ausmini
https://www.ausmini.com/forums/

PCV and Brake Servo vacuum fittings.
https://www.ausmini.com/forums/viewtopic.php?f=2&t=102135		 Page 1 of 1
Author:  gtr161 [ Mon Jan 22, 2024 4:01 pm ]
Post subject:  PCV and Brake Servo vacuum fittings.
Hi All, not sure if this has been covered before, some stuff pops up in a search but not exactly what Im looking for.
I have the aftermarket alloy twin inlet manifold for HS4, it has a drilling in the top for either the PCV valve,(or brake servo vacuum fitting), and a flat undrilled section next to it.
Im not sure if the PCV and brake servo fittings are different (although I suspect they are), I have one fitting but not sure which one it is.
Presumably I will need to drill and tap the flat blanked off section on top of the manifold to accept the brake servo fitting?
So i guess my questions are:
are the two fittings different?
what are the differences? (dia?)
are the threads different?
are they available?
Cheers,
Author:  timmy201 [ Mon Jan 22, 2024 5:39 pm ]
Post subject:  Re: PCV and Brake Servo vacuum fittings.
Do your HS4 carbs have ports for the CCV breathers? That might be a better option than trying to use a PCV
Author:  gtr161 [ Mon Jan 22, 2024 6:50 pm ]
Post subject:  Re: PCV and Brake Servo vacuum fittings.
Cheers ‘Timmy’, but no.. I have the 1/2” nipple are lead to believe the brake servo nipple is 3/8”


Sent from my iPhone using Tapatalk
Author:  68+86auto [ Mon Jan 22, 2024 7:11 pm ]
Post subject:  Re: PCV and Brake Servo vacuum fittings.
What are you trying to connect?

If you are trying to connect both you can simply use a T piece. If you carb has the CCV port it is better to use that for the breather and remove the PCV.
Author:  TDS76 [ Mon Jan 22, 2024 9:38 pm ]
Post subject:  Re: PCV and Brake Servo vacuum fittings.
I can't say for your HS4 manifold, but on my Cooper S HS2 AEG572 manifold both the PCV and servo holes are 5/8 UNF - I have bunged them both with ADP210 plugs.

Cheers, Paul
Author:  gtr161 [ Tue Jan 23, 2024 8:08 am ]
Post subject:  Re: PCV and Brake Servo vacuum fittings.
Hi all, thnaks for the responses. My carbs dont have the CCV ports, and Im after the original 'look' of the PCV - if I have to change it later, i'll cross that bridge then. What I need to know is, are the brake servo and PCV vacuum take off fittings the same? Or different sizes?
Cheers, Tom
Author:  TDS76 [ Tue Jan 23, 2024 11:53 am ]
Post subject:  Re: PCV and Brake Servo vacuum fittings.
These are as removed from my manifold. I cannot be sure that they are correct as a few things on the twins were also not right.

Attachment:
IMG_5019.jpg


Note that the PCV fitting diameter is 0.48" as measured with verniers, but the equivalent fitting on the PCV itself measures exactly 0.5".
Author:  Bill B [ Tue Jan 23, 2024 1:54 pm ]
Post subject:  Re: PCV and Brake Servo vacuum fittings.
I agree with TDS76 on the size of the 2 original hose adaptors, although I have them around the other way i.e. larger one on the PCV, but likewise, can't guarantee they are as per original. The brake booster takeoff has a slightly smaller opening but both adaptors have the same 0.5" O.D. from the flare down.
Attachment:
AEG573 manifold vacuum takeoff.jpg


Before you go drilling and tapping, I recommend you collect all the fittings for both ends of both hoses, as at least one adaptor is NLA and if using a VH44 booster, they have a smaller diameter (at 0.35") non-return valve than they used in 1970s.
Attachment:
VH44 booster non return valve.jpg
Author:  TDS76 [ Tue Jan 23, 2024 3:31 pm ]
Post subject:  Re: PCV and Brake Servo vacuum fittings.
I just checked the Tony Cripps book, and he has it the same way as Bill, so looks like mine were fitted the wrong way round.

Cheers, Paul.
Author:  gtr161 [ Tue Jan 23, 2024 5:10 pm ]
Post subject:  Re: PCV and Brake Servo vacuum fittings.
Thanks all… sorted now


Sent from my iPhone using Tapatalk
Page 1 of 1 All times are UTC + 10 hours
Powered by phpBB® Forum Software © phpBB Group
http://www.phpbb.com/