Just do rings?

[BAC5.2]

Well, I think the Forester might have blown a head gasket. This summer, I intend to pull the motor and completely reseal it.

And I was thinking, why not do rings too!

Is this a generally good idea? To pull the slugs, put new rings on, and drop them back in? Or will I run into problems?

Is there any problem with just replacing the rings on stock pistons?

The car's got 141k on it, and I expect to drive it until the headgasket issue further makes itself known. In 2 weeks, the Legacy will be back on the road (just in time for registration and emission!!), so I'll split driving between the two cars. When summer starts, I'm going to do the surgery on the Forester.

What do you guys think?

[555BCTurbo]

Well...its not as simple as just re ringing the pistons and slapping em back in.

At 141k miles, its not a bad idea, but not vital.

When you rering a motor you need to hone the cylinders, otherwise the rings won't seat correctly.

Also, it is a good idea to measure the tolerance between the ring and ringland, but on an NA Sube motor with 141k on it I doubt the clearance would be an issue.

Be careful with the headgasket...if you start getting any water in the oil or vice versa, I would quit running it!

[Matt Monson]

Don't go to all that trouble for naught. At 141k mi on a phase I Ej25, that engine is getting very due for the full monty. Just do the HG's and keep driving it until you take it down. I guarantee you that it's going to need rod bearings in the very near future...

[DLC]

Hooray for Phase I DOHC!

[douglas vincent]

Personally, I say just do the rings unless that motor is REALLY beat. With that low of milage, the cylinders are bound to still be in great shape.

[Matt Monson]

I am telling you the Ej25's are not like other Subaru engines. That mileage on an Ej25 is guaranteed to have bearings that are close to done.

And for just a minute, I'll put that aside and say I totally agree with 555bcturbo that IF one were to ring it, they would want to hone it and that requires cracking the case.

I have seen a number of 100k mi EJ25's that were both out of round and with taper out of spec. They will show cross hatching on most of the cylinder, and then 1/2" wide grooves where the notorious rod knock of the Ej25's had done it's deal. They required overboring.

Ej22's on the other hand, I have seen at 200k mi and all they needed was a hone. We are really talking apples and oranges...

[douglas vincent]

I'll stand corrected.

[greg donovan]

I am telling you the Ej25's are not like other Subaru engines. That mileage on an Ej25 is guaranteed to have bearings that are close to done.

And for just a minute, I'll put that aside and say I totally agree with 555bcturbo that IF one were to ring it, they would want to hone it and that requires cracking the case.

I have seen a number of 100k mi EJ25's that were both out of round and with taper out of spec. They will show cross hatching on most of the cylinder, and then 1/2" wide grooves where the notorious rod knock of the Ej25's had done it's deal. They required overboring.

Ej22's on the other hand, I have seen at 200k mi and all they needed was a hone. We are really talking apples and oranges...

i was told that the ej22 powerplant was designed to run for at least 250,000 miles w/minimal maintenance.

mine is at 245,000 and it needs some resealing again and that is about it.

[555BCTurbo]

I didn't know that EJ25's were that shitty...

Thanks for the insight Matt!

[Matt Monson]

I didn't know that EJ25's were that shitty...

Thanks for the insight Matt!

It's unfortunate, but it's true, and especially if one is talking about the 1st gen Ej25 as found in BAC's car. It was a streched design specification when they first released it. The biggest problem is that they didn't properly reinforce the bottom end to prevent crank from walking in the girdle. Add to that the rod knock issueand a huge bore that is known for flexing and you get rod bearings that take one hell of a beating. IMO, the phase I Ej25 is singlehandedly responsible for all center thrust EJ series blocks getting a bad wrap. Is the end thrust bearing a better design? Sure, but 100's of thousands of Ej18's, Ej20G's and Ej22's with 200k+ mi on them can't be wrong. I imagine there are another 20+0 members here that could pipe in with testimonials like Greg Donovon's about their bulletproof Ej22's.

I think the jury is still out on the phase II Ej25's. Based on the continuing head gasket issues of these engines, I don't trust that the thrust bearing relocation and crank girdle reinforcements of the phase II blocks really solved the problem. It's only been very recently where you are actually starting to see a large number of the SOHC Ej25 start to hit that 150-200k mileage mark and be broke open. It's hard to gauge because so many of these phase II blocks have been beaten on really hard in the quest for higher performance. Finding a way to sample the larger population of "normal" drivers would be a beter indicator. In a performance application, as much as I love using the EJ251 block, I will never it "solid" for continued flogging beyond the 100k mark. And in case someone like Thawa is reading this and thinking,"hey you are contradicting your previous defense of the Ej25" I just want to be clear. I think Ej25's are great little engines for high performance projects. I don't consider them weak or even flawed. I just don't consider them up in the same class of durability of the Ej series engines of old. And that's why, I am looking to use a '92-94 EJ22E NA block with SOHC EJ25 heads for my supercharger project...

[DLC]

Interesting stuff. I do hope my Phase II holds together for another 50k miles, or until someone can offer a replacement engine swap in the $5k range, labor included.

It's interesting to note that while my engine has had the HGs replaced 3 times, all three were as a result of the Subie Stop-Leak clogging up the radiator. I'm on radiator #4, with no stop-leak, and it's been smooth sailing for a year.