Hello! Log in or Register   |  Help  |  Donate  |  Buy Shirts  See all banner ads | Advertise on TheSamba.com  
TheSamba.com
 
Throttle body questions
Forum Index -> Bay Window Bus Share: Facebook Twitter
Reply to topic
Print View
Quick sort: Show newest posts on top | Show oldest posts on top View previous topic :: View next topic  
Author Message
furgo
Samba Member


Joined: September 06, 2016
Posts: 816
Location: Southern Germany
furgo is offline 

PostPosted: Tue Feb 13, 2018 8:44 am    Post subject: Throttle body questions Reply with quote

After replacing the intake runner boots and repainting the runners themselves, one thing lead to another and decided to inspect the throttle plate and the throttle body gasket for leaks.

Removal was easy: it's only held to the plenum by two screws that came out easily. There were also the remains of the linkage to the disabled EGR valve, so I removed that as well.

The throttle body was covered in grease, so the first thing I did was a preliminary cleanup:

Before:

Image may have been reduced in size. Click image to view fullscreen.

Image may have been reduced in size. Click image to view fullscreen.

Image may have been reduced in size. Click image to view fullscreen.


After:

Image may have been reduced in size. Click image to view fullscreen.


The gasket looked ok and had not hardened to the point of losing elasticity. I'll replace it, though.

I also did wonder how the throttle body ended up so much covered in dirt. That area in my engine is not particularly clean, so I'm wondering if that's indicative of another issue or defective/missing seal somewhere.

Screws

One thing that caught my eye were the screws that secure the throttle body to the plenum:

Image may have been reduced in size. Click image to view fullscreen.


I don't know whether they were supposed to be like that or someone modified them presumably to keep them from coming loose. If that's the case, not too effectively, as they could be undone fairly easily.

As they are standard metric screws and already rusted, I was going to just replace them. Now I'm not sure if new ones should be modified as the originals as well.

Any advice on those?

Plate wear

There is no axial play in the shaft when the plate is closed, but there is some when the plate is opened. There is also some wear, on the plate as can be seen from the light coming through. It does not seem a massive amount, though, so I'm not worried.

Image may have been reduced in size. Click image to view fullscreen.

Image may have been reduced in size. Click image to view fullscreen.


Or should I be?

EGR cover

I'm planning to get a new EGR valve gasket, fabricate a cover plate with the same outline, and remove the linkage and bit of pipe that are the last remains of the EGR.

My other question seems fairly obvious, but I prefer to ask than to later find out I was wrong...

Am I correct to assume that removing the mechanical EGR valve linkage has no effect on the throttle action? That is, the throttle plate return spring should work exactly the same with and without the EGR valve linkage.

Idle speed screw

Image may have been reduced in size. Click image to view fullscreen.


I was looking at the idle speed screw and noticed that when looking at it from the inside of the body, it is pretty much recessed into the thread.

Does the distance from the bottom of the screw to where the thread ends have a noticeable effect on the amount of air that is bypassed, or is the action of the screw only measurable from the end of the thread to the pressure plate's flattened side?
_________________
'79 Westy, P22 interior, FI 2.0 l Federal, GE engine (hydraulic lifters)
Back to top
View user's profile Send private message Gallery Classifieds Feedback
asiab3
Air-Schooled


Joined: April 04, 2012
Posts: 8973
Location: On Tour!
asiab3 is offline 

PostPosted: Tue Feb 13, 2018 8:58 am    Post subject: Re: Throttle body questions Reply with quote

Hey furgo,

That kind of self-starting fastener (some are screws, some are bolts) are spread throughout the car wherever getting a straight shot at the threads is thwarted by alignment and access (in this case) or whenever the assembly is under tension (like the shifter base or torsion bushing housings.) Clean up and keep the originals if you can, nothing else will thread on as easily. Also, I’m the case of any faster under tension or security a gasket, make sure you tighten them both evenly a few turns at a time once they’re past finger tight. This will prevent warping and leakage.

Good call replacing the throttle body cone gasket. There are a few on the market, but only one is the genuine VW gasket. I don’t recall who sells it, but you should be able to call around and ask. Clean the mating surface on the plenum before installation too.

