of the rotor clearance recess.

16. A method of timing the ignition of an internal combustion engine using the apparatus of claim 15, the engine having a distributor including a distributor cap and rotor, the engine further having timing marks thereon, the method comprising the steps of:

(a) aligning the timing marks on the engine;

(c) removing the distributor cap from the distributor;

(i) securing the distributor immovably to the engine;

(j) removing the closed top and collar from the distributor; and

(k) reinstalling the distributor cap on the distributor.

17. The ignition timing tool according to claim 15, further comprising a raised rotor contact height gauge disposed in the rotor clearance recess of the closed top.

18. A method of checking the ignition of an internal combustion engine using the apparatus of claim 17, the engine having a distributor with a distributor cap and rotor, the rotor further having an electrical contact thereon, the method comprising the steps of:

(a) removing the distributor cap from the distributor;

(b) seating the collar on the distributor so that the skirt of the collar conforms closely with the distributor;

(c) seating the closed top atop the rotor and with the collar so that the rotor clearance recess conforms closely with the rotor;

(d) rotating the distributor beneath the closed top, collar, and rotor, thereby seating the skirt of the collar on the rim of the distributor and rotationally locking the closed top, the collar, the rotor, and the distributor in registry with one another;

(e) confirming that the electrical contact of the rotor contacts the inner surface of the rotor contact height gauge;

(f) removing the closed cap and the collar from the distributor; and

(g) reinstalling the distributor cap on the distributor.

19. The ignition timing tool according to claim 15, wherein at least the closed top is formed of transparent material.