347:
278:. This space prevents the parts from binding as they expand with the engine's heat, but can also lead to noisy operation and increased wear as the parts rattle against one another until they reach operating temperature. The hydraulic lifter was designed to compensate for this small tolerance, allowing the valve train to operate with zero clearance—leading to quieter operation, longer engine life, and eliminating the need for periodic adjustment of valve clearance.
128:
66:
25:
322:(Model 452). Hydraulic lifters were nearly universal on cars designed in the 1980s, but some newer cars have reverted to bucket-and-shim mechanical lifters. Although these do not run as quietly and are not maintenance-free, they are cheaper. Nearly all modern non-hydraulic lifter arrangements are on overhead cam engines.
424:
It is a myth that in certain circumstances, a lifter can "pump up" and create negative valve clearance. The engine oil pump cannot generate enough pressure to cause "pump-up". The problem is due to weak valve springs which permit float at high engine speeds. The followers attempt to take up what they
420:
Generally, hydraulic tappets are more sensitive to engine oil quality and frequency of oil changes, as carbon sludge and residues may easily lock up the tappets or block oil channels, making the clearance setting ineffective. This has negative impact, especially on the engine camshaft and valves due
301:
Oil under constant pressure is supplied to the lifter via an oil channel, through a small hole in the lifter body. When the engine valve is closed (lifter in a neutral position), the lifter is free to fill with oil. As the camshaft lobe enters the lift phase of its travel, it compresses the lifter
281:
The hydraulic lifter, situated between the camshaft and each engine's valve, is a hollow steel cylinder encasing an internal piston. This piston is held at the outer limit of its travel with a strong spring. The lobed camshaft rhythmically presses against the lifter, which transmits the motion to
409:
will rattle loudly on startup due to oil draining from the lifters when the vehicle is parked. This is not considered a significant issue provided the noise disappears within a couple of minutes; typically it usually lasts only a second or two. A rattle that does not go away can indicate a blocked
305:
As the camshaft lobe travels through its apex, the load is reduced on the lifter piston, and the internal spring returns the piston to its neutral state so the lifter can refill with oil. This small range of travel in the lifter's piston is enough to eliminate the need for frequent
425:
see as extra clearance. As this speed is maintained, the lifter will continue to expand until the valve is held off its seat when it should be closed. Maintenance of the valve springs at the correct strength is therefore very important to avoid engine damage.
383:
364:
421:
to excessive wear if the clearance setting is not working correctly. As mentioned, one may avoid this by using the manufacturer-recommended grade of engine oil, and by not exceeding the prescribed oil change interval.
330:
As the whole process is actuated by hydraulic pressure at engine start, there is no need for service or adjustment. Another advantage is cheaper operation, as there is no need for service and charges associated with
384:
365:
382:
363:
410:
oil feed, or that one or more of the lifters has collapsed due to wear and is no longer opening its valve fully. The affected lifter should be replaced in the latter situation.
1142:
436:
Used hydraulic lifters should be drained of oil before installation, to prevent them from holding open the valves on startup and potentially causing damage to the
444:. This is easily accomplished by compressing them in a vice. Oil pressure will build quickly upon startup and they will set themselves to the proper height.
302:
piston, and a valve shuts the oil inlet. Oil is nearly incompressible, so this greater pressure renders the lifter effectively solid during the lift phase.
473:
417:
design. A number of subcompact car manufacturers prefer solid valve lifters due to lower design and production cost rather than hydraulic tappets.
1135:
385:
366:
1564:
1128:
466:
1534:
200:
1230:
1041:
172:
1559:
459:
179:
980:
335:
maintenance. Usually hydraulic tappets survive through the whole of the engine life without any service requirements.
237:
219:
149:
109:
52:
38:
157:
91:
186:
1478:
658:
153:
76:
897:
1120:
955:
168:
1699:
1288:
539:
375:
1519:
428:
Hydraulic lifters can also create "valve bounce" at high RPM, which is undesirable for performance uses.
