dashpot Posted January 18, 2015 Share Posted January 18, 2015 So me and a buddy have spent 12 hours today searching the web and tinkering firing up my Z for the first time. For some background, it's a motor out of another Z I put into a better shell, and I've seen it run and everything worked properly before the swap. The 77 motor is now in a 76 shell, but that's another story. We got it to fire up and quickly noticed no oil pressure so shut it down. We absolutely proved that by removing the plugs and hooking a gauge up to where the oil sender is that there is no pressure to be had (fuel filter also dry). The oil pump is new and we took it off and put it on at least 5 times to try and troubleshoot. Each time we go the timing right, turned it over and no pressure. From all of the searching I did through forums the last issue I saw as an option was related to the filler tube and a possible clog in the screen. Dreading an oil pan drop, we tried a few more things and eventually went ahead and did it. The filler tube was fine, screen not clogged. We even went ahead and replaced the gasket where the top of the tube mounts. So... back to square one. Many threads spoke of using a drill or modified driver to stick town the dizzy hole and spin the pump to prime the system. We hadn't tried this yet because it didn't make sense to us that it was any different than turning the motor over. Anyway, we used a drill as described and had the oil filter off to look for signs of oil... sure enough it came spilling out.. We put the filter back on, and hooked the spare gauge up to the sender and BOOM, oil pressure climbed. NOW, here's where we're confused. Since you have to remove the oil pump after using a drill, in order to insert the shaft and properly align everything, you lose some oil out the bottom end and all. We hurried and put oil in the pump itself and hooked it back up with the shaft now inside and distributor set properly. Cranked the car over with (2) 15 second sessions with a 20 second break in the middle. ZERO pressure as before. I don't get what we are missing with this. It seems like we're losing something during the removal of the oil pump to get the shaft back in. Some people mention pouring oil down the dizzy channel (???) Sorry for the ramble but I want to express how many things we've tried over a very exhausting day. Any help would mean a ton. Thanks! Quote Link to comment Share on other sites More sharing options...
djwarner Posted January 18, 2015 Share Posted January 18, 2015 Remove the Dizzy and try to turn the shaft. I'll bet the woodruff key locking the drive gear on to the crank is sheared or missing. Quote Link to comment Share on other sites More sharing options...
dashpot Posted January 18, 2015 Author Share Posted January 18, 2015 Does that mean turning the crank bolt will turn the crank but when the pulley turns, the crank will not necessarily turn? If so, how would the car run on it's own like it did when turning it over all put together? Quote Link to comment Share on other sites More sharing options...
NewZed Posted January 18, 2015 Share Posted January 18, 2015 I think that he means the key for gear #13. http://www.carpartsmanual.com/datsuns30/DatsunZIndex/Engine280Z/PistonCrankshaft/tabid/1602/Default.aspx Apparently, there are three keys in the crankshaft. The illustration shows their slots. Quote Link to comment Share on other sites More sharing options...
dashpot Posted January 18, 2015 Author Share Posted January 18, 2015 Ah ok. this makes sense. So this is the gear that meshes with the oil pump shaft? Only problem is if this key is broken or what I think is being suggested, that the crank isn't turning the oil pump, how is the car running? What else turns the dizzy? If this connection were broken the dizzy shouldn't turn when turning the car over with the key. Thanks in advance. Quote Link to comment Share on other sites More sharing options...
NewZed Posted January 18, 2015 Share Posted January 18, 2015 Good point. I didn't go that deep. On the second try, after confirming that a drill motor works, were you looking at a mechanical gauge or depending on the dash gauge? The stock sender and gauge are notoriously slow responding. Maybe you fixed the problem with the drill prime (the pumps do need priming) but went back to the bad measurement method. Quote Link to comment Share on other sites More sharing options...
dashpot Posted January 18, 2015 Author Share Posted January 18, 2015 We used a mechanical gauge and took the sender off, as from history I've relied on wrong information to make other things worse. I have good news though, and I can't explain it. I took a little bit of a risk and thought I would start the car from the ignition and all, let it idle for 15 seconds and no more (with no oil pressure beside the coating its had from tinkering). About 5 or 6 seconds at idle with the car running I watched the mechanical gauge (had to prop it up on the valve cover), the pressure started building up to 40-50psi and held steady. I'm pretty damned excited, but part of me is wondering why this works now - I live by the motto that these things are generally too good to be true. The only thing we recently did differently was that we used a drill to prime, dropped the oil pump to put the shaft back in and re-attached pump. My guess is a combo of this and giving the engine speed time to build (like you said the slow responding time) pressure, that solved it. Another little factor in my mind - the gasket for the pickup tube was shot, so we may have been sucking in air. We fixed that. Seems extremely minor for how paper thin that gasket is, but I thought I would mention it for anyone out there facing these issues and may have run out of things to check. Thanks guys! Quote Link to comment Share on other sites More sharing options...
Xnke Posted January 23, 2015 Share Posted January 23, 2015 My L has a worn pump right now...takes 5-10 seconds from a cold startup to get oil pressure. I've got a new pump to go on this week. Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted January 23, 2015 Share Posted January 23, 2015 I didn't see this mentioned, but when I replaced an oil pump I did not get any pressure until I primed the pump itself. It will not purge air until there is a good amount of oil inside it to seal it enough to draw oil from the pan. Quote Link to comment Share on other sites More sharing options...
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