Subaru ring land failure explained. Applies to all pistons. Ej25 and others.
ฝัง
- เผยแพร่เมื่อ 22 พ.ย. 2024
- This video is a quick run down on the highly misunderstood Subaru ring land failure, and how under the right circumstances any cast piston car could suffer the same fate!
Actually regardless of how it's discussed, it's a design flaw from the factory.
Appreciate the new camera orientation and resulting aspect ratio. Good info, thanks!
Boken Ring Lands on my EJ where no where near the ring gaps, the rings and wall's were immaculate. I think this is going to be a tough sell.
There is lots of literature on these failures available, check out multiple articles from hot rod magazine, episodes by engine masters, or simply read "engine failure analysis". This is not new information on cast piston engines. There are other ways it can happen of course, detonation for instance can knock the lands out. As i said "typically" this is the failure i see. Thats out of about 325 subaru engines i have built since 2008.
Thanks for the upload. Maybe you can help with my current problem. I have 2015 sti with 52k miles on the engine but I'm experiencing heavy oil consumption coupled with a burning oil smell. I have removed the intercooler only to find excessive amounts of fresh oil dripping from the turbo turbine outlet, Intercooler an inside of the throttle body( and in the intake manifold). My car runs smooth at idle and even into boost until on my access port I see the DAM suddenly start to drop towards zero. When it hits zero, the boost drops to 10 psi or less and will drastically reduce power coupled with an immediate oil burning smell. My cusco oil catch can fills up within about 80 miles but my engine still consumes oil. Also, when I get into boost, my fine spark knock jumps to about 13 on my Cobb access port. Does this seem like I need a motor? Pistons gone or what? Any of your expertise is more than welcome and thank you!
I would the a compression test ASAP, but more than likely a rebuild.
with as much boost as you import guys need to run ring gap would be a very common failure. Most attribute broken pistons to weak cast units and think you need forged. Most properly designed cast pistons are very strong. Its not the cast that failed it was the ring gap
Thanks for the informative video. Is there anyways of reducing the risk without taking the engine apart. For example, installing colder spark plugs to remove excess heat, getting your car custom tuned to remove knock etc. Your advice would be appreciated 👍
So its not because the piston has higher silicon content?
happened to me on all 4 cylinders on my turbo converted ford. i didnt change stock gap and cracked multiple lands on all cylinders. wont ever overlook this again
Very informative
Vw has the same problem broke ringlands twice on mine
Dont the rings rotate?
Question if you have a piston ring problem already but still runs fine just burns oil what ways you should do to make it last and what things you need to put on the engine if it’s possible
What does the gap need to be set at?
New owner here of a leftover 2018 STi limited. I have no plans tuning or modifying my car beyond a cat back exhaust. Is ring land failure anything I should be worried about?
Spend money on forged pistons to avoid ringland failure
Yes. Any time your pistons get hot. It's especially bad after cruising on the highway (leaner maps for mpg), rings are hot already and people go wot in 6th. Most common scenario in my experience. Local autoX guy blew up 4 motors that were all factory (tune too). My local builder regaps the rings on factory shortblocks and he hasn't seen one failure since, some are running 400whp.
Easy fix why not just put forged slugs from the factory
Not correct it's how the Subie motor is designed and physics. The Air Fuel mixture pools at the bottom of the combustion chamber and causes piston to have uneven firing to one side in the combustion process. Remember the engines rings go side to side. Gravity makes it pool at the bottom from uneven firing. More combustion force at the bottom cause knock slap and tons of other problems it's the design of the Flat Motor and gravity
Both apply...
pooled fuel does combust nearly as well as atomized fuel so this "uneven explosion" being higher on the pooled don't sound right. Now you could could have an argument about ring lift being caused be pooling fuel.