1735:
1514:
1394:
482:
356:
263:
1359:
1091:
1005:
970:
950:
902:
810:
1594:
1509:
1344:
1086:
927:
636:
138:
1458:
1389:
1283:
861:
142:
87:
1730:
1694:
1529:
1429:
683:
307:
193:
1704:
1483:
1444:
1409:
1250:
800:
641:
44:
1689:
1617:
1569:
1163:
1154:
795:
567:
267:
83:
8:
1740:
1658:
1364:
945:
843:
573:
319:
1673:
1524:
1473:
1369:
1303:
866:
663:
1554:
1434:
1404:
1399:
1354:
1339:
1200:
668:
608:
559:
294:
1323:
1313:
960:
917:
876:
825:
790:
711:
698:
270:
require regular adjusting to maintain a small clearance between the valve and its
1602:
1424:
1384:
1379:
1308:
1151:
1071:
782:
631:
588:
405:
There are a number of potential problems with hydraulic lifters. Frequently, the
1648:
1638:
1298:
1225:
1185:
937:
907:
762:
529:
287:
1150:
1724:
1574:
1419:
1414:
1349:
1293:
1205:
1109:
1000:
993:
815:
747:
742:
706:
623:
563:
524:
514:
451:
414:
1709:
1668:
1663:
1439:
1260:
1245:
1220:
726:
721:
688:
593:
583:
519:
503:
275:
1653:
1579:
1504:
1499:
1240:
1210:
1104:
988:
805:
757:
716:
673:
603:
286:
through a pushrod which actuates the valve via a rocker mechanism (in an
1643:
1633:
1584:
1374:
1318:
1255:
1195:
1076:
1036:
1015:
1010:
912:
820:
752:
678:
618:
549:
437:
406:
397:
271:
1031:
772:
767:
554:
534:
127:
94:. Statements consisting only of original research should be removed.
1607:
1190:
1180:
1054:
1050:
922:
653:
578:
544:
1081:
965:
1265:
1235:
892:
871:
648:
598:
441:
332:
1628:
293:
via direct contact with the valve stem or rocker arm (in an
1046:
318:
The first engine to feature hydraulic lifters was the 1930
413:
Hydraulic tappets require more complex and more expensive
493:
262:, is a device for maintaining zero valve clearance in an
1722:
481:
1136:
467:
156:. Unsourced material may be challenged and
53:Learn how and when to remove these messages
1143:
1129:
474:
460:
238:Learn how and when to remove this message
220:Learn how and when to remove this message
110:Learn how and when to remove this message
540:Crankcase ventilation system (PCV valve)
1723:
1124:
455:
282:the engine valve in one of two ways:
16:Device in internal combustion engines
154:adding citations to reliable sources
121:
59:
18:
1157:components, systems and terminology
13:
396:Problems playing these files? See
345:
14:
1752:
34:This article has multiple issues.
380:
361:
338:
126:
64:
23:
642:Overhead valve (pushrod) layout
42:or discuss these issues on the
1479:Propeller speed reduction unit
1:
447:
325:
1289:Capacitor discharge ignition
7:
90:the claims made and adding
10:
1757:
483:Internal combustion engine
313:
264:internal combustion engine
1682:
1616:
1593:
1547:
1492:
1466:
1457:
1332:
1299:Electronic fuel injection
1274:
1171:
1162:
1100:
1064:
1024:
979:
951:Diesel particulate filter
936:
903:Idle air control actuator
885:
852:
844:Engine control unit (ECU)
834:
781:
735:
697:
617:
502:
489:
1345:Aircraft engine starting
1016:Viscous fan (fan clutch)
928:Throttle position sensor
637:Overhead camshaft layout
431:
1390:Mean effective pressure
555:Core plug (freeze plug)
260:hydraulic lash adjuster
1430:Time between overhauls
376:Quiet hydraulic tappet
357:Noisy hydraulic tappet
350:
256:hydraulic valve lifter
1705:Ice protection system
1445:Volumetric efficiency
1410:Overhead valve engine
349:
297:(OHC) configuration).
