Head vent ports, needed? |
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Head vent ports, needed? |
yarin |
Feb 6 2006, 10:07 AM
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#21
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'14-X'in FOOL Group: Members Posts: 988 Joined: 13-May 03 From: Guttenberg, NJ Member No.: 693 Region Association: North East States |
While pulling my carbs off I noticed that each head has an air vent. One was capped off, the other was open.
Where should these go and why are they needed? Will capping these contribute to oil leaks? Here is a pic I found: http://www.914world.com/bbs2/uploads/blog-1...-1131214564.jpg Thanks |
dmenche914 |
Feb 8 2006, 03:29 PM
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#22
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Senior Member Group: Members Posts: 1,212 Joined: 27-February 03 From: California Member No.: 366 |
If I read that the way you meant, hooking up the any extra vent line to the intake manifold anyplace after (ie down stream) of the carborator, or in the case of L-jet the airflow meter, or in D- jet the thootle body, will cause what is termed "false air lean" which means that extra air leaking in will come in after the gas amount has been determined to match air amount, hence the engine will run lean, too much air in the mixture. Now adjustments can be made for that, the factory can compensate, and new cars have O2 sensors which can compesate for some variation in false air introduction.
Now if the engine was totally sealed, air tight, then you would draw a good vacuum on it, how ever that kind of vacuum I am assuming would tend to suck a good bit of air in thru tiny leaks, eventually at least. The L-jet for this reason (ie it has the case vent routed down stream of the airflow meter) is very sensitive to the oil cap being loose, cause that is aleak that allows more false air. (also dip stip seal, yes there is supposed to be a seal on it.) the more hoses you run to the intake down from the air meter, the more chances of false air. |
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