Andrew's DiySB Rebuild

[Tehnation]

If the pistons are in good shape why not just change piston rings and move on? and i didn't even notice my cracked ringland until i cleaned them.

[xt2005bonbon]

I am baffled . BTW which side of the cylinder wall is scratched? And do you see similar scratches in the other cylinders.

Btw, you seem to be a great dad .

[StkmltS]

let em soak overnight. mine went from this to this

Mine came pretty clean after running them through my ultrasonic cleaner with Simple Green, then soda blasting. Pics to come...

 

True enough, but save that for after the forensics. At this point, there is still no obvious reason for the OP's misfire. The plan is to use new OEM pistons anyway, as I understand it.

Yes, the plan is to use new or used OEM pistons, new intake and exhaust valves, and new bearings. Although I'm not sure what to do if I can't find anything wrong with the pistons, block, or heads.

 

Deposits on piston tops looks on the heavy side of normal. The flushing action on the piston edge could indicate poor oil control. Check for free movement of the oil rings.

 

Skirts look pretty worn. Not sure what that streaking on the skirts under the oil return ports is about. Is it possible this engine was run with a lot of dirty oil at some point?

The oil rings didn't move as easily as the top two rings did, but they're in there tighter anyways.

 

I'm the third owner so I assume the motor missed an oil change every once in a while.

 

I asked about the oil and streaks in my previous post because I didn't see that in my first teardown of a relatively well cared for SB, but I saw lots of it in my 180K engine that had a couple of years of poor oil change history. It was also burning a LOT of oil and all the piston tops had the telltale signs of oil wash around the edges. You didn't mention anything about oil consumption -- was that also a problem?

Since I've owned the car it's only consumed about 1-1.5 quarts per 3.5k miles, give or take a little.

[StkmltS]

Since none of the pistons have any noticeable flaws I decided to give them a good cleaning. My next step with the pistons is to use florescent penetrant to look for cracks. For FPI to be effective the parts must be extremely clean.

 

Testing several ways to clean pistons:

Top left: reference, no cleaning.

Top right: after 45 minutes in an ultrasonic cleaner with water and Simple Green (4:1 ratio).

Bottom left: after 45 minutes in water and carb cleaner (1:1 ratio).

Bottom right: after about 45 minutes of soda blasting (@ 90 psi).

 

The second photo is after:

(step 1) 24+ minutes soaking in carb cleaner.

(step 2) 24+ min of ultrasonic cleaning with Simple Green.

(step 3) 10+ min of soda blasting.

(step 4) 3 min of ultrasonic cleaning using water and Dawn liquid soap.

(step 4) blasting dry with filtered compressed air.

I'm really happy with the results... even though you can still see water spots on the faces and skirts

 

Piston 4 has a vertical scratch on the top ringland, and a small piece of material is missing on the underside.

[StkmltS]

I'm finished for today. Kid 3 still has a case of the funky stuff so I'm staying home with him while my wife takes the others to my parent's house for a classic 4th cookout. Bummer to miss it.

 

Here's my work table after today's festivities.http://uploads.tapatalk-cdn.com/20160702/3a94ea27d1e58e093e3375784b8dab2c.jpg

 

Sent from inner space.

[SBT]

Excellent, well-documented progress. Rest-up. The finish line is ahead... and your little one needs more Dad-time.

[BarManBean]

The amount of time you've spent blaring those Pistons...props for the effort, but damn I would've just pitched em and grabbed a new set from somewhere

 

Hope the FPI shows something solid tho!

[StkmltS]

The amount of time you've spent blaring those Pistons...props for the effort, but damn I would've just pitched em and grabbed a new set from somewhere

 

Hope the FPI shows something solid tho!

I'm determined to find a crack, probably to a fault. I just got out of bed to FPI the dang thing... it's gotta be there somewhere.

 

 

*edit* I didn't do it right, try again tomorrow.

Sent from inner space.

Edited July 3, 2016 by StkmltS

[StkmltS]

I got a little bit accomplished today.

 

FPI'd piston #2: no cracks found. I then proceeded to accidentally drop piston #2 on the washing machine lid, putting a small dent on the top edge of the piston. My mistake, but not too frustrating because that piston wasn't getting reused anyways. Note to self: don't let that happen again.

