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The "Servo Hose" from the brake servo to the Intake manifold should use this nipple unless i'm reading the parts list wrong.

http://212.247.61.152/us/main.aspx?page=article&artno=947043

This one is also listed
http://212.247.61.152/us/main.aspx?page=articlelist&requery=1&searchstr=943199&searchfld=

And this Checkvalve, a somewhat generic part should should be available at any discount auto parts supplier

http://212.247.61.152/us/main.aspx?page=article&artno=678407


I can't go out and check my cars right now, but I do believe that this nipple has the large opening, and the one for the Crankcase breather has a small 2mm orafice. So take the hose off of the nipple currently on your Weber Intake Manifold. And see if it has a small 2mm orafice or a large opening. If it is the large opening then that goes to your Brake Servo (Booster) (As it has no flow it dosen't feed false air into the intake.) and you need to buy the smaller orafice nipple for the crankcase ventilation

Note the "Calibrated Hole" in the description to avoid "False Air"
http://212.247.61.152/us/main.aspx?page=article&artno=460082

If you have the Brake Servo Nipple in there now, that could be causing issues as your getting a lot of false air and running really lean at times

EDIT: Just Thought that as you took the SU's off, go look at that Manifold and see if there is still a nipple on it. Could be ... Then you just need to use the right nipple on the right hose and get the CheckValve and another couple feet of hose.
 

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On the only Weber downdraft retrofit kit that I have ever seen the base of the manifold under the carb was tapped for two ports. In that second photo it looks like there is a brass plug in the port just behind the connection from the manifold to the brake booster and oil separator on the side of the engine. The two ports permits, as noted by scaramoucheii, the installation of the correct unrestricted nipple for the brake booster and the correct restricted nipple for the PCV system. It looks to me like somebody got lazy with the installation or didn't understand the difference in the nipples. If you currently have the restricted nipple installed it will result in poor brake booster performance and if you have the unrestricted nipple installed it will screw up fuel mixture.

The wiring is 'interesting''. It would not instill confidence in driving very far away from home; but, I tend to be risk adverse. This does look like a good Covid 19 project since you are not going to run out of stuff to improve any time soon.
 

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If you currently have the restricted nipple installed it will result in poor brake booster performance and if you have the unrestricted nipple installed it will screw up fuel mixture.
Just to elaborate, with an un restricted nipple in the current configuration, you will get both "False Air" into the fuel mixture AND poor brake booster performance as air will be flowing past that "T" and not holding the correct static vacuum on the brake booster.

The Air from the Air Filter to the Oil Filler cap is correct, so you have that going for you.

I think you really need to scrub through this thread and see what rabbit hole it leads you down, as it does mention most all the options and ports on the Weber Downdraft.

https://forums.swedespeed.com/showthread.php?339953-B18-valve-breather-weber-placement
 

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If you look at the set-up (a) photo in that link provided by scaramoucheii, you will see the correct installation with separate vacuum lines for the PCV and the brake booster.
 

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Discussion Starter #25
Thanks for clarifying, looks like I have some issues. The vacuum lines were setup like that on the SU's figured it was ok. So I need to add the crankcase barb to the intake manifold and remove the T and add a PCV valve to the booster line.

There is a second fitting on the left side of the intake manifold (below the choke) that I blocked off, not sure if that should be used instead of adding a second fitting to the right side of the manifold? And can you elaborate on the 2mm hole on the crankcase vacuum fitting?

I just drive this car around town, usually <2 miles and <35 mph, sort of a "running" project at this point. Someday I'll have some shop space or a garage and can pull everything apart.
 

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Response to questions in bold and italic

There is a second fitting on the left side of the intake manifold (below the choke) that I blocked off, not sure if that should be used instead of adding a second fitting to the right side of the manifold? - My understanding is that fitting is not used for anything. Plus, it is on the wrong side of the throttle plate so it won't have any significant vacuum so useless for either the brake booster or the PVC system. The two side by side ports at the base of the carb are the correct ports for the PCV and brake booster.

