Author Topic: Emission hose routing reduction question  (Read 1503 times)

Offline Eddie G

  • New Users
  • Posts: 2
  • Newbie
Emission hose routing reduction question
« on: December 28, 2018, 01:33:18 PM »
All,

This is my first post and I am new to working on vehicles so please bear with me.  I have a 1985 C10 Silverado with a 305 and a TH350.  I am getting rid of my 305 and putting in a stock crate 350.  I have had a fair amount of problems with the emission system springing leaks and just not seeming to function properly so I was hoping to reduce/remove what I can.  My Routing layout in my 305 was UHK.  What of the following would be safe to remove? The second picture (red outline) was my first crack at what to take out. 


Cheers,

Eddie

Offline Rapid Roy

  • Junior Member
  • ***
  • Posts: 635
  • Euless, Texas
Re: Emission hose routing reduction question
« Reply #1 on: December 28, 2018, 03:58:32 PM »
Welcome
1974 Cheyenne 10 LWB STOCK 350 W HEI /TH350/AC/4 BBL Quadrajet
Mopar by Birth
Chevy by Choice

Offline VileZambonie

  • Global Moderator
  • Senior Member
  • *****
  • Posts: 18980
Re: Emission hose routing reduction question
« Reply #2 on: December 28, 2018, 06:24:04 PM »
If you have no emissions testing/inspection you can basically remove all of it except vacuum advance, PCV, Canister and whatever else you are keeping.
,                           ___ 
                         /  _ _ _\_
              ⌠ŻŻŻŻŻ'   [☼===☼]
              `()_);-;()_)--o--)_)

74 GMC, 75 K5, 84 GMC, 85 K20, 86 k20, 79 K10

Offline 75gmck25

  • Frequent Member
  • **
  • Posts: 439
  • 1975 GMC K25 Camper Special, 350/TH350/NP203
Re: Emission hose routing reduction question
« Reply #3 on: January 30, 2019, 06:58:28 PM »
I had trouble reading the picture and figuring out how to best make comments, so I'll just make a list.

If you have no EGR or any temperature controlled vacuum switches, you should be able to get by with these lines.

Vacuum
- 3/8" vacuum line from carburetor base over to power brake booster.  Stock system has a steel hard line screwed onto the carburetor, and it reaches about half way over to the brake booster, then you add the rubber line to fill the gap.
- Two small vacuum lines, usually connected to a fitting on the intake manifold (using vacuum tree or vacuum tees)
 -- to HVAC reservoir/canister mounted on the A/C plenum. If you have A/C and don't connect this line, your controls won't work right because the vacuum motors won't work.
 -- to modulator for the TH350; not sure whether the 700R4 or TH400 needs it
- One small vacuum line from the carburetor to the vacuum advance - use either ported or manifold vacuum from the carburetor, depending on what you need

Emissions
- 3/8" PCV hose from carburetor over to PCV valve in one valve cover.  This hose is pulling air out of the crankcase and removing moisture.  Do not get rid of it.
- Other valve cover needs either a breather cap, or a hose connection up to the side of the air cleaner.  This provides the air that is being pulled into the crankcase.

You might also need to provide vacuum to the cruise control servo, thermac vacuum motor in the air cleaner, or other devices.  However, your engine will still run if these devices are not connected.

Bruce
« Last Edit: January 30, 2019, 07:00:39 PM by 75gmck25 »

Offline Eddie G

  • New Users
  • Posts: 2
  • Newbie
Re: Emission hose routing reduction question
« Reply #4 on: February 12, 2019, 11:49:29 AM »
Thank you all for your help on this!  It is greatly appreciated.

Cheers,

Eddie