Amille28

Stjoh,

You're right I shouldn't make blanket statements. There are reputable rebuilders out there. There are a lot of horror stories on this forum as well. If you've had a good experience you should write a thread detailing your experience so that other folks can make the right decision.

Imo000

KK.....how he sawed $5K is simple, leave the 3.2 in there and forget about fixing the 3.4. Heck if the 3.4 is good enough of a shape to be a core, it can be sold for almost as much as this replacement 3.2.

KrazyK

Because I based my commnet on his above statement. If hes changed his mind and is now happy with the 3.2 then it does make sense. Either way I respect the work done by him and what youve done with your project.

Amille28

As for now the 3.2 is staying in. I really thought that the performance might be underwhelming... but this is not the case. I love how it drives with the 3.2.
I'm hoping this motor will last me 2-3 years.. and by then slowly I should have the other engine refreshed. If the 3.4 is too badly damaged, I may sell the case halves and heads to recoup my investment on the 3.2. I plan on keeping the car so I will eventually probably rebuild the 3.4 and keep it as a spare.

Keep in mind the similaraties between the 3.2 and 3.4. Same camshafts, same crank, bearing carrier, rods, both sets of case halves can be relined at LN to 3.6. There is a member that liked the idea that the 3.2 had thicker cylinder walls and used the 3.6 bearing carrier and rods to make a 3.4. (smaller bore with longer stroke) If you plan on keeping the car for a long time having two engines might not be a terrible idea. Of course the more mods and money I put in it eats away at the savings I have now. I just wanted to show what options are available.

chsu74

Way to think outside of the box. Congrats! Much better than just blindly throw parts at a car.

Barn996

What a great solution IF you suffer an engine failure. I think you came up with an affordable alternative and you did it in your garage, outstanding.

Amille28

I wanted to bring up one interessting thing I noticed between the 3.2 and 3.4. The boxster S AOS has no coolant lines running to it. The 996 AOS has a coolant line that runs from the flange under the alternator, over the intake runners, then another line that I forget where it runs (maybe to the oil cooler).

Does anyone know the purpose of running coolant through the AOS? I was thinking of just running a coolant line from the alternator flange to wherever it goes (oil cooler i think) and using the boxster S AOS. My 996 AOS is new because I snapped off one of those coolant lines, so it seems like a point of failure. This would also reduce the amount of lines above the engine in that hard-to-get-to area.

Another mod to clean up the engine would be the secondary air injection block-offs. I'm not sure how the vacuum lines would get routed if this were all eliminated. I'm registered in FL with no emissions requirement. Is there any change in performance by eliminating this system? CEL?

alpine003

I suspect there is a layer of insulation since the boxster engine placement is in between the passenger compartment and trunk. Running coolant depends on where you live and how cold it gets. Another option ala BMW is to insulate the lines with foam if they aren't too close to any really hot parts of the motor.

Macster

Why does the AOS have coolant routed to it?

Impossible to say for sure but my WAG is to keep the AOS warm to avoid water vapor in the crankcase fumes from condensing out as the fumes pass through the AOS.

We know water can condense out of the crankcase fumes in cooler places.

Enough owners have posted questions (and pics) of their engine's oil filler tube and cap and the gunk that collects from water condensing along with entrapped oil vapor at that cool location.

In colder temperature the water could freeze and collect as ice and possibly block air flow through the AOS.

There is also the intake to think about. Even if the water doesn't condense in the AOS it can condense when it reaches the even cooler intake where it then enters the combustion chamber.

Or again in colder temperature could freeze/build up ice in the intake and if so I would not like a chunk of ice breaking loose from the intake and ending up in a cylinder.

Capt. Obvious

If you're gonna do a 3.2 swap, you might as well go old school and find a 3.2 out of an '84ish Carrera.

Do it. You know you want to.

Amille28

Mcaster,

If that theory were the case, why would the Boxter S AOS not have the coolant lines to it? I'm wondering if the increased heat from the coolant helps do a better job of separating oil from the crankcase gasses. Do you know if the super AOS (I think it costs about $500) that they have as an upgrade has coolant to it?

I'm willing to bet the same guy that designed the IMS designed the AOS.

I've seen the thread you refer to with the oil filler neck. My opinion would be to clean it out with a rag and drive the car every day. I have a Ford Expedition as well and it has an extended fill neck. The same residue is present when you flip the cap over if the truck hasn't been driven in a while. If you drive the car often less moisture builds up in the crankcase and you will have less gunk in the tube.

Capt. Obvious

The most popular theory I've heard about the Boxster vs. 911 AOS is that the Boxster's AOS is placed in a hotter area of the engine compartment than on the 911, so it doesn't need the coolant hose running through to keep it warm enough to burn off the water vapor.

Amille28

heres some food for discussion

http://www.jegs.com/p/JEGS-Performan...63433/10002/-1

JEGS Air Oil Separator is designed for vehicles with positive crankcase ventilation systems. This air oil separator prevents oil blow-by from being displaced into the intake tract on engines where crankcase pressure is high, such as high-RPM applications. When installing, always route separator away from heat sources. Made in USA.

Amille28

http://experformance.net/i-1831133.aspx

This one is different and has coolant flow.

Heated By Coolant
The base plate of the the AOS is heated by coolant drawn from the engine. By keeping the AOS the same temperature as the engine and blow-by gases, water condensation is decreased allowing oil and water vapor to separate and pass through the can.

This vital feature eliminates nearly all the sludge that can build up in the AOS body, which drastically reduce how often you must clean it.


So it looks like the AOS is attempting to keep at the same temperature as the engine in order to minimize sludge buildup. I haven't read about any boxster owners who had failed AOS due to sludge buildup. This of course could be due to the engine compartment being hotter on a boxster, however I'd venture to say there is not a whole lot of difference. The 996 AOS is pretty close to the engine.

If the 996 AOS fails you can bet its getting replaced with a boxster AOS. I'll reroute the coolant hoses. If you really wanted to go crazy you could cut apart an old AOS and make a flange, use it to route a custom catch can system that is in an area that is easy to get to.

alpine003

I vote this route if you're the kind of guy that actually checks his own oil and tire pressures without the need of a dummy computer monitoring them for you.

Catch can would be the most reliable and straight forward system but unfortunately, not everyone is hardcore enough to check and drain the catch can on a regular basis. And heaven forbid a Porsche owner having to get their hands dirty for something like this as they still struggle to get their hands dirty to even change a tire...



Factory Porsche Tire Changing Gloves. Factory Part # 99991400140.