Piston slap...What's the only way to fix it???

[driver_nick]

Hey guys,

I've been reading about piston slap all over the subby boards and it seem, that the ej25 is really bad.

Mine is really loud, even inside the cockpit, you could hear it. The car runs fine and the power is there. Also, there is an oil leak behing the engine where it connects to the the transmission though.

I have a 99 Outback Limited Edition / 110K miles / 55K on new motor.

I was wondering if there is anyway to fix it besides replacing pistons and thicker oil. I'm even considering selling it because it's driving me nuts. Today I'm going to use 10W-40 in it and let's see what happens.

I also have an 04 Sti and it's got a ej257 also. It has 31K miles on it. Will it start to do this on the STi also? If so, I'm starting to look away from Subarus.

Please help me come back to the Subby side... I love the AWD, and the boxer motor sound, but this knock/slap/rod bearing bad is driving me nuts.

Can I just open up the motor and put in new pistons and rod bearings myself or do I have to have anything machined. I just want my Outback to be a good daily driver. No performance or anything. That is the STi's job.

Thanks.

[d1giPhux]

I have a 1999 subaru legacy gt 2.5L.. doesnt seem to have piston slap. Some of the subarus do it. and some dont. When i pass subarus in traffic.. i generally hear piston slap.. its pretty common. Seems like thicker / better brands of oil are the only way to fix it.

Also, if you plan on doing the work yourself.. i have the factory service manual.. which you can download out of my signature if you would like.

[driver_nick]

Cool, thanks for the download. I'll be doing everything myself. I'm kind of new to Subarus, but I'm an awesome Honda Mechanic. I do all the work on Honda's but I don't do transmission work except replacing it.

[Huffer]

TWE (Techworks Engineering) make piston kits that have sleeves designed to eliminate piston slap.

The major issue is that the cylinder walls are too big for the pistons even when they're hot and fully expanded.

If you use Mobil Delvac (a diesel oil) the problem goes away. Up to you if you want to try using a diesel oil - even if it does meet the API specs for gasoline engines.

[LegacyRob]

I've had new pistons and a new short block and I still have slap. I've given up trying to cure it.

[Huffer]

I've had new pistons and a new short block and I still have slap. I've given up trying to cure it.

That's because the factory gear has too big of a tolerance.
TWE makes a set that reduces the gap and quiets the motor.

[d1giPhux]

I think the 'subaru slap' is kind of a unique sound to subaru owners. :lol:

[driver_nick]

Mine is really loud. I'd say, it might be louder than a deisel.

I love the Limited Outback with the heated seats, wiper, side mirrors, awd and all for winter, but it's driving me nuts. I want a daily driver. I don't need power.

I'm new to Subaru's, so is it possible to swap in a ej22 or something smaller or in fact, any other engine in there that wouldn't slap. Therefore, I can still keep the car as a daily driver.

If I can swap another motor in there. Where would I purchase one and how much should it run?

The Outback's body is great, but the motor is shitty like that. It runs fine though.

Thanks.

[LegacyRob]

Mine is really loud. I'd say, it might be louder than a deisel.

I love the Limited Outback with the heated seats, wiper, side mirrors, awd and all for winter, but it's driving me nuts. I want a daily driver. I don't need power.

I'm new to Subaru's, so is it possible to swap in a ej22 or something smaller or in fact, any other engine in there that wouldn't slap. Therefore, I can still keep the car as a daily driver.

If I can swap another motor in there. Where would I purchase one and how much should it run?

The Outback's body is great, but the motor is shitty like that. It runs fine though.

Thanks.

So why not pick up one of those piston kits to quiet the motor, definately gonna be cheaper than a whole motor swap.

[Lemanschamp]

It won't automatically be cheaper. ever pull a EJ motor out of a car and then take it apart bolt by bolt, seal by seal?

The only way to truly solve the problem is to either get smaller diameter cylinder sleeves, or larger diameter pistons. And out of those choices, cylinder sleeves would be simpler IMHO.

[LegacyRob]

It won't automatically be cheaper. ever pull a EJ motor out of a car and then take it apart bolt by bolt, seal by seal?

The only way to truly solve the problem is to either get smaller diameter cylinder sleeves, or larger diameter pistons. And out of those choices, cylinder sleeves would be simpler IMHO.

Wouldn't you still have to take the pistons out in order to get the sleeves in?? Which means having to unbolt and reseal everything as well.

[driver_nick]

All this info is great. Thanks.

Sounds like getting the pistons is good, but I don't know if it's piston slap. What if it was the bearings or something else. I'll post a video on youtube to be more clear. Does the kit come with everything. I'll have to check it out.

Also, does the 2.2L motors have the same problem? It it doesn't, swapping my EJ25 for an EJ22 will be quicker.

I live in Wisconsin and the winter is comming. For the time being, should I use 10W-40 or 5W-30? It snows over here and gets to -5 sometimes.

[MCarp22]

Also, does the 2.2L motors have the same problem?

Mine does. You don't want a 2.2 anyhow, trust me.

[subba]

i have the slap, it is driving me nuts, i was almost gonna dish out a fork load of cash to rebuild my engine because i thought it was a serious problem.

One of my buddies legacy have it also, i thought it was a NA thing but his is a TT, so it is a subaru thing, i am gonna try the oil u guys recommend.

