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| | | | Joined: Aug 2017 Posts: 76 'Bolter | | 'Bolter Joined: Aug 2017 Posts: 76 | I have a 283 with the canister and draft tube at the rear. At the moment I've fitted a new intake manifold which has got rid of the oil filler tube at the front and an edelbrock 1404 ,4 jet carb which has a port for a pcv.The valve covers have no breather or oil filler. Question is can I attach the draft tube to the pcv inlet on the carb or do I have to get valve covers with holes for a pcv fit a pcv and pipe that to the inlet on the carb.Can I leave the draft tube open or do I have to block it off? | | | | | Joined: Jan 2022 Posts: 2,443 'Bolter | | 'Bolter Joined: Jan 2022 Posts: 2,443 | A PCV system needs to let air into the system as well as to evacuate air, via the PCV valve and into manifold vacuum. The bottom of the draft tube is designed to create a low pressure area to evacuate fumes from the crankcase, so it would be "fighting" the vacuum provided by the PCV system.
Another problem you have with your current setup is "where do you add oil?" Kill two birds with one stone, or two valve covers in this case. Block off the draft tube. Get two valve covers with breather holes. Leave a breather in one and use the other to feed crankcase air through your PCV valve and into the 1404 carb.
An alternative would be to remove the draft tube and plumb in a fitting that would provide a connection to the PCV valve and on to the carb. Then replace one of the valve covers with a breather type valve cover. That is how I plumbed a PCV system into my '57 GMC V8 with an Edelbrock 1404.
Last edited by Bill Hanlon; 07/21/2023 1:15 PM.
'57 GMC 102, Original 347 V8, HydraMatic, 3.08 rear gear, added A/C, disk front brakes, HEI, AFB carb, '98 Honda Black Currant paint. T-boned and totaled 10/12
'52 GMC 152 Stake Bed, Original 228, SM420, added A/C, HEI, disk front brakes, '67 Chev 3.55 rear gear. Gets used as a real truck.
| | | | | Joined: Nov 2005 Posts: 6,100 'Bolter | | 'Bolter Joined: Nov 2005 Posts: 6,100 | Hy Stooby, in the situation you find yourself in you have no way to add oil to your engine. If you hooked the carburetor PCV port to the open road draft tube you would have a huge vacuum leak. There was a special cap made for the road draft tube port which had a hose connection built into it, but you also need a way for fresh air to enter the engine crankcase. You could accomplish that with vented valve covers with one of their ports connected to the engines air filter, hope that helps. | | | | | Joined: Aug 2017 Posts: 76 'Bolter | | 'Bolter Joined: Aug 2017 Posts: 76 | So. I have fitted a vented oil filler in one valve cover and a pcv valve in the other which is piped to the pcv inlet on the carb. The draft tube has been blocked off. Will this set up do the job | | | | | Joined: Jan 2022 Posts: 2,443 'Bolter | | 'Bolter Joined: Jan 2022 Posts: 2,443 |
'57 GMC 102, Original 347 V8, HydraMatic, 3.08 rear gear, added A/C, disk front brakes, HEI, AFB carb, '98 Honda Black Currant paint. T-boned and totaled 10/12
'52 GMC 152 Stake Bed, Original 228, SM420, added A/C, HEI, disk front brakes, '67 Chev 3.55 rear gear. Gets used as a real truck.
| | | | | Joined: Mar 2004 Posts: 6,214 'Bolter | | 'Bolter Joined: Mar 2004 Posts: 6,214 | I believe it should! Mike B  | | |
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