Tool for use in adjusting engine valves

A tappet adjusting tool for use in replacing the adjusting pads in the valve lifters of overhead cam, internal combustion engines, such as those commonly used in motorcycles and some automobiles, includes a main tool body having a generally curved lower extension adapted to fit loosely between the cylinder head and the cam of the engine. When in proper position between the cam and cylinder head, the tool is locked into that position such as by a wedge member which is normally swung in toward the tool body but which can be biased into locking position against the cylinder head. A plunger extends from the tool extension and makes contact with the edge of the valve lifter. The plunger is extended to move the lifter and adjusting pad of the engine being worked on away from the cam so that the adjusting pad can be removed and replaced.

BACKGROUND OF THE INVENTION 
1. Field 
The invention is in the field of tools for use in adjusting and replacing 
the adjusting pad on the tappets or valve lifters in internal combustion 
engines, such as the four cycle, dual overhead cam engines generally used 
in motorcycles and some types of automobiles. 
2. State of the Art 
In performing a proper tune-up of a motorcycle or similar type engine, it 
is necessary to determine whether the ajdusting pads in the valve lifters 
are of correct thickness so as to give proper valve clearance. If not, 
these adjusting pads must be replaced. With most current tools available, 
the cam shaft in the engine has to be rotated to the position where the 
valve is extended or opened to its maximum position, i.e. the cam lobe is 
in contact with the adjusting pad. A holding tool is then inserted, which 
is generally secured to the cylinder head using a cylinder head cover bolt 
hole. The cam then has to be rotated in the opposite direction so that the 
heel of the cam is toward the adjusting pad, thus giving clearance between 
the cam and the pad. The tool holds the valve lifter in its extended 
position while the cam is rotated to provide the clearance. Such tools 
have to be carefully positioned so that they catch only the bucket of the 
tappet and not the adjusting pad, and care has to be taken to carefully 
rotate the cam in only one direction after installation of the tool; 
otherwise, the cam may be ruined. 
Another tool currently available, while not requiring rotation of the cam, 
is in two pieces, one of which is used to move the valve lifter against 
its spring tension while the other is placed to hold the valve after being 
so moved, these two tools require both hands to manipulate which causes 
problems in the small space available. Also, because one is actively 
working against the valve spring tension, the tools can easily slip, 
thereby causing injury to the worker. 
In addition to the possible damage to the cam and injury to the worker that 
can occur using currently available tools, such tools are difficult to use 
and much time is expended in positioning them and rotating the cams to 
proper position. Using the current tools, it usually takes about half an 
hour or more to properly check the adjusting pads. Because of the time and 
difficulty involved, many times when such adjustments should be checked 
the mechanics do not do so. 
SUMMARY OF THE INVENTION 
According to the invention, a tool is provided which eliminates the 
necessity of rotating the cam. With the cam in position so that its heel 
is against the valve tappet or lifter, a tool having a main body with a 
lower extension curved to fit loosely between the cylinder head and the 
cam is moved into position. A wedge member, normally swung in toward the 
main body so that the curved extension can easily be placed in position 
between the cam and the cylinder head, allows easy positioning of the tool 
extension. When in position between the cam and the cylinder head, the 
wedge is locked into a biased position against the cylinder head so that 
the tool body is locked into position and cannot slide out of position 
between the cam and the cylinder head. A plunger extends from the curved 
extension of the body to the outside edge of the valve lifter. The plunger 
contacts the rim of the valve lifter, so does not contact the adjustment 
pad. When the tool is locked into position between the cam and cylinder 
head, the plunger is moved so as to move the valve lifter and adjusting 
pad away from the cam so that the adjusting pad may be easily removed. 
This requires no rotating of the cam and, thus, substantially decreases 
the chance of damage to engine parts. It makes the checking of the 
adjusting pads a quick and easy operation.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS 
Referring to FIGS. 1 through 7, one preferred embodiment of the invention 
is shown and includes a main tool body 10 having a lower extension 11 
which is curved so as to fit loosely in the space in a normal four cycle, 
dual overhead cam, internal combustion engine such as the ones commonly 
used in motorcycles, between the cam 12 and cylinder head 13, FIGS. 6 and 
7. The curved extension does not have to fit against the cam along its 
length, as shown, as long as some portion fits against it. The radius of 
curvature may be larger than the radius of curvature of the cam. 
