Setright Posted February 21, 2006 Share Posted February 21, 2006 Ok, Blitz, I know I was quoting directly, but I still cannot see how you can increase stroke without changing the crank? Moving the wrist pin won't alter the stroke length. On that wheel: The Citroen Xantia Hydractive suspension uses the front wheel movement to "read" the road surface and adjust the rear suspension settings - both spring and damper. The "Activa" which also has added features such as anti-roll and anti-dive/squat has the most amazing ride quality I have ever experienced. Not only does the car remain flat in crazy cornering, but it really does iron out road irregularities. Of course, that car does have 11 of those not entirely reliable nitrogen gas spheres to make it all happen. And the ride is TERRIBLE when they fail. Quote Link to comment Share on other sites More sharing options...
blitz Posted February 21, 2006 Share Posted February 21, 2006 Ok, Blitz, I know I was quoting directly, but I still cannot see how you can increase stroke without changing the crank? Moving the wrist pin won't alter the stroke length. Again, quoted directly from my original post: ...then lengthen it's stroke by moving the crankpin further out from it's centerline so it swings a wider arc as it rotates. REPEAT: ...then lengthen it's stroke by moving the crankpin further out from it's centerline so it swings a wider arc as it rotates.Where am I saying that moving the wrist pin increases the stroke? What I'm saying is that after the stroke increase, the wrist pin (and the piston) will be higher up in the bore at TDC. The top of the piston will be poking up above the deck. At that point how would you get the piston crown back to a zero deck height? Simple, you fit a piston with a cut-down crown. The same thing happens at the bottom. The piston needs to be cut away at the bottom so it clears the crank and the block webbing. There's no room to spare in that dimension with the boxer ... duece and a quarter slant-six maybe, but a subaru boxer no man. The result is a piston shaped like kinda like a wafer ...very tippy in the bore. Quote Link to comment Share on other sites More sharing options...
Setright Posted February 22, 2006 Share Posted February 22, 2006 Oh my Lord! What was I drinking???? Sorry, I must have read it wrong to begin with, and then the blindness set in. Pardon me Quote Link to comment Share on other sites More sharing options...
blitz Posted February 22, 2006 Share Posted February 22, 2006 No prob. man. My rant is that Subaru literature plays up the piston design (cut-down crown/high ring pack position, trimmed skirt, and twin coatings) as being a deliberate ecological move when in fact it's just a result of pushing the otherwise excellent EJ platform beyond reasonable design parameters (to wit: more displacement). All the EJ-series motors (1.8, 2.0, 2.2) are based on a common 75mm stroke geometry and use the same connecting rod ...but not the EJ-25. http://www.drive.subaru.com/SubaruDrive-Sum02/Piston-Cranky.asp Regarding the "advanced" 2.5 piston; the fact that the piston used in the EZ-30 has it's ring-pack returned to a normal position away from the crown and has it's skirt length returned back to a normal length sums it up. Quote Link to comment Share on other sites More sharing options...
shaggywerewolf Posted March 14, 2006 Share Posted March 14, 2006 Haha...."stylish" pistons... "The result was an all-new piston with a pleasing shape and a stylish two-tone color." That's exactly why I bought a Subaru Friend: What's that sound? Me: Piston slap. Friend: What's that? Me: It's when the piston smacks around laterally in the cylinder because of how Subaru "redesigned" their pistons. It's normal. Friend: Oh. Me: But they're pretty.....oh, wait, no one can actually see them..... Quote Link to comment Share on other sites More sharing options...
donald893 Posted March 15, 2006 Share Posted March 15, 2006 Haha.... just a thought but isn't the ez30 basicly a ej 20 with 2 pistons added? i was thinking that each piston would be around 500cc's thus 4 would be a 2.0l (ej 20) and 6 would be 3.0l(ez30) Quote Link to comment Share on other sites More sharing options...
phil08075 Posted March 22, 2006 Share Posted March 22, 2006 I have a 2003 Outback/4cyl/auto with 42,000 miles. The piston slap noise started this winter and it's getting worse. Under warranty, the dealer replaced the timing belt tensioner and the nose remains. I now have an appointment with the zone rep coming up soon. And this car is a replacement for a 2002 that was returned as a lemon. I also have a 1995 Mazda 626 with 226,000 miles and that engine doesn't make a bit of noise. So Subaru has a big problem here. Back in the 60's, when I was in high school, only worn out engines had piston slap. My wife's '03 Forester with 46k mi started making cold start knocking noises this winter. Just took it to the dealer who, without prompting and on the 1st visit, said they would replace the left side pistons (from this forum and others I've learned the problem is always on the left, for some reason). phil08075 Quote Link to comment Share on other sites More sharing options...
Hank Roberts Posted June 2, 2006 Share Posted June 2, 2006 Ack. There are six topics mentioning piston slap in the list at the bottom of the page. How serious is this? We just got offered a 2003 Forester, does Subaru's warranty go with the car or end when the first owner sells it? Quote Link to comment Share on other sites More sharing options...
cookie Posted June 2, 2006 Share Posted June 2, 2006 can't say about the warranty but the piston slap is only an irritation. Many companies are having slap problems and my oil tests come up clean. If it goes away when warm it should be fine. Quote Link to comment Share on other sites More sharing options...
johnceggleston Posted June 2, 2006 Share Posted June 2, 2006 this is a long thread and i didn't read it from the beginning, so if i repeat , please frogive me . if you search, you can find a thread on how to diagnose piston slap. it has to do with shorting out the spark to the suspect cylinders, if the sound goes away , it's slap. if not then it's something else, rod, wrist pin, etc. Quote Link to comment Share on other sites More sharing options...
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