And can you elaborate on the 2mm hole on the crankcase vacuum fitting? - scaramoucheii provided this link to the correct fitting for use with the PCV system http://212.247.61.152/us/main.aspx?page=article&artno=460082. From the outside it may look like a conventional nipple; but, when you look down the bore of the nipple you will see that the internal diameter is restricted by a 2 mm orifice to limit the airflow.
 

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And can you elaborate on the 2mm hole on the crankcase vacuum fitting?
2 thousand words worth. the one on the left is the Brake Booster. These came from a D-Jet, but are the same on my B20B. AB1I0252.jpg

***
THERE IS A SLIGHT DIFFERENCE IN OUTSIDE APPEARANCE AS WELL


AB1I0253.jpg

EDIT: If you need one or the Other PM me, I have boxes of bits for sale ....
 

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Just watching the Amazon up for sale on BaT

Seems he also has the "T" arrangement. Look at the Engine photos.

I wonder what Nipple he has in there? In this case you may as well have the 2mm restrictor PVC nipple as the brake Booster won't get any Vacuum anyway as it's vented to the crankcase.

On These Alloy Manifolds there is an additional port on the front end of the cross flow that can be used for the second nipple. The Very early B18 cars that had neither Power Brakes or a PVC system I cann't comment on as I haven't experienced those. I'll write more later with pictures and comments of the Manifolds I have

https://bringatrailer.com/listing/1967-volvo-122s-35/
 

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Here are some images of various Intake vacuum arrangements

All the pictures are of my cars / spare parts except the first one, (Blue Amazon)

You Should make sure all your nipples are clean and clear and that the Flame Trap is also cleaned and not clogged with old oil and dust.


**** Amazon B20A ****
70_122_B20A.jpg
  • The Oil Filler Cap gets fresh air in, from the air filter (This is correct on your cars Weber)
  • The Brake Booster gets static Vacuum from the unrestricted nipple on the Intake above Cylinders 1 and 2.
  • The PVC Vacuum Nipple is in the center of the Manifold, as it needs to feed it's "False but regulated" air equally to both cylinders 1-2 and 3-4.
  • NOTE On This car it is missing the hose that goes from the Flame trap to this PVC Intake Nipple, but it makes it clearly visible it's location on the Manifold.



**** 1973 1800ES Intake Manifold - D-Jet ******
73_1800ES_B20E.jpg
  • 2mm restricted nipple between the Intake Runners to share the REGULATED crankcase air between cylinders 1-2 and 3-4
  • The Unrestricted Brake Booster nipple in a central area of the manifold cavity.
  • Note the "Spare" vacuum port most likely for cars that used the Vacuum Accumulator for Heater Vent Controls
  • On my 1800ES I run the Oil Filler cap vent to the 2mm restricted nipple and have an Air Filter on the Flame Trap (see 142 below)


**** 1973 142 Intake Manifold - B20B Twin SU's ******
73_142_B20B.jpg
  • 2mm restricted nipple between the Intake Runners to share the REGULATED crankcase air between cylinders 1-2 and 3-4
  • NOTE this is biased a little bit towards the front cylinders 1-2, and there is a second CAPPED port just behind it,
  • Air to the Crankcase enters through the air filter on the Flame Trap and out the Oil Filler cap to the intake manifold 2mm nipple.
  • NOTE The FLOW is in the opposite direction to your car but makes little if any difference and eliminates a hose
  • The Unrestricted Brake Booster nipple Between Cylinders 1-2
  • Un Restricted nipple for Heater Control Vacuum Accumulator between cylinders 3-4

**** 19?? Alloy Intake Manifold - B18/20B Twin SU's ******
Unknown_Year_intake_manifold_B20B_2.jpg
Unknown_Year_intake_manifold_B20B.jpg