A wedge member 14 is pivotally mounted on body extension 11, as by means of 
a shaft 15, so that it may either be swung in toward the body of the tool 
or may be biased to extend outwardly from the tool. A central shaft 16 in 
the tool is slidably received by a central bore 17 in plunger member 18. A 
spring 19, positioned in bore 17 between a roll pin 20 and shaft 16, 
biases shaft 16 toward wedge member 14. A portion of the end of shaft 16 
to wedge member 14 is cut away, so that, with the shaft 16 in position as 
shown in FIG. 4, the portion 16a of shaft 16 causes wedge member 14 to 
swing upwardly and in toward the tool. When shaft 16 is rotated so that 
the portion 16a is over at least a portion of wedge member shaft 15, wedge 
member 14 is pivoted outwardly away from the tool and is biased outwardly 
by spring 19 acting on shaft 16. Thus, as shaft 16 is rotated and wedge 
member 14 is swung and biased away from the tool, shaft 16 is forced 
upwardly and compresses spring 19. The amount of compression depends upon 
the distance wedge member 14 can pivot outwardly. Further, when in biased 
position, wedge member 14 can still be pivoted inwardly toward the tool 
and when so pivoted, will cause further compression of spring 19. 
Shaft 21 is secured to and extends outwardly from shaft 16 and has a handle 
22 at its opposite end. Shaft 21 and handle 22 are used to rotate shaft 16 
to place wedge member 14 in its retracted or biased positions. 
Shaft 15 for wedge member 14 may be secured to wedge member 14 and may be 
placed into slots 23 in body extension 11, where it is held by action of 
shaft 16 biased against wedge member 14. With such arrangement, the wedge 
member 14 with shaft 15 may easily be removed by moving shaft 16 against 
spring 19 enough to allow shaft 15 to be withdrawn from slots 23. This 
arrangement is advantageous so that different size wedge members may be 
inserted, where necessary, to properly fit different engines. 
Plunger member 18 is slidably received in a central bore 24 in main tool 
body 10. Central bore 24 is enlarged toward the end of the body away from 
the extension 11 to rotatably receive therein a portion of operating 
member 25. Operating member 25 is held in position in main body bore 24 by 
means of pin 26 secured to operating member 25 and extending into slots 27 
and 28 in main body member 10. Slots 27 and 28 are sloped as shown in 
FIGS. 1-3 so that, as operating member 25 with pin 26 is rotated and pin 
26 slides in slots 27 and 28, operating member 25 moves longitudinally 
along the axis of bore 24 in main body 10, i.e. in the orientation of the 
tool in the drawings, moves up and down in relation to the main body of 
the tool. A shaft 29 with handle 30 extends from operating member 25 so 
that member 25 may be easily rotated. 
Plunger member 18 extends from bore 24 in main tool body 10 into central 
bore 31 in operating member 25 where it abuts adjustment member 32, which 
is also within central bore 31 of operating member 25. Adjustment member 
32 is slotted at 33 to fit about pin 26. 
Adjustment screw 34 is threaded through the end of operating member 25, 
with its head resting against adjustment member 32 in bore 31. The other 
end of adjustment screw 34 is slotted at 35 to receive a screw driver or 
similar tool. Adjusting screw 34 is shown in its extreme upward position. 
As adjusting screw 34 is turned, the end of the screw against adjustment 
member 32 moves linearly and causes adjustment member 32 to move within 
central bore 31. Movement of adjusting member 32 causes movement of 
plunger member 18, since the two are in abutting relationship. The 
adjustment of screw 34 determines the distance that end 18a of plunger 
member 18 extends from the tool. This may need to be adjusted in some 
instances for different types of engines. 
To use the tool, the engine cam is rotated so that the heel of the cam is 
against the valve lifter. This occrs through about 30.degree. of cam 
rotation. The valve clearance is measured to determine if it is correct or 
if a change in adjusting pad is needed. Up to this point, the procedure is 
the same regardless of what type of tool is to be used if the adjusting 
pads needs to be changed. 
If it is determined that a change of adjusting pads is needed, the tool of 
the invention is inserted between the cam 12 and the cylinder head 13 as 
illustrated in FIG. 6. When in position so that the plunger 18a is 
adjacent to the edge of the valve lifter 36, shaft 16 is rotated by means 
of handle 22 so that wedge member 14 is biased against cylinder head 13. 
