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cdorety
Samba Member
Joined: May 10, 2021
Posts: 23
Location: OR
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 Posted: Fri Sep 09, 2022 1:38 pm Post subject: yet another balance tube question. '68 T3, dual weber 34ict |
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Hey all,
Boy oh boy, I have been all up under and inside my squareback this week.
I'm still new to all this, but I learn a lot every time I get in there....and on thesamba
The previous owner had this engine built...roughly 6000 miles ago.
It's got a 34 ict on each side with dual port manifolds.
The manifolds were never drilled and tapped for a balance tube.
(Here are the other threads on the t3 forum about this subject that I could find -- https://www.thesamba.com/vw/forum/search.php?searc...=titleonly
So here's my two dumb questions....
1. Do I need a balance tube on this setup? as it seems to run pretty good without
and if I do
2. Can I use the vacuum port which already exists at the bottom of the carb? It seems that location would share the same pressure with the dual port manifold. (right now they are capped with rubber)
thanks! |
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Bobnotch
Samba Member
Joined: July 06, 2003
Posts: 23529
Location: Kimball, Mi
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| Posted: Fri Sep 09, 2022 2:43 pm Post subject: Re: yet another balance tube question. '68 T3, dual weber 34ict |
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If it runs well without a balance tube, run it without it. The balance tube is mainly for idle, as at low engine speed vacuum pulls from both sides of the engine to "help balance" it out.
As for using the vacuum port at the base of the carb, you're wasting your time trying to use it as a balance port, as it's not large enough to pull any air.
I hope this helps.
_________________
Bob 65 Notch S with Sunroof
71 Notch ...aka Krunchy; build pics here;
http://www.thesamba.com/vw/forum/viewtopic.php?t=249390 -been busy working
64 T-34 Ghia...aka Wolfie, under construction... http://www.thesamba.com/vw/forum/viewtopic.php?t=412120
| Tram wrote: |
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| Tram wrote: |
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cdorety
Samba Member
Joined: May 10, 2021
Posts: 23
Location: OR
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| Posted: Fri Sep 09, 2022 4:15 pm Post subject: Re: yet another balance tube question. '68 T3, dual weber 34ict |
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| Bobnotch wrote: |
If it runs well without a balance tube, run it without it. The balance tube is mainly for idle, as at low engine speed vacuum pulls from both sides of the engine to "help balance" it out.
As for using the vacuum port at the base of the carb, you're wasting your time trying to use it as a balance port, as it's not large enough to pull any air.
I hope this helps. |
Thanks Bob!
It idles just fine and sounds good and steady at around 975 rpm. Takes just a few moments after starting to warm up and settle into that.
Maybe someday if I'm in that deep, I'll drill and tap the manifolds and put balance ports on there. |
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Bobnotch
Samba Member
Joined: July 06, 2003
Posts: 23529
Location: Kimball, Mi
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| Posted: Sat Sep 10, 2022 12:32 pm Post subject: Re: yet another balance tube question. '68 T3, dual weber 34ict |
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| cdorety wrote: |
Thanks Bob!
It idles just fine and sounds good and steady at around 975 rpm. Takes just a few moments after starting to warm up and settle into that.
Maybe someday if I'm in that deep, I'll drill and tap the manifolds and put balance ports on there. |
Yeah, I wouldn't tear it apart just to add a balance tube or drill and tap the manifolds. I'd wait until I have the engine out for another reason, or I'd buy another set of manifolds (that are already drilled and tapped) from CB Performance and install them over the winter or while the car is down.
The 975 rpm at idle sounds a little high, but if your car has an automatic trans that's about right.
_________________
Bob 65 Notch S with Sunroof
71 Notch ...aka Krunchy; build pics here;
http://www.thesamba.com/vw/forum/viewtopic.php?t=249390 -been busy working
64 T-34 Ghia...aka Wolfie, under construction... http://www.thesamba.com/vw/forum/viewtopic.php?t=412120
| Tram wrote: |
| "Friends are God's way of apologizing for relatives." |
| Tram wrote: |
| People keep confusing "restored" and "restroyed". |
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cdorety
Samba Member
Joined: May 10, 2021
Posts: 23
Location: OR
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| Posted: Mon Sep 12, 2022 10:09 am Post subject: Re: yet another balance tube question. '68 T3, dual weber 34ict |
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| Bobnotch wrote: |
Yeah, I wouldn't tear it apart just to add a balance tube or drill and tap the manifolds. I'd wait until I have the engine out for another reason, or I'd buy another set of manifolds (that are already drilled and tapped) from CB Performance and install them over the winter or while the car is down.
The 975 rpm at idle sounds a little high, but if your car has an automatic trans that's about right. |
I'm still getting used to tuning the carbs....It might be less than 975. I don't have a tach other than the ISPwest one I put in the dash. The needle hovers a little under 10 (1000rpm) when warm.
Also, on one of the carbs, there's something going on with the throttle control lever and the associated parts there. Things are a little loose and don't seem to want to tighten properly. So the lever wiggles a bit and doesn't always return all the way.
I'll be addressing that shortly.
Ah, and btw, it is a manual trans. I believe it is original, but I don't know much about this car's history.
Thanks again |
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Multi69s
Samba Member
Joined: January 24, 2006
Posts: 5562
Location: Lefty, CA
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| Posted: Mon Sep 12, 2022 10:59 am Post subject: Re: yet another balance tube question. '68 T3, dual weber 34ict |
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Even though I like them, ICTs never seem to have the same balance tube requirements from engine to engine. Some need a balance tube, while others don't. You even see this when looking at similar engines. If it runs good with out the BT don't worry about it. As far as the vacuum ports on the carbs, they are way to small to really do anything. Now if you wanted to run a SVDA distributer, you could pull vacuum from those ports. However, it would be manifold vacuum, which requires a little different approach to tuning. But if you have a rough idle, it will usually clean it up.
_________________
69 road Bug 2110
73 Squareback - 2L, T4, Automatic W/ AC
Gone, but many fond memories 69 Baja Bug 2010 - 5 Rib Bus Transaxle
Gone but not forgotten 72 Baja Bug 2010
My builds
T4 into Squareback http://www.thesamba.com/vw/forum/viewtopic.php?t=458944&highlight=
Auto Trans Rebuild http://www.thesamba.com/vw/forum/viewtopic.php?t=516066&highlight=
AC in Squareback https://www.thesamba.com/vw/forum/viewtopic.php?t=...highlight= |
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cdorety
Samba Member
Joined: May 10, 2021
Posts: 23
Location: OR
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| Posted: Tue Sep 13, 2022 9:47 am Post subject: Re: yet another balance tube question. '68 T3, dual weber 34ict |
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| Multi69s wrote: |
| Even though I like them, ICTs never seem to have the same balance tube requirements from engine to engine. Some need a balance tube, while others don't. You even see this when looking at similar engines. If it runs good with out the BT don't worry about it. As far as the vacuum ports on the carbs, they are way to small to really do anything. Now if you wanted to run a SVDA distributer, you could pull vacuum from those ports. However, it would be manifold vacuum, which requires a little different approach to tuning. But if you have a rough idle, it will usually clean it up. |
Thanks!
It's got an 009 with electronic ignition. So far so good. |
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