Got my baseline measurements and pulled the valves out of one EJ25D head.  There's a reason two of the exhausts were way out of spec (.013 and .018) - they were bent, alright, by the timing failure.  Busy with the cleanup and the lapping will come shortly, but I have a question:  Since the rebuild kit included stem seals (and this motor was an oil burner prior to the timing boo-boo, so I want to be sure to seal up every possible leakage path), I pulled the old seals out.  I notice, though, that the old seals are clearly marked IN and EX, but the new seals are all the same.  Does it matter?

Probably not. And you didn't need to replace them. They never fail. 

Oil consumption is from carbon impacted oil control rings and/or bad PCV valve. 

GD

I figured what the he11, I paid for 'em, might as well use 'em.

I took care to clean out the holes under the oil rings, and the PCV is on the list, so no worries on those fronts.

 

You had the pistons out - I hope you swapped them for 251 pistons right?

GD

No, just rebuilding with what I had.  It's a low-budget, first-time, try-not-to-screw-it-up job.  Did I make a mistake?

If GD recommends swapping the pistons out, then I guess you could say you made (an unknown) mistake...

I didn’t know of this swap either, but it kind of makes sense. 

Cheers 

Bennie

Please elaborate.  What are the differences, and what would the benefits be?

I'm jamming econo, so buying (new) pistons is probably out of the question, as is buying an entire junkyard motor in order to get a used set.  It doesn't strike me as practical to try to remove a set in the boneyard.

[Edit]

I'm kinda stoopid and haven't actually laid hands on any engines other than EJ22, EJ25D, and EJ25S.  Now, is what's commonly referred to as EJ25S actually EJ251?  If so, I have a borken one out of my short-lived '02 Forester (PO ran it dry and busted a rod through the crankcase, so the engine swap was my first work on it).   Given the circumstances, it's unlikely there'll be usable parts in it, but getting a look at the pistons might be educational.

Edited December 27, 20187 yr by jonathan909

EJ251 pistons allow the use of the EJ257 (part number ending in 642) head gasket which is less than half as thick. This solves the head gasket issues the 25D had with blowing fire rings due to the gasket being too thick and allowing too much cylinder wall movement. The 25D was notorious for this and it was widely regarded as a giant mistake by Subaru. The 251 piston/642 gasket combo improves the quench and also increases compression slightly. It does need premium fuel but that's the only trade off. 

GD

Edited December 27, 20187 yr by GeneralDisorder

Gotcha.  So where do I find EJ251 pistons?  Is that what my '02 Forester had?

Yes. All the 99 to 05 SOHC engines have the piston in question. Although 2005 models specifically switched to a thinner oil control ring setup stolen from the turbo model pistons. 

GD

I'll pull them, but suspect one or more may be NFG, so I guess I'll be sticking with stock this time.

Back to valves, though:  I'm just coming to fully appreciate the high-magnitude SNAFU that is the suction-cup-stick hand lapping tool.  I like listening to the abrasive and getting a feel for it, but the non-grippyness of the cup to the valve is taking all the fun out of the job.  Is there a better way e.g. someone who makes a cup that really sticks?

That job sucks, and is for suckers. 

Pull the valve out, wire wheel the face of it. Some contact cement on the valve and the cup helps too. 

I use one of these:

https://www.ebay.com/itm/Oscillating-Valve-Lapping-Tool-MAKES-JOB-SO-EASY/180976014021

GD

 

 

That looks sweet.  Still suffers from the sucker problem, but if you say it's the best way to go, it'll get added to my wish list.

Trying to get the clearances right on this thing - especially with a very limited set of spare shims - really is a PITA.  I'm taking a stab at grinding the stems, and controlling how much I take off doesn't seem to be too bad.  But the constant dis/re-assembly with each adjust/measure iteration is something else.

I'm working to the .008 intake, .010 exhaust spec, but what it doesn't tell me is what the tolerance is.  What say you?

I usually go for .006 and .008 personally. The D heads tend to be loud if you don't go pretty tight on the lash. 

