woldson Posted July 24, 2009 Share Posted July 24, 2009 Don't be a loop! That's just plain loopy;) Quote Link to comment Share on other sites More sharing options...
HowlerMonkey Posted July 24, 2009 Share Posted July 24, 2009 Strange that nobody has mentioned what nissan did in the later L28s. They used a dual port barb on the rear of the head with an extra nipple facing forward and add a T fitting into the middle of the long hose. The only pic I could find shows they system but someone has bypassed the heater core. It is a bypass that does the "looping" while allowing heater core to be part of the system.....but in parallel of the looping. It is my guess that nissan wanted the "loopback" effect when the car was started cold so the temperature would stay consistent throughout the engine as it warmed up before the thermostat opened and then the thermostatic piece in the T fitting would stop the "looping"......at least until you turned on the heater. Either way.....most every one i've seen was melted internally into a plastic blob. Quote Link to comment Share on other sites More sharing options...
280zNHChris Posted July 25, 2009 Share Posted July 25, 2009 Mine is looped. If I go to the hardware store tomorrow anyone know what size plugs I ask for or is it the same as a spark plug? Quote Link to comment Share on other sites More sharing options...
FlatBlack Posted July 25, 2009 Share Posted July 25, 2009 Mine is looped. If I go to the hardware store tomorrow anyone know what size plugs I ask for or is it the same as a spark plug? Drain the coolant, pull the 90* fitting and just match it at the store. Quote Link to comment Share on other sites More sharing options...
280zNHChris Posted July 25, 2009 Share Posted July 25, 2009 Funny, I was looking at the 83 FSM and on page 6 of 10 in the lube & cooling section, it shows the system as looped. The back near firewall is a T, goes to heater if open and front and if heater is closed goes to front at inlet with a tee off to under the thermostat and the cold inlet. (which is how mine is (no heater installed)) Quote Link to comment Share on other sites More sharing options...
dhp123166 Posted July 25, 2009 Share Posted July 25, 2009 Mine is looped. If I go to the hardware store tomorrow anyone know what size plugs I ask for or is it the same as a spark plug? I used 1/2 " brass plumbing plugs and don't forget the teflon tape!!! Quote Link to comment Share on other sites More sharing options...
Tony D Posted July 27, 2009 Share Posted July 27, 2009 Strange that nobody has mentioned what nissan did in the later L28s. They used a dual port barb on the rear of the head with an extra nipple facing forward and add a T fitting into the middle of the long hose. It is a bypass that does the "looping" while allowing heater core to be part of the system.....but in parallel of the looping. It is my guess that nissan wanted the "loopback" effect when the car was started cold so the temperature would stay consistent throughout the engine as it warmed up before the thermostat opened and then the thermostatic piece in the T fitting would stop the "looping"......at least until you turned on the heater. Either way.....most every one i've seen was melted internally into a plastic blob. Er....kinda! That is a pressure relief valve for idiots who rev the hell out of their engines cold, BEFORE the thermostat is opened. It pops open and allows bypass to the front of the pump to prevent cavitation. SEVERE cavitation. The thermostat is spring loaded to open under extreme pressure, but it didn't stop cavitation in the pump. The purpose of that 't' is to allow bypass under these severe cases of abuse. At the same time, this LOOP makes the car warm up quicker due to the faster recirculation of massive ammounts of coolant straight back to the inlet of the pump. Kind of like the AMOT 'bypass to cooler' setup used on some race cars... For an example, I'd say it was like the guy with the gold chain who's late for the disco date in New Jersey, and jumps out of the window so his mother doesn't know he's going out again. All suited up in black with his gold chain (you know, like the guy in the AD!) He jumps into his beyotchin' ZX at 10 degrees in February, fires it up and ROARS off to the turnpike without any warmpup whatsoever. That little poppett blows open and gives a full 5/8" recirc to really heat that baby up fast under those conditions. Not only does it get you heat in the cabin quicker by making a LOOP, but it prevents cavitation in the pump during that brief period when insufficient flow for the pump's rpm is extant. This is explained in the valve function description in some Nissan Manual somewhere. When I read it, it was like "Oh, THAT is what that thing is for!" The visual of Disco Boy was added to help people understand what is going on in some people's heads (insert Frank Zappa Soundtrack Here...) Quote Link to comment Share on other sites More sharing options...
TimZ Posted July 27, 2009 Share Posted July 27, 2009 The visual of Disco Boy was added to help people understand what is going on in some people's heads (insert Frank Zappa Soundtrack Here...) I might be totally wrong but I'm a... DANCIN' FOOOO-OO-OO-OO-OOL Quote Link to comment Share on other sites More sharing options...
woldson Posted July 27, 2009 Share Posted July 27, 2009 I might have gone a dancing a few times too;) Quote Link to comment Share on other sites More sharing options...
HowlerMonkey Posted July 29, 2009 Share Posted July 29, 2009 Ah....relief valve. Still haven't found one that isn't melted internally.......well.....I did find one about 4 years ago but I left it on the car when it went to the crusher....doh! Quote Link to comment Share on other sites More sharing options...
Tony D Posted July 29, 2009 Share Posted July 29, 2009 I might be totally wrong but I'm a... DANCIN' FOOOO-OO-OO-OO-OOL I am so glad someone picked up the correct and exact phrase I was thinking about when I put that in there! "Disco Boy" would be the 'fart joke' Simpsons reference, but this indeed is the deeper thinking viewers here! Quote Link to comment Share on other sites More sharing options...
TimZ Posted July 30, 2009 Share Posted July 30, 2009 I am so glad someone picked up the correct and exact phrase I was thinking about when I put that in there! "Disco Boy" would be the 'fart joke' Simpsons reference, but this indeed is the deeper thinking viewers here! I seldom miss a Zappa reference. Quote Link to comment Share on other sites More sharing options...
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