New Knowledge Means Better Work

[datsun_celaya620]

Hey everyone its been a while. I am now 21. Since last time when I first introduced my 78 620 I've moved 3 hours away and started studying at Universal Technical Institute for auto and diesel tech and have been learning a lot and feel like I am now more capable and knowledgeable to start rebuilding my L20B. Even though I may have more knowledge I am far from being a master at this so will accept any advice and or criticism when it comes to working on the motor. I have already removed the head and have taken it to a local machine shop that an instructor recommended for a valve job, resurface,  and a few Heli coil inserts for thread repair. Been reading up on the forums and have been wondering if I should add heat wrap to my exhaust manifold in order to keep the close intake manifold cold and safe from excessive heat. I know this can overheat the manifold and traps moisture but is there a benefit for me since the intake is on the same side? Another question is should I run bolts like stock or go with head studs? and any clue how I can find new hardware for the intake and exhaust manifold (studs and bolts)Ask me any questions because I am still really curious on what else I would need to rebuild this motor and just so you'll know it will be daily driven not looking for speed or anything like that just want it back to its stock glory. Sorry if this is a lot I'm still getting used to this forum thing. dat_620

[datsun_celaya620]

[datzenmike]

 

That '78 L20B of yours has coolant flow through the intake runners which serves to warm the intake air when it's cold out but will also absorb and remove heat in very hot weather. Heat wrap is not really going to make much difference but you can if you want. There is also a plastic spacer between carburetor and intake to reduce conducted heat and all L20Bs have a fuel return line. This allows cool fuel to be circulated past the carburetor and over heated fuel to be returned to the fuel tank preventing vapor lock from extreme under hood temperatures.

 

Coolant exits the head between and below each pair of intake ports travels to the front base of the carburetor where it is piped to the by pass line down the front of the engine and into the lower radiator inlet to the  water pump. You won't find this on the '75-'77 U67 heads, but all other L16/18 and L20B heads do. 

 

 

Coolant outlet

 

 

Head bolts...

 

are totally reusable, if in good condition, and are not the latest one time use TTY or torque to yield bolts. They are more than capable of holding a stock head on but again it's up to you if you want to use studs.