WO2017165259A1

WO2017165259A1 - Lash adjustment on type ii engine

Info

Publication number: WO2017165259A1
Application number: PCT/US2017/023131
Authority: WO
Inventors: Jr. James Edward Mccarthy; Karl J. SIEVERSTEN; Grant Stephen TERRY
Original assignee: Eaton Corporation
Priority date: 2016-03-22
Filing date: 2017-03-20
Publication date: 2017-09-28

Abstract

A lash adjustment system for adjusting lash between a rocker arm and a valve stem in a Type II valvetrain arranged relative to a cylinder head is provided. The lash adjustment system includes a locking assembly having a positioning rod and a locking member. The positioning rod extends along a longitudinal axis and has a ball portion and an opposite end portion. The ball portion is received by a spherical receiving portion of the rocker arm. The end portion is received by a bore defined in the cylinder head. The locking member moves between an unlocked position and a locked position. In the unlocked position the positioning rod is free to move along the longitudinal axis relative to the locking member thereby altering a gap defined between the valve stem and the rocker arm. In the locked position, the positioning member is precluded from moving along the longitudinal axis.

Description

LASH ADJUSTMENT ON TYPE II ENGINE

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Patent Application No. 62/311 ,783 filed on March 22, 2016. The disclosure of the above application is incorporated herein by reference.

FIELD

[0002] The present disclosure relates generally to systems and method for setting lash on a rocker arm for a Type II internal combustion engine.

BACKGROUND

[0003] Valve lash can be defined generally as a clearance between a rocker arm and a valve stem tip. It is important to set the clearance at a desired value for a particular application to achieve optimal performance. In some examples feeler gauges are used to measure the clearance and use as a reference during adjustment of lash.

[0004] The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.

SUMMARY

[0005] A lash adjustment system for adjusting lash between a rocker arm and a valve stem in a Type II valvetrain arranged relative to a cylinder head is provided. The lash adjustment system includes a locking assembly having a positioning rod and a locking member. The positioning rod extends along a longitudinal axis and has a ball portion and an opposite end portion. The ball portion is received by a spherical receiving portion of the rocker arm. The end portion is received by a bore defined in the cylinder head. The locking member moves between an unlocked position and a locked position. In the unlocked position the positioning rod is free to move along the longitudinal axis relative to the locking member thereby altering a gap defined between the valve stem and the rocker arm. In the locked position, the positioning member is precluded from moving along the longitudinal axis thereby fixing the gap at a desired distance.

[0006] According to additional features, the locking member rests on the cylinder head in the locked position. The locking member can comprise an arm and a collar. The collar receives the positioning rod therethrough. In the locked position, the collar is clamped around the positioning rod inhibiting relative translation of the positioning rod relative to the locking member.

[0007] A lash adjustment system for adjusting lash between a rocker arm and a valve stem in a Type II valvetrain arranged relative to a cylinder head according to another example includes a locking assembly having a positioning rod and a tool engaging portion. The positioning rod extends along a longitudinal axis and has a first portion that extends toward the rocker arm and a second portion that extends toward the cylinder head. The tool engaging portion is configured to move the positioning rod along the longitudinal axis thereby altering a gap defined between the valve stem and the rocker arm.

[0008] According to additional features, the positioning rod has first threads that threadably mate with second threads defined on the bore of the cylinder head. The tool engaging portion can be integrally formed on the positioning rod. In another configuration, the positioning rod has first threads that mate with second threads defined on the tool engaging portion. The tool engaging portion can include a nut. The nut can rest on the cylinder head. The nut can alternatively rest on the rocker arm. A socket can extend from the cylinder head that receives the second portion of the positioning rod.

[0009] According to further examples, the locking assembly further comprises a ratchet assembly including a gear and a spring loaded finger. The spring loaded finger locates between respective teeth of the gear during rotation of the nut. The spring loaded finger can locate between respective teeth of the gear precluding rotation of the nut in a first rotational direction. The first portion can include a ball portion received by a spherical receiving portion of the rocker arm. The second portion can be received by a bore defined in the cylinder head. The tool engaging portion can comprise a hexagonal nut.

