jasongeek

so i sold my 82 280zxna about six months ago before i left for the navy. now after being without it i decided i wanted another one and plan on buying 1980 280zx blackgold 10th anniversary edition. The one problem other than the t-tops leak is there is low compression on cylinder #2 i dont know the exact compression specs all he said was low. now with this limited information can someone tell me what this could possibly be from?

NismoPick

Possible reasons for low compression reading:
-Blown head gasket
-Burnt / bent valve
-Worn piston rings

Google-machine results:
What will cause cylinder compression to be low
low compression... possible causes?
What Causes Engine Compression Loss? | eHow.com
causes for low compression? - Nissan Forums: Nissan Forum

Could also be someone who doesn't know how to do a compression test...

ThaPimpShrimp

Probably pistons rings, valves, or head gasket.

If you're going to go look at it, check the compression yourself dry and wet. If it goes up when wet it's likely piston rings.

Does it run?

Edit: Urgh Nismo you were seconds ahead of me :P

jasongeek

yes it does run. once i get it i will do the compression test myself. also would a valve seal have anything to do with it? not nessiceirly a valve.

SHADY280

does it blow any blue when running? if not it could be a burnt valve (this also can make it run very rough) if a valve seal is worn or piston ring, it will run fine but there will be some smoke out the pipe. head gasket could be causing the failure, there may be a coolant leak or oil leak into the cylinder that would also cause smoke but that is less likely as cylinder pressure sometimes hides this. you may get a constant disapearing coolant problem as well

jasongeek

found a guy who will do a valve and ring job for me just decided to replace the rings, valves, seals, and resurface the head, gonna keep everything stock though. unless you guys know of something else i should replace while he has it open i was thinking about going for a torquier cam?

NismoPick

Don't forget the crank & rod bearings. Also the timing chain kit.

How much did he quote you? Is he pulling the engine for you too?

jasongeek

he is not pulling the engine. He is doing it for free because hes a buddy of mine
he just said you buy everything ill need and ill do it for you. are the crank and rod bearings the same as a main bearing set? That is all i see come up at the oreilly autopart website when i search or connecting rod bearings

SHADY280

whats your head casting number? if its p79 get it shaved .080 and get a cam tower shim kit from derek at hybridz. well worth it while your there.