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Hyundai Coupes/Sedans 1986-1993 Repair Guide

Jet Valve



1468cc And 2351cc Engine

See Figures 1 through 5

The jet valve clearance is normally adjusted with the engine stopped and at normal operating temperature. However, after the engine has been rebuilt or a valve job done, the valves should first be set and adjusted with the engine cold. The basic procedure is the same, hot or cold, the only differences being the engine temperature and the jet valve clearance setting. The cold setting is 0.007 in. (0.17mm). The hot setting is 0.010 in. (0.25mm).

  1. Start the engine and allow it to reach normal operating temperature.
  3. Turn the engine off and disconnect the negative battery cable. Remove the air cleaner. Disconnect the large crankcase ventilation hose from the front of the air cleaner. Disconnect the smaller hoses from the rear of the rocker arm cover and the intake manifold.
  5. Loosen and remove the nuts and bracket which secure the air cleaner to the rocker arm cover.
  7. Lift the bottom housing of the air cleaner off of the intake, with the hose from the exhaust manifold heat stove attached.
  9. Unsnap the spark plug wires from their clips on the rocker arm cover.
  11. Remove the rocker arm cover bolts.
  13. Carefully lift the rocker arm cover off the cylinder head. Using a 5/16 in. (8mm) Allen socket and a torque wrench, torque the cylinder head bolts. Turn each bolt, in sequence, to specifications. After the first bolt, in sequence, has been torqued, move on to the second one, repeating the procedure. Continue, in order, until all the bolts have been torqued. Make sure the cylinder head bolts are all tightened, in sequence, to specification.
  15. Remove the spark plugs.
  17. Remove the distributor cap.

A crankshaft pulley access hole is located on the left side frame member. Remove the covering plug and use a ratchet extension to turn the crankshaft when adjusting the valves.

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Fig. Fig. 1: Intake and Exhaust valve clearance adjusting sequence-1990-93 Excel

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Fig. Fig. 2: Align the camshaft and cylinder head marks for jet valve adjustment-Sonata

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Fig. Fig. 3: Adjust these jet valves first

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Fig. Fig. 4: Adjust these jet valves second

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Fig. Fig. 5: Adjusting the jet valve-Sonata

  1. Rotate the crankshaft until the No. 1 cylinder is at TDC of the compression stroke. Turn the engine by using a wrench on the bolt in the front of the crankshaft until the TDC or 0 timing mark on the timing cover lines up with the notch in the front pulley. Observe the valve rockers for No. 1 cylinder. If both are in identical positions with the valves up, the engine is in the right position. If not, rotate the engine exactly 360 degrees until the TDC or 0 degree timing mark is again aligned. Each jet valve is associated with an intake valve that is on the same rocker lever. In this position, adjust No. 1 and No. 2 jet valves, which are located on the rockers on the intake side only.
  3. To adjust the appropriate jet valves, first loosen the regular (larger) intake valve adjusting stud, by loosening the locknut and backing the stud off 2 turns (1468cc only). Now, loosen the jet valve (smaller) adjusting stud locknut, back the stud out slightly and insert a 0.010 in. (0.25mm) feeler gauge between the jet valve and stud. Make sure the gauge lies flat on the top of the jet valve. Being careful not to twist the gauge or otherwise depress the jet valve spring, rotate the jet valve adjusting stud back in until it just touches the gauge. Now, tighten the locknut. Make sure the gauge still slides very easily between the stud and jet valve and they both are still just touching the gauge. Readjust, if necessary. Note that, especially with the jet valve, the clearance must not be too tight. Repeat the entire procedure for the other jet valves associated with rockers labeled No. 1 and 2.
  5. Turn the engine exactly 360 degrees, until the timing marks are again aligned at TDC or 0 . Perform the adjustment procedure for all the jet valves on rockers labeled No. 3 and 4, intake side only.

Loose valve clearances will result in excessive wear and valve train chatter; tight valve clearance will result in burnt valves.

  1. Apply non-hardening sealer to the rocker arm cover gasket. Always use a new gasket.
  3. Install the cover, hoses, spark plug wires and the air cleaner in the reverse order of removal. Tighten the rocker arm cover bolts to 48-60 inch lbs. (5.4-6.7 Nm)
  5. Start the engine and check for leaks. It's best to install new gaskets and seals wherever they are used and to observe torque specifications for the cam cover bolts.