[0010] A lash adjustment system for adjusting lash between a rocker arm and a valve stem in a Type II valvetrain arranged relative to a cylinder head according to another example includes a locking assembly having a positioning rod, a pivot shaft and a tool engaging portion. The positioning rod extends along a longitudinal axis and has a first portion that extends toward the rocker arm and a second portion that extends toward the valve stem. The pivot shaft is fixed to and extends from the cylinder head. The pivot shaft has a ball that is received by a spherical receiving portion on the rocker arm. The tool engaging portion is configured to move the positioning rod along the longitudinal axis thereby altering a gap defined between the valve stem and the rocker arm.

[0011] According to other features, the positioning rod is threaded to the rocker arm. An elephant foot can be positioned between the positioning rod and the valve stem. The tool engaging portion comprises a hex head integrally formed on the positioning rod.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The present disclosure will become more fully understood from the detailed description and the accompanying drawings, wherein:

[0013] FIG. 1 is a front perspective view of a lash adjustment system constructed in accordance to one example of the present disclosure;

[0014] FIG. 2 is a rear perspective view of the lash adjustment system of FIG. 1 ;

[0015] FIG. 3 is a cross-sectional view taken along lines 3-3 of the lash adjustment system of FIG. 1 and shown in an unlocked position;

[0016] FIG. 4 is a cross-sectional view of the lash adjustment system of FIG. 3 and shown in a locked position;

[0017] FIG. 5 is a front perspective view of a lash adjustment system constructed in accordance to another example of the present disclosure;

[0018] FIG. 6 is a rear perspective view of the lash adjustment system of FIG. 5; [0019] FIG. 7 is a cross-sectional view taken along lines 7-7 of the lash adjustment system of FIG. 5 and shown in an unlocked position;

[0020] FIG. 8 is a cross-sectional view of the lash adjustment system of FIG. 7 and shown in a locked position;

[0021] FIG. 9 is a rear perspective view of a lash adjustment system constructed in accordance to another example of the present disclosure;

[0022] FIG. 10 is a cross-sectional view taken along lines 10-10 of the lash adjustment system of FIG. 9 and shown in an unlocked position;

[0023] FIG. 1 1 is a cross-sectional view of the lash adjustment system of FIG. 10 and shown in a locked position;

[0024] FIG. 12 is a front perspective view of a lash adjustment system constructed in accordance to another example of the present disclosure;

[0025] FIG. 13 is a rear perspective view of the lash adjustment system of FIG. 12;

[0026] FIG. 14 is a cross-sectional view taken along lines 14-14 of the lash adjustment system of FIG. 12 and shown in an unlocked position;

[0027] FIG. 15 is a cross-sectional view of the lash adjustment system of FIG. 14 and shown in a locked position;

[0028] FIG. 16 is a rear perspective view of a lash adjustment system constructed in accordance to another example of the present disclosure;

[0029] FIG. 17 is a cross-sectional view taken along lines 17-17 of the lash adjustment system of FIG. 16 and shown in an unlocked position;

[0030] FIG. 18 is a cross-sectional view of the lash adjustment system of FIG. 17 and shown in a locked position;

[0031] FIG. 19 is a rear perspective view of a lash adjustment system constructed in accordance to another example of the present disclosure;

[0032] FIG. 20 is a cross-sectional view taken along lines 20-20 of the lash adjustment system of FIG. 19 and shown in an unlocked position;

[0033] FIG. 21 is a cross-sectional view of the lash adjustment system of FIG. 20 and shown in a locked position;

[0034] FIG. 22 is a rear perspective view of a lash adjustment system constructed in accordance to another example of the present disclosure; [0035] FIG. 23 is a cross-sectional view taken along lines 23-23 of the lash adjustment system of FIG. 22 and shown in an unlocked position; and

[0036] FIG. 24 is a cross-sectional view of the lash adjustment system of FIG. 23 and shown in a locked position.

DETAILED DESCRIPTION

[0037] With initial reference to FIGS. 1-4, lash adjustment system constructed in accordance to one example of the present disclosure is shown and generally identified at reference 10. The lash adjustment system 10 is configured for use in a Type II valvetrain arrangement. The lash adjustment system 10 generally comprises a rocker arm assembly 20, a valve stem 22 and a locking assembly 24. The rocker arm assembly 20 includes a rocker arm 30 and a roller bearing 32 rotatably mounted to the rocker arm 30 through an axle 36.

