TheSamba.com :: View topic - EJ25 JDM that I've put 25,000 miles on (and took it apart!)

Fri Mar 01, 2024 12:09 am

Not just for fun! :wink:
The timing belt jumped a few teeth and bent some valves.
See other thread: EJ25 timing belt skipped a (few) teeth. See this PSA (video)

Four intake valves were bent. Here's one.
The other intake valve was not being used because this engine uses only 3 valves for low RPM.
At some higher RPM little hydraulic cylinders push a latch and engage a tappet, and the 4th valve opens.

I took the heads off.
Then was persuaded to take the pistons out, hone & re-ring.
I promise I'm going to stop there and put it back together.
Wish me luck.

The bores look good (to me) with hone marks remaining, all the way around and zero detectable ridge at the top.

Here's where I'm at this evening.

My worst piston. All others are less worn.
You can still see the original machining marks.
To me, this is 'good".
Curious what a real mechanic says.

Also I expected the oil rings to be "coked up".
They look clean to me.
But they look much less "energetic" than the compression rings.
Again, what does a Subaru mechanic say?

I will put them in the bores and measure the gap.
Does anyone know the EJ25 2010 ring gaps?

Fri Mar 01, 2024 1:04 am

I don't really "know" what I'm looking at but....

Any idea how many miles on engine before you got it?

Neil.

Fri Mar 01, 2024 1:06 am

Casey sez “ you can put a WBX in there as an interim solution for the next 100k miles while you repair that”

:lol:

Sounds you like you need Bentley for the Roo for those specs

https://www.youtube.com/watch?v=p8JjvCHvAIo

Fri Mar 01, 2024 1:27 am

As a guess, as shown in the image, skirts et al of 2 pistons at LH of image look more worn than pistons at RH side.

Neil.

Fri Mar 01, 2024 7:28 am

everything visually looks "good enough" but proper thing would be to mike for cylinder taper etc. prolly don't need to do that with an engine that was running good and low oil consumption. just hone and clean clean clean.

consider the use of Total Seal's Quick Seat treatment on the cylinder walls plus using a true break-in oil like Driven BR30 for the first 500 miles to really bed those rings nicely.
https://www.dragzine.com/news/sealed-up-total-seals-quick-seat-piston-ring-lubricant/

https://drivenracingoil.com/i-30497749-br30-5w-30-conventional-break-in-oil.html

what grit and composition ball hone ball hone are you thinking? i used a BRM 240 SC on mine for the WBX but i'd call Brush Research to get their advice.
https://cdn2.hubspot.net/hubfs/484035/FlexHone_Resource_Guide.pdf

Fri Mar 01, 2024 8:01 am

Sodo,
Any chance you can post the pcv line diagram?
I have conflicting info
Thanks

Fri Mar 01, 2024 9:02 am

DanHoug wrote: mike for cylinder taper etc. prolly don't need to do that with an engine that was running good and low oil consumption
….
call Brush Research to get their advice

If the original hone scratches are visible all the way around, do you think there could be measurable taper? The Ring Ridge at top is “zero”.

I was told not to use a ball hone when diagnosing oil consumption because it obliterates any out-of-roundness evidence that I need to see.
Dang I don’t have a rigid hone.

I don’t have a PCV diagram. I need to compare to the various diagrams to see which configuration I have. My intake manifold and ports are clean. There’s very little oil in the hoses.

Fri Mar 01, 2024 9:29 am

2005 EJ253 Ring Gap - I would "Assume" the same for your block

Fri Mar 01, 2024 9:58 am

I will check that, (later today) thanks Paul !
I hear that 2010 has a tiny oil control ring.
It's definitely about the smallest I have seen.
It's 2mm tall.
Smaller than a motorcycle oil control ring.

Fri Mar 01, 2024 10:27 am

I forgot the change ocurred in 2010. 2005-2009 outbacks were the same except in 2006 they went to the VVT.

Fri Mar 01, 2024 10:39 am

It's interesting the verticle lines on the pistons show up in the cylinder walls as well. Can't tell if the piston skirts were factory coated or if that is some sort of build up. I also find it interesting that the one piston shows the lines directly aligned with the oil hole in the bottom ring land and the oil ring expander edge is over one of the holes.

Unless you are buying oversized rings that need to be fitted, I'm going to guess you are stuck with the end gaps you get. There is also a formula you can use for determining ring gaps that will get you close.

