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Discussion Starter #1
Bought a 2000 Outback with a bad motor to use to teach my 16 year-old how to rebuild an engine.

Got the motor apart today, mostly (haven't split the block yet)...found pieces of inserts in the pan. Yep...that was definitely a rod knock ;)

http://s561.photobucket.com/albums/ss57/5322009/?action=view¤t=insert2.jpg

Cylinders appear to be ok. Can still see the hone marks.

Intake valve tips all have a weird little dimple in the center..never seen this before...

http://s561.photobucket.com/albums/ss57/5322009/?action=view¤t=intake1.jpg

Exhaust valve tips looked normal...

Bought a UEL header on EBAY ($138)...fits very well...would have been nice if they had added just another 1/2" clearance around the front of the oil filter....so simple...no performance hit....DUHHHH!

Bought a Stage 1 clutch kit too...

Gotta say, been building engines since 1964...Subie engines are the weirdest combination of brilliant and stupid I think I've seen.
 

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2001 VDC/SC One of a Kind
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"Gotta say, been building engines since 1964...Subie engines are the weirdest combination of brilliant and stupid I think I've seen."

Corvair, yes. Subie, no. Since you've been building so long, once you get it apart you will see what makes it work so well. It is a relatively easy engine to work with.
 

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Discussion Starter #3
I agree, it has been a relatively easy engine to work on. But Jeez, is it over designed some places. Its the first engine I've ever come across that had eight bolts in the bell-housing. All my mid-70's Datsun (Nissan) had just four and were bullet proof. Eight bolts in the flywheel too? And I haven't counted how many are holding the blocks together yet.

And those exhaust ports....what were they thinking!? Didn't save one inch of exhaust tubing by torturing the exhaust gases trying to get out of that skewed port.

Then there's that one bolt between the exhaust and the cats that's nearly impossible to get to without a lift...and of course its the only one that seizes and has to be torched off...and that Y-branch in the pipe...can't label that anything but a bad idea.
 

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Discussion Starter #6
I was thinking the same thing about the crank...will measure it tonight. cylinders look good. WIll measure pistons tonight.

know a good source for a crank and rods?

Suggestions on different cams?
 

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Discussion Starter #7
#1 journal 2.047" and round
#2 journal 2.044" and round
#3 journal 2.044" and round
#4 journal 2.047" and round

AfrikkingMAZING....betting the undersized ones were that way from the factory and they used the 0.002" undersized bearings...
 

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Discussion Starter #8
BTW...EVERY bearing in the timing belt idlers was dry as a bone and rusty noisy...as well as the pilot bearing in the flywheel.

Just bought a stage one clutch kit on EBAY.
 

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2001 VDC/SC One of a Kind
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Crank/Cams, just shop around. Make sure they are spec'd and warrantied. When you machine the block and heads, center bore the rod journals as well. They are close enough oversized bearings will be okay. If you want to replace them, get them from the same supplier as the crank and cams. Makes things easier and you may be able to work in a lower price on a bundle purchase.
 

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Discussion Starter #10
Hey cardo I really appreciate your comments. Since 3 of the rods are toast (warped big ends) that leads me to...

Which of the EBAY H-beam rods are worth the money? Obviously Manley's are ($330)...but there are several suppliers in the $230 range claiming forged 4340 and ARP bolts. Ever heard of ETD, CXR, GSP, or ORGIN?

Also I live near Arlington, so Alamo Autosports is just a hop down the road...they have Eagle rods for $310.
 

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Discussion Starter #11
Well, now I'm astounded

miked the pistons and cylinders tonight...did it twice cause I didn't believe it.

ZERO wear on all four holes and pistons...and I know the inside and outside mikes are good 'cause the were professionally calibrated and checked against each other.

Pistons have lost most of their dry film coating...but look what I found...DIY ceramic and dry film coating at home for less than $100...and the materials vendor is 12 miles from my house...:D

DIY Internal Engine Coatings, First Attempt, Check it out................ - Honda-Tech
 

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Discussion Starter #13
miked the valve stems tonite....all are in spec. and the seats look like all they need is a little lapping....no pits...now, if I can find out what's up with the tips of the intake valves...

Given the wear...or rather total lack of it I have found...if a person drove one of these things sensibly, I bet it would make well over 500k miles. Biggest problem (excepting that the previous owner must have run it out of oil) was the carbon in the oil rings locking them up. Cure that problem...and who knows how long one of these engine would run.
 

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Discussion Starter #15
Update...am going to have the cylinders honed 10 over...a few scratches did not clean up with the glaze breaker.

Am going to buy Eagle H-beam rods...only a $50 premium over replacing the three warped stock rods.


Will balance/check the balance of the flywheel and pressure plate this next week (used to do a lot of spin-balancing on the side - I own a small soft bearing balancer)

Got the manifolds and ports matched to the gaskets...except that I left a 1/8" lip on the intake manifold and on the exhaust ports. Its an old Datsun anti-pressure reversion trick that works very well!

Smoothed the bowls under the valve seats (most were ok but a few had a sharp little lip).

