Robitussin Posted January 20, 2012 Report Share Posted January 20, 2012 So... 1st post, I'm a newb mechanic btw. Anyways got that L28 in the ol' 280zx. I was thinking either the piston rings or cylinder walls that need attention. I heard that a damaged up head gasket can cause 2 adjacent cylinders to drop in compression. I'm trying to figure out what to look for before I open it up, and whether or not to bring it to a shop. Thanks for any tips/input Also-- i'm trying to save $! Quote Link to comment
Guest kamakazi620 Posted January 20, 2012 Report Share Posted January 20, 2012 So... 1st post, I'm a newb mechanic btw. Anyways got that L28 in the ol' 280zx. I was thinking either the piston rings or cylinder walls that need attention. I heard that a damaged up head gasket can cause 2 adjacent cylinders to drop in compression. I'm trying to figure out what to look for before I open it up, and whether or not to bring it to a shop. Thanks for any tips/input Also-- i'm trying to save $! Are All 6 plugs oily??? Quote Link to comment
datzenmike Posted January 20, 2012 Report Share Posted January 20, 2012 ....also what are the compression readings on all cylinders? There's no reason for oiliness just because the gasket may be blown. The rings, including the oil rings may be worn out. Quote Link to comment
EricJB Posted January 20, 2012 Report Share Posted January 20, 2012 Welcome to the pack. Good bunch of people here. We need to know more before you start taking it apart. Have you driven it enough to know how much oil it consumes? does it smoke? When does it smoke? morning startup, accelaration or decelaration? Morning startup and decelaration is usually bad valve stem seals. Accelaration is worn rings. Having a leakdown test done will solve the mystery as well. If it has a blown head gasket between two cylinders, the adjoining cylinders will usually have the same low compression. Almost identicle. They are pushing their compression into each other. Are the plugs in question black and powdery looking, or sticky and shiney? I would hate to see you pull your motor down because of a dirty air filter. Hope this helps. Quote Link to comment
Robitussin Posted January 21, 2012 Author Report Share Posted January 21, 2012 thanks for the welcome aboard-- can't check all the spark plugs right now, been raining all day, and I don't have access to my garage right now. I checked 2 of them a couple days ago, both were oily. 2 cylinders were around 100psi, the rest about 150psi morning startup: white smoke, goes away after the engine warms up seems like the acceleration/power could be faster the engine has shut off a couple times when: (all at the same time) cold engine, on a steep incline and idling oil depletion-- real slow. Can't really gauge the rate bc only had the car for a couple weeks Quote Link to comment
flatcat19 Posted January 21, 2012 Report Share Posted January 21, 2012 By description...I could tell you what I would condemn. But throwing parts at something without ruling out all possible causes is not the way to go. Inspect oil and coolant. Do either look odd? Milky? Coolant frothy with white/brownish foam? Check ALL plugs. Confirm compression test readings.---You said you checked 2 plugs, but all cylinders are between 100-150. What? Then you should've seen the other 4 plugs. White smoke...obvious...BUT, not your determining factor to start condemning anything. Maybe just a touch of condensation build up from sitting? Remove valve cover; inspect. Perform a leak down test. If all is fine here-then start putting blame on faulty/blown HG. ================================================================================== The cut-off/acceleration issues could possibly be related. Or you could have something completely separate happening. Might all be the same. Or you could have 3 different things happening. Something to get you busy. Good luck. Quote Link to comment
I'm BLUE Posted January 21, 2012 Report Share Posted January 21, 2012 Great advice àbove! Which two cylinders. ? If you end up doing a head gasket ... not that hard ... pull it with the manifolds on if you can lol (lazy way) ... use a good brand hg... check head and block surfaces for flatness ...... if overheated have head pressure checked at a machine shop .... i like the fel-pro or beck arnley ... typically .... make sure to buy or make a timing chain tensioner holder tool or make one or you will be sorry if you do not! Lol ... its not that hard ... scrape gasket surfaces, vacuum any debris, wipe down mating surfaces with brake clean, and apply a touch of solicone at the front to edges where the timing cover meets ... use a known good torque wrench .. 10mm Allen bit ... 60ft lbs i believe and your done ... re-torque a bit after driving car around ... :) ... In addition ... make sure compression test is done on a fully charged battery ... Check timing chain stretch... Check fuel pressure ... change fuel filter if you have not done so ... run fuel system cleaner through it, and no cheaply brand gas! Check air intake boots ... make sure no holes (underside) ,,,, Leak down test is priceless many times ... :cool: All else fails ... Hybrids.org has lots of information ... use the search ... tons of info ... do not post without searching thoroughly .... ive seen people get banned on there for little things like asking an already asked question ... lol We are hear to help, and welcome Quote Link to comment
metalmonkey47 Posted January 21, 2012 Report Share Posted January 21, 2012 Welcome! These guys will take good care of you here.. Out of curiosity, where do you live? Quote Link to comment
KC Phirus Posted January 21, 2012 Report Share Posted January 21, 2012 If you have low compression on two cylinders and they both have oily plugs then I'd say blown headgasket between the two? Quote Link to comment
EricJB Posted January 21, 2012 Report Share Posted January 21, 2012 Just like Flatcat said, "white Smoke" is probably a bit of condensation from a cold exhaust. Put your hand in back of the tailpipe and leave it there till your hand is wet. Does it smell like coolant? Oil makes blue smoke, Rich fuel mixture makes black smoke Water or coolant makes steam. But once the cat warms up, you might not see anything. Thats where the compression test comes in. As far as compression goes. the #'s need to be within 10 percent of each other. If you tear it down and the problem doesn't rear it's ugly head, you will be guessing. Quote Link to comment
Robitussin Posted January 21, 2012 Author Report Share Posted January 21, 2012 Nothing like a barrage of great info-- thanks, everyone for the input. I'm takin notes, and I should have some free time next week to monkey around with it---- I'll post an update then. And metalmonkey47 I'm in sanfranciscocalifornia- thanks for the welcome Got some frame damage on the pass front arm/rail, getting it straightened out on tues... Quote Link to comment
racerx Posted January 23, 2012 Report Share Posted January 23, 2012 Not to hijack this thread but like your avatart Robitussin..that's Mr. Han in Enter the Dragon Quote Link to comment
Robitussin Posted January 25, 2012 Author Report Share Posted January 25, 2012 Not to hijack this thread but like your avatart Robitussin..that's Mr. Han in Enter the Dragon Yup sure is Mr. Hahn. cigarring it up! Quote Link to comment
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.