WAWalker

Sorry was one number lite. 22663AA010

You have to remember that the PCV system is tied into the intake, on the piston side of the throttle plate. All that increased vacuum in the intake is sucking on the crank case. There is vacuum in the crank case, not atmospheric pressure.

If you would like to start a new thread, I'm game. We may be discussing a phenomonon that dosen't even exist in gasoline engines. The more I think about it, the engine braking effect is only apparent when the transmission is manually shifted into a lower gear. When simply decelarating, the car naturally slows due to no power being produced by the engine. When shifting to a lower gear there is a significantly noticable amount of slowing due to increase in resistance due to gearing. So..................if compression braking in a gasoline engine is negated, due to the "air spring" affect, and the small amount of combustion that takes place on the "power stroke". I can wrap my mind around that. And if a closed throttle plate in the intake system can in fact produce enough resistance to provide engine braking..................... Then if I jump in my '96 OB with manual trans., and run it down a nice long steep hill, turn off the ignition........................ coasting in gear, at sufficiant speed to maintaine engine RPM's around 3000......................with throttle closed there should be noticable engine braking, then with throttle open there should be a noticable lack of engine braking and increase of speed. I'll give it a try.

Just any grease or assembly lube. Assembly lube/grease = break in lube/grease. Prevents wear to moving parts/seals untill oil gets there.

Torque on those bolts should be 95 in/lbs. max. Do not reuse your old cam seals. Apply break in grease to the sealing surface of the seals. Yes, you need to apply sealant to the front cam caps. Yes, put assembly lube or oil on all moving internal parts. Lifter buckets, cam journels. With out the special tool for adjusting valves, you will need to pull the cams back off to replace shims as needed. So check before complete assembly.

I agree with the statement about the volume of air at idle and while "engine braking" is not "proportional" went you consider the RPM differance. If it was you would have an "eat the steering wheel" breaking effect. But the fact is there is still sufficiant air to fill the void in the cyl. when the intake valves open. Not sufficiant volume to produce any amout of "power" on the cumbustion stroke, but enough that there will be significant energy to compress it. The fact that the ECU is still injecting any fuel what so ever means that there is air enough to be compressed to provide combustion when the spark plug fires. The fuel being injected would not ignite in a vacuum and would be pushed into the exhaust, causeing some massive destruction at the converter.

The intake system on any engine will not produce a tight enough seal to creat the vacuum that would be need to be to slow a car down when engine braking, sorry. What you are saying is that the braking effect comes from a total reversal of what normally goes on inside an internal combustion engine. That there is so much restriction due to a closed throttle and high RPM's that the pistion can not pull air into the cylinder, resulting in a vacuum inside the cyl once the valves are closed, and that this vacuum is actually pulling the pistion back up on the compression stroke. Sorry, I ain't buying it.

Will do.

I have read them all. The second Wikipedia reference seems to have made you see the light? Did you read the first one?

No, but I am having a hard time understanding how it is that you had a perfectly clear understanding of engine braking in post #21, but are now saying the total oppisite.

I'm not that good at math, so I don't know if there is a way to convert in/hg (vacuum) to compair to psi (compression pressure), but............ Let's look at this in a unsientific way. Take a car with a maunal transmission. Park it on a hill in gear, without the e-brake. Engine compression keeps it from rolling down the hill. Now remove the intake valves from this engine. Without the intake valves, there will still be vacuum when the pistion travels downward in the cylinder, but there will be no compression. Park it on a hill in gear, without the e-brake. It will roll down the hill like it was in nuetral. Oh, and...................There is still fuel being injected into the cylinders, and the spark plugs are still firing during engine braking. Cumbustion has not ceased 100%, so no, there is not a vacuum being drawn during the cumbustion stroke.

If you look at the numbers I posted, then engine is "pumping" more air on decel. There for there is more air in the cylinder that needs to be compressed, and more energy used in compressing it. There is not enough fuel being injected into the cylinders to produce power from combustion to aid in compressing the next cylinders air charge, there for you get a braking effect due to the need to compress more air without the help of power from combustion. I'm not saying that the increase of vaccum has NO affect. But I think if you did the math it would be nill. It takes much more energy to compress a cylinder full of air than it does to draw air from the intake into the cylinder.

Now that is a good question. As far as I know it has to due with the classification of the vehical, car truck ect. for one thing. Like all Subarus are classified as light trucks, so they don't have to meet the standards set for passanger cars. I think there are other things that play into it too. It would seem that the type of transmission plays some role. Auto's use more power= more emissions= need for more emissions control? Honestly don't know.

As far as the two user created encyclopedia (Wikipedia) references go. They contardict themselves. The first says that the compression stroke provides compression braking. The second says that increased vacuum provides compression braking. As the name implies, compression braking is compression braking. Compare engine compression psi to intake vacuum in/hg, and see which one is going to use the most energy to produce.

