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tips, technology, tools and techniques related to vehicle driveline components

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donfaber
Don Faber
Terra Alta WV
(117 posts)

Registered:
10/31/2007 10:53PM

Main British Car:
1979 MGB 3.9L Rover V8

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Crankcase ventilation Rover 3.9L V8 w/ Edelbrock carb
Posted by: donfaber
Date: July 27, 2021 12:13PM

In a nutshell (I'm 66 and still learning) - for my rover V8 with Edelbrock carb.... PVC valve from one valve cover to base of Carb, vent line from other valve cover to air filter inlet on carb.


donfaber
Don Faber
Terra Alta WV
(117 posts)

Registered:
10/31/2007 10:53PM

Main British Car:
1979 MGB 3.9L Rover V8

authors avatar
Re: Crankcase ventilation Rover 3.9L V8 w/ Edelbrock carb
Posted by: donfaber
Date: July 27, 2021 09:44PM

Is the setup I've described "correct?"


DiDueColpi
Fred Key
West coast - Canada
(1386 posts)

Registered:
05/14/2010 03:06AM

Main British Car:
I really thought that I'd be an action figure by now!

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Re: Crankcase ventilation Rover 3.9L V8 w/ Edelbrock carb
Posted by: DiDueColpi
Date: July 27, 2021 10:00PM

Absolutely Don. It's the classic way to ventilate the engine. And it will work just fine. You will have to play around with PCV sizes to fine tune it, mostly to stabilize the idle.
The more modern set up is to use a constant depression regulator to provide a regulated pressure drop inside the engine. This is a little more complex to achieve but it virtually eliminates oil leaks. That's the downside as you no longer know if your British car has oil in it.
Live like you mean it.
Fred
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donfaber
Don Faber
Terra Alta WV
(117 posts)

Registered:
10/31/2007 10:53PM

Main British Car:
1979 MGB 3.9L Rover V8

authors avatar
Re: Crankcase ventilation Rover 3.9L V8 w/ Edelbrock carb
Posted by: donfaber
Date: July 28, 2021 10:08AM

Thanks, Fred!


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(6516 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

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Re: Crankcase ventilation Rover 3.9L V8 w/ Edelbrock carb
Posted by: BlownMGB-V8
Date: July 28, 2021 02:52PM

Use the largest practical hose you can for the vent line. 3/4 is good and 1" isn't too big. 5/8" would be OK if these engines didn't have a reputation for blowby. Be sure there is a flame trap in that line.

Jim


MGBV8
Carl Floyd
Kingsport, TN
(4574 posts)

Registered:
10/23/2007 11:32PM

Main British Car:
1979 MGB Buick 215

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Re: Crankcase ventilation Rover 3.9L V8 w/ Edelbrock carb
Posted by: MGBV8
Date: July 29, 2021 09:29AM

"The more modern set up is to use a constant depression regulator to provide a regulated pressure drop inside the engine. This is a little more complex to achieve but it virtually eliminates oil leaks. "

Would love to hear more about this, Fred. As Jim mentioned, these engines tend to be heavy breathers.


donfaber
Don Faber
Terra Alta WV
(117 posts)

Registered:
10/31/2007 10:53PM

Main British Car:
1979 MGB 3.9L Rover V8

authors avatar
Re: Crankcase ventilation Rover 3.9L V8 w/ Edelbrock carb
Posted by: donfaber
Date: July 29, 2021 12:45PM

Jim - I assume that's not the same as a breather - can you recommend a flame trap or supplier? Thanks



DiDueColpi
Fred Key
West coast - Canada
(1386 posts)

Registered:
05/14/2010 03:06AM

Main British Car:
I really thought that I'd be an action figure by now!

authors avatar
Re: Crankcase ventilation Rover 3.9L V8 w/ Edelbrock carb
Posted by: DiDueColpi
Date: July 29, 2021 01:13PM

Virtually all newer vehicles use some form of this breather system Carl.
It's essentially a large pressure regulator connected between the crankcase and the intake plenum.
It maintains a constant pressure drop differential in the crankcase of around 2 psi. No other vents or breathers are used.
It works very well. We see engines with several hundred thousand miles on them that are perfectly dry.
A good example is the Jag/Rover part AJ87773 to give you an idea.


ex-tyke
Graham Creswick
Chatham, Ontario, Canada
(1166 posts)

Registered:
10/25/2007 11:17AM

Main British Car:
1976 MGB Ford 302

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Re: Crankcase ventilation Rover 3.9L V8 w/ Edelbrock carb
Posted by: ex-tyke
Date: July 30, 2021 08:06AM

Crankcase Control Vent Valve AJ87773.png
Here ya go, Carl!