 

I leak tested the valves using water and gravity: a couple intake valves leak a drop or two every 20 minutes or so. Almost all exhaust valves leak immediately after pouring water in the exhaust ports (one #2 valve is noticeably worst than the rest), then a drip or two about every minute or less.

 

Tomorrow morning's plan is to remove all valves, springs, keepers, seals, and then visually inspect and clean both heads. Tomorrow is a family day... but not until they're awake

 

Sent from inner space.

[birkhoff]

Diesel/Kerosene is a better bet. Its incredible creep -ability will find any crack eventually, no matter how small. Surface tension in water is going to limit this test. But anyway, you have some information there that may indicate something up with Cyl #2.

 

Re: dropping parts. Better to get this out of your system now. We've all have been there. Wait 'till you drop your $150 micrometer on the floor

Edited July 6, 2016 by birkhoff
human spell-check

[StkmltS]

Diesel/Kerosine is a better bet. Its incredible creep -ability will find any crack eventually, no matter how small. Surface tension in water is going to limit this test. But anyway, you have some information there that may indicate something up with Cyl #2.

 

Re: dropping parts. Better to get this out of your system now. We've all have been there. Wait 'till you drop your $150 micrometer on the floor

 

I probably should have used kerosene, but with the amount of water that came out of the exhaust valves kerosene probably would have just leaked more, faster.

[StkmltS]

Happy Independence Day!

 

I'm finished in the garage for today and I'm happy with what got done. All valves, keepers, springs, and seals are out. I overslept a little (4:30 vs 4:00) so I didn't have time to clean the heads. I know, I know, I need to re-evaluate my priorities

 

I'm really happy with the tool I made to compress the springs. It's the center portion from an old timing belt idler pulley (the large pulley). Just push (hammer) out the center cylinder from the pulley and cut some windows into the side of it. I took the flat end off my c-clamp to expose the ball on the end of the screw, and it seated perfectly into the piece scavenged from the pulley. Put some cardboard around the other end of your c-clamp to protect the head/block mating surface and bam! you're done. Zero dollars spent = victory.

 

Notes:

• 
  The front exhaust valve seal for cyl 2 (my #23) fell off the valve guide without any effort at all. The end of the valve guide looks a little darker than rest, and the valve seat looks a little dirtier than the rest. The exhaust port behind valve #23 is much dirtier than the rest, an it's partner valve (#24) looks MUCH cleaner that the others.

• All of the intake and exhaust valves look similar to each other, nothing stands out as unique or obviously damaged.

 

I'll upload pics of the heads later today, probably after lunch during the kids' naps.

[StkmltS]

Just for fun here's a couple pics of the #2 cylinder getting FPI'd.

 

How it works: coat the part in penetrant and let it sit (dwell) for about 15 minutes. Gently rinse the penetrant off and let the part dry. If you have developer (I dont) apply it to the dry part, and then let it dry again. Then you turn on your black light and look for cracks. Penetrant gets deep into cracks and glows bright green under UV light. If you don't see green then you don't have cracks.

 

http://uploads.tapatalk-cdn.com/20160704/4001a1d7de0f16bc0a6f212104fb0bfb.jpg

 

http://uploads.tapatalk-cdn.com/20160704/9190cf3a70ad4a8f5220a0bc39677dec.jpg

[xt2005bonbon]

Thanks for posting and documenting your work like that.

So why do you think at this point you've been having these misfire issues?

IIRC, didn't you say your valve clearances were OK? But even then, it looks like your exhaust valves are not sealing very well?

 

Also did you ever post pictures of your cylinder walls for all cylinders?

[StkmltS]

Thanks for posting and documenting your work like that.

So why do you think at this point you've been having these misfire issues?

IIRC, didn't you say your valve clearances were OK? But even then, it looks like your exhaust valves are not sealing very well?

 

Also did you ever post pictures of your cylinder walls for all cylinders?

 

I honestly don't really know what to think at this point. So far the only thing that seems less that acceptable are the exhaust valves. My plan to replace the pistons and reuse the SB doesn't sound smart if I can't find anything obviously wrong. I knew I'd get discouraged at some point, but I thought it would be because of my inability to perform work (honing, decking, etc), not my struggle to find a problem.