Removing the egr system on mechanical-style setups like yours is typically don’t with a block-off plate at the muffler and at the plenum. Leaving any parts installed is asking for build-up of gunk or atrophy. I use a proper gasket for the location, a clean mounting flange, custom plate, and thin smear of ultra-copper RTV, because it is O2 sensor safe, and I’ll use an O2 sensor once in a blue moon for troubleshooting.

As for the idle bypass screw, yours looks about average. The gap created by the screw is your idle speed setting, so even a recessed screw will allow more airflow and a higher idle as a result.

Nice job cleaning up th throttle body! Next step is to dress the edges of the throttle plate so you don’t get the typical “sticky throttle body” which manifests as an obnoxiously sticky accelerator pedal off idle.

Good luck!
Robbie
_________________
www.airschooled.com
Back to top
View user's profile Send private message Send e-mail Visit poster's website Instagram Gallery Classifieds Feedback
busdaddy
Samba Member


Joined: February 12, 2004
Posts: 40505
Location: Surrey B.C. Canada, Land of the giant flying moose!
busdaddy is offline 

PostPosted: Tue Feb 13, 2018 8:59 am    Post subject: Re: Throttle body questions Reply with quote

The screws have thet notch in the end to remove the paint that's in the threads on a newly dipped plenum, you don't need that for the replacements.
That play and wear eventually results in a throttle that sticks shut and requires more force to get off idle, it can also create inconsistant idle speeds depending on how it randomly closes when it wears enough.
The EGR shouldn't effect throttle action at all.
The screw is a bypass channel, the further away it is from the plate the more air gets by.
_________________
Rust NEVER sleeps and stock never goes out of style.

Wanted, OG paint 1971 Niagara blue decklid.

Stop dead photo links! Post your photos to The Samba Gallery!
Back to top
View user's profile Send private message Gallery Classifieds Feedback
furgo
Samba Member


Joined: September 06, 2016
Posts: 816
Location: Southern Germany
furgo is offline 

PostPosted: Tue Feb 13, 2018 10:17 am    Post subject: Re: Throttle body questions Reply with quote

Excellent thanks Robbie and busdaddy!

Taking note of:

• Evenly tightening throttle body screws upon reinstallation
• Using the original VW gasket - found it: https://www.volkswagen-classic-parts.de/dichtung-ec9621.html
• Removing disabled EGR bits and pieces and properly blocking EGR valve opening at the plenum. I was already planning to.

As per the screw, after your replies I ended up scribing its current position and counting the turns until the fully screwed position. That showed me that mine is set 1.5 and a bit turns from fully screwed (minimum air flow). Most importantly, that even when fully screwed the screw end is recessed from the body, which helped me understand how it works. Initially I thought the fully screwed position would be nearer to the cutout of the plate.

asiab3 wrote:
Nice job cleaning up th throttle body! Next step is to dress the edges of the throttle plate so you don’t get the typical “sticky throttle body” which manifests as an obnoxiously sticky accelerator pedal off idle.


Right now I've cleaned it up to the shiny brass and it's not binding (it wasn't before either). I was simply planning to lubricate the shaft next.

How should the edges be dressed, though? I'd be worried of removing too much material and I'd probably have to take the whole thing apart, right? I was planning for a deeper refresh at a later point in time, probably not now.
_________________
'79 Westy, P22 interior, FI 2.0 l Federal, GE engine (hydraulic lifters)
Back to top
View user's profile Send private message Gallery Classifieds Feedback
raygreenwood
Samba Member


Joined: November 24, 2008
Posts: 15079
Location: Oklahoma City
raygreenwood is offline 

PostPosted: Tue Feb 13, 2018 10:44 am    Post subject: Re: Throttle body questions Reply with quote

The very best method ai have found to make the throttle body gasket have the best fit and best sealing......and it helps if you have a spare plenum laying around......is to put a thin even layer of high temperature, oil resistant RTV....like permatex ultra black......on the TB side of the gasket ONLY.
Then apply the TB to the plenum and tighten the screws maybe 1/2 to 1 turn past finger tight. Make sure the TB is straight and the o-ring does not turn. Let this dry completely.