MGBV8
Carl Floyd
Kingsport, TN
(4574 posts)

Registered:
10/23/2007 11:32PM

Main British Car:
1979 MGB Buick 215

authors avatar
Re: Crankcase ventilation Rover 3.9L V8 w/ Edelbrock carb
Posted by: MGBV8
Date: July 30, 2021 09:23AM

I need one!


donfaber
Don Faber
Terra Alta WV
(117 posts)

Registered:
10/31/2007 10:53PM

Main British Car:
1979 MGB 3.9L Rover V8

authors avatar
Re: Crankcase ventilation Rover 3.9L V8 w/ Edelbrock carb
Posted by: donfaber
Date: July 30, 2021 10:20AM

Let me know where u find it, Carl!
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BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(6516 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: Crankcase ventilation Rover 3.9L V8 w/ Edelbrock carb
Posted by: BlownMGB-V8
Date: July 30, 2021 10:22AM

Is that any different from the big metal one used on the TR4? So no fresh air inlet with those huh?

Jim


ex-tyke
Graham Creswick
Chatham, Ontario, Canada
(1166 posts)

Registered:
10/25/2007 11:17AM

Main British Car:
1976 MGB Ford 302

authors avatar
Re: Crankcase ventilation Rover 3.9L V8 w/ Edelbrock carb
Posted by: ex-tyke
Date: July 30, 2021 11:59AM

Seems to be used on 2000 - 2009 vintage Jags.
Could spend $50+ for a new one, try the wrecking yards or steal one off Kelly's XK8 .



Edited 1 time(s). Last edit at 07/30/2021 12:00PM by ex-tyke.


DiDueColpi
Fred Key
West coast - Canada
(1386 posts)

Registered:
05/14/2010 03:06AM

Main British Car:
I really thought that I'd be an action figure by now!

authors avatar
Re: Crankcase ventilation Rover 3.9L V8 w/ Edelbrock carb
Posted by: DiDueColpi
Date: July 30, 2021 01:35PM

Nope no fresh air Jim just a light vacuum. The Oringed part goes to the valve cover and the barbed fitting goes straight into the intake manifold plenum. A silicone diaphram and spring regulate the pressure in the crankcase.
Try undoing the oil filler cap while the engine is running Graham. You'll see what I'm talking about.


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(6516 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: Crankcase ventilation Rover 3.9L V8 w/ Edelbrock carb
Posted by: BlownMGB-V8
Date: July 31, 2021 09:36AM

So... is that any different from the big metal one used on the 1966 TR4?

Jim



MGBV8
Carl Floyd
Kingsport, TN
(4574 posts)

Registered:
10/23/2007 11:32PM

Main British Car:
1979 MGB Buick 215

authors avatar
Re: Crankcase ventilation Rover 3.9L V8 w/ Edelbrock carb
Posted by: MGBV8
Date: July 31, 2021 09:42AM

Sounds like an oversize PCV.


donfaber
Don Faber
Terra Alta WV
(117 posts)

Registered:
10/31/2007 10:53PM

Main British Car:
1979 MGB 3.9L Rover V8

authors avatar
Re: Crankcase ventilation Rover 3.9L V8 w/ Edelbrock carb
Posted by: donfaber
Date: July 31, 2021 02:51PM

Found #379-580 - for 70-71 TR6 - Moss Motors


ex-tyke
Graham Creswick
Chatham, Ontario, Canada
(1166 posts)

Registered:
10/25/2007 11:17AM

Main British Car:
1976 MGB Ford 302

authors avatar
Re: Crankcase ventilation Rover 3.9L V8 w/ Edelbrock carb
Posted by: ex-tyke
Date: July 31, 2021 03:36PM

A GM version of the crankcase regulator valve # 25097699
GM No. 25097699 crankcase valve.png


MGBV8
Carl Floyd
Kingsport, TN
(4574 posts)

Registered:
10/23/2007 11:32PM

Main British Car:
1979 MGB Buick 215

authors avatar
Re: Crankcase ventilation Rover 3.9L V8 w/ Edelbrock carb
Posted by: MGBV8
Date: August 01, 2021 10:06AM

"Found #379-580 - for 70-71 TR6 - Moss Motors"

Moss says that is a just flame trap, Don.
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BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(6516 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: Crankcase ventilation Rover 3.9L V8 w/ Edelbrock carb
Posted by: BlownMGB-V8
Date: August 01, 2021 11:25AM

[rimmerbros.com]
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