The claws on wedge member 14 against cylinder head 13 hold the tool 
securely in place. 
If the tool is adjusted for the particular engine being worked on, when the 
tool is in proper position the plunger 18a will just rest against the edge 
of valve lifter 36. If the tool is not adjusted for the particular engine 
being worked on, the plunger is adjusted by turning adjusting screw 34 
until the plunger is just resting against the edge of valve lifter 36 when 
the tool is secured in position between the cam and engine block. It has 
been found that an adjustment of only about one-fifth of an inch is needed 
to accommodate all common motorcycle engines. 
With the tool locked in position, operating member 25 is rotated by means 
of handle 30. This causes pin 26 to move in slots 27 and 28, causing 
operating member 25, adjusting member 32, and plunger 18 to move 
downwardly. This causes plunger 18a to move away from the tool and push 
valve lifter 36 away from cam 12, as shown in FIG. 7. The adjusting pad 38 
can now be removed and replaced. Removal is commonly accomplished by use 
of a magnetic tool. It has been found that a clearance of one-eighth inch 
between cam and adjusting pad is all that is needed for replacing the 
adjusting pad. Accordingly, slots 27 and 28 are adapted to cause a 
one-eighth inch movement of the plunger. 
When the replacement adjusting pad has been placed in the valve lifter, 
handle 30 is moved to its normal position, allowing the valve lifter to 
move back against the cam. Handle 22 is rotated to release wedge member 
14, and the tool is removed. The valve clearance is again checked to see 
if it is proper. If not, the process is repeated until the proper 
adjusting pad is installed to give proper valve clearance. 
A slightly different embodiment of the tool is shown in FIGS. 8 and 9. 
In this embodiment, a main tool body 40 and extension thereof 41 has the 
upper portion of a central bore 42 therein threaded. Plunger member 43 is 
slidably positioned within bore 42. A threaded adjusting member 44 is 
secured to a handle 45. Thus, as handle 45 is turned, adjusting member 44 
turns and advances or retracts in central bore 42, depending upon the 
direction of rotation. 
A wedge member 46 is pivotally mounted by shaft 47 in body extension 41, so 
that it can be biased outwardly away from the body. 
A shaft 48 passes through a central bore in adjusting member 44 and through 
handle 45. As in the embodiment of FIGS. 1-7 already described, a portion 
of the end of shaft 48 adjacent wedge member 46 is cut away, so that, with 
the shaft 48 in position as shown in FIG. 9, the portion 48a of shaft 48 
causes wedge member 46 to be swung upwardly and in toward the tool. When 
shaft 48 is rotated so that the portion 48a is over at least a portion of 
wedge member shaft 47, wedge member 46 is pivoted outwardly away from the 
tool. Shaft 48 is reduced in diameter part way along its length to form a 
shoulder 49 upon which a spring 50 rests. The reduced diameter portion of 
shaft 48 extends through handle 45 to handle 51 where it is secured. 
Spring 50 is positioned between shoulder 49 and a reduced diameter portion 
of the central bore in adjusting member 44, which forms shoulder 52. 
Spring 50 thus biases shaft 48 downwardly, so as to swing wedge member 46 
upwardly toward the tool when shaft 48 is in the position shown in FIG. 9 
and to pivot and bias wedge member 46 outwardly away from the tool when 
shaft 48 is rotated. Shaft 48 is rotated by rotating handle 51. 
The tool is used in the same way as previously described. It is locked into 
position by rotating handle 51. Plunger 48 is extended from the tool by 
turning handle 45. The handle is turned until the desired clearance is 
obtained. When the adjusting pad has been replaced and handle 45 is 
rotated in the opposite direction. The spring tension on the valve lifter 
causes plunger 43 to retract. When no more spring tension remains from the 
valve lifter on plunger 43, handle 51 is rotated to release the wedge 
member and the tool is removed. 
Whereas this invention is here illustrated and described with specific 
referennce to embodiments thereof presently contemplated as the best mode 
of carrying out such invention in actual practice, it is to be understood 
that various changes may be made in adapting the invention to different 
embodiments without departing from the broader inventive concepts 
disclosed herein and comprehended by the claims that follow.