1690:Auxiliary power unit
1570:Flight data recorder
796:Compression ignition
150:improve this article
1659:Pressure carburetor
1395:Naturally aspirated
1365:Engine displacement
946:Catalytic converter
268:solid valve lifters
1674:Updraft carburetor
1548:Engine instruments
1474:Propeller governor
1370:Four-stroke engine
1072:Knocking / pinging
664:Combustion chamber
351:
254:, also known as a
169:"Hydraulic tappet"
75:possibly contains
1736:Engine components
1718:
1717:
1555:Annunciator panel
1543:
1542:
1453:
1452:
1435:Two-stroke engine
1405:Overhead camshaft
1385:Manifold pressure
1355:Compression ratio
1118:
1117:
1087:Stratified charge
854:Electrical system
836:Engine management
669:Compression ratio
609:Starter ring gear
508:rotating assembly
386:
367:
295:overhead camshaft
248:
247:
240:
230:
229:
222:
204:
120:
119:
112:
77:original research
57:
1748:
1700:Hydraulic system
1520:Counter-rotating
1464:
1463:
1216:Hydraulic tappet
1169:
1168:
1145:
1138:
1131:
1122:
1121:
961:Exhaust manifold
826:Spark plug wires
712:Boost controller
699:Forced induction
476:
469:
462:
453:
452:
388:
387:
369:
368:
348:
252:hydraulic tappet
243:
236:
225:
218:
214:
211:
205:
203:
162:
130:
122:
115:
108:
104:
101:
95:
92:inline citations
68:
67:
60:
49:
27:
26:
19:
1756:
1755:
1751:
1750:
1749:
1747:
1746:
1745:
1721:
1720:
1719:
1714:
1695:Coffman starter
1678:
1621:
1612:
1603:Carburetor heat
1595:Engine controls
1589:
1539:
1515:Contra-rotating
1488:
1449:
1380:Ignition timing
1328:
1309:Ignition system
1276:
1270:
1173:
1158:
1149:
1119:
1114:
1096:
1092:Top dead centre
1060:
1020:
975:
932:
881:
855:
848:
837:
830:
777:
731:
693:
649:Tappet / lifter
632:Flathead layout
622:
613:
507:
498:
485:
480:
450:
434:
403:
402:
394:
392:
391:
390:
389:
381:
378:
372:
371:
370:
362:
359:
352:
346:
341:
328:
316:
266:. Conventional
244:
233:
232:
231:
226:
215:
209:
206:
163:
161:
147:
131:
116:
105:
99:
96:
81:
69:
65:
28:
24:
17:
12:
11:
5:
1754:
1744:
1743:
1738:
1733:
1716:
1715:
1713:
1712:
1707:
1702:
1697:
1692:
1686:
1684:
1680:
1679:
1677:
1676:
1671:
1666:
1661:
1656:
1651:
1649:Inlet manifold
1646:
1641:
1639:Fuel injection
1636:
1631:
1625:
1623:
1614:
1613:
1611:
1610:
1605:
1599:
1597:
1591:
1590:
1588:
1587:
1582:
1577:
1572:
1567:
1562:
1557:
1551:
1549:
1545:
1544:
1541:
1540:
1538:
1537:
1535:Variable-pitch
1532:
1527:
1522:
1517:
1512:
1510:Constant-speed
1507:
1502:
1496:
1494:
1490:
1489:
1487:
1486:
1481:
1476:
1470:
1468:
1461:
1455:
1454:
1451:
1450:
1448:
1447:
1442:
1437:
1432:
1427:
1422:
1417:
1412:
1407:
1402:
1397:
1392:
1387:
1382:
1377:
1372:
1367:
1362:
1357:
1352:
1347:
1342:
1336:
1334:
1330:
1329:
1327:
1326:
1321:
1316:
1311:
1306:
1301:
1296:
1291:
1286:
1280:
1278:
1272:
1271:
1269:
1268:
1263:
1258:
1253:
1248:
1243:
1238:
1233:
1228:
1226:Obturator ring
1223:
1218:
1213:
1208:
1203:
1198:
1193:
1188:
1186:Connecting rod
1183:
1177:
1175:
1166:
1164:Piston engines
1160:
1159:
1148:
1147:
1140:
1133:
1125:
1116:
1115:
1113:
1112:
1107:
1101:
1098:
1097:
1095:
1094:
1089:
1084:
1079:
1074:
1068:
1066:
1062:
1061:
1059:
1058:
1044:
1039:
1034:
1028:
1026:
1022:
1021:
1019:
1018:
1013:
1008:
1003:
997:
996:
991:
985:
983:
981:Cooling system
977:
976:
974:
973:
968:
963:
958:
953:
948:
942:
940:
938:Exhaust system
934:
933:
931:
930:
925:
920:
915:
910:
908:Inlet manifold
905:
900:
895:
889:
887:
883:
882:
880:
879:
874:
869:
864:
858:
856:
853:
