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PCV for Weber carbs?
https://slantsix.org/forum/viewtopic.php?t=29460		 Page 1 of 2
Author:  Wesola78 [ Wed Jun 11, 2008 12:31 pm ]
Post subject:  PCV for Weber carbs?
I'm about to install a 2bbl Weber carb (36DCNVA) onto an Offy 4bbl manifold with an adapter. Where do I connect the hose coming from the PCV?
Thanks, thanks, thanks, in advance!!!
Wes
Author:  Wizard [ Wed Jun 11, 2008 12:42 pm ]
Post subject: 
Central manifold vacuum for even distribution.

Cheers, Wizard
Author:  coconuteater64 [ Wed Jun 11, 2008 1:55 pm ]
Post subject: 
I teed into my power brake line. So far, so good.
Author:  LUCKY13 [ Wed Jun 11, 2008 6:36 pm ]
Post subject: 
You "dont" want to hook it to the number six runner vacum port, it will lean that cylinder down and cause the exhaust valve to burn.



Jess
Author:  SlantSixDan [ Wed Jun 11, 2008 6:48 pm ]
Post subject: 
Jess is correct; you must not connect your PCV to the rearmost intake runner. It needs to go to the central plenum area of the intake. If there's no such provision on your Weber carb, drill and tap the intake or the adaptor for a pipe nipple.
Author:  coconuteater64 [ Wed Jun 11, 2008 10:32 pm ]
Post subject: 
Not to steal a thread, but you're saying I should move mine? It's not been on there but a few months, and I haven't changed the plugs yet, so I don't know what it might be doing to that cylinder. Am I destroying something?
Author:  68barracuda [ Wed Jun 11, 2008 10:32 pm ]
Post subject: 
Still weber related

With the manifold project we will not be drilling the #6 boss - thinking of leaving it out totally.

The plenum balancer tube will be getting either a christmas tree or - a mini plenum with different nipples on it for pcv, brake booster, vacuum for ac etc.
Author:  68barracuda [ Wed Jun 11, 2008 10:50 pm ]
Post subject: 
Quote:
Not to steal a thread, but you're saying I should move mine? It's not been on there but a few months, and I haven't changed the plugs yet, so I don't know what it might be doing to that cylinder. Am I destroying something?
Yup - that and the brake line to a central position - so all cylinder are affected the same way

If your carb is not equipped with a full vac port - you have to drill and tap the plenum and install a nipple - as Dan said
Author:  SlantSixDan [ Thu Jun 12, 2008 7:28 am ]
Post subject: 
Quote:
Not to steal a thread, but you're saying I should move mine?
Yes. Sooner = better. You're introducing a whackload of extra air into the rearmost cylinder and causing it to run lean. This is very bad for the health of cheap things like spark plugs and expensive things like valves and pistons.

I wouldn't worry about the power brake booster line, if applicable; a central location would be preferable for that one, but it just admits occasional gulps of not very much air and the factory did use the #6 runner for that hose.
Author:  coconuteater64 [ Thu Jun 12, 2008 11:55 am ]
Post subject: 
Will do! :shock:
Author:  LUCKY13 [ Thu Jun 12, 2008 3:36 pm ]
Post subject: 
coconuteater64


You should notice a smoother running engine when you move the PVC, Carb idle mix screw ajustment may be needed after making the move.



Jess
Author:  Wesola78 [ Fri Jun 13, 2008 11:09 am ]
Post subject: 
Update: The Weber carb is on and she runs. I still need to hook up the trans kickdown linkage, and I still don't have the PCV hooked up yet. I guess I'll have to drill a hole and tap it, probably in the carb adapter.
Thanks for all the responses guys!
Wes
Author:  Joshie225 [ Fri Jun 13, 2008 12:37 pm ]
Post subject: 
My Offy manifold has a drilled and tapped hole on the outside center of the plenum. Would be easy to add if it's not already there.
Author:  Wesola78 [ Fri Jun 13, 2008 8:50 pm ]
Post subject: 
Josh,
I read your reply, and then I remembered that there is a trheaded hole on my Offy manifold where you described. I plugged it with a brass plug years ago. Its not that big, but I guess a PCV port doesn't have to be big, is that right?
Author:  SlantSixDan [ Sat Jun 14, 2008 7:42 am ]
Post subject: 
The PCV inlet needs an 11/32" O.D. pipe nipple. That's not a common size, so usually you go to 3/8".
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