Oilspot Posted July 3, 2021 Report Share Posted July 3, 2021 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? Quote Link to comment
datzenmike Posted July 3, 2021 Report Share Posted July 3, 2021 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.... 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. Quote Link to comment
Oilspot Posted July 3, 2021 Author Report Share Posted July 3, 2021 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.... 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. Quote Link to comment
datzenmike Posted July 3, 2021 Report Share Posted July 3, 2021 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. Quote Link to comment
Oilspot Posted July 3, 2021 Author Report Share Posted July 3, 2021 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? Quote Link to comment
datzenmike Posted July 4, 2021 Report Share Posted July 4, 2021 The fitting the air injection pipe goes to. Unscrew it and remove and you'll see there's more pipe underneath to remove. 4 cylinder are the same. You'll want to remove these. Quote Link to comment
Oilspot Posted July 4, 2021 Author Report Share Posted July 4, 2021 the ones in my truck are inverted flare, but the unit in your pic hangs way down in there!!!!! Quote Link to comment
datzenmike Posted July 4, 2021 Report Share Posted July 4, 2021 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. Quote Link to comment
Oilspot Posted July 4, 2021 Author Report Share Posted July 4, 2021 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". Quote Link to comment
Stoffregen Motorsports Posted July 4, 2021 Report Share Posted July 4, 2021 I have a custom carb wrench I made about 25 years ago by heating and bending it. It has two open ends and both are handy, with different lengths and angles. Quote Link to comment
KELMO Posted July 5, 2021 Report Share Posted July 5, 2021 HA, I did the same thing Datzenmike did, but was for an "A" motor. Same theory. Quote Link to comment
Oilspot Posted July 11, 2021 Author Report Share Posted July 11, 2021 Engine compartment is a much nicer place to work with that crap outta the way. I Need to pick up a plug for that nipple you can see sticking out the side of the intake manifold! Quote Link to comment
vicdat Posted July 15, 2021 Report Share Posted July 15, 2021 On 7/3/2021 at 10:01 PM, datzenmike said: I have one... Quote Link to comment
vicdat Posted July 15, 2021 Report Share Posted July 15, 2021 I had one too but it got stolen with my other junkyard tools at LKQ.....dam... Quote Link to comment
datzenmike Posted July 15, 2021 Report Share Posted July 15, 2021 Top left intake bolt is missing or broken. By-Pass tube under the top rad hose needs new hose to connect to fitting on the intake below the front glass of the carburetor. Quote Link to comment
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