Top ring, Bore x 0.0045"
Middle ring Bore x 0.005

Fri Mar 01, 2024 10:48 am

Well you're getting right after it. Those are short fat pistons aren't they. When I re ringed / re rung? my engine, it probably had 75k on it. My oil rings were loaded up. Cylinders still had a tad of original cross hatch, and no feelable step at top but likely measurable. I did a light hone to break the glaze, 3 bar hones are cheap. Your cylinders look good. Id be tempted to just put it back together. How about a pic of the smile left by the valves :D .

Fri Mar 01, 2024 2:15 pm

Sodo wrote: I was told not to use a ball hone when diagnosing oil consumption because it obliterates any out-of-roundness evidence that I need to see.
Dang I don’t have a rigid hone.

so what if it obliterates? you aren't going to replace the cylinders regardless of what showed up, right? because hone marks aren't the correct measurement tool to determine that. besides, there's no way a hand drill operated rigid hone is going to straighten out cylinder taper anyway. you need a true machine shop Sunnen type hone to cut straight.

whatever honing method, just keep cleaning and cleaning until a new paper towel comes out without a hint of darkness on it after wiping.

Fri Mar 01, 2024 3:26 pm

Dingle berry hones have their place. You are at a crossroads. As stated, only serious honing will straighten worn cylinders at the risk of adding too much clearance and resulting piston slap. So, if you have taper or out of round, you are looking at new oversize pistons and machine work.

If the goal is to install new rings, the dingle berry will knock down glaze and give you a cross hatch for the new rings to seat on. This is more of an economy move. Getting the hang of measuring cylinders with a bore gauge does take gaining experience. A machine shop could do it for you. Then decide how you are going to proceed.

Oil rings became narrower and had less tension to reduce friction improving mpg. That yours don’t seem to have a lot of tension would not surprise me.

Fri Mar 01, 2024 4:14 pm

Save yourself a TON of money, time, and frustration...and bore the cylinders out for the next size piston.

Or, simply install new rings, which is not ideal.
Subaru runs much tighter piston to cylinder wall clearance, and using a dingleberry and re-ringing it will lead to oil consumption

You have been warned.

Fri Mar 01, 2024 4:18 pm

MarkWard wrote:

Top ring, Bore x 0.0045"
Middle ring Bore x 0.005

Set 1st ring at .007" to .009"
Set 2nd ring at .002" to .004" larger than 1st ring.

Fri Mar 01, 2024 4:29 pm

11BC2 wrote:
Subaru runs much tighter piston to cylinder wall clearance, and using a dingleberry and re-ringing it will lead to oil consumption
You have been warned.

Not necessarily.
I ball honed to knock down the glaze, installed new rings and don't use a drop of oil. 210 psi at the last check. That engine has been in my Van since 2013.

Fri Mar 01, 2024 4:36 pm

Franklinstower wrote:
Not necessarily.
I ball honed to knock down the glaze, installed new rings and don't use a drop of oil. 210 psi at the last check.

You got lucky.
How many miles were on that engine?
How many miles are now on it, since re-ringing?

Fri Mar 01, 2024 5:13 pm

11BC2 wrote: Franklinstower wrote:
Not necessarily.
I ball honed to knock down the glaze, installed new rings and don't use a drop of oil. 210 psi at the last check.

You got lucky.
How many miles were on that engine?
How many miles are now on it, since re-ringing?

I don't know. It was a short block I grabbed from the Junk Yard, but it was a factory replacement phase 2 block in a '99 DOHC outback. I got the block in 2013. I re-ringed that engine and it has been running in my van since 2013 - I would guess I have 60k on it since doing the work.

Fri Mar 01, 2024 6:02 pm

DanHoug wrote: Sodo wrote: I was told not to use a ball hone when diagnosing oil consumption because it obliterates any out-of-roundness evidence that I need to see.
Dang I don’t have a rigid hone.

so what if it obliterates? you aren't going to replace the cylinders regardless of what showed up, right? because hone marks aren't the correct measurement tool to determine that. besides, there's no way a hand drill operated rigid hone is going to straighten out cylinder taper anyway. you need a true machine shop Sunnen type hone to cut straight.

Not using the hone as a boring bar. :wink:
He was saying that the rigid hone can informs you where it's out-of-round.
Whereas the ball hone obliterates that useful info.

DanHoug wrote: whatever honing method, just keep cleaning and cleaning until a new paper towel comes out without a hint of darkness on it after wiping. Thats something I’d be inclined to do.
But….how do the rings bed in without abrasion?