So yeah... I now know for sure that my EJ22 has piston slap. I know that this may be "acceptable" during warmup, but it is getting to the point where it takes a lot of warm-up to go away. Actually I think I can hear it faintly all the time.

So how long can I play this out? I'm not too eager to be swapping engines anytime soon. I know that this is supposed to cause minimal damage to the engine, but I don't think an engine with full blown metal to metal impacts is going to last forever.

Hi there,

Piston slap in modern engines is often caused by deposits on piston heads in emissions reducing engines that have a piston clearance of less than 1mm at top dead center. It likely is not caused by metal to metal impact.

It may be a little pricey for an additive (~$10), but the first thing I would do it add a bottle of Chevron Techron to your next fill up. It does wonders for removing deposits fuel injector AND piston head deposits. If possible, fill up with Chevron Supreme too.

Repeat if it still doesn't go away.

You should notice your piston slap disappearing and more power since your engine probably has been retarding the spark to compensate for the increased compression too.

Check this link out for more info:

http://www.chevron.com/prodserv/fuel...rgas/ch6.shtml

Hmmm... that is an interesting thought. I have never heard anybody say that before. I might as well throw in some Techron anyway... the thing has enough miles to justify it and I'm always hearing people talk about how awesome it is. Plus my driving style is 95% grandma / 5% fast so that would contribute to carbon deposits.

I'll bump the thread when I get around to doing it. (if I can remember)

This is not correct at all. First off, I haven't heard of too many EJ22's having piston slap, but it's possible...

Piston slap in Subarus is when the piston skirts are too short, and the ring of the piston goes slightly below it at BDC. When the engine warms up, the skirt expands and the sound goes away. It does not really do any damage, this is correct... But no additive or any other "easy fix" will do anything about it. The only solution is to tear down the engine and replace the piston skirts...

Yeah, this is why I was confused. I haven't really heard about it in the 2.2... just on the EJ20T and EJ25. Heck, seems like the only thing I ever hear about the EJ22 is how bulletproof the thing is and how it lasts forever.

But, yeah, I'm really not feeling like tearing it apart and replacing the pistons. So we'll see how long she lasts.

How long did the engine end up lasting after you started hearing the piston slap?