  • [*Currently a Unrestricted Brake Booster Nipple installed in the center of the crossflow. So maybe came off a car with a Brake Booster and no PVC?
  • 2mm restricted nipple could be installed between the Intake Runners to share the REGULATED crankcase air between cylinders 1-2 and 3-4
  • Then the Unrestricted Brake Booster could be attached to the FRONT of the cross flow where the plug currently is
  • NO place for a nipple for Heater Control Vacuum Accumulator, so if you used this manifold on a car that needs that you would need to add a 2 port fitting to the SPARE port in front of Cylinders 1-2
 

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Discussion Starter #32
Here are some images of various Intake vacuum arrangements

All the pictures are of my cars / spare parts except the first one, (Blue Amazon)

You Should make sure all your nipples are clean and clear and that the Flame Trap is also cleaned and not clogged with old oil and dust.


**** Amazon B20A ****
View attachment 64331
  • The Oil Filler Cap gets fresh air in, from the air filter (This is correct on your cars Weber)
  • The Brake Booster gets static Vacuum from the unrestricted nipple on the Intake above Cylinders 1 and 2.
  • The PVC Vacuum Nipple is in the center of the Manifold, as it needs to feed it's "False but regulated" air equally to both cylinders 1-2 and 3-4.
  • NOTE On This car it is missing the hose that goes from the Flame trap to this PVC Intake Nipple, but it makes it clearly visible it's location on the Manifold.



**** 1973 1800ES Intake Manifold - D-Jet ******
View attachment 64319
  • 2mm restricted nipple between the Intake Runners to share the REGULATED crankcase air between cylinders 1-2 and 3-4
  • The Unrestricted Brake Booster nipple in a central area of the manifold cavity.
  • Note the "Spare" vacuum port most likely for cars that used the Vacuum Accumulator for Heater Vent Controls
  • On my 1800ES I run the Oil Filler cap vent to the 2mm restricted nipple and have an Air Filter on the Flame Trap (see 142 below)


**** 1973 142 Intake Manifold - B20B Twin SU's ******
View attachment 64333
  • 2mm restricted nipple between the Intake Runners to share the REGULATED crankcase air between cylinders 1-2 and 3-4
  • NOTE this is biased a little bit towards the front cylinders 1-2, and there is a second CAPPED port just behind it,
  • Air to the Crankcase enters through the air filter on the Flame Trap and out the Oil Filler cap to the intake manifold 2mm nipple.
  • NOTE The FLOW is in the opposite direction to your car but makes little if any difference and eliminates a hose
  • The Unrestricted Brake Booster nipple Between Cylinders 1-2
  • Un Restricted nipple for Heater Control Vacuum Accumulator between cylinders 3-4

**** 19?? Alloy Intake Manifold - B18/20B Twin SU's ******
View attachment 64327
View attachment 64329

  • [*Currently a Unrestricted Brake Booster Nipple installed in the center of the crossflow. So maybe came off a car with a Brake Booster and no PVC?
  • 2mm restricted nipple could be installed between the Intake Runners to share the REGULATED crankcase air between cylinders 1-2 and 3-4
  • Then the Unrestricted Brake Booster could be attached to the FRONT of the cross flow where the plug currently is
  • NO place for a nipple for Heater Control Vacuum Accumulator, so if you used this manifold on a car that needs that you would need to add a 2 port fitting to the SPARE port in front of Cylinders 1-2
This is great, thank you! I was able to get the vacuum lines re-routed, just ended up having to order the pcv online so will get that added. Also, I was able to find the old fitting with my stock manifold so I got that installed too.
 

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So the nipple that you have currently in the Weber that has the Crankcase hose connected (with the T to the brake booster) Looks like a NON VOLVO nipple. so just curious if this was a Un Restricted nipple? Looks like it most likely is.

Would be good to know and if this was part of your problem

Also don't forget to re-tune the Weber after you get this sorted out

****

Screen Shot 2020-08-01 at 10.18.13 AM.jpg
 

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It looks like a rather pedestrian NPT-barbed fitting from Home Depot et al. Should work just fine for the brake booster connection. Definitely not OK for the PCV connection which requires the restricting orifice.

