Wrx valve adjustment

Getting ready to replace the timing belt on an’02 subaru wrx with roughly 102,000 that runs well. my mechanic insists I need to have the valves adjusted although they are not making appreciable noise. Any thoughts about his recommendation?

What does your owner’s manual say? While they’re working on it, they can measure the gap pretty easily, maybe they don’t actually need adjusting.

They should be adjusted every 30k miles at most even though this practice is not recommended and is seldom done.

People are under the perception that mechanical lifters can be inspected audibly and this is very bad information. Even the factories make what I consider idiotic recommendations about extended valve lash inspections and “audible” inspections. The former is horrible and the latter is downright laughable.

A valve that is way loose and out of specs can be detected with the ears but the quiet ones are the ones that really cause damage the fastest. (burned valves) There is no way on Earth for anyone to determine by listening if a valve is too tight.

Your mechanic is spot on for even making this recommendation.
The majority will luck out and not have a problem with ignoring this procedure. The minority will discover the hard way why it is important; after the fact.
The purpose of the valve inspection is to assure that you remain a member of the majority.

The valves get inspected at 105k miles on a 2.0L WRX.

There is no need for the inspection more often as it is very rare with WRX’s to have issues with their valves. The EJ20 (2.0L) is a very reliable/low maintenance Subaru engine despite its turbo. The only exception is it requires timely oil changes.

While they’re in there, they should measure the valve clearance. It’s time and they’ll have it apart anyway. You can’t tell anything by listening.

In the days when almost all cars had mechanical lifters I never saw valves wear too tight, the only ones I saw that caused problems were those that were adjusted too tight in an effort to make the engine really quiet.
Although on second thought, on an engine with aluminum heads, they could get too tight by overreving the engine and pounding the seats deeper into the head.

Just based on my dealership experience with foreign makes of cars (with the majority using mechanical valve lifters) my rough guesstimate would be that about half of the ones I’ve inspected needed to be adjusted; and that includes both screw/locknut types and shim type adjusters.

I’ve also run across a number of engines that had already suffered damage either due to not inspecting them regularly or they were caught at the last minute and damage was prevented.
Usually overly tight adjustment from the factory when new, normal stem stretch (exhaust), or overheating episodes causing stem stretch is the usual cause.

The gentleman who brought his 7000 miles Subaru in to our shop no doubt wished the valves were adjusted correctly after finding out that both cylinder heads were so far gone due to this that they were not even repairable. It wasn’t just the valve heads that were gone; the seats and chunks of the aluminum head were also missing in action.
The same could be said for the lady who posted on this forum a few months ago who was facing a 3000 dollar repair bill on her Subaru for this little oversight.

This is only 2 examples and neither of these people were aware this kind of damage could be caused by ignoring the lash adjustment. Imagine how many more out there who are suffering the same problems and may not even be told by the shop that failure to inspect the lash was behind this. They’re simply told you need engine work, sorry. Pony up.