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The part in the yellow box ("B" in your photo) above is the balance pipe to help balance out the two intake manifolds. It may also do some tuning of the manifolds by opening/closing a vacuum controlled valve. The blue/green box is where the vacuum actuator lives, on the side of the balance pipe. There is likely a flap type valve inside the balance pipe - and it sounds as if that and/or the vacuum actuator is broken.

it sounds as if he's removing the entire intake manifold since he lists 6 intake manifold gaskets (1 for each cylinder), this might be needed if he suspects any broken bits have gotten into the intake manifold itself. Then it sounds as if he's just going to replace the vacuum actuator.
It seems like the AOS should be easy to change at that point since it is also in the same general area. So he shouldn't be charging regular labor rate for the full job when most, if not almost all of it, will be right there.

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It seems like the AOS should be easy to change at that point since it is also in the same general area. So he shouldn't be charging regular labor rate for the full job when most, if not almost all of it, will be right there.

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That was my initial reaction too - I thought his labor rates seemed high until I looked up the book-rate from AllDataDIY. They give 3.7 hours of labor for EACH side of the intake manifold - so 2x3.7=more than 7 hours, meaning it will probably take him 5 or so. Then you have the hour of prep and hour of reassembly of all the crap you have to remove to get to the engine. Since there isn't a quoted charge for that work, I assume he folded that time into the estimate for the manifold R&R. Also this is the .1 AOS which is more of a PITA to replace from everything I've seen. We're spoiled with the 987.2 engines - easier to work on besides not needing as much work.

Does it seem high? It's not a bargain, but I can see how it would be justifiable.
 

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Discussion Starter · #43 ·
So are there two of those actuators on the balance pipe? And are two of those electric changeover devices? Does anyone have a 987 service manual that can see what's involved with manifold removal etc...
 

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Discussion Starter · #44 ·
I'm thinking about doing the work so I can deep clean along the way. Going to the shop tomorrow to have them show me in person. But do you guys agree that this could be causing my issues. I haven't seen to much searching for something similar.
 

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So are there two of those actuators on the balance pipe? And are two of those electric changeover devices? Does anyone have a 987 service manual that can see what's involved with manifold removal etc...

If that doesn't work - contact me via PM.
 

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I'm thinking about doing the work so I can deep clean along the way. Going to the shop tomorrow to have them show me in person. But do you guys agree that this could be causing my issues. I haven't seen to much searching for something similar.
Certainly if the vacuum actuator has gone pear-shaped, and is causing a vacuum leak, there is a decent chance it's causing your issues.. and if it's broken the car isn't running right anyway, so it needs to be fixed.
 

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So are there two of those actuators on the balance pipe?
There's a second one on the backside of the hard plastic intake plenum (the T-shaped tube the throttle body is strapped to). I haven't done the full job, but I did have the plenum out to clean the oil from it when I did the AOS. It's not too bad, but I'd either get the service manual, or at least do some serious googling for the torque values and tightening order on the intake manifold bolts.

You do NOT want to overtorque and snap one of those off in the head.

(also @deilenberger I may ping you as well, as the person in that other thread seems to visit infrequently)
 

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Discussion Starter · #48 ·
Visited the mechanic today, He showed me where the vacuum leak was: started the car and used a bar to keep the pedal down to keep it running. then sprayed brake cleaner (or some sort of solvent) right in between the balance tubes and the car accelerated. Then showed me the vacuum actuator that was missing the arm and thats where he believes the leak is at. I asked him why he wanted to remove the entire intake to repair that and he said because he was worried about breaking the balance tubes when he took them off. So i dont think hes worried about pieces broken off inside the intake, he just wanted to play it safe and remove the whole intake (which seems a bit excessive) he also said he would replace any vacuum lines too. I paid him and thanked him for his diagnosis. Car has been towed back to my home and I ordered a new AOS, two vacuum actuators and the six intake manifold gaskets thru pelican ( i had called the local porsche dealer and they were a few weeks out since some of the parts were not in stock, he kept saying they were in germany :) ) Anyhow at this point im planning on taking the upper balance tube out tomorrow and inspect where the leak is happening and replacing the actuators and AOS and crossing my fingers thats the issue. What do you guys think. was he over doing it by wanting to remove the entire air intake manifold?
 

