Change camshaft

From TechWiki
Jump to: navigation, search

This method is for changing the camshafts without replacing the cambelt. It is possible to just loosen the cambelt tensioner to slide the belt off the camshaft pulleys without loosening the crankshaft bolt. With a few additions to this procedure, you could also replace the cambelt, tensioner and waterpump but these extra steps are left out.


Special tools

  • Low range torque wrench (10NM for cam carrier, cover etc)
  • High range torque wrench (65NM for pulley bolts etc)
  • 22mm offset ring spanner or cut-down 22mm socket to turn crankshaft


Parts List

  • Camshafts (I used MGTF 135 camshafts)
  • 2 x LUC100220 red/brown rear camshaft seals
  • 2 x LUC100290 black front camshaft seals
  • NJJ10001L or NJJ10001 – drive spindle if your camshaft doesn't have one
  • Camcover gasket
  • Rover K16 CAMLOCKING tool
  • Loctite 574 or OEM Rover liquid gasket LVV000108EVA (or another anaerobic sealant *not* silicone, hylomar or wellseal).
  • Cellulose thinners or acetone/nail polish remover


Optional

  • Pair of vernier pulleys


Preparation

  1. Remove the diffuser and undertray
  2. Loosen rear wheel nuts
  3. Jack up the car and put the rear on axle stands underneath the engine subframe – jacking points D.
  4. Remove RHS rear wheel
  5. Remove RHS rear arch
  6. Remove engine cover
  7. Disconnect battery (important to avoid any risk that the starter is engaged while this work is being carried out)


Camshaft replacement

  1. Remove spark plug cover, spark plugs and camshaft cover.
  2. Remove upper outer timing belt cover; it is held in with 5 M6 bolts, + 1 hidden behind the oil dipstick tube
  3. Turn crank clockwise with 22 mm offset ring spanner or cut-down socket to align engine to 90 BTDC so that the cam pulley marks line up. Insert camshaft locking tool to hold the pulleys. (At BTDC, the crankshaft is ‘flat’, 90 from vertical, and all pistons are at the middle of their stroke. In this position, there is no risk of piston contact with the valves, and the camshafts can be turned freely). Lock the flywheel with a large screwdriver or allen key slotted into the hole in the gearbox just in front of the RH drive-shaft.
  4. With the cam locking tool holding the pulleys, loosen both 17mm bolts holding the pulleys onto the cams. Make sure both bolts are loose before removing a pulley or belt otherwise you won’t be able to loosen the other pulley.
  5. Loosen cambelt tensioner, slide the top of the belt off the pulleys.
  6. Remove the pulleys; rock them back and forth and they should come loose.
  7. Loosen cam carrier bolts in order shown in service manual. Remove all the carrier bolts. Lift carrier off the head while holding the camshafts against the head so they don’t fall out of the carrier when you are lifting the carrier.
  8. Remove old camshafts;
  9. Clean off old sealant from cam ladder and head with cellulose thinners or acetone; make sure top-end is meticulously clean.
  10. Remove the followers with a magnet and inspect/planish to remove all visible wear marks. Use wet/dry 180 with WD40, then finish with wet/dry 240 against a glass plate or other flat surface.
  11. If fitting symmetrical camshafts (eg MGTF135 or VVC EX), choose and mark one camshaft as intake and one as exhaust.
  12. Fit the new dizzy drive spindle part NJJ10001L in the end of the new intake camshaft, using the same angle as the original camshaft as a guide (mine was about 14° from vertical). It helps to put the new spindle in the freezer before trying to fit it. Once it is snug on at the correct angle, tap it in against a wood block until fully seated.
  13. If fitting vernier pulleys, choose and mark one pulley as intake and one as exhaust. Carefully match new intake vernier to original intake pulley, mark 90 BTDC point. Repeat with exhaust pulleys.
  14. Fit new cams with new oil seals at each end; red seals go to the back of the engine, black seals towards the front (behind the pulleys). The cams should be more or less positioned so that the cam lobes on cylinder one point in a downwards v-shape towards each other.
  15. Put Loctite 574 or Rover Part # LVV000108EVA onto the clean cam carrier; Make a thin line, then smear wide and thin with your finger. You have 20 minutes to install and torque the ladder into place before the gasket material sets.
  16. Progressively tighten the carrier bolts in order and torque as per manual to 10NM. As you tighten down the cam carrier the last 1-2mm onto the head, check again that the seals are square in their bores.
  17. With the crankshaft still blocked at 90 BTDC, fit pulleys and rotate the camshafts to match the 90 BTDC marks and refit cam locking tool. Torque pulley bolts to camshafts to 65 NM
  18. Fit cambelt over camshaft pulleys. Pull the belt up tight on the exhaust side, around the exhaust pulley, about half width. Remove the pulley locking tool and turn the intake pulley ½ a tooth clockwise and feed the belt onto the intake pulley, about half width. Feed the belt over the tensioner, if it doesn’t fit, turn the intake counter-clockwise a few degrees to pull the slack over to the tensioner. Re-check that the pulley marks are aligned. Adjust cambelt tensioner to correct tension mark. The manual tensioner adjuster nut should be tightened to 10nm and the main M8 hex bolt in the pulley to 45nm.
  19. Remove pulley lock and remove flywheel locks. Turn crankshaft two full revolutions clockwise back to 90 BTDC. There should be no ‘clicks’ or fouling of the valves on the pistons. Recheck that the pistons are at the same height, and that the timing marks line up on the pulleys. If there is a problem or doubt, ensure that the engine is at BTDC by rechecking piston heights are equal; then carefully check that the belt is properly fitted and that the pulleys are in the correct positions. On the non-firing strong at TDC, the camshaft lobes nearest the pulleys should be pointing in a downwards v-shaped towards each other; the intake is just about to open and the exhaust is just closing.
  20. If you are going to time the camshafts; now is a good time to do it; see DVA Power excellent guide or the MGTF forum instructions.
  21. Refit sparkplugs, distributor rotor and cap, cam cover with gasket, cambelt cover, wheel arch, reverse preparation steps.