In the morning remove the TB and carefully clean up any RTV that squeezed out.
Then apply a THIN even coating of RTV....around the plenum opening....but keep it ahout,1/8" back from the opening so as it squeezes out thinner.....it will not squeeze past to the opening. Apply the TB evenly....finger tight....give it 15-20 minutes to set up or thicken up a little and then tighten it down evenly.

Open the throttle and clean up any excess with a cloth swabs in forceps. Do not run this until it has a day to cure fully.

While you are in there....I cannot remember if it was mentioned....replace both throttle shaft seals. Ray
Back to top
View user's profile Send private message Gallery Classifieds Feedback
asiab3
Air-Schooled


Joined: April 04, 2012
Posts: 8973
Location: On Tour!
asiab3 is offline 

PostPosted: Tue Feb 13, 2018 10:44 am    Post subject: Re: Throttle body questions Reply with quote

If the throttle plate isn't binding, I wouldn't mess with it, personally. There may be a way to prevent the inevitable burr that forms around 200,000 miles on every old FI bus I've driven, but until then, drive on! The throttle shaft itself should have rubber seals on the outer edge, so I've always just done a drop of light motor oil on every movable point on the shaft, including the two-stage throttle return spring. Wipe up any excess, as it will attract dirt.

Robbie
_________________
www.airschooled.com
Back to top
View user's profile Send private message Send e-mail Visit poster's website Instagram Gallery Classifieds Feedback
aerosurfer
Samba Member


Joined: March 25, 2012
Posts: 1546
Location: Indianapolis, IN
aerosurfer is offline 

PostPosted: Tue Feb 13, 2018 11:50 am    Post subject: Re: Throttle body questions Reply with quote

Is the gasket for the bypass screw available or anything special?
_________________
Rebuild your own FI Harness..My Harness

77 Westy 2.0L Rockin and Rolling Resto!

72 Sportsmobile (sold)
79 Tran$porter... Parts car money machine (gone)
Back to top
View user's profile Send private message Gallery Classifieds Feedback
aerosurfer
Samba Member


Joined: March 25, 2012
Posts: 1546
Location: Indianapolis, IN
aerosurfer is offline 

PostPosted: Tue Feb 13, 2018 11:54 am    Post subject: Re: Throttle body questions Reply with quote

raygreenwood wrote:
The very best method ai have found to make the throttle body gasket have the best fit and best sealing......and it helps if you have a spare plenum laying around......is to put a thin even layer of high temperature, oil resistant RTV....like permatex ultra black......on the TB side of the gasket ONLY.
Then apply the TB to the plenum and tighten the screws maybe 1/2 to 1 turn past finger tight. Make sure the TB is straight and the o-ring does not turn. Let this dry completely.

In the morning remove the TB and carefully clean up any RTV that squeezed out.
Then apply a THIN even coating of RTV....around the plenum opening....but keep it ahout,1/8" back from the opening so as it squeezes out thinner.....it will not squeeze past to the opening. Apply the TB evenly....finger tight....give it 15-20 minutes to set up or thicken up a little and then tighten it down evenly.

Open the throttle and clean up any excess with a cloth swabs in forceps. Do not run this until it has a day to cure fully.

While you are in there....I cannot remember if it was mentioned....replace both throttle shaft seals. Ray


From a practical standpoint, how the hell would you be able to clean RTV off the inside of the TB after the valve with it bolted to the plenum, unless the engine was out? even then what a PITA
_________________
Rebuild your own FI Harness..My Harness

77 Westy 2.0L Rockin and Rolling Resto!

72 Sportsmobile (sold)
79 Tran$porter... Parts car money machine (gone)
Back to top
View user's profile Send private message Gallery Classifieds Feedback
furgo
Samba Member


Joined: September 06, 2016
Posts: 816
Location: Southern Germany
furgo is offline 

PostPosted: Tue Feb 13, 2018 12:41 pm    Post subject: Re: Throttle body questions Reply with quote

asiab3 wrote:
If the throttle plate isn't binding, I wouldn't mess with it, personally. There may be a way to prevent the inevitable burr that forms around 200,000 miles on every old FI bus I've driven, but until then, drive on!


