Plastic tube bolted to front of block

[rb6667]

I have a black plastic tube that is bolted to the front of the block, and goes up to the distributor.  This tube is open at the top.  What is this?  Timing port maybe?  This is not the vac advance tube.  

Thanks,

RB6667

[hkollan]

Hi,

Sounds like a broken fuel vent line found on later US cars. It should be routed along fuel and brakeline back to the fuel vapor plastic tank in the trunk left side.

Hans

[ja17]

I agree with Hans, its  a broken fuel  vent

[rb6667]

Thanks Gents.  I must say this is  surprise.  Is this tube plastic all the way to trunk?  I'm having a hard time trying to figure out how it was routed all the way back to the trunk.   It's mounted above and off to the side of the crank lower pulley, then it turns up and terminates right next to the distributor.   

Thanks Again,

RB6667 

[hkollan]

Yes, its black all the way. My guess is that if you look under the car where the brake and fuel lines go you'll find the rest of the black plastic tube that connects the fuel vapor expansion tank with the engine block, just where you describe it to be. There should be four lines routed together, fuel feed and fuel return line, brake line to the rear and the black plastic fuel vent line.

[Iconic]

rb6667,
I agree it is a line intended to go to the black plastic fuel vapor tank in the trunk (left side).
But, do you have this tank in your trunk?
I agree with hkollan about the four lines together.
If you find the four lines together, I can try to describe how it gets to the bundle of four .. but it won't be until this weekend because I am far from my car now.

[280SE Guy]

I'm not sure how it is on the Pagoda but on my W108 the black vent line has a push on metal connector in the area of the distributor. The metal connector is like a dual prong hose barb, I could imagine that it was placed there to ease the removal of the engine from the car (by disconnecting the vapor line) but I could just be making things up again (in my mind).

Regards,

280SE Guy

[rb6667]

Thanks for the information.  Iconic, yes this car does have the vapor tank mounted in the trunk.  I plan on replacing all the rubber lines going to it from the fuel tank.  I'll take a look on the underside and see if I can find the other end of that plastic tube.  I sure do not see it in the engine bay!

Thanks again,

RB6667

[Iconic]

OK, now that I look at mine, it might not be the exact factory routing from below the brake power booster (assuming yours is a Left-Drive) car to the front of the engine.
But, you should see the black plastic tube/line right below the brake power booster grouped with a brake line and the return line for fuel back to the tank.
Now, I am curious how the line is supposed to be routed between the front of the engine and the area below the brake power booster.

[glenn]

What is this line venting at the engine end? 

[Iconic]

Please correct me if I am wrong, but I believe it pulls gas fumes from the plastic tank in the trunk (which pulls fumes out of the gas tank) to reduce evaporative gasoline fumes into the atmosphere.
Therefore, it seems the later Pagodes are the "greener" Pagodes. 

[glenn]

So, ?? What sucks??  The plastic tube runs to the intake manifold from the trunk??  Sucking fumes from the gas tank??

[hkollan]

Glenn,

So, ??

Not sure what you are asking here..

What sucks??  

Nothing sucks as far as I know.

The plastic tube runs to the intake manifold from the trunk??

No it enters the engine block as described earlier in this thread
 

Sucking fumes from the gas tank??

No, I assume its more like fuel fumes expanding in the fuel tank, and pressure being relieved  thru the expansion tank and fuel vapor line.

Hans

[glenn]

Just trying to get the basics of the venting. ...   The gas tank is at atmospheric pressure.  The vent line goes to the crankcase?, to the intake manifold?, to the valve cover??., to the atmosphere(no way!!)....?? 

[twistedtree]

Here's how I presume it works, but I don't know for sure....

The crankcase is vented to the air intake, and with the intake vacuum it will be sucking fumes out of the crankcase.  Then by venting the tank to the crankcase, the tank fumes get sucked into the crank case, then the crankcase fumes and tank fumes get sucked into the intake and burned off in the engine.

[rb6667]

Thanks for the responses guys.  I have no doubt that someone will know how this system works.  Just seems to be a very strange way of routing gas vapors. 

RB6667

 

[glenn]

Still don't know where the plastic tube ties into the block/crankcase...??

[Iconic]

My perception of how it worked is the same at twistedtree (three posts back).

Glenn,
The connection is a barbed connector in the front of the engine.

[280SE Guy]

Iconic,

Thanks for confirming the barbed connection.

Here is a picture of it located just forward of the power steering reservoir, just under the distributor:



Attached is the BBB section concerning the vapor recovery system, hope this helps. You can thank the USA EPA for this item/option.

Regards,

280SE Guy

[Naj ✝︎]

Crankcase vent for fuel vapors

[rb6667]

Many thanks 280 SE Guy and Naj.  So this is a crankcase vent and not a fuel vent.  That makes more sense.  I was having a hard time figuring out how gas vapors could be vented from the front of the block.    It looks like I am missing the connection tube between the dist. area and the back of the engine near the brake master.  I'll go on the hunt for that!

Thanks again guys,

RB6667

[Iconic]

rb6667,
Naj and 280SE Guy didn't say that it wasn't a fuel vapor vent.
Just read the attachment in 280SE Guy's post.
It states: "The evaporative emissions are flowing to the engine via the venting line, which runs in parallel to the fuel line."

There is vacuum in the crankcase. It sucks off the evaporative emissions so that they are not released into the atmosphere.
I guess the later Pagodes are truly "greener".
 

[glenn]

My '69 280SE coupe doesn't have it.   But, here goes.   Gasoline vapors from the gas tank go to the plastic duhickey in the trunk, up a plastic tube under the car, thru a barbed connector on the dissy/FIP gearing, into the crankcase, up thru the head, out of the head thru the plastic crossover tube, into the filtered air between the air filter and the butterfly, out into the idle air screw line, and into the intake manifold.
  How does this affect lambda??

Ain't pollution controls great??

If you are in California with 20(?) different volatility fuel mixes, can you idle on tank vapors only???

[49er]

Been following this thread for a while and I finally went out to look at my car to see if I have the mysterious plastic tube. Nope. My car was built in July '68 and sold as a '69 so this must have been a later addition to the California SL's.

John

[Iconic]

All USA 1970 and 71 SLs have the line going to the engine, not just the California ones. (That is if I understand the BBB correctly.)
Since your car is a '69, it probably has the conpensating tank in the trunk, but it vents to the atmosphere, not the engine.