Andrew's DiySB Rebuild

[xt2005bonbon]

As soon as I got home I could tell that my wife needed a break from me+LGT, so I didn't mess with the motor last night. It's difficult sometimes, but long-term priorities need attention too. Changing diapers, holding the baby, talking about our feelings... yeesh!

 

That's exactly why my valve clearance job took like 2-3 months to do . And that's OK in my book (as long as you have another car of course).

Edited July 8, 2016 by xt2005bonbon

[StkmltS]

That's why I've been staying up until 1-2 am most nights. Hang out with my wife and play with the kids until their bedtime, then play in the garage when everyone's asleep. Family is too important to neglect.

 

My extra car got towed last night. I don't want to leave my wife + 4 kids at home without a car, but if the 'burban doesn't get fixed soon that's just how it's going to be.

[StkmltS]

Another delay this weekend... free NASCAR tickets on Saturday!

It's not as exciting as IMSA racing, but there's nothing better than the sound of screaming engines going 180 mph. Getcha some!

[StkmltS]

The correct way to transport pistons.

 

http://uploads.tapatalk-cdn.com/20160708/b3d63dd2c17d338ea3ac84bea5f4baab.jpg

 

Sent from inner space.

Edited July 11, 2016 by StkmltS

[xt2005bonbon]

^

[SBT]

Possibly a little over-protective

[seanyb505]

Let me know if you somehow get a chance to go to vir or road Atlanta for imsa. It's not alms, but at least it's the same-ish gt class.

[StkmltS]

This weekend I remeasured all of the cylinders and put all of the data into a spreadsheet. What's strange is that my measurements don't agree with Subaru's "AAAB" stamping on the block. Even if my calipers are off by 0.001" my numbers still don't agree. Too bad I left the laptop at home and the spreadsheet isn't in my dropbox folder... I'll post the data after work, or sooner if my wife can turn on the computer on and get TeamViewer running.

 

 

I'd love to see an IMSA race but my wife and I usually budget about $0 a year for races Seriously though, If IMSA comes to mid-Ohio next season I'll find a way to go. With four kids and a wife that only kinda likes racing, VIR and Atlanta are semi-impossible for me. Oh yeah, and my LGT eats up all of that extra money anyways.

 

I watched a few minutes of this weekend's race(s) on my phone Saturday. It's awesome watching prototypes, Ferraris, Lambos, Vettes, Porsches, BMWs, Audis, Nissans, and Hondas all running around at the same time.

Edited July 11, 2016 by StkmltS

[seanyb505]

Settle a bet for me - how do you feel about the BMW keeping pace with exotic supercars?

 

What are the ranges for A and B cylinders? Probably a dumb question, but did you include piston to wall clearances in the measurements? Is it possible somewhere along the line a piston was mis-numbered?

[birkhoff]

You are shooting for 0 PTW clearance.

 

From ME-77/78:

 

Cylinder: Standard diameter:

A: 99.505 — 99.515 mm (3.9175 — 3.9179 in)

B: 99.495 — 99.505 mm (3.9171 — 3.9175 in)

 

Piston: Standard

A: 99.505 — 99.515 mm (3.9175 — 3.9179 in)

B: 99.495 — 99.505 mm (3.9171 — 3.9175 in)

 

Cylinder to piston clearance at 20°C (68°F): Standard

−0.010 — 0.010 mm (−0.00039 — 0.00039 in)

 

Realistically, with new A pistons in reconditioned A-Bores, you are going to be at the upper limit for PTW: +0.0004

 

Just checking StkmltS, but you plan to measure and record everything to tenths, right?

[StkmltS]

Settle a bet for me - how do you feel about the BMW keeping pace with exotic supercars?

 

What are the ranges for A and B cylinders? Probably a dumb question, but did you include piston to wall clearances in the measurements? Is it possible somewhere along the line a piston was mis-numbered?

 

I didn't watch enough to anything about what you're talking about

 

I haven't measured the pistons yet so I haven't figured out piston clearances yet.