Well I came on to this thread about a month to late to offer anything to the OP. But I am a sucker for a good tech discussion. Basicly Suzam was 99% correct rather than the 100 times no. My dad always told me "it is better to remain quite and be thought of as a fool, than to open my mouth and remove all doubt", so I have refrained from comment till I had some data. Pluged in my Select Monitor and went for a drive. Lets just look at what it takes air/fuel wise to "keep and engine running" in an automatic '98 Legacy, at idle, and on decel/engine braking. At idle RPM- 700 MAF- 2.35 grams/second Fuel injector pulse width- 2.56 ms On decel RPM- 2500-3000+ (manualy shifting down) MAF- 3.91 g/s Fuel- .26 ms That is as close to shutting the injectors off as you can get without turning off the key. So minimal combustion on decel/engine braking. YES Increased vacuum (due to high rpm and closed throttle plate) on worn intake valve guide seals causeing oil to be drawn into cylinders. YES (The rings are creating the vacuum on the intake stroke when the intake valves are open. The increased vacuum, due to the closed throttle, is acting much more on the intake side of the pistion then it is on the crank case side of the piston. Thus, if the valve guides and seals are worn, that is the path of least resistance for oil to be drawn into the cylinder.) Cylinders and exhaust loading up with oil that is not burned untill normal combustion resumes. YES Oil cunsumption due to worn rings, is mostly because of blow by, higher crank case pressures than the PCV system can handle. And just plain old poor oil control (rings not scraping oil of the cylinder walls like thay should). Could the rings in this engine contribute to oil comsumption? Sure, but if the smoke stops after normal driving, and it doesn't smoke on hard accel (due to blow by), and with normal and even comprssion readings, a valve job will probably reduce oil comsumption considerably.

The problem is that on Car #1 the fans are not coming on when they should. They are only coming on when engine temp reaches the point that the fans are needed to drop engine temp. They are not running when the A/C compressor is running. In the winter, no this is probably never going to be a "problem". Summer, it may very well be a "problem". As far as I know I haven't checked but I sure can................The A/C compressor runs continuously when in Defrost mode, and the fans will as well. In A/C mode the compressor runs as needed to maintain an output temp at the evaporator of ~32-38 deg. F. The fans will cycle on and off with the compressor. If this is not happening then the system is not working as designed. Weather it is a "problem" is personal opinion and/or weather the car is going to over heat in the summer with the A/C going.

The gap in the mount that you are refering to is normal. Only the large square block of rubber is suposed to be bonded. As long as the rubber in the mount is not oil soaked a mushy, or rock hard, I don't see any reason to replace. I have had to replace a lot of auto trans. mounts due to seperation of the rubber from the steel, but have not seen it with maunal trans. mounts. I would recommend sorceing a used transmission. Subaru transmissions are expensive to rebuild right. The only sorce for parts is SUBARU. No after market support that I have found.

You say that the A/C is A OK, on car #1. So we will have to assume that there are no problems with the control panel, or the A/C relay. If both fans cycle on and off as needed for engine cooling, then we have to assume the main fan and sub fan relays and fuses are good. To tell you the truth this is a fairly complicated system. I would have to spend quite a bit of time studying a wiring diagram. According to the FSM, when the A/C relay is activated it is then a function of the ECU to turn the fans on. I don't have a wiring diagram handy today, so I'm not sure were to start testing.

You have code 23- MAF Sensor, and 35- Purge control solenoid. Sounds like a bad MAF.

EGR is the only effective way to reduce NOX. Thats why it has been used since the invent of emissions controls and is still in use. An old car only has to meet the emissions standards that it was required to meet at the time the car as manufactured. Not saying I am a fan of the EGR system (it is the one emission control system that really decreses engine performance in the name of cleaner air) but it is just part of life.

He has had the t-stat replaced twice. You would hope the system was blead of air properly once. There were no leaks found....................... I am one who has said that the HC test does not always show positive. And that a copression test will never result in a positive diagnoisis of failed head gaskets. I have alway said, if you want a positive diagnoisis you have two or three choices. HC test or cylinder leak down test, or smell and residue in coolant recovery bottle. But if diagnoisis is being done buy someone with little or not experiance with this head gasket issue. None of these tests are 100% I feel for people in this situation. I just finished a HG job Thursday. Same deal............They paid someone eles to flush the cooling system, replace the thermostat, upper and lower radiator hoses, and radiator cap......................... On these cars it is just easier a probably cheaper in the long run to just get the head gasket diagnoisis out of the way from the get go.

Do not put a used 2.5L engine in without replacing head gaskets, seals, water pump..........................you will just have the same problems down the road.

Rebuilt heads are quite spendy. You say that it had a valve job ~30k miles ago. With over 200k on the engine I wouldn't spend the money on remaned heads, or a complete rebuild of your heads. I would probably just replace the valves that are bent. Hard to say for sure without seeing the engine after tear down.

Absolutly. The head gaskets are allowing combustion to leak into the cooling system, causeing an "air pocket". Thermostat won't open. Coolant won't flow.

Another classic symtom of bad head gaskets.