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521 l16 desmog?


Oilspot

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I've only had this truck for a few days. I took off the air cleaner to pull/ rebuild carb. Seems to be a lot of what looks like smog pump type "stuff" all wrapped around the manifold and carb (reminds me of a smogpump setup on a toyota 22RE). Does pulling all this crap off hurt drivability at all. 

And what might i need for blockoff plates etc. if pulling this stuff is a decent option?

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There are almost no emissions equipment on the 521. Air injection pump, retarded set of points, (including a transmission switch a temperature switch in the cab and a switch on the carburetor and a relay to turn the retarded points set on and off) gas tank vent.

 

Cut the air injection tubes off short on the outside, then use a socket to unscrew the pipe plug and pull it out. Cut the tube off the inside of the nut and weld closed and put back in to plug the holes or like I did a pipe plug.... 

 

xVkEyEu.jpg

 

Anything relating to the air pump can be removed. Pump, mount. belt and hoses and the pipe manifold.

 

You should not need any kind of block off plate as the L16 does not have an EGR valve but definitely keep the PCV valve functional. Leave the gas tank vent through the flow guide valve. It allows the engine to draw gas fumes into the engine and burn them and is part of the PCV system. It's not in the way, does not affect running in the least and pulling hoses off might allow fumes into the cab or dirt back into the tank.

 

The distributor has dual points with about a 4 degree difference in the opening position. This allow the emissions system a way to run retarded or advanced. For best performance the later opening (retarded) set can be simply disconnected or removed. 

 

 

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2 hours ago, datzenmike said:

There are almost no emissions equipment on the 521. Air injection pump, retarded set of points, (including a transmission switch a temperature switch in the cab and a switch on the carburetor and a relay to turn the retarded points set on and off) gas tank vent.

 

Cut the air injection tubes off short on the outside, then use a socket to unscrew the pipe plug and pull it out. Cut the tube off the inside of the nut and weld closed and put back in to plug the holes or like I did a pipe plug.... 

 

xVkEyEu.jpg

 

Anything relating to the air pump can be removed. Pump, mount. belt and hoses and the pipe manifold.

 

You should not need any kind of block off plate as the L16 does not have an EGR valve but definitely keep the PCV valve functional. Leave the gas tank vent through the flow guide valve. It allows the engine to draw gas fumes into the engine and burn them and is part of the PCV system. It's not in the way, does not affect running in the least and pulling hoses off might allow fumes into the cab or dirt back into the tank.

 

The distributor has dual points with about a 4 degree difference in the opening position. This allow the emissions system a way to run retarded or advanced. For best performance the later opening (retarded) set can be simply disconnected or removed. 

 

 

I'm glad you got back to me so quick on this, it helped out a lot! figured I may get to pulling that stuff sooner or later, but when I went to pull the carb that air injection manifold was completely in the way of pulling the front, passenger side carb bolt out. 

Ill cut and weld up the threaded pieces here in a little bit. Good to know i can delete the retard set of points, i can't see that they're gonna do me any favors especially with the other smog pieces pulled out. I'm pretty sure I Saw that the distributor drive only fits in one way (offset boss), if so I figure i'll just pull it to set the points and clean up the distributor at the same time. On the old VW vac advance distributors the advance mech. engaged easily enough when you sucked on the tubing like a straw. The vac mechanism in the truck doesn't. Thinking everything may just be gummed up in there so I'll give it a good going over while i've got the distributor pulled. If not hopefully a new vac cannister or diaphragm isn't to hard to locate. 

Oh yeah, what the point gap set to on the l16.  I tend to assume all points gaps are set to 0.016, but i could be wrong for all i know. 

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You can just disconnect the late opening point set or wire it to the primary set and re time the engine. You can just leave them in, no one will know. Save taking the distributor out and losing or breaking something else. Yes, there is no way to take the distributor out and put it back wrong. Remove the two 10mm? bolts and lift it out with it's mounting pedestal. P-oint gap is 0.018" to 0.022"

 

Under the bolt the air injection pipe goes down the exhaust port almost to the valve so take them out and cut that obstruction off before welding the nut closed.

 

Suck on the advance tube and put your tongue over the end. Does it hold the vacuum??? If not then the diaphragm is broken. If it does hold vacuum try turning the breaker plate with the points on it clockwise. It may just be stuck. Try to get this working as it improves light and part throttle economy and response.

 

 

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2 hours ago, datzenmike said:

 

 

Under the bolt the air injection pipe goes down the exhaust port almost to the valve so take them out and cut that obstruction off before welding the nut closed

 

 

Not sure what your saying here. Cut the pipe, weld it flush. What am I concerned about contacting?

 

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Did not know. I thought they were all long. The hottest part of the exhaust is at the valve. The air injected in is all that's needed for the unburned hydrocarbons to burn off. Well that's how the Later L20B pipes are. This will be a lot easier.

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again, thank you for the info on getting all that crap outta the way! I'm not exactly sure how you're supposed to get the carb off with it in the way. Even with the space cleared up I'll prob end up throwing a open ended 12mm wrench in the ol' chop saw to make a custom "521 carb wrench". 

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