Subaru Engine >> NOISY VALVE LIFTERS

Subaru Engine >> NOISY VALVE LIFTERS

Noisy Lifters On
Subaru 1985-90 1.8L OHC Engines

AERA members have reported occasional lifter noises on Subaru 1.8L OHC engines. This condition may be noted before or after a valve job and may not be related to that service procedure.

A faulty lifter or varnish buildup may cause erratic operation and produce valve train clatter. Before blaming the lifter, verify that hot engine oil pressure is above 14 psi at 550 rpm. A high rpm reading should also show 57-65 psi. If the values are lower, consider this a possible cause.

To check for lifter reuse, put a clean lifter upright in a container of fresh (unused) light engine oil. Pump the lifter by moving the center plunger up and down. After doing so several times, replace any assembly that will depress more than .020
with light hand pressure.

If the oil pressure readings are normal and lifters are good, check the following:

1. Timing Belt Tension
A loose timing belt tensioner may allow the distributor
drive and driven gears to lash back and forth, sounding
like valve clatter.

2. Rocker Arm Oiling Tubes
Sludge contaminated oiling tubes or a sticky relief
valve may restrict the amount of oil to the rockers.

3. Installed Valve Stem Height
In order for the hydraulic valve lifter to operate in
the middle of its plunger travel, maintain an installed
valve stem height of 1.8430-1.8620 for all valves.

4. Aerated Engine Supply Oil
Low oil levels, or a leak at the pickup screen will
cause lifters to react erratically.

The AERA Technical Committee

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