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Visited the mechanic today, He showed me where the vacuum leak was: started the car and used a bar to keep the pedal down to keep it running. then sprayed brake cleaner (or some sort of solvent) right in between the balance tubes and the car accelerated. Then showed me the vacuum actuator that was missing the arm and thats where he believes the leak is at. I asked him why he wanted to remove the entire intake to repair that and he said because he was worried about breaking the balance tubes when he took them off. So i dont think hes worried about pieces broken off inside the intake, he just wanted to play it safe and remove the whole intake (which seems a bit excessive) he also said he would replace any vacuum lines too. I paid him and thanked him for his diagnosis. Car has been towed back to my home and I ordered a new AOS, two vacuum actuators and the six intake manifold gaskets thru pelican ( i had called the local porsche dealer and they were a few weeks out since some of the parts were not in stock, he kept saying they were in germany :) ) Anyhow at this point im planning on taking the upper balance tube out tomorrow and inspect where the leak is happening and replacing the actuators and AOS and crossing my fingers thats the issue. What do you guys think. was he over doing it by wanting to remove the entire air intake manifold?
Here's what I would recommend. Take lots of pictures during disassembly especially if you will be waiting weeks for your parts to arrive. I'd search YouTube for videos that may help you. I'd watch a few before starting disassembly.

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What do you guys think. was he over doing it by wanting to remove the entire air intake manifold?
Any good mechanic is going to be cautious and try to avoid having a come-back. In this case - that logically would mean removing the entire intake just in case something broke internally and is floating around in the intake waiting to start trouble down the road.

My WAG - if you take out the intake/balance tubes - you'll be able to see into the intakes and see if there is any reason to go further with the removal. The endoscopes for a cell phone are marvelously cheap and marvelously good (mine is much clearer than my dedicated video probe system.) You might want to Amazon one if you don't have one. Mine is a "Pancellent" Borescope for Android, "USB Endoscope Pancellent 2"

Here is a WiFi version (mine plugs in): https://www.amazon.com/dp/B07HJ3HNNX?ref_=cm_sw_r_cp_ud_dp_93RA071STE41WX38WB04

This is a plug-in one: 3-in-1 USB Endoscope Waterproof Semi-Rigid SnakeCable, Borescopes 5.5mm Inspection Camera IP67 Waterproof Snake Camera with 6 Adjustable LED Lights for Type-C & Android & PC, (5M/16ft): Amazon.com: Industrial & Scientific
 
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Discussion Starter · #51 ·
I was able to get the balance tube, plenum and AOS out today.
Car Vehicle Motor vehicle Hood Automotive lighting


All came out pretty easily. When I flipped the balance tube over it looked fine (thats the one the mechanic suspected was broken) . Then i noticed the flapper from the plenum side was just sitting in the intake manifold tunnel. I took a closer look at the plenum tube and noticed a hole where the arm of the intake actuator was supposed to connect to:
Automotive tire Gas Camera lens Rim Auto part

so, somehow the flapper broke free and took a ride through the intake to the other side.

So gaping hole there, flapper moving around, broken pieces? i got the endoscope today so i will take a look tomorrow.

Here is the flapper piece from the plenum:

Automotive tire Sleeve Material property Eyewear Automotive wheel system


Also, i noticed that there is a section on vacuum line missing/not connected under all of that. So one vacuum line to each actuator and then two hard lines sitting free with no way to connect them, so broken off i guess.

hoping i can get this easily locally (ridgid):
Textile Sleeve Creative arts Finger Collar


I got the parts overnighted from pelican 2x actuators and AOS, intake manifold gaskets. So now i need the plenum. im guessing this is an expensive piece of plastic. Anyone have a spare from an upgrade?


