NewZed Posted December 20, 2011 Share Posted December 20, 2011 The instructions in the FSM are not good enough? I don't see the problem, maybe I'm missing something. Page from 1978 FSM attached. Quote Link to comment Share on other sites More sharing options...
Leon Posted December 20, 2011 Share Posted December 20, 2011 The instructions in the FSM are not good enough? I don't see the problem, maybe I'm missing something. Page from 1978 FSM attached. Thank you, I was going to say the same thing. Quote Link to comment Share on other sites More sharing options...
josh817 Posted December 21, 2011 Share Posted December 21, 2011 I was just saying! lol I don't even mess around with that. Quote Link to comment Share on other sites More sharing options...
madkaw Posted December 21, 2011 Share Posted December 21, 2011 Glad this thread came about. I have been fighting a leaking rear main seal on my car and i am on my second rear seal. I am thinking excessive pressure now and with this thread I will be better informed. The best thing to do is to put a mechanical guage in parallel with my stock guage. I also need to check my oil pump pressure spring set-up, since at one time I was messing with the springs, but don't remember what i left in there. Plus I was watching my video I made of my in car driving and the oil pressure was mysteriously stable around 60psi---even at idle. Quote Link to comment Share on other sites More sharing options...
josh817 Posted December 21, 2011 Share Posted December 21, 2011 (edited) That means the blow off is working... Even if the pump makes excessive pressure (more than 60PSI at idle) the fact that the gauge reads 60PSI at all times and doesn't rise above when off idle, tells us that the blow off is working. Even then, the oil supplies rear main, not the seal. Rear main seal... I installed mine terribly and always had a drip from the rear, but other causes could be if you don't have a vacuum on the crank case. For carbs, hook the crank case to the manifold for constant vacuum, for turbos, I have no idea. For both, be sure to use a PCV valve and make sure it is working properly. If the valve is stuck, on a turbo system, I can imagine you pressurizing the crankcase to 13PSI of boost or whatever you're running. For carbs, sometime the spit out fuel and back fire when cold, and can pressurize the case like a firecracker; maybe blow out a seal. An old worn out motor obviously has some blow-by too which can pressurize the crankcase. Another thing to consider although doubtful is the crank itself. Sometimes for instance on a diff or tranny flange, the seal wears a groove into the flange. I just put a new rear seal in my tranny on the truck yet it still leaks. For flanges, you can get a Speedy Sleeve which restores the surface to its original or slightly larger size. It's a sleeve that taps onto the sealing surface; runs about $35. Can't see this working on a crank though because you can't press a sleeve on due to the flywheel flange... Just a thought though. Edited December 21, 2011 by josh817 Quote Link to comment Share on other sites More sharing options...
madkaw Posted December 22, 2011 Share Posted December 22, 2011 Josh, thanks for the insight. I have checked my pcv system and replaced my valve for good measure. I also have had a headgasket going out-maybe slowly, and wondered if this was all tied into my leak. Also complicating the diagnosis is the fact that the first seal looked like the rubber was dry rotted(fresh rebuilt motor). Then I nicked up the flange on the crank trying to get the first one out. Don't believe any of the nicks are on the sealing surface-but I will always wonder. I have not ran the engine since head gasket replacement, so I haven't verified oil pressure either. One other thing is that I over filled the oil on the last oil change. Didn't have a chance to run the engine much after removing excess oil before I tore it apart to do head gasket. Quote Link to comment Share on other sites More sharing options...
josh817 Posted December 22, 2011 Share Posted December 22, 2011 (edited) Could just be overfilled I guess... I would imagine it would take a lot of oil to reach the rear seal level, but then again it could also fling the oil around that area more so than if it were filled with the right amount... No leaks out the front cover with the pulley? The thing that screwed up on mine were those tap in strips at the back with the rear seal. The ones that you are suppose to tap in after you install the rear main cap. Not only did I not fill those holes with sealant and then tap the strips in, but I don't think I tapped them in deep enough either! I remember on the Z I trimmed a lot of the strip off the top so the oil pan could seal up but on the truck I only had a nub to trim off. There is an error in my last post. I forgot the big ring seal, seals around the flywheel flange, not the journal. This would mean oil pressure has nothing to do with it and also means a speedy sleeve can be made if you need one. Oil has to get past those two strips before it gets to the big ring seal. Edited December 22, 2011 by josh817 Quote Link to comment Share on other sites More sharing options...
madkaw Posted December 22, 2011 Share Posted December 22, 2011 Those seals actually will stick out a bit and don't need to be trimmed. Probably why Nissan recommends sealant in that area. I will be better off commenting more once I'm up and running again Quote Link to comment Share on other sites More sharing options...
josh817 Posted December 22, 2011 Share Posted December 22, 2011 I never tried to put everything back together without snipping the nubs. Didn't think the pan would seal up properly with them poking out. Quote Link to comment Share on other sites More sharing options...
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