Datsun-San Posted January 21, 2012 Report Share Posted January 21, 2012 Hey guys, I just picked up an early '74 260Z here in Seattle and am waiting for the snow and ice to clear before picking it up. Pretty psyched about getting it home! Problem is, the exhaust manifold seems to be shot. When running the car, you can hear leaking as the car roars up front. The previous owner (who currently has the Z stored at his service garage) thought that a gasket replacement would solve the noise issue, but we've since discovered cracking in the manifold itself that is beyond patching up. The plan is to drive the car home and remove the intake manifold and carbs (the carb setup consists of two downdraft webers), gaining access to remove the exhaust manifold for replacement. My question to you all who read this is whether there are any tips for carrying out this kind of job? The process for dismantling seems straight-forward but a little daunting. I'm also unsure whether its worth searching for a replacement manifold or to just go with something like the Monza headers like the ones displayed on Black Dragon Automotive. The stock muffler and exhaust are in very good condition I'm hoping to keep that set up on the car for now. I've been doing some research on pros and cons of headers versus manifolds, but was wondering if anyone here had their own opinions on the matter? I wasn't really expecting to carry out this fix, so I'm a little unsure on how to go about doing it. I'd greatly appreciate it if I could get some help! Quote Link to comment
I'm BLUE Posted January 21, 2012 Report Share Posted January 21, 2012 spray exhaust manifold studs and bolts with Pb blaster ... a few times a day ... for a few days ... Expect front and rear manifold studs to come off/snap/strip ( can be helix coiled) Carefully replace each bolt/nut as you pull off the parts ... intake dry sealed ... and exhaust is "ok" to use a little high temp copper coat rtv red bottle permatex if needed only ... Check intake and exhaust manifold mating surface for flatness when pulled out completely ... Carefully scrap mating surfaces with razor blades ... do not gouge ... stuff some rags or chunks of industrial paper towels ineach port before scraping ( keep crap from harming engine) when done ... vacuum ... and degrease surfaces with a little bit of brake parts cleaner o. A rag. :) Expect 1-2 bolts or studs to break ... especially on exhaust manifold down pipe ... ( i have an extra i believe) ... Pb blast the crap outstanding all of those bolts .... never enough ... start now or sooner than later... Replace rubber coolant lines running through intake while there ... auto parts place sells it by the foot :D Replace with another cast manifold ... almost zero realistic gain with header ( except sound) unless you have a heavily modified engine ;) ... i run a header ... only for the sound ... makes a bitch to get out even when disconnected lol 1 Quote Link to comment
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