[driver_nick]

Well, here's the video:

http://www.youtube.com/v/7NVjR4CYrCw

I've tried the 10W-40 and it's still making noise. The video is with 10W-40 @ 45 degree F outside. Notice car is not warm yet.

[2.5GT]

That's exactly how mine sounds, but less noisy like yours tho.

Im running Torque 10W-30 now, gonna switch over to Castrol 5W-50..see what'll happens.

[Sarra]

Get a block that isn't a bitch?

Wow, mine isn't that bad after all...

[subba]

Get a block that isn't a bitch?

Wow, mine isn't that bad after all...

Same here. that sounds pretty bad

[Sarra]

The Loyale has really bad slap. :lol: I think one of the rods isn't happy. It's not running, so I don't really care atm.

If it was slapping that bad, I would probably try some aftermarket pistons and rings.

[Jedi Taxi]

TOTALLY UNRELATED!!!

If you don't mind taking draining the oil and taking off the oil pan, removing the sump, and getting to the crank shaft, you can knife the crankshaft without even taking the crank out of the engine. Note: be careful of metal shards. suggestion: use a dremel and put the crank in a position so that the dremel always puts the metal downwards away from inside the engine. old hot rodder trick of the day.

(sorry for the unrelated-ness for those who get pissed)

[Sarra]

TOTALLY UNRELATED!!!

If you don't mind taking draining the oil and taking off the oil pan, removing the sump, and getting to the crank shaft, you can knife the crankshaft without even taking the crank out of the engine. Note: be careful of metal shards. suggestion: use a dremel and put the crank in a position so that the dremel always puts the metal downwards away from inside the engine. old hot rodder trick of the day.

(sorry for the unrelated-ness for those who get pissed)

I saw the 'unrelated' thing there... But I still want to know, what does that even have to do with this thread?

[MCarp22]

you can knife the crankshaft without even taking the crank out of the engine.

WTF? Just hacking a bunch of weight off the carefully balanced crankshaft isin't the best idea.

[Jedi Taxi]

meh, i'm not going to go into it. no since in making a huge post nobody will read.

[Jedi Taxi]

(in responce to mcrap22, sorry for double posting)

carefully balanced my ass. have you even blananced a prop before? no? then GTFO. more so, have you seen the amount of casting flash on a crankshaft? casting flash is not carefully balanced. granted its not a good idea for the casual weekend mechanic. I simply stated it because i was bored. so get off my ass, editorial prick.

[MCarp22]

I don't need any credentials to read something and think "wow, that sounds like a really bad idea that would end in tears."

[Jedi Taxi]

you co signed one book and you call that credintials? where is the materialisc cup from race sieres you have won. This would only end in tears if it wasn't carefully calculated properly. balancing requires that. How about an acutal tuned ITB set That you designed yourself. or mabye incorperate how you actually took parts from other cars, did the math and time to make them make your car faster. acutally, lets take this off this topic, and just PM eachother. even better, i'll just go take a breather before i get pissy.

[MCarp22]

you co signed one book and you call that credintials?

What part of "I don't need any credentials" implies that the book is involved here? Clearly I've never balanced a prop before.


This would only end in tears if it wasn't carefully calculated properly. balancing requires that.

Where's the careful calculations in: suggestion: use a dremel and put the crank in a position so that the dremel always puts the metal downwards away from inside the engine. ??


How about an acutal tuned ITB set That you designed yourself. or mabye incorperate how you actually took parts from other cars, did the math and time to make them make your car faster.

How is this relevant to hacking metal off the crankshaft with a dremel?

[Jedi Taxi]

(Mcrap22)

PM sent, now let this poor argument leave this thread. and let the entire thing resume it's topic.

[driver_nick]

LOL...you guys are incredibly funny...

Well, I sold the car. I was asking for $4500, but ended up selling it for $3700. I guess the price is okay.

Oh well. I'll stick with a Honda for my daily driver. I wanted the AWD though. But I can't spend that much to get a newer 2000 up Subby with a different motor.

I figured if I get anything 99 and down, it'll probably have the same thing.

Thanks for all the help and comments guys. I still have my STi though.

[2.5GT]

LOL...you guys are incredibly funny...

Well, I sold the car. I was asking for $4500, but ended up selling it for $3700. I guess the price is okay.

Oh well. I'll stick with a Honda for my daily driver. I wanted the AWD though. But I can't spend that much to get a newer 2000 up Subby with a different motor.

I figured if I get anything 99 and down, it'll probably have the same thing.

Thanks for all the help and comments guys. I still have my STi though.

You could of sold it for more, winter season is here :grin:

[badbasser98]

I had bad piston slap in my BE when I bought it. Luckily it still had the drivertrain warranty. So SOA replaced the block and that fixed the problem. They said the number 2 cylinder was out of round.

[miatapaul]

I know he has sold the car, but that sounds like more than just piston slap. Sounds like some valve noise in there as well.

PS I have still not figured out why there was a suggestion to lighten the crank, with a Dremmel no less! :roll:

[Jedi Taxi]

I know he has sold the car, but that sounds like more than just piston slap. Sounds like some valve noise in there as well.

PS I have still not figured out why there was a suggestion to lighten the crank, with a Dremmel no less! :roll:

i'm not going into it, i could explain it, but few here would understand and most wouldn't care. don't knock the dremel, lots can be gained by using it to modify parts on a car for better performance

[subba]

5 30w Cleared mine up significantly. a very small amount of slappping goin on but its more than likely wear.