Ok, that puts my mind at ease and aligns with my initial plans. I'll drive on worry-free (but aware) for the next 70,000 miles then Smile

asiab3 wrote:
The throttle shaft itself should have rubber seals on the outer edge, so I've always just done a drop of light motor oil on every movable point on the shaft, including the two-stage throttle return spring. Wipe up any excess, as it will attract dirt.


Taking note of lubricating points and lubricant, thanks. Although on my throttle body I can only see one seal on the spring end of the shaft. The other end seems to have rather a stopper that's the same diameter as the shaft, no rubber seal. In any case, at least visually, the one seal I can see still looks good.

aerosurfer wrote:
Is the gasket for the bypass screw available or anything special?


Both the gasket and the bypass screw are still available from Volkswagen Classic Parts, so I'm sure a reseller in the US also haves them:

Bypass screw - 043 133 145
https://www.volkswagen-classic-parts.de/en/schraube-871e91.html

Bypass screw gasket - 043 133 148
https://www.volkswagen-classic-parts.de/en/dichtring-2707c5.html

In fact, given that they're less than $2 altogether, I just ordered them along with some other bits and pieces that I needed. My screw is slightly rusted, so I might as well replace it rather than regalvanize it.
_________________
'79 Westy, P22 interior, FI 2.0 l Federal, GE engine (hydraulic lifters)
Back to top
View user's profile Send private message Gallery Classifieds Feedback
furgo
Samba Member


Joined: September 06, 2016
Posts: 816
Location: Southern Germany
furgo is offline 

PostPosted: Tue Feb 13, 2018 12:49 pm    Post subject: Re: Throttle body questions Reply with quote

aerosurfer wrote:
raygreenwood wrote:
The very best method ai have found to make the throttle body gasket have the best fit and best sealing......and it helps if you have a spare plenum laying around......is to put a thin even layer of high temperature, oil resistant RTV....like permatex ultra black......on the TB side of the gasket ONLY.
Then apply the TB to the plenum and tighten the screws maybe 1/2 to 1 turn past finger tight. Make sure the TB is straight and the o-ring does not turn. Let this dry completely.

In the morning remove the TB and carefully clean up any RTV that squeezed out.
Then apply a THIN even coating of RTV....around the plenum opening....but keep it ahout,1/8" back from the opening so as it squeezes out thinner.....it will not squeeze past to the opening. Apply the TB evenly....finger tight....give it 15-20 minutes to set up or thicken up a little and then tighten it down evenly.

Open the throttle and clean up any excess with a cloth swabs in forceps. Do not run this until it has a day to cure fully.

While you are in there....I cannot remember if it was mentioned....replace both throttle shaft seals. Ray


From a practical standpoint, how the hell would you be able to clean RTV off the inside of the TB after the valve with it bolted to the plenum, unless the engine was out? even then what a PITA


Thanks for posting these instructions Ray. I've also got a fundamental question on this procedure: I can see how this can improve the seal, but is the gasket generally so bad that it needs to be sealed with RTV on both sides (*)?

(*) although I'm not sure I can follow it correctly: in the "In the morning remove the TB" step I assume the gasket to remain glued to the plenum by the RTV and not come out with the TB?
_________________
'79 Westy, P22 interior, FI 2.0 l Federal, GE engine (hydraulic lifters)
Back to top
View user's profile Send private message Gallery Classifieds Feedback
raygreenwood
Samba Member


Joined: November 24, 2008
Posts: 15079
Location: Oklahoma City
raygreenwood is offline 

PostPosted: Tue Feb 13, 2018 1:22 pm    Post subject: Re: Throttle body questions Reply with quote

aerosurfer wrote:
raygreenwood wrote:
The very best method ai have found to make the throttle body gasket have the best fit and best sealing......and it helps if you have a spare plenum laying around......is to put a thin even layer of high temperature, oil resistant RTV....like permatex ultra black......on the TB side of the gasket ONLY.
Then apply the TB to the plenum and tighten the screws maybe 1/2 to 1 turn past finger tight. Make sure the TB is straight and the o-ring does not turn. Let this dry completely.

