Socalman Posted August 21, 2020 Report Share Posted August 21, 2020 Hello again knowledgeable people, would not allow me to upload photo, but there’s a steel hose under intake coming off the block into a rubber hose to intake manifold about 3/4” diameter. Is this just a crankcase breather? New manifold doesn’t have a provision for it, can I add a breather filter to it? Or can it be plug up all together? Thank you Quote Link to comment
datzenmike Posted August 21, 2020 Report Share Posted August 21, 2020 What new manifold? All L series intakes have a threaded hole for a PCV valve. Yes that is the block vent and the hose connects it to the PCV valve. It's a very good idea to have a functioning PCV (positive crankcase ventilation) 1 Quote Link to comment
Socalman Posted August 21, 2020 Author Report Share Posted August 21, 2020 I’m adding dual DCOE carbs. Quote Link to comment
datzenmike Posted August 21, 2020 Report Share Posted August 21, 2020 Well that's too bad. The PCV ventilates and draws away the combustion blow by, water vapor and gas fumes that will condense when the engine cools that will dilute the oil. You will need to change your oil more often. Do not plug the block vent or the hose on the top of the valve cover. Quote Link to comment
Socalman Posted August 21, 2020 Author Report Share Posted August 21, 2020 Maybe I should hook an oil catch can you it? Are you not a fan of the DCOE’s? 😁 Quote Link to comment
datzenmike Posted August 21, 2020 Report Share Posted August 21, 2020 Not at all, I'm a big fan of functioning PCV valves. Quote Link to comment
mainer311 Posted August 22, 2020 Report Share Posted August 22, 2020 Mike is right. I ran a large K&N breather filter on mine for a while, and I noticed that my oil started smelling like gasoline. I have since added back in a new PCV valve and rubber connector hose. The intake pulses pull all of that crap out of the crankcase. 1 1 Quote Link to comment
datzenmike Posted August 22, 2020 Report Share Posted August 22, 2020 Prior to about '62 the block vent tube just ran down the side of the block and vehicle speed would (sort of) suck the fumes out. In fact they were called 'draft tubes'. Paved highways were black with oil drippings in the center of lanes. 1 Quote Link to comment
banzai510(hainz) Posted August 22, 2020 Report Share Posted August 22, 2020 (edited) I have sidedraft Mikunis and just open vent it but a breather catch Can will work also. As motor speeds up it will actually suck air in. At idle blows out Have had no proplems and don't change the oil a lot as I don't drive it alot On my daily driver with downdraft I run the PCV valve as its there and hooked up. Edited August 22, 2020 by banzai510(hainz) 1 1 Quote Link to comment
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