How to avoid piston failure

[Daz-RSK]

I thought I would have a look at this ring land issue that some of you have been mentioning on here. Not surprisingly, this is all a bit new on me. Perhaps I have been blessed with motors where this type of failure can't be easily attributed. So having not really come across the term, I thought I would have a look.

Funny what you find when searching the internet. The first site on the net links to our lot - Subaru's with the 2.5L lump. That's why it has bypassed me as I have only had 2.0L lumps.

OK, don't tell me - they're prone as well and I have been ignorant of this.

It may pay all of you to look at this if you don't know what this issue is or how it affects your motor. They seem to isolate the 2.5L Scooby lump as being a sucker for this - in stock form as well. But then go on to say all Scooby lumps. I don't know whether it is hype or not and I make my apologies if this link or others have been placed up previously. If it is not hype, then probably is worth flagging up every so often anyway.

Hmmmmm.........another thing to keep an eye on. As you read through, you can see there is a swipe at Subaru's short cutting as well.

https://www.maperformance.com/blogs/maperformance-blog/77034371-how-to-avoid-piston-failure-subaru-performance-tips

 

[Tidgy]

2.0 are fine on the main, 2.5 swapped to crappy pistons as well as some other shortcuts, such as head studs, map etc. but not everyone one fails. It's just a higher percentage than other engine types get

I hear lots of reasons for failure sprouted on the 2.5's but simply put i don't think there is a single cause, some blow head gaskets, some blow ring lands. standard and moded 2.5's fail, block flexing etc etc but there doesn't seem to be a hard or fast rule. just case of your lucky or unlucky.

[savage bulldogs]

Quite a good write up on the main issues with 2.5 ltr failures and as tidgy said "luck" seems to play a big part .

I'm always taking my scoob to bits (out of choice) but if I add anything that changes fueling or air flow , I head for the dyno to check everything running ok before using boost .

Even if you haven't added any mods on a standard scoob , I'd suggest a annual dyno run .

As £50 dyno run can diagnose issues and save you a fortune in the long run . It also gives you piece of mind when you do give it the big "bwaap stu" too [emoji6]

[Steven252]

Just install a wideband gauge, save you on dyno time. 

[savage bulldogs]

Afr gauge is a good idea for any turbo car (it's on my list of things to fit) but it won't tell you if your getting det or knock (somtimes caused by exessive oil vapour from the breather system) or if there's a timing/electrical issue .

[Seminole81]

6 hours ago, savage bulldogs said:

Afr gauge is a good idea for any turbo car (it's on my list of things to fit) but it won't tell you if your getting det or knock (somtimes caused by exessive oil vapour from the breather system) or if there's a timing/electrical issue .

Volt gauge? I've got fuel pressure, oil temp, water temp in 3 hood in the centre console where clock was, and a boost and oil pressure on the a pillar...want a wideband AF gauge but yeah...think the Apexi Trubi Timer can do it if I set it up?

[savage bulldogs]

I'd imagine most electrical faults would flash up a eml anyway but any flat spots or blips in the graph can show any underlying issues (misfire, air leak ,timing ect) plus det and knock can be heard through "det cans " by the mapper .Those main things and or sudden drop in oil pressure would probably be the main cause for any turbo cars engine to eat itself.

Knock can also be monitored by the ecu (Bluetooth interface might work on newage to read it ) or aftermarket stuff like , a old skool "knocklink" ,apexi fc ecu or toucan ect . Don't think a turbo timer would monitor any engine parameters though ,bud .

It's also a good excuse to tell the Mrs that a trip to the dyno is best for the scoobs health ....... and if you accidently end up getting a map tweek while your there ,who's to know [emoji55]