[0038] The rocker arm 30 includes a valve engaging end 44, a pivot end 46 and an intermediate portion 48. The roller bearing 32 is generally arranged at the intermediate portion 48. The valve engaging end 44 includes a valve engaging pad 50. The pivot end 46 includes a spherical receiving portion 54. As is conventional in a Type II valvetrain arrangement, a cam shaft 60 (shown in FIG. 3) having one or more valve actuating lobes 62 drives the rocker arm assembly 20. Specifically, as the lobe 62 slidably engages the roller bearing 32, the rocker arm 30 is caused to rock generally counterclockwise as viewed in FIG. 1 , causing the valve engaging end 44 of the rocker arm 30 to actuate the valve stem 22 while generally pivoting about the pivot end 46.

[0039] As will become appreciated from the following discussion, the lash adjustment system 10 can be used to set valve lash. Valve lash can be defined generally as a mechanical clearance in the valvetrain from a valve tip 66 of the valve stem 22 to the valve engaging pad 50 of the rocker arm 30. The locking assembly 24 includes a positioning rod 70 and a locking member 72. The positioning rod 70 extends along a longitudinal axis 73 and includes a ball portion 74 and an opposite end portion 76. The ball portion 74 is received by the spherical receiving portion 54. The end portion 76 is received by a bore 80 defined in a cylinder head 82 of the engine. The locking member 72 is movable between an unlocked position (FIG. 3) and a locked position (FIG. 4). [0040] In the unlocked position, the positioning rod 70 is free to move along its longitudinal axis 73 relative to the locking member 72. In the locked position, the positioning rod 70 is precluded from moving along its longitudinal axis 73 relative to the locking member 72. The locking member 72 generally comprises an arm 90 and a collar 92. The collar 92 receives the positioning rod therethrough. To move the locking member 72 from the unlocked position to the locked position, an arm 90 is generally rotated causing a collar 92 to clamp around the positioning rod 70 inhibiting further relative translation of the positioning rod relative to the locking member 72. As the locking member 72 rests on the cylinder head 82, the positioning rod 70 can be moved upward in the unlocked position until a gap 94 between the valve engaging pad 50 and the valve tip 66 is taken up (FIG. 3 to FIG. 4). Once the gap is taken up, the locking member 72 can be moved to the locked position.

[0041] Turning now to FIGS. 5-8, a lash adjustment system constructed in accordance to another example of the present disclosure is shown and generally identified at reference 1 10. The lash adjustment system 1 10 is configured for use in a Type II valvetrain arrangement. The lash adjustment system 1 10 generally comprises a rocker arm assembly 120, a valve stem 122 and a locking assembly 124. The rocker arm assembly 120 includes a rocker arm 130 and a roller bearing 132 rotatably mounted to the rocker arm 130 through an axle 136.

[0042] The rocker arm 130 includes a valve engaging end 144, a pivot end 146 and an intermediate portion 148. The roller bearing 132 is generally arranged at the intermediate portion 148. The valve engaging end 144 includes a valve engaging pad 150. The pivot end 146 includes a spherical receiving portion 154. As is conventional in a Type II valvetrain arrangement, a cam shaft 160 (shown in FIG. 7) having one or more valve actuating lobes 162 drives the rocker arm assembly 120. Specifically, as the lobe 162 slidably engages the roller bearing 132, the rocker arm 130 is caused to rock generally counterclockwise as viewed in FIG. 5, causing the valve engaging end 144 of the rocker arm 130 to actuate the valve stem 122 while generally pivoting about the pivot end 146.

[0043] As will become appreciated from the following discussion, the lash adjustment system 1 10 can be used to set valve lash. The locking assembly 124 includes a positioning rod 170. The positioning rod 170 extends along a longitudinal axis 173 and includes a ball portion 174, an opposite end portion 176 and a tool engaging portion 178. In one example the tool engaging portion 178 is machined into the positioning rod 170. The opposite end portion 176 has first threads 179 formed thereon. The ball portion 174 is received by the spherical receiving portion 154. The end portion 176 is threadably received by second threads 180 defined along a bore 181 in a cylinder head 182 of the engine. In the example shown, the tool engaging portion 178 is a hexagonal nut however other configurations are contemplated. To adjust the locking assembly 124, a user rotates the tool engaging portion 178 causing the first threads 179 to advance along the second threads 180 thereby causing the positioning rod 170 to move along the longitudinal axis 173. The positioning rod 170 can be moved upward until a gap 194 between the valve engaging pad 150 and the valve tip 166 is taken up (FIG. 7 to FIG. 8). The positioning rod 170 remains fixed along its longitudinal axis 173 absent rotation of the tool engaging portion 178.