Lapping valves just sucks. It does help with idle quality though. The drill adaptor definitely makes it a lot easier. If you can afford a proper three angle grind at the machine shop like we do on the turbo models it will free up a lot of beer drinking time.

GD

I have been using a cordless drill alternating directions and going very slowly for 20 years now and it work great. You just chuck up the valve on the back side after removing the spring. Make sure you don't use too much lapping compound as you don't want to get any of it in the guides.

Is there some bad reason why everyone doesn't do this?

 

Edited January 1, 20197 yr by Crazyeights

4 hours ago, GeneralDisorder said:

I usually go for .006 and .008 personally. The D heads tend to be loud if you don't go pretty tight on the lash. 

I don't mind a little extra noise.  So you're saying spec +0/-2 on both - that'll certainly help it breathe better.  But how much over spec on the clearance can one get away with before it starts to suffer?  I'm just trying to get a sense of how nervous I have to be about grinding the stems.

The heads get noisy at higher lash. Also things tend to loosen up once they are running and forces are in play. Thus I generally like my lash a little tight. I have set some to 8 and 10 and had them give some ticking from the heads.

GD

12 hours ago, Crazyeights said:

I have been using a cordless drill alternating directions and going very slowly for 20 years now and it work great. You just chuck up the valve on the back side after removing the spring. Make sure you don't use too much lapping compound as you don't want to get any of it in the guides.

Is there some bad reason why everyone doesn't do this?

 

Some heads you can't really get the chuck down in there. The oscillation of the special adapter tool is very fast - it doesn't makes complete revolution before switching directions. Just like hand lapping with the suction cup stick. 

GD

Well, I think I have one head in the right neighborhood, but I know one thing for damn sure:  I want to sell this car and never own another D engine.  Adjusting clearance with these bucket/shim lifters is a fate nobody should have to suffer.

Lots of engines have been built this way. It's not unique to Subaru. The newer ones use shimless buckets and you have go buy the whole bucket. Or cut the stems/seats till what you have fits. It's a lot easier if you invest in the proper spring removal/installation tool. IE: the ValveMaster:

https://www.toyotool.com

It's still less difficult than measuring for pushrod length on a SBC... but I would still rather be doing the SBC. lol. 

GD

Sure, but isn't this the only Subaru engine with nonadjustable lifters thanks to the DOHC?  Aren't all the others like the EJ251 - SOHC w/ adjustable rockers?

2 hours ago, jonathan909 said:

Sure, but isn't this the only Subaru engine with nonadjustable lifters thanks to the DOHC?  Aren't all the others like the EJ251 - SOHC w/ adjustable rockers?

No.  All EZ engines, some EJ turbos have shim or buckets, and EA82, ER27s, 90s EJ were non adjustable HLAs. 

On 12/31/2018 at 5:10 PM, jonathan909 said:

really is a PITA.  I'm taking a stab at grinding the stems, and controlling how much I take off doesn't seem to be too bad. 

Grinding shims is way easier.

Can you mic the clearance without the shim,  mic the shim, and then calculate how much of the valve stem needs to come off?   Probably too risky?

6 hours ago, idosubaru said:

No.  All EZ engines, some EJ turbos have shim or buckets, and EA82, ER27s, 90s EJ were non adjustable HLAs. 

Grrrrr....  The EZ include the H6s, right?  That's actually what I want to get, and I thought I'd be getting back to the land of adjustable rockers.  So my choice is a later SOHC EJ25 or the DOHC EZ30.  Bummer.

Edited January 2, 20197 yr by jonathan909

2 hours ago, idosubaru said:

Grinding shims is way easier.

Can you mic the clearance without the shim,  mic the shim, and then calculate how much of the valve stem needs to come off?   Probably too risky?

I can measure the clearance and the shim, but have no way of measuring how much I grind off the stem.  I just did that with one of the exhaust valves I replaced, and it went okay, though it was an even more tedious process.  I had to take the valve out a couple of times to take more off - then still go through the shim hassle.