Just ping Delta cams....what do ya think...1000 or 1500 grind? (this is gonna be my bad weather car)
 

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Discussion Starter #16
finally got to work the heads....smoothed out the little ridges around the valve seats (left by the grinder...matched the ports to the gaskets...except...left a 1/8th inch downstream facing step on the intake manifold and the head's exhaust port....still need to work the header flange

That's an old Datsun racer trick to stop reversion....and it works well...

2000 Outback :: blended-cc.jpg picture by 5322009 - Photobucket

2000 Outback :: intake-manifold-overlap.jpg picture by 5322009 - Photobucket

2000 Outback :: exhaust-port-overlap.jpg picture by 5322009 - Photobucket

2000 Outback :: intake-gasket-matched.jpg picture by 5322009 - Photobucket

2000 Outback :: header-gasket-match.jpg picture by 5322009 - Photobucket
 

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Discussion Starter #17
Got the Eagle rods...

Nice!

big end little end total
390.0g 136.1g 526.1g
390.2g 136.1g 526.2g
390.2g 137.3g 527.5g
390.3g 137.3g 527.5g

Stock rods weighed 611 grams so I lost .74 lbs in connecting rod weight

Counting the flywheel I have lowered the rotating mass in the engine by a little over 13 lbs!
 

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1999 obw 2.5l Auto 194,000 mi
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looks awsome and nice posts and weight loss! just for my own clarification is that 13lbs of actual weight shed or X number of lbs/oz with rotational forces added in. also could you expound on reversion? most port work ive seen matches the gaskets right up so the reasoning for the 1/8 lip intrests me. thanks
 

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Discussion Starter #19
looks awsome and nice posts and weight loss! just for my own clarification is that 13lbs of actual weight shed or X number of lbs/oz with rotational forces added in. also could you expound on reversion? most port work ive seen matches the gaskets right up so the reasoning for the 1/8 lip intrests me. thanks

Yep, thats 13 +lbs total rotating weight reduction. I'm making a solid model of the flywheels and I'll post the reduced inertias shortly
 

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Discussion Starter #20
Pressure pulse effects in intake and exhaust tracts....the short version....

In simplified terms, both the intake and exhaust tubing have shock waves that travel back and forth between the cylinder and the first junction in the tubing. The shock wave travels at the speed of sound and is caused by the valve opening on a cylinder whose pressure is different than the surrounding air.
The speed of sound is heavily influenced by the temperature of the gas it is traveling in. On the intake side, the speed of sound is roughly 1,150 feet per second (fps). Standard temperature and pressure (STP) air has a speed of sound of 1114 fps (but the intake air is usually warmer by 50 degrees or so...so 1150 fps is a good compromise).
The traveling shock wave has an effect on the pressure in the tube in which it is traveling, and causes the pressure in the tube to rise and fall in a wavelike fashion. Without getting into details, the shock wave must travel out and back twice for a full pressure cycle in the tube (four lengths of the tube total). Under certain conditions, the pressure fluctuation is strong enough to actually reverse the flow in the tube temporarily.
Traveling from a smaller to larger tube diameter has very little effect on the shock wave progression and pressure effect. However, traveling from a larger diameter to a smaller diameter passage...and having a sharp lip at the transition...causes a portion of the shock wave to reflect off the lip. This reflected shock wave acts like a dam to help reduce any reversed flow. Typically, the lip ineeded is ~1/8” (i.e. the intake manifold tube ID is ¼” smaller than the intake port ID)
Due to the incredibly nice, smooth, intake ports and manifold runners on the old Datsun L series engines, reversion could be a significant problem....even so strong as to force the fuel air mixture out of the mouth of the carbs....making a nice little fog of fuel-air you could actually see. Since they were carburated engines, the reversed flow could also cause extra fuel to be mix into the air stream, seriously screwing up the fuel mixture calibration. The offset step between the manifold and head did wonders for these engines.
On the exhaust side we are dealing with much higher pressures and temperatures. The shock wave velocity can reach nearly 2000 fps. “Tuned” headers use the shock wave induced pressure fluctuation to create a low pressure condition just as the valve overlap period occurs. During that time the exhaust tubing pressure gets connected to the intake manifold though the cylinder. So, when the timing is right, you getthe exhaust sucking on the cylinder, which inturn sucks on the intake manifold.
On the exhaust side, because of the increased energy in the heated gasses, pressure fluctuations of as much as +/- 6 psi can occur. Thus, you get can get the equivalent of 6 psi of “boost” on the intake side...i.e. the intake side has -6 psi of suction helping to start the intake flow.
On the exhaust side, you want to help the suction (negative pressure) and block the reversion (positive pressure) going back into the cylinder during the overlap period...so you leave the exhaust port ¼” smaller in diameter than the header pipe ID.
Now, if you’ve followed this...you’ve realized that the timing of that whole suction effect only works for certain RPMs, and is tied directly to the length of the header primary tubes. Longer header primary tubes cause the timing to be correct at lower RPMs.
 
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