 

Cylinder diameters (per FSM "A"= 3.9175-3.9179, "B"= 3.9171-3.9175):

Cyl 1 - 3.91744", measured "B", block marked "A"

Cyl 2 - 3.91734", measured "B", block marked "A"

Cyl 3 - 3.91719", measured "B", block marked "A"

Cyl 4 - 3.91723", measured "B", block marked "B"

 

Measured taper (max per FSM is 0.0006"):

Cyl 1 - 0.00019"

Cyl 2 - 0.00044"

Cyl 3 - 0.00031"

Cyl 4 - 0.00038"

 

Measured Out of Round (max per FSM is (0.0004"):

Cyl 1 - 0.00025"

Cyl 2 - 0.00038"

Cyl 3 - 0.00025"

Cyl 4 - 0.00019"

 

*** worth noting is that the resolution of my measuring equipment is only 0.0005", so anything smaller than that is a calculation or an estimate.

 

So my block is within the limits for taper and out of roundess, but my diameter measurements are puzzling. Why did I measure my block to be BBBB, but it's marked from the factory as AAAB?

 

Even if my micrometer's 3" set block (the mic was used to set the bore gauge) is under (small) by three tenths (2.9997") that would make my block AABA, still not AAAB.

 

Regardless of what the issue is with how I measured the cylinders, I'm going to check the pistons tomorrow evening (they're in the hot garage today) using the same micrometer and see if my measured piston diameters are what they should be, compared to my measured cylinder diameters.

 

I'll post the raw data later today after I clean it up and make it presentable.

Edited July 11, 2016 by StkmltS

[SBT]

Your cylinder #2 Outlier for sure.

[StkmltS]

Here's the raw data

Cylinder bore measurements.pdf

[StkmltS]

I'm overthinking this whole thing. I need to be careful to not let myself get hung-up on my (apparent) inability to correctly measure the bores.

 

People buy drop-in pistons all the time and their motors run just fine. Slap an A piston in an A bore and call it a day. The pistons are stamped A/B, and the block is stamped A/B, it doesn't get much easier than that.

 

I'm going to keep measuring everything, and try my best to understand the numbers and interpret them correctly. But I already know my pistons, cyl taper, and cyl roundeness are acceptable, and I may need to accept that info as "enough".

 

Sent from inner space.

[SBT]

Diminishing returns...you've reached it.

 

Not that I wouldn't do the same thing, multiple times. Just the nature of anal-retentive, left-brain thinkers.

[StkmltS]

Here's a decent pic of the crud on the cyl 2 exhaust valve seats. This is probably one of the contributing factors to my motor's problem. It looks terrible but I think it'll all clean off after thorough soda blasting.

 

http://uploads.tapatalk-cdn.com/20160712/b53d02c8961086d5fb7bf8ac72a3097e.jpg

 

Sent from inner space.

[Tehnation]

They just look dirty... i've seen terrible lol, that looks normal!

[StkmltS]

That's good to hear, I like positive feedback! The novelty has worn off and I'm ready to get this thing finished.

 

And here's post-soda blast. The discoloration that's left seems to be stained into the seat.

 

For future reference: if you're ever in Northern Kentucky (Cincy area) and need something blasted just look me up. I won't do it for you but you can use my DIY blast booth any time

 

http://uploads.tapatalk-cdn.com/20160712/c4e9c6456a4ac0c52e7cae0965f7a515.jpg

 

Sent from inner space.

[Tehnation]

when you lap the valves the compound will grind it out smooth. But it looks like you can get it a bit cleaner. That's all carbon buildup so a chemical could finish the job as well. Brake cleaner?

[SBT]

Was thinking the same thing.

[BarManBean]

Dunno. I had some "tarnish?" on my cam caps that didn't come off after cleaning with simple green pro (better for aluminum). All of the "crud" was removed and they were nice and clean, but they seemed "stained" for lack of a better word.

[birkhoff]

Is it possible that your #2 exhaust valves (they were the tight ones, right?) were out of spec long enough to carbon up the seats?

 

Then, even though you corrected the valve lash, the valves could not fully seat properly after that, pounding the carbon into the `lands' we see on the valves and seats.

 

That would be interesting, as in, if you find way-out-of spec-lash, with symptoms, and the symptoms don't respond to correcting valve lash in a reasonable amount of time, then, basically, you may just need a simple valve job. Or a host of other scary things, but best not to jump to conclusions.

 

Can you remind us: what was your leak down result, cylinder 2 vs the others? If I recall, it was inconclusive.

[birkhoff]

That is an impressive amount of measuring you have there. For the record, it looks much more consistent than what I found, but I have bore gauges measuring to tenths, with interpolation to 0.000025, one more significant digit. Not necessarily a good thing.

