Vacuum open inlet

[BigBrother-84]

Hi Gentlemen!

I am making some cleaning underhood and I am wondering if I accidentally disconnected something...


Is it normal that there is an open inlet vacuum circuit, I don't remember it.


If I block it, the engine RPM drop.

Thanks for advice!

[85lebaront2]

That would have gone to the evaporative canister purge. Cap it.

[ArdWrknTrk]

Many PCV valves are sold with that top outlet blocked (and you have to snip the end of or ream them)
So definitely put a vacuum cap on it.

I am not certain if your Canadian 351HO would have had something attached but I don't see anything on your reproduction vacuum label.  
Surprised you wouldn't have heard it if it was open before.

Another good find!
You'll have much better oil control and the oil will stay cleaner too.

[BigBrother-84]

Thanks guys!

ArdWrknTrk wrote

Surprised you wouldn't have heard it if it was open before.

Jim, I pulled out the valve to give some blue paint refresh on the engine valves covers.
It was quiet dirty, so I cleaned it thoroughly.
Maybe this could explain why I didn’t hear this vacuum noise before?


Anyway, going to cap it, thanks for the advice!

[ArdWrknTrk]

It's pretty hard to completely  block a PCV and I know you take good care of your truck.
Back in the day we used the does it rattle method of determining useful life.

I Googled a PCV valve for a 1984 F-350 and they all seem to be single port.  

I'm not saying that it wasn't connected to the charcoal purge before, but for under $20 US I know id appreciate the peace of mind that there was no second inlet to leak.

[BigBrother-84]

ArdWrknTrk wrote

I'm not saying that it wasn't connected to the charcoal purge before, but for under $20 US I know id appreciate the peace of mind that there was no second inlet to leak.

Jim, when you say «charcoal purge», are you talking about the coal canister?  This truck never had one, nor catalytic converter.
There is an EGR valve, but I suspect it came with this replacement engine (around 2012 if I remember well).  It is well caped and there’s nothing plugged to it.

I started the truck and I heard the vacuum noise loud and clear from the cabin.  I swear I never heard it before!
Can’t explain… As shown on the following picture, Big Brother’s vacuum pattern is quite simple, there’s not a lot of things to “forget”.


Anyway, I caped it, now quiet, job done.

[ArdWrknTrk]

I'm responding to Bills comment above, that it went to the evaporative canister purge (AKA charcoal can)

Canada was different RE: emissions, like a lot of the trucks never had EGR...
No doubt US Federal regulations hobbled this generation more than your government did.

So perhaps Bill was making a general statement regarding dual port PCV valves and not specifically your truck.
I was saying that when I looked by application an '84 F-350 shouldn't have that style of PCV.

Edit: if you look at mine or Bill's vacuum routing diagram (I think Gary has both on the site somewhere) they look more like the iconic 'pipes' screensaver, or a bowl of spaghetti!
Though I know you're a Mac guy and probably didn't see much of early Windows.

[BigBrother-84]

ArdWrknTrk wrote

Edit: if you look at mine or Bill's vacuum routing diagram (I think Gary has both on the site somewhere) they look more like the iconic 'pipes' screensaver, or a bowl of spaghetti!
Though I know you're a Mac guy and probably didn't see much of early Windows.

I didn’t see yours but I can easily imagine that they can look as this notorious Windows screensaver!
Even if I’m on Apple since more than 30 years, I had no choice to work with Win OS, so I know it.
And seems that some Mac aficionados found the way to install it on their Apple machines.

[Gary Lewis]

Something like this from the page at Documentation/Vacuum/Vacuum System Diagrams/460 V8:

[BigBrother-84]

Gary, I sincerely hope for you, Bill, Jim and all other “Vacuum Master-Teachers” here, that there will never happen to come a newbie like me , rebuilding a really complicated Bullnose spaghetti vacuum system.
It would take years to help him understanding his machine!


That’s a chance for you guys that Big Bro has one of the simplest vacuum diagram that Ford ever made.

Thanks again for your patience!

[85lebaront2]

Jeff, I have an older MacBook Pro that I have as a dual boot, MAC OS and Win 10. I use it for tuning Darth and running a diagnostic program called Forscan on the Flexes. Once all the bugs on the software and hardware are resolved it will run MPScan and MPTune for the Chrysler electronics.

I think my 1966 Shelby GT350 had the simplest one, PCV valve only or the 1958 F100, vacuum advance only.

Here is the vacuum "spaghetti" I removed from Darth when I installed the EFI system:

[Gary Lewis]

No problem, Jeff. We are happy to help others learn. And glad that you should have improved performance from Big Bro.

[BigBrother-84]

85lebaront2 wrote

Jeff, I have an older MacBook Pro that I have as a dual boot, MAC OS and Win 10. I use it for tuning Darth and running a diagnostic program called Forscan on the Flexes. Once all the bugs on the software and hardware are resolved it will run MPScan and MPTune for the Chrysler electronics.

Yep, I also run Bootcamp to boot Macs directly under Windows, but this is no more possible with Apple’s latest Silicone chips (M1, M2…).
That’s why Intel Macs still be useful.
Otherwise, Win emulators such as Parallels Desktop usually work well, if the running software isn’t to power hungry.
We live in a Windows world, almost impossible to not run it occasionally.

85lebaront2 wrote

I think my 1966 Shelby GT350 had the simplest one, PCV valve only or the 1958 F100, vacuum advance only.

Ahhh, these good old days where even simpletons like me could understand an engine…
😜
Bill, did you post somewhere picts of these two babies?

85lebaront2 wrote

Here is the vacuum "spaghetti" I removed from Darth when I installed the EFI system

OMG!
That’s one of the reasons guys like me need guys like you!

[81-F150-Explorer]

You ought to see the vacuum lines on my 1981.

Glad things are coming together.