 

I've taken tons of pics of the heads, so I'm going to clean them off and let them sit inside all of tonight and tomorrow and thoroughly inspect them tomorrow evening.

 

I'll inspect the SB tomorrow or Wednesday and get good pics of the cylinders then.

[BarManBean]

If you're not finding anything "broken," my guess is a valve clearance issue. From my experience, measuring valve clearances as a layman takes some practice and has a bit of a learning curve to it. Even if you think you measured correctly, I'm interested to see how everything looks when you reassemble and remeasure valve lash.

 

You have it torn down now, and regardless of finding a large issue you have the chance to reassemble and make things right.

[StkmltS]

Yeah, it may be just the valves. That could explain why it only misfired at idle, more specifically it only misfired when it was under no load (stationary, any RPM). It just sucks piston 2 didn't fall apart. I soooooo wanted to be in the #ringland club, now I'll never be accepted by the Internet.

 

Is it normal for the valve seats to have a litte carbon on them, as in, on the surface between the seat and the valve? That seems a little problematic.

 

Words of encouragement are helpful. In the end the motor will run, I just need to figure out what to do about the SB. Stay tuned for Decision Week 2016!

 

The heads (decks) are looking pretty clean and sitting inside all day acklimating to the low humidity and cool air. Tonight I'm going to clean the SB and take it inside to sit for a day. I should have some good pics of the cylinders tonight.

http://uploads.tapatalk-cdn.com/20160705/d18cd7b772dd3a3d5f3d8bf5a99ed749.jpg

 

Sent from inner space.

[StkmltS]

Well, I need a new used catless UP. The one I bought was getting a bung welded on by a coworker of mine, and he died this weekend. He had a heart attack while driving on the highway on Saturday. Fortunately nobody else was in the car and no other vehicles were involved. News photos show the accident looked pretty minor. It sucks I'm out the cost of an UP and bung, but that's nothing compared to what he lost.

 

Anyone on here have a catless UP laying around that you want to get rid of?

[xt2005bonbon]

Man, that must be hard for your coworker's family ...

 

 

So, it sounds like the culprit may be valve clearance? But I recall you fixed the valve clearance . Or maybe, the adjusted clearances were now within specs, but the valves were still not sealing properly for some reason?? Super strange man.

 

In any case, seeing how fast you teared down your engine, you'll probably be driving it in no time with lots of powa .

[StkmltS]

Man, that must be hard for your coworker's family ...

 

 

So, it sounds like the culprit may be valve clearance? But I recall you fixed the valve clearance . Or maybe, the adjusted clearances were now within specs, but the valves were still not sealing properly for some reason?? Super strange man.

 

In any case, seeing how fast you teared down your engine, you'll probably be driving it in no time with lots of powa .

 

Until I inspect the cylinders I'm not ruling out a SB problem, but yes, so far it looks like the valves may be the sole problem. I'll have some sexy valve and cylinder pics tonight for your guys to internet inspect.

 

Good news > I talked to our level 2 NDT (non-destructive testing) inspector this morning, and she's willing to accept donuts in exchange for FPI'ing my pistons. She'll use level 4 penetrant and emulsifier (vs the level 2 stuff I have) and run it through our NADCAP certified FPI line. I have almost no idea what I'm talking about, but level 4 and emulsifier sounds way better than level 2! She laughed and said "of course you didn't find anything, level 2 doesn't work on smooth surfaces!" Believe it or not, my diy-at-home-FPI skills are severely sketchy, and I'm not confident that I did it properly. After she inspects the pistons I'll be ready to emotionally let go of the ringland idea.

[birkhoff]

Is it normal for the valve seats to have a litte carbon on them, as in, on the surface between the seat and the valve? That seems a little problematic.

 

In a word, no.

 

If you are seeing that on the exhaust valve seats on cylinder 2, along with the liquid test, you probably have found your problem. You should be happy! Your car just needed a `valve job'

 

Early in the life cycle of these cars, broken ring lands were all the rage. Now we are moving into the late stage of designed lifetime, I suspect we are going to see more top end problems. That was the case with my engine, and perhaps yours. Careless mods and hard driving can break pistons no matter what the condition of the bottom end. But with 150K and no attention to valve clearance, top end problems will start to appear. I expect we are going to see more and more valve issues on top of the usual broken pistons.