In the morning remove the TB and carefully clean up any RTV that squeezed out.
Then apply a THIN even coating of RTV....around the plenum opening....but keep it ahout,1/8" back from the opening so as it squeezes out thinner.....it will not squeeze past to the opening. Apply the TB evenly....finger tight....give it 15-20 minutes to set up or thicken up a little and then tighten it down evenly.

Open the throttle and clean up any excess with a cloth swabs in forceps. Do not run this until it has a day to cure fully.

While you are in there....I cannot remember if it was mentioned....replace both throttle shaft seals. Ray


From a practical standpoint, how the hell would you be able to clean RTV off the inside of the TB after the valve with it bolted to the plenum, unless the engine was out? even then what a PITA


Read what I wrote.......more carefully. Its simple.

1. You are FIRST adhering the TB...to the gasket.....NOT the plenum.

2. Then when the RTV is dry... pull the TB back off and remove any RTV that squeezed out. You can either use a blunt exact blade edge just rub it off.

3. When you put the RTV on the plenum side....when you are FINALLY installing the assembly on the plenum....put the RTV on THIN....and spaced back from the inlet opening.....its better than about 95% chance that you get 0 squeeze out. However a quick wipe around with a strip of cloth on hemostats.....will tell you if you have.
Hold the TB open with one hand and use the other.

Its not even close to the hardest thing to do on these vehciles....once in 100k miles.

Do I need to do a pictorial? Wink ....I will if asked.

Ray


Last edited by raygreenwood on Tue Feb 13, 2018 1:43 pm; edited 1 time in total
Back to top
View user's profile Send private message Gallery Classifieds Feedback
raygreenwood
Samba Member


Joined: November 24, 2008
Posts: 15079
Location: Oklahoma City
raygreenwood is offline 

PostPosted: Tue Feb 13, 2018 1:31 pm    Post subject: Re: Throttle body questions Reply with quote

furgo wrote:
aerosurfer wrote:
raygreenwood wrote:
The very best method ai have found to make the throttle body gasket have the best fit and best sealing......and it helps if you have a spare plenum laying around......is to put a thin even layer of high temperature, oil resistant RTV....like permatex ultra black......on the TB side of the gasket ONLY.
Then apply the TB to the plenum and tighten the screws maybe 1/2 to 1 turn past finger tight. Make sure the TB is straight and the o-ring does not turn. Let this dry completely.

In the morning remove the TB and carefully clean up any RTV that squeezed out.
Then apply a THIN even coating of RTV....around the plenum opening....but keep it ahout,1/8" back from the opening so as it squeezes out thinner.....it will not squeeze past to the opening. Apply the TB evenly....finger tight....give it 15-20 minutes to set up or thicken up a little and then tighten it down evenly.

Open the throttle and clean up any excess with a cloth swabs in forceps. Do not run this until it has a day to cure fully.

While you are in there....I cannot remember if it was mentioned....replace both throttle shaft seals. Ray


From a practical standpoint, how the hell would you be able to clean RTV off the inside of the TB after the valve with it bolted to the plenum, unless the engine was out? even then what a PITA


Thanks for posting these instructions Ray. I've also got a fundamental question on this procedure: I can see how this can improve the seal, but is the gasket generally so bad that it needs to be sealed with RTV on both sides (*)?

(*) although I'm not sure I can follow it correctly: in the "In the morning remove the TB" step I assume the gasket to remain glued to the plenum by the RTV and not come out with the TB?


Yes....actually the gasket sucks. Not so much because its a bad gasket.....but because the TB mounting method is a total pain in the ass...especially when the engine is in.....and....

I realize this pain in the ass and the reach angle is exactly what aerosurfer was getting at.....so I DEFINATELY see his point.

Back against the fire wall tin.....holding the TB straight while you get the screws made up....is a PERFECT recipe for gettting the gasket on crooked.

The RTV on the TB side is primarily an adhesive that insures that the gasket stays exactly where you want it to be no matter how much you have to screw around with the TB. The fact that it also is a good insurance seal.....is just a bonus

Another tip...for working with the engine in the car....is to get rid of the stock "cheese head" style screw and go to 6mm bolts with 10mm heads.
I use a 1/4 drive, deep well socket with two nuts stacked inside to allow the bolt to stand straight out to start the bolts in. There is much less fiddling around.

