piston slap in a 97 Legacy 2.2 ?

[Daryl]

Ever since I got this 97 Legacy with 2.2 engine, I have assumed that it has piston slap. Start it up when cold, it taps. The colder it is, the louder and more "hammer-like" the tapping is. After driving the car for 30 minutes at hiway speed, the tapping becomes much less noticeable, but still there a little bit. I've been reading a variety of Subaru forums, and now I'm wondering if what I have in this 2.2 is actually not piston slap at all. From what I read, I'm led to believe that piston slap is entirely within the domain of the 2.5 engine. If this is correct, what would the tapping in my 2.2 be? Maybe a valve badly out of adjustment? Or, did a few 2.2 engines have piston slap? Thanks. Daryl

[Plays_with_Toys]

Could be an exhaust leak where your header meets up to the motor. It could also be a sticky or out of adjustment lifter like you said. Your 97 shouldn't have HLA's (hydraulic lash adjusters), it should be shimmed.

Exhaust gaskets are cheap, and so are valve cover gaskets. I'd adjust my valves, and if it doesn't go away, then go on to the exhaust gasket.

Can you isolate a side of the motor that it is coming from?

[shazapple]

My car taps a lot when its cold. Always figured it was the lifters.

Put some lower weight oil in yoru car for winter

[badbasser98]

all scoobs "knock" when they are cold. The EJ25's are worse. This noise should pretty much go away once the engine is to temp. I have been told by the dealer that if the noise fades drastically but is still slightly noticeable, it is described as normal operation. I had piston slap bad on my BE. The knock was loud, even after it warmed up. Luckily, I still had the factory drivetrain warrenty on the car and got a new short block compliments of SOA. If the knock/tap does't completely fade after the car is warmed up, but fades significantly, I would not suspect piston slap, I would try a different weight oil like Lee suggests and see if you notice a reduction. The oil you are using might be a bit heavy to get pushed into the topend as good as it sould be.

[Daryl]

Last weekend, I changed the oil to 5W20 Mobil 1. The knocking became louder. The knock is definitely metallic, not a gaseous leak from the exhaust. I haven't heard of a metallic knocking from an exhaust system before, but maybe I have something to learn about that type of problem. The knocking seems to be coming from the rear section of the engine, but I have been fooled before by sound telescoping to another part of an engine. This morning, the car had stood outdoors all night, temperature 28F. Upon starting, the noise was so loud, I could hear it from nearly 100 feet away. Drove the car 30 miles at speed limit. At destination, the noise was still there, but reduced by 80%. Sounds like a small ball peen hammer tapping on a steel anvil. I don't know if this car has hydraulic lifters or not. I also have a 99 2.2, but it is a different engine, an interference type with adjustable solid lifters, a phase II. The 97 is a non-interference 2.2, but as I said, I do not know what type of lifters it has, as I don't have a manual for it. The local Subaru dealership service manager said it sounded like piston slap, but also acknowledged that piston slap occured only in the 2.5 engine. At least, that was his personal experience. He'd never heard of it in a 2.2 before. I called a second dealership, and they gave me the same story. I haven't called a third dealership service center yet, as I'm not convinced they have all of the correct answers either. There is a neighborhood mechanic who has served me well in the past, and I'm inclined to take the car to him to check the valve clearances. Does this car have mechanical, adjustable valve lifters? If so, to what clearances should the valves, intakes and exhausts, be set? Thanks to everyone who has replied!