 

In your position, what I would do is try to get a measurement just above, and just below the ring travel low in the bore perp to the piston skirts. That will give you an idea of how much the bores have been opened up. Forget the H1 - H4 stuff. If the difference is less than 0.00025, then you are probably safe to re-hone and put like back into like. If it is more than that, you may want to get your new pistons first, then mix and match to keep the PTW numbers under control. That means more measuring, unfortunately in the latter scenario.

 

The next step is to torque the halves together and check your mainline. Not quite out of the woods yet, but well on your way

[StkmltS]

Is it possible that your #2 exhaust valves (they were the tight ones, right?) were out of spec long enough to carbon up the seats?

 

Then, even though you corrected the valve lash, the valves could not fully seat properly after that, pounding the carbon into the `lands' we see on the valves and seats.

 

That would be interesting, as in, if you find way-out-of spec-lash, with symptoms, and the symptoms don't respond to correcting valve lash in a reasonable amount of time, then, basically, you may just need a simple valve job. Or a host of other scary things, but best not to jump to conclusions.

 

Can you remind us: what was your leak down result, cylinder 2 vs the others? If I recall, it was inconclusive.

 

My leak-down results during my "what the heck is going on" pre-rebuild adventure were wonky. I give all of that credit to the 1.5-gal compressor I used

 

Using my new 20-gal compressor returned acceptable, and good results for all four cylinders.

Leak-down results on 6/26/16

Cyl 1, (16%)

Cyl 2, (15%)

Cyl 3, (17%)

Cyl 4, (15%)

 

Who knows how long the valves were out of spec. For all I know it was like that for years. I'm not sure if under-spec lash would allow carbon to build up on the seats. Not enough lash means the valves aren't opening enough, which I think would work against carbon build up (in a good way). Who knows.

 

That is an impressive amount of measuring you have there. For the record, it looks much more consistent than what I found, but I have bore gauges measuring to tenths, with interpolation to 0.000025, one more significant digit. Not necessarily a good thing.

 

In your position, what I would do is try to get a measurement just above, and just below the ring travel low in the bore perp to the piston skirts. That will give you an idea of how much the bores have been opened up. Forget the H1 - H4 stuff. If the difference is less than 0.00025, then you are probably safe to re-hone and put like back into like. If it is more than that, you may want to get your new pistons first, then mix and match to keep the PTW numbers under control. That means more measuring, unfortunately in the latter scenario.

 

The next step is to torque the halves together and check your mainline. Not quite out of the woods yet, but well on your way

 

I'm going to hone all four cylinders and reuse my 1, 3, and 4 pistons in the same cylinders they came out of. I'll have 3 new used pistons to choose from to replace my dented #2. As long as one of the three is an A then I should be fine.

 

I'm not looking forward to checking the mainline and I haven't quite figured out how I'm going to do it. Any ideas?

 

Current status:

Block - simple green washed, pressure washed, cylinders inspected, flatness inspected - still need to measure mains.

Pistons - soaked in carb cleaner, simple green washed, ultrasonic cleaned, soda blasted, FPI'd - still need measured.

Heads - simple green washed, pressure washed, soda blasted, decks inspected - still need to lightly sand the decks to remove the fire rings.

Oil pump - simple green washed, pressure washed, ultrasonic cleaned (sort of), soda blasted.

Oil cooler - simple green washed, ultrasonic cleaned.

Oil pan - simple green washed, pressure washed - need to blast with aluminum-oxide to remove some rust near the dip stick tube.

Crank - simple green washed, pressure washed - still need to remove rods and inspect journals.

 

Things to order ASAP:

Piston rings

Main bearings

Rod bearings

A few hoses

Clamps for the TB hose and inlet-to-intake

 

It looks like I'll probably be getting my DP back sometime this week. I don't know if the bung got welded on or if I'll get that small piece back, you know, 'cause he had a heart attack and died

 

Does copious amounts of baking soda kill grass? I'm going to blast the case halves to prep them for paint, but its too cumbersome (good song) to shoot them in my diy-booth. Yes, I budgeted for an adequate respirator

[xt2005bonbon]

Not enough lash means the valves aren't opening enough, which I think would work against carbon build up (in a good way). Who knows.

 

Isn't it the opposite? From my understanding, a tighter clearance (assuming valve shape and stem length are still like new) means that the valve cannot fully close, which would also result in the valve opening more I'd think.