datzenmike Posted July 26, 2015 Report Share Posted July 26, 2015 I have the terrible exhaust heated intake on my '76. This was Nissan's answer to lower emissions but the spring 'heat riser valve' rusts and sticks from exhaust deposits. Usually full closed so warm up in cold weather takes forever, or full open and the intake is over heated. Later '78 and up are like the early L16/18 and use a coolant passage in the base of the intake runners the warms quickly in the cold and draws away radiant heat from the exhaust when it's hot out and under hood temps soar. U67 equipped heads and intakes do not have the coolant holes in them and the intake is bolted to the exhaust. Hot exhaust is directed up onto the under outsides of the intake to 'warm' it and help vaporize fuel droplets when the intake air is very cold. Anyway I want to rid myself of this set up and have a '79 intake (separate) and the choice of the '79 exhaust (also separate) or I may run an L16 4 into 2 manifold but this will require some exhaust pipe work. Haven't decided yet when I will do this yet but I could just run the '79 manifolds for now. So... while looking at the intake I got to wondering how much bother it would be to remove the small EGR manifold that bolts to the main intake manifold below the carb. I want to avoid those cheesy home made bolt on block off plates with JB all over them and poor fitting EGR valves. The earlier L16/18 (pre smog) intakes are smaller ports and I don't want that on my 2 liter engine. I have a spare '79 intake to modify but it looks like this. The missing fitting is for vacuum lines for the charcoal canister and the AB valve that, for now, I want to keep With the hoses and pipes off and the EGR manifold removed it looks like this. The problem is the PCV valve and the vacuum fitting is now gone also. The EGR ports into the L&R intake runners are the black part. They can simply be JB welded up and the studs removed. So I drilled out that upper hole and drilled diagonally from the right EGR port in and to the center coming out Just below the upper one I drilled. A tap was about $7 Pretty close! Below Above. Looks reasonably stock and has the larger diameter runners than the 'pre smog' L16/18 intakes. . 1 Quote Link to comment
MicroMachinery Posted July 26, 2015 Report Share Posted July 26, 2015 Great info! Thanks for sharing! Quote Link to comment
Tolkmod Posted July 27, 2015 Report Share Posted July 27, 2015 Will the JB weld hold up to the heat and general usage? Quote Link to comment
datzenmike Posted July 27, 2015 Author Report Share Posted July 27, 2015 Good to 450 F Quote Link to comment
Tolkmod Posted July 27, 2015 Report Share Posted July 27, 2015 hum... good to know for future projects. Quote Link to comment
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