 

I was going to suggest you get some lapping compound and see how uniform your contact area was on the #2 exhausts, but you have kind of answered that already if I understand what you are seeing. Another possibility, that could be a parallel problem, is a hairline crack in an exhaust valve that may have distorted the valve head, or opened up at operating temps making #2 compression marginal at hot idle. All speculation of course.

 

As far as the SB, rebuilding what you have now is even more viable than when you started since nothing failed. A new SB is still an option, just less necessary than when you started. I would see that as a good thing, given your plan!

[xt2005bonbon]

OP, didn't you say you had misfires at idle no matter the engine temperature?

[birkhoff]

Let's say you find a hairline crack in a piston. Would you consider that significant? Unless a chunk falls off a piston during inspection, I would focus on the valve issues you seem to have uncovered.

 

Those poor subaru pistons. They never get a break!

[StkmltS]

In a word, no.

 

If you are seeing that on the exhaust valve seats on cylinder 2, along with the liquid test, you probably have found your problem. You should be happy! Your car just needed a `valve job'

 

Early in the life cycle of these cars, broken ring lands were all the rage. Now we are moving into the late stage of designed lifetime, I suspect we are going to see more top end problems. That was the case with my engine, and perhaps yours. Careless mods and hard driving can break pistons no matter what the condition of the bottom end. But with 150K and no attention to valve clearance, top end problems will start to appear. I expect we are going to see more and more valve issues on top of the usual broken pistons.

 

I was going to suggest you get some lapping compound and see how uniform your contact area was on the #2 exhausts, but you have kind of answered that already if I understand what you are seeing. Another possibility, that could be a parallel problem, is a hairline crack in an exhaust valve that may have distorted the valve head, or opened up at operating temps making #2 compression marginal at hot idle. All speculation of course.

 

As far as the SB, rebuilding what you have now is even more viable than when you started since nothing failed. A new SB is still an option, just less necessary than when you started. I would see that as a good thing, given your plan!

If the valves and seats are the problem, I'll be a happy camper. I don't WANT to find a cracked piston, that's just what I've had in my head for so long.

 

OP, didn't you say you had misfires at idle no matter the engine temperature?

It misfired at all temps. Well, the first 10-20 seconds were sometimes miss-free, but no consistently.

 

Let's say you find a hairline crack in a piston. Would you consider that significant? Unless a chunk falls off a piston during inspection, I would focus on the valve issues you seem to have uncovered.

 

Those poor subaru pistons. They never get a break!

I'd definitely consider a hairline crack significant. My misfire was present, but it didn't seem to affect performance much if any. A small crack would explain why the motor ran healthy with a miss.

[StkmltS]

Last night I inspected the heads for flatness, and I didn't find one single spot where my 0.0015" shim fits. I might dig around today at work and try to get my hands on a 0.0005" and 0.001" shims to try again just for fun. See what this project is doing to me? I'm calling this stuff fun.

 

Fire rings are present but very shallow, probably only 0.001-0.002 deep.

 

Inspecting the valves

I'm using a numbering system to keep track of where the buckets, valves, and springs go in each head.

The first digit is the cylinder, the second digit is the valve number per cylinder.

Valves #11 and #12 are for cyl 1, intake. #11 is front #12 is rear.

Valves #13 and #14 are for cyl 1, exhaust. #13 is front #14 is rear.

Repeat for each cylinders.

 

Aaaaaaand the pictures...

 

Intake valves

All intake valves look fairly consistent to each other.

The cyl 1 valves are slightly cleaner and not quite as quite as dark as the rest.

I'm treating the differences as minor and not worth a second thought.

 

Exhaust valves

The exhaust valves are all over the place, even from the same cylinder.

The sealing surface of each valve has what looks like very shallow of pitting. I'm not sure if this is normal for 109k mi old valves.

Valve #14 is very dirty, all of the way up to where the stem slides into the guide.

Both cyl 2 valves have an obvious red tint to them and are relatively clean.

Valve #33 is dark and dirty near the sealing surface, but pretty clean and grey elsewhere.

Both cyl 4 valves are pretty clean and grey in color.

 

I'd be interested to hear your guys' thoughts on the exhaust valves while I spend some time researching online.