dagold Posted November 15, 2009 Share Posted November 15, 2009 So shortest version of this story goes a little something like this. My first car 1985ish was a 76 280z and have some sort of Z ever since. I currently own a 90tt, but my son caught the bug also. He traded his CRX for a 77 280 with a "bad fuel injector". After playing with it for a little bit and removing some of the cob webs have remembered some of the tricks to the Z.have not had a car that has a l28 for the last 10 years). Anyways after doing a compression test we believe it is the head, not "bad injector". Have a nasty tick/ clacking sound from 5 and pulling the wire from that plug does nothing. So after several searchs, I was wondering if anyone knows of a step by step writeup on pulling the head? We have an old Chiltons and downloaded the FSM for the car, but the other would really be nice to have in the garage. For those wondering 1. 150 2. 152 3. 152 4. 110 5. 95 6. 145ish Anyways thanks for any help. Dagold Quote Link to comment Share on other sites More sharing options...
morbidsunroof Posted November 16, 2009 Share Posted November 16, 2009 It sounds to me like you just need to adjust the valves! That would eliminate the noise and equalize the comp. numbers. Nick Quote Link to comment Share on other sites More sharing options...
dagold Posted November 16, 2009 Author Share Posted November 16, 2009 You really think I can correct 55PSI lose by simply adjusting the valves? Quote Link to comment Share on other sites More sharing options...
Lazyeye Posted November 16, 2009 Share Posted November 16, 2009 Adjusting the valves should help with the clacking (it did with my L28), but I can't say about the compression loss. Quote Link to comment Share on other sites More sharing options...
morbidsunroof Posted November 17, 2009 Share Posted November 17, 2009 A valve that loose is barely opening. If ya got no gazinto, yer not gonna get any squeeze! Nick Quote Link to comment Share on other sites More sharing options...
Guest Rolling Parts Posted November 17, 2009 Share Posted November 17, 2009 Wow, two adjacent cylinders are low? That sounds like a crack or a bad head gasket. You can adjust the valves and add a little MMO to see if those two come back in line. However, I suspect that the previous owner let cob webs grow on the car because he knew it was a little more severe than just getting and dropping in a $50 injector. To pull the head, you need to prepare by getting a new head gasket, intake/exhaust manifold gasket, and make a block (1/2 plywood cut 7.5" x 3/4") to block the timing chain tensioner, torque wrench, 10mm hex for torque wrench, etc etc. The downloaded FSM actually has a really good writeup... Quote Link to comment Share on other sites More sharing options...
Mayolives Posted November 18, 2009 Share Posted November 18, 2009 The FSM has an excellent step by step guide for the job. Read it a few times and "puppy" along with it. You can't go wrong. There are a few hidden bolts here and there but the manual points them out. Pay particular attention to correctly dealing with the timing chain and how to hold it in place or you will create a few more hours of additional work when you reassemble the engine. Buy your parts from Nissan and don't cheep out on a little better prices from the auto parts store. I would suggest having the head checked out at a good machine shop when you remove it. Take your time and ask intelligent questions if you get stuck. It aint no biggie. Quote Link to comment Share on other sites More sharing options...
Austin240Z Posted November 20, 2009 Share Posted November 20, 2009 I dont imagine you did a wet compression test in addition to the dry compression test by any chance? Having too much gap between the rocker arm and the cam would not cause low compression, just valve chatter. If there it is adjusted too tightly, the cam pushing down mildly on the rocker arm all the time, it could cause a compression leak due to the valve being slightly open all the time.... but that is unlikely. I would have to imagine your rings are worn out, or what was mentioned before, a possible head gasket leak. Do a wet compression test (squirt one or two drops of oil in the cylinder) and see what numbers you get. Quote Link to comment Share on other sites More sharing options...
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