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| What's that line? https://www.slantsix.org/forum/viewtopic.php?t=13310 |
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| Author: | ol ron [ Wed Jun 08, 2005 9:56 pm ] |
| Post subject: | What's that line? |
My Demon is getting lighter each day. The teardown for restoration moves along nicely. There is a steel line coming from the frame, on the right side of the engine bay (passenger side) with a rubber hose piece on it, plugged with a screw. I see no holes where a charcoal cannister could have been. What the heck is it? It's a 1971 \6 225/904. Any ideas? Thanks! Ron 
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| Author: | SlantSixDan [ Thu Jun 09, 2005 6:29 am ] |
| Post subject: | |
The '70-'71 evaporative emission control system (ECS) used the engine crankcase to store fuel vapors piped from the fuel tank and carburetor bowl. The interface point was a fitting on the fuel pump body on slant-6 cars, and extra fittings on the engine breather cap on V8s. When the engine was started, the collected vapors were drawn off via the PCV valve. This system did a reasonably effective job of containing the vapors, since the crankcase was well sealed, but caused hot start/hot idle problems, since there was no control over when the vapors were and were not extracted from the crankcase. Most of the unburned hydrocarbons wound up out in the atmosphere anyhow, having been first put through the engine (and emitted as black smoke). For '72, things got very much better. The crankcase was no longer used to contain fuel vapors. Instead, a cannister containing activated charcoal was mounted at the right front corner of the engine bay. Lines led to it from the carb bowl and the fuel tank vent. There was a "purge valve" mounted atop the cannister, with a small diameter vacuum line teed into the distributor vacuum advance line, and a large diameter line from the underside of the purge valve, teed into the PCV valve hose. There's vacuum in the distributor vacuum line only above idle, so the purge valve only opened above idle. Voila, no more hot start/hot idle problems, since fuel vapors were only drawn off and burned above idle. This system works very well and is still used, almost unchanged, to this very day. |
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| Author: | ol ron [ Thu Jun 09, 2005 5:49 pm ] |
| Post subject: | Thanks Dan |
So I can expect to find a plugged (I hope) nipple on the fuel pump body for a rubber hose? Pretty covered in grease down there now, so I'll poke around and look. It'll all make more sense when the engine comes out. Could be a replacement pump doesn't have it. Many Thanks for your help! Ron |
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