[0044] Turning now to FIGS. 9-11 , a lash adjustment system constructed in accordance to another example of the present disclosure is shown and generally identified at reference 210. The lash adjustment system 210 is configured for use in a Type II valvetrain arrangement. The lash adjustment system 210 generally comprises a rocker arm assembly 220, a valve stem 222 and a locking assembly 224. The rocker arm assembly 220 includes a rocker arm 230 and a roller bearing 232 rotatably mounted to the rocker arm 230 through an axle 236.

[0045] The rocker arm 230 includes a valve engaging end 244, a pivot end 246 and an intermediate portion 248. The roller bearing 232 is generally arranged at the intermediate portion 248. The valve engaging end 244 includes a valve engaging pad 250. The pivot end 246 includes a spherical receiving portion 254. As is conventional in a Type II valvetrain arrangement, a cam shaft 260 (shown in FIG. 10) having one or more valve actuating lobes 262 drives the rocker arm assembly 220. Specifically, as the lobe 262 slidably engages the roller bearing 232, the rocker arm 230 is caused to rock generally counterclockwise as viewed in FIG. 10, causing the valve engaging end 244 of the rocker arm 230 to actuate the valve stem 222 while generally pivoting about the pivot end 246. [0046] As will become appreciated from the following discussion, the lash adjustment system 210 can be used to set valve lash. The locking assembly 224 includes a positioning rod 270. The positioning rod 270 extends along a longitudinal axis 273 and includes a ball portion 274 and an opposite end portion 276. A tool engaging portion or nut 278 has first threads 279 that are threadably by second threads 280 formed along the positioning rod 270.

[0047] The ball portion 274 is received by the spherical receiving portion 254. In the example shown, the nut 278 is a hexagonal nut however other configurations are contemplated. To adjust the locking assembly 224, a user rotates the nut 278 causing the first threads 279 to advance along the second threads 280 thereby causing the positioning rod 270 to move along the longitudinal axis 273. The positioning rod 270 is received by a bore 281 defined in the cylinder head 282. The positioning rod 270 can be moved upward until a gap 294 between the valve engaging pad 250 and the valve tip 266 is taken up (FIG. 10 to FIG. 1 1 ). The positioning rod 270 remains fixed along its longitudinal axis 273 absent rotation of the nut 278. The nut 278 rests on the cylinder head 282.

[0048] Turning now to FIGS. 12-15, a lash adjustment system constructed in accordance to another example of the present disclosure is shown and generally identified at reference 310. The lash adjustment system 310 is configured for use in a Type II valvetrain arrangement. The lash adjustment system 310 generally comprises a rocker arm assembly 320, a valve stem 322 and a locking assembly 324. The rocker arm assembly 320 includes a rocker arm 330 and a roller bearing 332 rotatably mounted to the rocker arm 330 through an axle 336.

[0049] The rocker arm 330 includes a valve engaging end 344, a pivot end 346 and an intermediate portion 348. The roller bearing 332 is generally arranged at the intermediate portion 348. The valve engaging end 344 includes a valve engaging pad 350. The pivot end 346 includes a spherical receiving portion 354. As is conventional in a Type II valvetrain arrangement, a cam shaft 360 (shown in FIG. 14) having one or more valve actuating lobes 362 drives the rocker arm assembly 320. Specifically, as the lobe 362 slidably engages the roller bearing 332, the rocker arm 330 is caused to rock generally counterclockwise as viewed in FIG. 14, causing the valve engaging end 344 of the rocker arm 330 to actuate the valve stem 322 while generally pivoting about the pivot end 346.