850:
849:
847:
846:
840:
838:
835:
832:
831:
829:
828:
823:
818:
813:
808:
803:
798:
793:
787:
785:
779:
778:
776:
775:
770:
765:
763:Fuel injection
760:
755:
750:
745:
739:
737:
733:
732:
730:
729:
724:
719:
714:
709:
703:
701:
695:
694:
692:
691:
686:
681:
676:
671:
666:
661:
656:
651:
645:
644:
639:
634:
628:
626:
615:
614:
612:
611:
606:
601:
596:
591:
586:
581:
576:
571:
557:
552:
547:
542:
537:
532:
530:Connecting rod
527:
522:
517:
511:
509:
500:
499:
490:
487:
486:
479:
478:
471:
464:
456:
449:
446:
433:
430:
393:
379:
374:
373:
360:
355:
354:
353:
344:
343:
342:
340:
337:
327:
324:
315:
312:
299:
298:
291:
290:(OHV) engine);
288:overhead valve
246:
245:
228:
227:
134:
132:
125:
118:
117:
72:
70:
63:
58:
32:
31:
29:
22:
15:
9:
6:
4:
3:
2:
1753:
1742:
1739:
1737:
1734:
1732:
1731:Engine valves
1729:
1728:
1726:
1711:
1708:
1706:
1703:
1701:
1698:
1696:
1693:
1691:
1688:
1687:
1685:
1683:Other systems
1681:
1675:
1672:
1670:
1667:
1665:
1662:
1660:
1657:
1655:
1652:
1650:
1647:
1645:
1642:
1640:
1637:
1635:
1632:
1630:
1627:
1626:
1624:
1620:and induction
1619:
1615:
1609:
1606:
1604:
1601:
1600:
1598:
1596:
1592:
1586:
1583:
1581:
1578:
1576:
1575:Glass cockpit
1573:
1571:
1568:
1566:
1563:
1561:
1558:
1556:
1553:
1552:
1550:
1546:
1536:
1533:
1531:
1528:
1526:
1523:
1521:
1518:
1516:
1513:
1511:
1508:
1506:
1503:
1501:
1498:
1497:
1495:
1491:
1485:
1482:
1480:
1477:
1475:
1472:
1471:
1469:
1465:
1462:
1460:
1456:
1446:
1443:
1441:
1438:
1436:
1433:
1431:
1428:
1426:
1423:
1421:
1420:Shock cooling
1418:
1416:
1415:Rotary engine
1413:
1411:
1408:
1406:
1403:
1401:
1398:
1396:
1393:
1391:
1388:
1386:
1383:
1381:
1378:
1376:
1373:
1371:
1368:
1366:
1363:
1361:
1358:
1356:
1353:
1351:
1348:
1346:
1343:
1341:
1338:
1337:
1335:
1331:
1325:
1322:
1320:
1317:
1315:
1312:
1310:
1307:
1305:
1302:
1300:
1297:
1295:
1294:Dual ignition
1292:
1290:
1287:
1285:
1282:
1281:
1279:
1273:
1267:
1264:
1262:
1259:
1257:
1254:
1252:
1249:
1247:
1244:
1242:
1239:
1237:
1234:
1232:
1229:
1227:
1224:
1222:
1219:
1217:
1214:
1212:
1209:
1207:
1206:Cylinder head
1204:
1202:
1199:
1197:
1194:
1192:
1189:
1187:
1184:
1182:
1179:
1178:
1176:
1170:
1167:
1165:
1161:
1156:
1155:piston engine
1153:
1146:
1141:
1139:
1134:
1132:
1127:
1126:
1123:
1111:
1108:
1106:
1103:
1102:
1099:
1093:
1090:
1088:
1085:
1083:
1080:
1078:
1075:
1073:
1070:
1069:
1067:
1063:
1056:
1052:
1048:
1045:
1043:
1040:
1038:
1035:
1033:
1030:
1029:
1027:
1023:
1017:
1014:
1012:
1009:
1007:
1004:
1002:
999:
998:
995:
994:Water cooling
992:
990:
987:
986:
984:
982:
978:
972:
971:Oxygen sensor
969:
967:
964:
962:
959:
957:
954:
952:
949:
947:
944:
943:
941:
939:
935:
929:
926:
924:
921:
919:
916:
914:
911:
909:
906:
904:
901:
899:
896:
894:
891:
890:
888:
886:Intake system
884:
878:
877:Starter motor
875:
873:
870:
868:
865:
863:
860:
859:
857:
851:
845:
842:
841:
839:
833:
827:
824:
822:
819:
817:
816:Ignition coil
814:
812:
809:
807:
804:
802:
799:
797:
794:
792:
789:
788:
786:
784:
780:
774:
771:
769:
766:
764:
761:
759:
756:
754:
751:
749:
748:Petrol engine
746:
744:
743:Diesel engine
741:
740:
738:
734:
728:
725:
723:
720:
718:
715:
713:
710:
708:
707:Blowoff valve
705:
704:
702:
700:
696:
690:
687:
685:
682:
680:
677:
675:
672:
670:
667:
665:
662:
660:
657:
655:
652:
650:
647:
646:
643:
640:
638:
635:
633:
630:
629:
627:
625:
624:Cylinder head
620:
616:
610:
607:
605:
602:
600:
597:
595:
592:
590:
587:
585:
582:
580:
577:
575:
572:
569:
565:
561:
558:
556:
553:
551:
548:
546:
543:
541:
538:
536:
533:
531:
528:
526:
523:
521:
518:
516:
515:Balance shaft
513:
512:
510:
505:
501:
497:
495:
488:
484:
477:
472:
470:
465:
463:
458:
457:
454:
445:
443:
439:
429:
426:
422:
418:
416:
415:cylinder head
411:
408:
401:
399:
377:
358:
339:Disadvantages
336:
334:
323:
321:
311:
309:
303:
296:
292:
289:
285:
284:
283:
279:
277:
273:
269:
265:
261:
257:
253:
242:
239:
224:
221:
213:
210:November 2014
202:
199:
195:
192:
188:
185:
181:
178:
174:
171: –
170:
166:
165:Find sources:
159:
155:
151:
145:
144:
140:
135:This article
133:
129:
124:
123:
114:
111:
103:
93:
89:
85:
79:
78:
73:This article
71:
62:
61:
56:
54:
47:
46:
41:
40:
35:
30:
21:
20:
1710:Recoil start
1669:Turbocharger
1664:Supercharger
1530:Single-blade
1440:Valve timing
1261:Sleeve valve
1246:Poppet valve
1221:Main bearing
1215:
1001:Electric fan
801:Coil-on-plug
727:Turbocharger
722:Supercharger
594:Main bearing
584:Firing order
574:Displacement
520:Block heater
504:Engine block
492:Part of the
491:
435:
427:
423:
419:
412:
404:
395:
329:
320:Cadillac V16
317:
310:adjustment.
304:
300:
280:
276:cam follower
259:
255:
251:
249:
234:
216:
207:
197:
190:
183:
176:
164:
148:Please help
136:
106:
97:
74:
50:
43:
37:
36:Please help
33:
1654:Intercooler
1580:Hobbs meter
1505:Blade pitch
1500:Autofeather
1493:Terminology
1400:Monosoupape
1360:Dead centre
1333:Terminology
1241:Piston ring
1211:Gudgeon pin
1025:Lubrication
989:Air cooling
806:Distributor
758:Fuel filter
736:Fuel system
717:Intercooler
684:Timing belt
674:Head gasket
604:Piston ring
438:valve-train
100:August 2007
1741:Valvetrain
1725:Categories
1644:Gascolator
1634:Carburetor
1585:Tachometer
1467:Components
1459:Propellers
1375:Horsepower
1340:Air-cooled
1319:Spark plug
1284:Alternator
1277:components
1275:Electrical
1256:Rocker arm
1196:Crankshaft
1174:components
1172:Mechanical
1077:Power band
1037:Oil filter
1011:Thermostat
956:EGT sensor
918:MAF sensor
913:MAP sensor
898:Air filter
862:Alternator
821:Spark plug
753:Carburetor
679:Rocker arm
619:Valvetrain
550:Crankshaft
494:Automobile
448:References
407:valvetrain
398:media help
326:Advantages
180:newspapers
84:improve it
39:improve it
1304:Generator
811:Glow plug
773:Fuel tank
768:Fuel pump
535:Crankcase
137:does not
88:verifying
45:talk page
1608:Throttle
1525:Scimitar
1231:Oil pump
1201:Cylinder
1191:Crankpin
1181:Camshaft
1152:Aircraft
1110:Category
1055:Dry sump
1051:Wet sump
1042:Oil pump
1006:Radiator
923:Throttle
783:Ignition
654:Camshaft
579:Flywheel
560:Cylinder
545:Crankpin
1484:Spinner
1324:Starter
1314:Magneto
1251:Pushrod
1082:Redline
966:Muffler
867:Battery
791:Magneto
442:pistons
314:History
194:scholar
158:removed
143:sources
82:Please
1622:system
1425:Stroke
1266:Tappet
1236:Piston
1105:Portal
893:Airbox
872:Dynamo
599:Piston
589:Stroke
568:layout
496:series
333:tappet
272:rocker
196:
189:
182:
175:
167:
1629:Avgas
1565:EICAS
1065:Other
689:Valve
659:Chest
432:Notes
201:JSTOR
187:books
1618:Fuel
1560:EFIS
1350:Bore
1047:Sump
564:bank
525:Bore
308:lash
173:news
141:any
139:cite
1032:Oil
621:and
506:and
274:or
258:or
152:by
86:by
1727::
1053:,
566:,
250:A
48:.
1144:e
1137:t
1130:v
1057:)
1049:(
570:)
562:(
475:e
468:t
461:v
440:/
400:.
241:)
235:(
223:)
217:(
212:)
208:(
198:·
191:·
184:·
177:·
160:.
146:.
113:)
107:(
102:)
98:(
80:.
55:)
51:(
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