You can also adhere the gasket to the plenum with RTV....but this ia best done with the plenum out.

NOTE......you are adhering the gasket to the TB ONLY.....FIRST. you are flakling it to the plenum overnight....while the RTV between the gasket and TB dries.

This is so the gasket does not slip sideways....or get bubbles between it and the TB. You will notice that the gasket is ribbed and those ribs need to compress slightly to get the best seal and fit.

You take this assembly off in the morning.....the assembly being the seal and TB adhered together......to then apply RTV to the plenum. Ray
Back to top
View user's profile Send private message Gallery Classifieds Feedback
furgo
Samba Member


Joined: September 06, 2016
Posts: 816
Location: Southern Germany
furgo is offline 

PostPosted: Tue Feb 13, 2018 1:50 pm    Post subject: Re: Throttle body questions Reply with quote

Ok, I think I got it from your second post now, thanks Ray. Still, if the main point is to prevent getting the gasket in crooked, would it not be enough to just adhere the gasket to the throttle body?

Something else that caught my eye, while we're on the subject of throttle body maintenance. I'm not planning to do it, but it never hurts knowing more...

If the throttle plate shaft were to be taken apart, what's the best way to undo the screws that hold the plate in place?

Image may have been reduced in size. Click image to view fullscreen.


They seem to have been stamped at their ends with a Y-shaped mark, presumably to expand those ends to keep the screws in place. I assume that they cannot be removed as-is without damaging the threads in the shaft.

I'm wondering if carefully drilling them with a smaller diameter bit from the back to break the expanded ends would be the way to go.
_________________
'79 Westy, P22 interior, FI 2.0 l Federal, GE engine (hydraulic lifters)
Back to top
View user's profile Send private message Gallery Classifieds Feedback
raygreenwood
Samba Member


Joined: November 24, 2008
Posts: 15079
Location: Oklahoma City
raygreenwood is offline 

PostPosted: Tue Feb 13, 2018 3:14 pm    Post subject: Re: Throttle body questions Reply with quote

furgo wrote:
Ok, I think I got it from your second post now, thanks Ray. Still, if the main point is to prevent getting the gasket in crooked, would it not be enough to just adhere the gasket to the throttle body?

Something else that caught my eye, while we're on the subject of throttle body maintenance. I'm not planning to do it, but it never hurts knowing more...

If the throttle plate shaft were to be taken apart, what's the best way to undo the screws that hold the plate in place?

Image may have been reduced in size. Click image to view fullscreen.


They seem to have been stamped at their ends with a Y-shaped mark, presumably to expand those ends to keep the screws in place. I assume that they cannot be removed as-is without damaging the threads in the shaft.

I'm wondering if carefully drilling them with a smaller diameter bit from the back to break the expanded ends would be the way to go.


You want to seal the TB to the plenum as well.....because....the plenum mouth is STAMPED sheet metal. It is not perfect in shape.....and a leaking TB to plenum seal is VERY common....and very hard to diagnose....because it frequently ONLY leaks when warmed up and the engine is vibrating.

I have been through the vacuum leak dance a thousand times......and in about 25% of all cases.....the TB seal....even new ones.....were a frequent leak and one of the last to be found and one of the hardest to find.


I have said this many times......when new VW fuel injected aircooled VW owners ask.....how to be sure vacuum hoses and joints are not leaking....when they "LOOK" fine, are relatively new and still flexible.

You do this by clampijg all hoses, sealing all gaskets and replace any line you do not know the age of condition of or installation technique.

Just seal it and you will KNOW its not leaking. Knowing what is NOT leaking is the fastest and most sure way to diagnose vacuum leaks.

Understand this as well. That gasket/o-ring is ahout .080" thick. You are compressing it between two surfaces. As it heats up and ages.....it flattens out and leaks. It is sealing a "CURVE" on one side and an angle on the other.
The most frequent cause of leaking....outside of the gasket being installed crooked.....is gasket compaction from heat and vibration. On about half of peoples fuel injected type 4's I have worked on over the years.....when you reach in and turn the TB mounting screws....they will easily turn a full turn at least. This means the clamping pressure between the TB and plenum.....is poor....because the gasket has flattened out.