[0050] As will become appreciated from the following discussion, the lash adjustment system 310 can be used to set valve lash. The locking assembly 324 includes a positioning rod 370. The positioning rod 370 extends along a longitudinal axis 373 and includes a ball portion 374 and an opposite end portion 376. A nut 378 has first threads 379 that are threadably by second threads 380 formed along the positioning rod 370.

[0051] The ball portion 374 is received by the spherical receiving portion 354. In the example shown, the nut 378 is a hexagonal nut however other configurations are contemplated. To adjust the locking assembly 324, a user rotates the nut 378 causing the first threads 379 to advance along the second threads 380 thereby causing the positioning rod 370 to move along the longitudinal axis 373. The positioning rod 370 is received by a bore 381 defined in the cylinder head 382. A ratchet assembly 384 includes a gear 386 and a spring loaded finger 388. The spring loaded finger 288 locates between respective teeth of the gear 386 during rotation of the nut 378. In one example, the ratchet assembly 384 can preclude rotation of the nut 378 in a first rotational direction without manual adjustment of the gear 386 away from engagement with the teeth of the gear 386. The positioning rod 370 can be moved upward until a gap 394 between the valve engaging pad 350 and the valve tip 366 is taken up (FIG. 14 to FIG. 15). The positioning rod 370 remains fixed along its longitudinal axis 373 absent rotation of the nut 378.

[0052] With reference now to FIGS. 16-18, a lash adjustment system constructed in accordance to another example of the present disclosure is shown and generally identified at reference 410. The lash adjustment system 410 is configured for use in a Type II valvetrain arrangement. The lash adjustment system 410 generally comprises a rocker arm assembly 420, a valve stem 422 and a locking assembly 424. The rocker arm assembly 420 includes a rocker arm 430 and a roller bearing 432 rotatably mounted to the rocker arm 430 through an axle 436.

[0053] The rocker arm 430 includes a valve engaging end 444, a pivot end 446 and an intermediate portion 448. The roller bearing 432 is generally arranged at the intermediate portion 448. In this example, the locking assembly 424 is arranged at the valve engaging end 444. The pivot end 446 includes a spherical receiving portion 454. A ball 456 extending from a pivot shaft 458 is received by the spherical receiving portion 454. The pivot shaft 458 is fixed to cylinder head 459. As is conventional in a Type II valvetrain arrangement, a cam shaft 460 (shown in FIG. 17) having one or more valve actuating lobes 462 drives the rocker arm assembly 420. Specifically, as the lobe 462 slidably engages the roller bearing 432, the rocker arm 430 is caused to rock generally counterclockwise as viewed in FIG. 17, causing the valve engaging end 444 of the rocker arm 430 to actuate the valve stem 422 while generally pivoting about the pivot end 446.

[0054] As will become appreciated from the following discussion, the lash adjustment system 410 can be used to set valve lash. The locking assembly 424 includes a positioning rod 470 located on the valve engaging end 444. An elephant foot 472 is positioned between the positioning rod 470 and the valve stem 422. The positioning rod 470 includes a ball portion 474 and an opposite end portion 476. The end portion 476 has first threads 379 that are threadably by second threads 380 formed on the rocker arm 430.

[0055] The end portion 476 of the positioning rod 470 includes a tool receiving end 482 in the form of a hex although other configurations are contemplated. To adjust the locking assembly 424, a user rotates the positioning rod 470 causing the first threads 479 to advance along the second threads 480 thereby causing the positioning rod 470 to move along the longitudinal axis 473 and changing an effective span 488 between the rocker arm 430 and the valve stem 422. The positioning rod 470 can be moved downward until no gap exists between the positioning rod 470, elephant foot 472 and the valve tip 466 is taken up (FIG. 17 to FIG. 18).

[0056] Turning now to FIGS. 19-21 , a lash adjustment system constructed in accordance to another example of the present disclosure is shown and generally identified at reference 510. The lash adjustment system 510 is configured for use in a Type II valvetrain arrangement. The lash adjustment system 510 generally comprises a rocker arm assembly 520, a valve stem 522 and a locking assembly 524. The rocker arm assembly 520 includes a rocker arm 530 and a roller bearing 532 rotatably mounted to the rocker arm 530 through an axle 536. [0057] The rocker arm 530 includes a valve engaging end 544, a pivot end 546 and an intermediate portion 548. The roller bearing 532 is generally arranged at the intermediate portion 548. The valve engaging end 544 includes a valve engaging pad 550. As is conventional in a Type II valvetrain arrangement, a cam shaft 560 (shown in FIG. 20) having one or more valve actuating lobes 562 drives the rocker arm assembly 520. Specifically, as the lobe 562 slidably engages the roller bearing 532, the rocker arm 530 is caused to rock generally counterclockwise as viewed in FIG. 20, causing the valve engaging end 544 of the rocker arm 530 to actuate the valve stem 522 while generally pivoting about the pivot end 546.

