April 13, 201114 yr Any one have trouble with piston slap lasting more than 10min on an EJ22?, mine seems to do it for about 20min of driving and then it goes away, sometimes its still present after 30min but slowly goes away. At first I thought it was a rod knock but I'm pretty sure they do not go away and I would hear it at idle as well. This one seems to be only while accelerating I get the light tap,tap,tap in conjunction with acceleration but not while decelerating. New T-Belt job done by GD Fresh oil change Mobil 1 5w30 New OEM knock sensor new OEM plug wires and NGK plugs New(used)5MT with new Exedy clutch & TOB rebuilt OEM front axles New coil pack new battery I'm just stumped on this, I though piston slap only effected the ej25d but I might be wrong. And a rod would not go away and I'm sure it would tap,tap,tap at idle as well if that were the case. I'm just not sure how many miles I will get out of it with the slap. It just started 6 months ago, but it did it when it was cold before but recent months it takes a LLLOOOONNGGG time to dissipate. Hell I have even tried different grades of fuel to see what that might due, and nothing. please let it be piston slap and not a rod:eek: maybe it will lighten up as summer approches.
April 13, 201114 yr How many miles. Usually the 2.5 have it more then the 2.2. Sometimes playing with different oils helps. PS that lsats this lonmg is not a good thing.
April 13, 201114 yr I'm just not sure how many miles I will get out of it with the slap.piston slap doesn't hurt anything, typically benign and you just keep driving the car. why yours is lasting so long i have no idea. i think you should look into it a little bit more. sometimes it's suprising what else might be making that noise. what year is your EJ22? the timing tensioners can make a slap sound that's been mistaken for rod knock before. they're on the drivers side and can physically be seen to move if you have the cover off. yours only doing it under acceleration (under load) might make it harder to visually see or detect. the newer style tensioner (started around 1997) are known to fail and they make a slapping/knocking noise. was the oil pump removed and the rear backing plates tightened? GD may have done it with the Tbelt?
April 13, 201114 yr Excessive piston slap is not always harmless. What is happening is that the piston skirt is knocking aournd in the sylinder walls (short explination), Usually it goes away in a 5-10 minutes depending upon how cold it is outside.'Slap lasting longer then that may be scoring the pistons and the cylinder walls. But the question is is it lifters pumping up just (an FYI example), a connecting rod bearing, wrist pins, carboned psiton rings or actual slap. The wrist pin or small end or gudgeon pin knock is very distinctive. It is a double knock in time with revs. It may or may not go away as the engine warms up. A bad lifter makes a single knock in time with revs. I would use seafoam first and see if it is a carbon issue. Time how long the noise lasts and what the temp is outside. Another FYI I wold check (and make sue) the idlers are replaced with the timing belt, but since GD did the belt, I am sure they were. A tensioner can sound like slap too.
April 14, 201114 yr Author GD said the tensioner was ok, are you talking about the hydraulic thingy? I got the kit from Import experts. Its a 97 lego. Ive done the seafoam job through the intake. Should I try it in the oil? The oil pump plate was checked and all was well. am I right about the whole rod bit though? rod knocks get louder as things heat up in my experience.
April 15, 201114 yr I get the light tap,tap,tap in conjunction with acceleration but not while decelerating. Sounds like piston slap. II'm just stumped on this, I though piston slap only effected the ej25d but I might be wrong. And a rod would not go away and I'm sure it would tap,tap,tap at idle as well if that were the case. It just started 6 months ago, but it did it when it was cold before but recent months it takes a LLLOOOONNGGG time to dissipate. I've seen cracked piston skirts, but not in a Subaru. The sound made with them is the same as piston slap. The noise even goes away when it's warmed up. But some subarus don't even have "slapper skirts". The EJ as designed originally had piston skirts, don't know if your motor has them though. Here's a visual of some Subaru pistons. Two EA-82 on the left. An EJ-25, then a EA-81. Edited April 15, 201114 yr by Quidam Bigger picture.
April 15, 201114 yr Sounds like piston slap. Here's a visual of some Subaru pistons. Two EA-82 on the left. An EJ-25, then a EA-81. let's see, what is it i want to say, ummm .....WOW !!! no ''f***ing'' wonder.
April 16, 201114 yr Thank you for posting that piston picture people always thought I was nuts saying the EJ25 hardly had any piston skirts. from what I hear the skirt would hit the counter weights if they were longer on the Ej25.. I've never seen a Ej25 out and opened with the pistons at BDC but I'm sure it would be close.
April 16, 201114 yr Notice: "The piston pin is offset to eliminate piston slap. some one should have told the ej25 designer.
April 17, 201114 yr Thank you for posting that piston picture people always thought I was nuts saying the EJ25 hardly had any piston skirts. from what I hear the skirt would hit the counter weights if they were longer on the Ej25.. I've never seen a Ej25 out and opened with the pistons at BDC but I'm sure it would be close. Never said they dont have skirts, just that are extreemly short as are most modern engines compared with older pistons. And another cause http://en.wikipedia.org/wiki/Hypereutectic_piston
April 17, 201114 yr Thank you for posting that piston picture people always thought I was nuts saying the EJ25 hardly had any piston skirts. from what I hear the skirt would hit the counter weights if they were longer on the Ej25.. I've never seen a Ej25 out and opened with the pistons at BDC but I'm sure it would be close. Hi. YW. Boxer Diesel
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