Seal it both sides.

To take the plate out.....the best way is to take a Dremel rotary tool with a cut off wheel and carefully grind the small deformed nub away. Then the screw will come out. Ray
Back to top
View user's profile Send private message Gallery Classifieds Feedback
furgo
Samba Member


Joined: September 06, 2016
Posts: 816
Location: Southern Germany
furgo is offline 

PostPosted: Tue Feb 13, 2018 4:12 pm    Post subject: Re: Throttle body questions Reply with quote

Thanks for the clarification.

raygreenwood wrote:
when new VW fuel injected aircooled VW owners ask.....how to be sure vacuum hoses and joints are not leaking....when they "LOOK" fine, are relatively new and still flexible.

You do this by clampijg all hoses, sealing all gaskets and replace any line you do not know the age of condition of or installation technique.


That's actually the process I'm going through right now. When I did the (nearly) full vacuum hose replacement, I had missed the intake runner boots and the throttle body gasket, which I'm doing now.

I must say though, both the boots and the TB gasket were in much better shape that I thought. While the braid on the intake runner boots had frayed ends, the rubber had no cracks and was still very much elastic and firmly wrapping the runners. I still replaced them.

raygreenwood wrote:
Understand this as well. That gasket/o-ring is ahout .080" thick. You are compressing it between two surfaces. As it heats up and ages.....it flattens out and leaks. It is sealing a "CURVE" on one side and an angle on the other.
The most frequent cause of leaking....outside of the gasket being installed crooked.....is gasket compaction from heat and vibration. On about half of peoples fuel injected type 4's I have worked on over the years.....when you reach in and turn the TB mounting screws....they will easily turn a full turn at least. This means the clamping pressure between the TB and plenum.....is poor....because the gasket has flattened out.

Seal it both sides.


Ok, understood. I might have been the lucky other half though, as the mounting screws were still tight!

raygreenwood wrote:
To take the plate out.....the best way is to take a Dremel rotary tool with a cut off wheel and carefully grind the small deformed nub away. Then the screw will come out. Ray


Great, thanks for the tip!
_________________
'79 Westy, P22 interior, FI 2.0 l Federal, GE engine (hydraulic lifters)
Back to top
View user's profile Send private message Gallery Classifieds Feedback
furgo
Samba Member


Joined: September 06, 2016
Posts: 816
Location: Southern Germany
furgo is offline 

PostPosted: Fri Feb 16, 2018 9:23 am    Post subject: Re: Throttle body questions Reply with quote

I got the new throttle body gasket. According to the Volkswagen Classic parts, it's a VW remake with the same quality as the original part... only that the one they sent me was defective and had to give it back :/

Missing material on new gasket. A reminder to double-check all parts, even if they come directly from VW. TBH, I've had more defective parts sold from them than from any online reseller.

Image may have been reduced in size. Click image to view fullscreen.


New (left) vs old (right). Notice that on the new one the outer rim is a full circumference now. I don't know what the three notches on the old one were: IIRC there was no alignment to be made upon installation.

Image may have been reduced in size. Click image to view fullscreen.


New (left) vs old (right). Notice the thicker inner lip of the old one. This might be part of the defect on the new one, though.

Image may have been reduced in size. Click image to view fullscreen.


The idle speed screw and o-ring. Notice the fine pitch.

Image may have been reduced in size. Click image to view fullscreen.


Finally, I fabricated a stainless steel cover for the EGR valve opening on the plenum. I'm thinking I might be better off making a gasket without the central hole than using the original one, though.

Image may have been reduced in size. Click image to view fullscreen.

_________________
'79 Westy, P22 interior, FI 2.0 l Federal, GE engine (hydraulic lifters)
Back to top
View user's profile Send private message Gallery Classifieds Feedback
Display posts from previous:   
Reply to topic    Forum Index -> Bay Window Bus All times are Mountain Standard Time/Pacific Daylight Savings Time
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum

About | Help! | Advertise | Donate | Premium Membership | Privacy/Terms of Use | Contact Us | Site Map
Copyright © 1996-2018, Everett Barnes. All Rights Reserved.
Not affiliated with or sponsored by Volkswagen of America | Forum powered by phpBB