[0058] As will become appreciated from the following discussion, the lash adjustment system 510 can be used to set valve lash. The locking assembly 524 includes a positioning rod 570. The positioning rod 570 extends along a longitudinal axis 573 and includes a ball portion 574 and an opposite end portion 576. A nut 578 has first threads 579 that are threadably mated with second threads 580 formed along the positioning rod 570.

[0059] The ball portion 574 is received by a spherical receiving portion 554 formed on a cylinder head 582. The cylinder head 582, and other cylinder heads discussed throughout this disclosure, can be formed of aluminum. A surface treatment may be disposed between the spherical receiving portion 554 of the cylinder head 582 and the ball portion 574. In the example shown, the nut 578 is a hexagonal nut however other configurations are contemplated. To adjust the locking assembly 524, a user rotates the nut 578 causing the first threads 579 to advance along the second threads 580 thereby causing the positioning rod 570 to move along the longitudinal axis 573 and the rocker arm 520 to generally rock closer or further from the cylinder head 582. The positioning rod 570 can be moved upward until a gap 594 between the valve engaging pad 550 and the valve tip 566 is taken up (FIG. 20 to FIG. 21 ). The positioning rod 570 remains fixed along its longitudinal axis 573 absent rotation of the nut 578.

[0060] Turning now to FIGS. 22-24, a lash adjustment system constructed in accordance to another example of the present disclosure is shown and generally identified at reference 610. The lash adjustment system 610 is configured for use in a Type II valvetrain arrangement. The lash adjustment system 610 generally comprises a rocker arm assembly 620, a valve stem 622 and a locking assembly 624. The rocker arm assembly 620 includes a rocker arm 630 and a roller bearing 632 rotatably mounted to the rocker arm 630 through an axle 636.

[0061] The rocker arm 630 includes a valve engaging end 644, a pivot end 646 and an intermediate portion 648. The roller bearing 632 is generally arranged at the intermediate portion 648. The valve engaging end 644 includes a valve engaging pad 650. As is conventional in a Type II valvetrain arrangement, a cam shaft 660 (shown in FIG. 23) having one or more valve actuating lobes 662 drives the rocker arm assembly 620. Specifically, as the lobe 662 slidably engages the roller bearing 632, the rocker arm 630 is caused to rock generally counterclockwise as viewed in FIG. 23, causing the valve engaging end 644 of the rocker arm 630 to actuate the valve stem 622 while generally pivoting about the pivot end 646.

[0062] As will become appreciated from the following discussion, the lash adjustment system 610 can be used to set valve lash. The locking assembly 624 includes a positioning rod 670. The positioning rod 670 extends along a longitudinal axis 673 and includes a ball portion 674 and an opposite end portion 676. A nut 678 has first threads 679 that are threadably mated with second threads 680 formed along the positioning rod 670.

[0063] The ball portion 674 is received by a spherical receiving portion 654 formed in a socket 656 extending from the cylinder head 682. In the example shown, the nut 678 is a hexagonal nut however other configurations are contemplated. To adjust the locking assembly 624, a user rotates the nut 678 causing the first threads 679 to advance along the second threads 680 thereby causing the positioning rod 670 to move along the longitudinal axis 673 and the rocker arm 620 to generally rock closer or further from the cylinder head 682. The positioning rod 670 can be moved upward until a gap 694 between the valve engaging pad 650 and the valve tip 666 is taken up (FIG. 23 to FIG. 24). The positioning rod 670 remains fixed along its longitudinal axis 673 absent rotation of the nut 678.

[0064] The foregoing description of the examples has been provided for purposes of illustration and description. For example, in any of the examples disclosed herein, a flowable adhesive such as Loctite^® may be disposed between mating threaded portions subsequent to attaining a desired lash. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular example are generally not limited to that particular example, but, where applicable, are interchangeable and can be used in a selected example, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.

