Hello z forum, I need help with my 77 280z stock engine. A little history, I bought this car in a none running condition, when me and my dad pick this car up it was pretty much growing shrubs out the door sill. We trailered it home and I've been working on it since. What Ive done so far is drained the fuel, replaced the fuel pump & filter(because when I finally got it started it ran for about 2mins and shut of and would not start back up unless I pulled the hose on top of the fuel filter to release the pressure build up,then runs for another 2mins. this was because the fuel pump was clogged badly from old sitting fuel.That problem was fixed, now stays running but rough) Next I pulled the valve cover off (because i heard loud machanical noise) and found that four lash pads were out, so I put them back where they go and adjusted the valve clearance on all valves, adjusted the mechanical timing at 10 degrees, put the valve cover back and and started it up. It idled ok but is rough on acceleration. I rev'd it a few times and found that black and white smoke was coming form the exhaust. I did a compression test and found that #2 cylinder(second from the radiator) was getting low to almost no compression. I researched the problem and found that I should replace the valve seals( I only replaced the intake valve seal because it was the one that appeared to be worn) replaced the cover and still a great amount of smoke is put out. My question is what else should I do to to get good compression out of this cylinder? What all does low compression indicate? sorry for writing a book but I wanted to be thorough.

thanx...

Edited April 24, 201014 yr by ZTEC

IF, those lash pads were found free floating under the valve cover, I am going to bet you have sticky valves. Caused by gum or rust on the stems. This also may explain loss of compression in cylinder two! Suspicions also supported by the rust on the lash pads in the photo, if those are yours. I think that is a stock MSA image though. MSA sells rusty lash pads these days anyhow. Just clean them up and use them.

Anyone have any magic potion to pour down onto the valve stems when he changes the seals that might free up the valves a little?

Edited April 24, 201014 yr by cygnusx1

Yes the photo of the lash pads is a msa photo, was just using it as an example. If there is something that i can use to un gum the sticky valves please let me know, these would really make it easier then pulling the head and doing a valve job.