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Re: need advice on fixing a partially de-smogged engine

To: smarc@abs.net
Subject: Re: need advice on fixing a partially de-smogged engine
From: Bob Howard <mgbob@juno.com>
Date: Sat, 6 Apr 2002 10:40:22 -0500
Mark,  
  I'm going to suggest what I believe appropriate from what I
read---based on my interpretations of what you wrote.  There are a couple
of ways to address your questions, but this is the way I would follow.  
   Exhaust leak? - rule that out first. Have someone put his sneaker-shod
foot onto the exhaust pipe while you listen to the pipe. No someone
around? Shove a raw potato onto it.  Listen for hissing and puffing, and,
if the system is tight, for the engine to stumble in a couple of seconds.

   One hose from absorbtion cannister should run over to the valve cover.
That should be there unless you have good reason for an alternate
arrangement.  This vapor recovery system actually makes sense, takes no
power off the engine, might give you the occasional teaspoon of gas that
would otherwise be evaporated, and takes no power to operate.  
   Vent line from the gas tank should not be capped off. If it is, you're
going to run out of gas when the pumps cannot pull gas against the vacuum
formed in the tank.  Connect the vent line to one of the three ports on
the charcoal cannister.  The vent line you see runs to the vapor
separator in the boot, with a line from it to the tank.   Keep the VS.   
When this is working right, it captures the evaporated gasoline,
separates liquid from vapor, returns liquid to the tank and vapor to the
charcoal cannister. Engine then burns the captured vapor (in theory, at
least) but it doesn't go to atmosphere.  
  On left front side of engine is the vent off the front tappet cover. A
rubber line should lead up to a Y fitting, and a rubber hose from it to
each carb, where there is a port on the side.
   With this hookup, the vapor from the tank is contained. Engine sump
vapors are vented by air entering the rocker cover via hose from charcoal
cannister and sucked out from the tappet cover to the carbs for burning.
   All the other stuff, the gulp valve, the anti-run-on valve, whatever
else is there.... , can be removed.  Plug the holes, air tight.   The
engine will run well, plumbed this way, though it may not get past a
visual inspection if the guy knows that there are supposed to be other
bits of metal attached to the engine.
Bob


On Sat, 6 Apr 2002 02:03:58 -0500 Marc <smarc@abs.net> writes:
> I have a 73 B. It's missing the air pump, and the rest of the 
> emissions 
> system is a shambles. When the car is running, there is a strong 
> smell that 
> is very crankcase like. I do not believe it to be exhaust, but 
> haven't
> completely ruled out an exhaust leak.
> 
> The odor in the car is very strong. There is a hose from the 
> Absorption
> cannister that is just dangling in front of the firewall. I'm going 
> to 
> try plugging this up tomorrow to see if that is where it is coming 
> from.
> 
> I don't know whether I should just cap off all the hoses or what?! 
> I've been 
> looking at the complete official MGB book to try and determine a 
> reasonable 
> set up, but would like to hear from anyone who has already done 
> this!
> 
> The diagrams in the book show gulp valves, oil separators, and what
> not, but my car didn't have any of those when I got it.
> 
> What I believe to be the remains of the anti-runon valve is rusted 
> apart.
> 
> Should the vent line from the gas tank be plugged in the engine 
> compartment, 
> or disconnected at the tank. There is a small round tank in the boot 
> which I 
> think is a vapor separator. Should that be pulled out as well?
>   
> -- 

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