While cleaning out the top of the engine, i found some treasures and lots of crud:
Wood Sleeve Dress shirt Beige Flooring

Looking at it now i think the round piece may be the socket that the exterior arm on the plenum flap rotates on. ill verify .

So I need a plenum and to figure out the disconnected vacuum lines.

Still wondering if resetting the CELs did something to trigger the flapper part to self destruct, doesnt seem likely.
 

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Great progress! I think you're on the path to a solution. Cool beans!

And you found my 10mm socket even! :D
 

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So just curious, I see the upgraded ipd plenums and they don't appear to have the flap at all. Why is that?
Magic. Some things touted as "upgraded" really aren't. I'd have to see back-to-back dyno runs before I'd consider believing it's an upgrade.

In the motorcycle world where this sort of quest for HP the manufacturer thought you didn't need so, they left it on the table for some joker in his garage to discover and sell it to you.. Frequently if you do legit dyno runs (same dyno, same day, same engine, same operator - all that changes is the magic bit..) you see things like a 1-2 HP bump at high RPM with a gutting of the HP/torque at mid RPM (where you need it..) Porsche is pretty good at getting performance out of their engines, I don't believe they leave a lot on the table.

A flap like that frequently is used by manufacturers to change the resonance of the intake system to help tune it for different RPMs. Not having one limits the ability to do that. But they do have "magic" going for them.
 

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Discussion Starter · #55 ·
well... shes back together (kinda)

I thought since i cant get a new plenum this weekend.. and some aftermarket plenums dont even have the flap. what if i plug up the hole for now and see if it at least runs:
Computer Laptop Personal computer Touchpad Netbook

This white ring is the piece that fell out of the hole that retains the flap(its missing the tensioning bit to keep it in place) so i measured that and 3D printed a plug for the hole:
Automotive tire Motor vehicle Sports equipment Rim Gas


and glued in (the bits of blue are my gloves that stuck to the superglue:
Automotive tire Motor vehicle Bicycle part Tire Wheel


Remade a bunch of the vacuum tubes and connected the two extra ends that were disconnected.

AOS bottom tube was a pain to connect but its on. I'm not convinced it was on well originally because it pulled off with no effort.

Here is the first start after buttoning up:

So obviously much better. (ignore the high pitched squeel, its coming from a disconnected radio, ive got an unusual radio setup and i took it out before i left it at the mechanic) I am noticing some very loud valve tapping noise that i dont remember, loud on both sides. The cover is off still and i dont have an air filter yet but took it around the neighborhood slowly. Some crazy whooshing sounds when press and let off the pedal. I should have the air filter this afternoon, so ill put that in and then put the cover back on i think.

Would you drive 50 miles round trip to work (this is my daily) like this? or would you wait for the correctly flapping plenum? Im going to order one on monday.
 

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Discussion Starter · #58 · (Edited)
i was so excited that it started up but now im getting a very loud ticking from what sounds like the valve train. Oil level is good the only changes ive made are the new coils and plugs and then reconnecting the vacuum lines. Any idea why this would be so loud now? i dont remember the ticking at all prior to the vacuum issue. Would an incorrect vacuum line cause that? i wouldnt think so. so makes me think the new plugs /coils.

 

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Discussion Starter · #59 ·
I managed to get the replacement plenum from the porsche dealership and install that and put in the new air filter and cover for that. took it for a drive with the engine cover off still and man it sounds strange, all kinds of loud wooshing as i let off on the gas. strange motor noises (which im guessing may have been there all along but with the cover off its really noticeable. Im starting to second guess my vacuum routing. Trying to make this simple:
1. changeover on the drivers side intake
2. changeover on the passenger side intake
3. changeover under the plenum hold down bolt
A. balance tube flapper
B. plenum tube flapper

I have 1 connected to A
and 3 connected to B

not sure if thats correct, i cant seem to find a diagram that looks close. Im going to look at the service manual again but didnt see this layout.
maybe 2 should connect to B?

there are a lot more tubes running from 1 to 2 with a 4 way junction but lets start here. does anyone know?
Vehicle Motor vehicle Car Automotive design Hood
 
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