Since we seem to have strayed slightly from the original topic, to add to your to-do list those serrated adjustable hose clamps that you have on your various rubber lines are really meant for use on garden hoses and the like. They should be avoided on a car as the serrations tend to chew up the hose rubber. The best solution is the spring style clamp used on modern cars; but, everybody hates those because they have to be sized correctly and they can be a hassle to remove and install. The next best solution is the banded hose clamp which does not have the rubber eating serrations on it. In the picture above the clamp on the fuel filter hose is a correct banded clamp.

Finding a local supplier of banded clamps that fit fuel lines is normally fairly easy to do. Finding banded clamps for the larger hoses like heater hoses and rad hoses may not be so easy. I had to go to a hydraulic hose specialist to find good banded clamps locally. Something more that you can add to your to-do list if you get bored.
 

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Discussion Starter #35
So I got the restricted nipple installed and you're right looks like a genertic plumbling nipple for the other. I don't really see any changes but still good to get this sorted out. Got the check valve in the mail so going to install that and try this other distributor today.

And you're 100% right re: the clamps, I just haven't been able to find any locally. Bought some online but they were the wrong size. I'll add it to my list next trip down to LA.
 

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Discussion Starter #36
Ok that didn't go so great, I had switched the #2 and #3 wires on the distributor and had a nice backfire.

I think it's right now although with the ignition on and a timing light attached I don't see the light when spinning the crank around. But I know it's getting spark bc the backfire. Is there another way to test I have this hooked up right?

I rotated the distributor so the rotor is slightly before (counter clockwise) the #1 wire while the #1 cyl is 10 deg btdc.

 

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That appears to be correct. By timing light do you mean an inductive timing light or a test light on the points? I assume an inductive timing light and you have the pick-up on the #1 spark lead? Is the arrow on the pick-up pointed in the correct direction? I know that my inductive pick up timing light has a 'correct' orientation for the pick up (arrow points to spark plug). If for some other reason the plug is not firing the timing light will not fire. I suggest trying the old fashioned pull the plug from the head and hold the ground electrode against the head to check for spark across the electrode gap while cranking the engine. If you have a spark at the plug gap and the timing light is not flashing then you may have a timing light problem. If you have no spark then other things are at play.

When all else fails, go here for enlightenment:

https://www.sw-em.com/Volvo Ignition from Scratch.htm
 

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Discussion Starter #38
Yep got an inductive timing light, just weird I couldn't see the light flash when spinning the crank slowly. Going to try an inline spark plug light tomorrow, I just want to be sure the timing is 100% correct before giving it another try. I'll read through the sw-em link too, thanks!
 

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Guys;

Is it me...?...but this thread is all over the place!!..the title is "Car bogs down at 4500 RPMs" (which the video didn't even show!)...then carbs...now we have swapped plug wires and no spark...it's like the English Setters of threads...I don't even know where to start...well maybe I do...I suggest you get your ignition working and able to start engine...

Good Hunting!
 

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Yep got an inductive timing light, just weird I couldn't see the light flash when spinning the crank slowly. Going to try an inline spark plug light tomorrow, I just want to be sure the timing is 100% correct before giving it another try. I'll read through the sw-em link too, thanks!
Perhaps your using the light incorrectly. You don't spin the crank slowly, you run the engine at idle, and the "Strobe" effect of the timing light will show you where the timing marks line up when #1 spark plug fires. should be 10 D btdc, then when you increase the RPM you will see the timing marks re align as the timing advances, caused by the centrifigulal mechanism within the distributor, which should max out at ~32 D btdc once the RPM is over ~ 2.5K

EDIT: Added these links. Note that the frame rate of the video is probably 29 Frames per second, and @ 900 RMP the #1 plug only fires 15 times a seconds, and it has to align with the frame of the video, so the Strobe effect in the video is not how it looks in real life, you should see a constant strobe effect at ~ 15 flashes per second at 900RMP

https://www.youtube.com/watch?v=MX3vsRDfKJg

https://www.youtube.com/watch?v=wifTHbb06_I
 
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