Claims

CLAIMS What is claimed is:

1 . A lash adjustment system for adjusting lash between a rocker arm and a valve stem in a Type II valvetrain arranged relative to a cylinder head, the lash adjustment system comprising:

a locking assembly comprising:

a positioning rod that extends along a longitudinal axis and has a ball portion and an opposite end portion, the ball portion received by a spherical receiving portion of the rocker arm, the end portion received by a bore defined in the cylinder head; and

a locking member that moves between an unlocked position and a locked position, wherein in the unlocked position the positioning rod is free to move along the longitudinal axis relative to the locking member thereby altering a gap defined between the valve stem and the rocker arm, and wherein in the locked position, the positioning member is precluded from moving along the longitudinal axis thereby fixing the gap at a desired distance.

2. The lash adjustment system of claim 1 wherein the locking member rests on the cylinder head in the locked position.

3. The lash adjustment system of claim 1 wherein the locking member comprises an arm and a collar, wherein the collar receives the positioning rod therethrough.

4. The lash adjustment system of claim 3 wherein in the locked position the collar is clamped around the positioning rod inhibiting relative translation of the positioning rod relative to the locking member.

5. A lash adjustment system for adjusting lash between a rocker arm and a valve stem in a Type II valvetrain arranged relative to a cylinder head, the lash adjustment system comprising:

a locking assembly comprising:

a positioning rod that extends along a longitudinal axis and has a first portion that extends toward the rocker arm and a second portion that extends toward the cylinder head; and

a tool engaging portion configured to move the positioning rod along the longitudinal axis thereby altering a gap defined between the valve stem and the rocker arm.

6. The lash adjustment system of claim 5 wherein the positioning rod has first threads that threadably mate with second threads defined on the bore of the cylinder head.

7. The lash adjustment system of claim 6 wherein the tool engaging portion is integrally formed on the positioning rod.

8. The lash adjustment system of claim 5 wherein the positioning rod has first threads that mate with second threads defined on the tool engaging portion, wherein the tool engaging portion comprises a nut.

9. The lash adjustment system of claim 8 wherein the nut rests on the cylinder head.

10. The lash adjustment system of claim 8 wherein the nut rests on the rocker arm.

1 1. The lash adjustment system of claim 8, further comprising Loctite^® disposed between first and second threads.

12. The lash adjustment system of claim 10, further comprising a socket extending from the cylinder head that receives the second portion of the positioning rod.

13. The lash adjustment system of claim 9, further comprising a ratchet assembly including a gear and a spring loaded finger, wherein the spring loaded finger locates between respective teeth of the gear during rotation of the nut.

14. The lash adjustment system of claim 13 wherein the spring loaded finger locates between respective teeth of the gear precluding rotation of the nut in a first rotational direction.

15. The lash adjustment system of claim 5 wherein the first portion includes a ball portion received by a spherical receiving portion of the rocker arm, and the second portion is received by a bore defined in the cylinder head.

16. The lash adjustment system of claim 5 wherein the tool engaging portion comprises a hexagonal nut.

17. The lash adjustment system of claim 5, further comprising a cylinder head wherein the cylinder head is formed of aluminum.

18. A lash adjustment system for adjusting lash between a rocker arm and a valve stem in a Type II valvetrain arranged relative to a cylinder head, the lash adjustment system comprising:

a locking assembly comprising:

a positioning rod that extends along a longitudinal axis and has a first portion that extends toward the rocker arm and a second portion that extends toward the valve stem;

a pivot shaft that is fixed to and extends from the cylinder head, the pivot shaft having a ball that is received by a spherical receiving portion on the rocker arm; and a tool engaging portion configured to move the positioning rod along the longitudinal axis thereby altering a gap defined between the valve stem and the rocker arm.

19. The lash adjustment system of claim 18 wherein the positioning rod is threaded to the rocker arm.

20. The lash adjustment system of claim 19, further comprising an elephant foot positioned between the positioning rod and the valve stem.

21. The lash adjustment system of claim 20 wherein the tool engaging portion comprises a hex head integrally formed on the positioning rod.