Guest bastaad525 Posted September 22, 2003 Share Posted September 22, 2003 Afshin if you're still out there and at all interested... I would still appreciate your input on this mystery of a problem. And I do really apologize I HAD meant to get around to doing this sooner but things have really been a mess lately. and of course anyone else who has been following along with the 'saga' here.... Adjusted the valves hot today and then did a compression test. Things just keep getting weirder with this motor. When I pulled the plugs today, now they are ALL SIX coated with oil again (as opposed to two nights ago when only three had oil on them..... as opposed to some two weeks ago when they all had oil on them... WTF?? Damn car can't make up it's mind...) and they look like they are also running richer than they were two nights ago, which also makes sense as I've changed nothing that I know of that affects mixture. Anyways, here are the compression test results. Cylinders: 1 - 132 psi 2 - 135 psi 3 - 140 psi 4 - 135 psi 5 - 138 psi 6 - 135 psi Now you guys tell me what that means. This is with the motor hot and holding the throttle wide open. To be honest (and I've already stated this before) these are just about the results I expected. So... the mystery. An engine that NEVER smoked before, suddenly bends a valve during low rpm cruising, so the head gets rebuilt, and immediately we reinstall it it starts burning oil, fouling the spark plugs in all cylinders and smoking really bad. Ran the motor with the turbo completely disconnected from the intake and verified it's not coming from the turbo as the motor still smoked. Checked the valve seals and they are brand new and installed correctly and appear to be the right size. And now a compression test showing good, even numbers on all cylinders. What do you guys make of this?? My theory on the compression test, and this is something I already mentioned and why I did think that the compression test would really not reveal anything. Either a) the oil control rings may be bad but the compression rings could be just fine, or the oil and compression rings may be bad but since oil is leaking up into the cylinders, it is coating and helping to seal the compression rings, hence giving the same kind of results as you'd get when you squirt oil in there to retest cylinders with low compression. Other than that, I am completely baffled. Either way I'm dropping the car off this coming thursday, gonna have the head pulled and inspected, and most likely have the block honed, re ringed, and put new bearings in as well. Any last guesses/bets as to what the problem really is? Quote Link to comment Share on other sites More sharing options...
Guest Nic-Rebel450CA Posted September 22, 2003 Share Posted September 22, 2003 compression does look good. did you want to try out my idea with the UV leak checking stuff? if you cant find any I will ship you a bottle. Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted September 22, 2003 Share Posted September 22, 2003 nah dude it's okay by the time it would get here the engine will most likely already be taken apart. I'm actually pushing the guy to let me drop it off on wednesday since that's my day off... hopefully he'll have the head off and at the machine shop by thursday. It's definately leaking oil into all cylinders though, the plugs were pretty badly coated when I pulled them out today. Thank you for the offer though. Quote Link to comment Share on other sites More sharing options...
Guest Nic-Rebel450CA Posted September 22, 2003 Share Posted September 22, 2003 Ok, then by this weekend we can hope for a YAY! post from you. Quote Link to comment Share on other sites More sharing options...
fl327 Posted September 22, 2003 Share Posted September 22, 2003 compression levels are excellent, i dont think its the bottom end-those numbers are as high as my engine-and my engine is pretty fresh. Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted September 23, 2003 Share Posted September 23, 2003 Then I am completely at a loss.... if the valve seals are definately good, and the turbo seal is definately not the cause either... and compression is good across the board... how in the heck is the motor burning oil in all six cylinders? Guess Afshin isn't going to pitch in anymore... well if anyone else has any other possible ideas... let me know now before I let go of $500+ more dollars to get the block redone. Quote Link to comment Share on other sites More sharing options...
Z-Gad Posted September 23, 2003 Share Posted September 23, 2003 OK, compression tests are good and your results look good as well... I've never dove a compression test as you described This is with the motor hot and holding the throttle wide open. All compression tests I have done were with the engine somewhat cooled down and with no spark to the cylinders. I attach the compression tester to the cylinder I wish to test, have someone turn the engine over while I watch the gauge and see where it peaks. I check all six in that manner and then shoot a couple of squirts of oil (like a wd-40) into the cylinder and check all the pressures again. If the rings are bad, you will notice a discrepency in the non-oiled and oiled readings. Ideally, a leak down test would tell you more than a compression test. Each cylinder is pressurized, with both valves closed, and there are 2 gauges. One gauge shows the amount of pressurized air entering the cylinder and the other gauge shows the amount of air leaking out of the cylinder. If you have a noticable amount of leakdown, you can determine whether it is coming from the head by air exiting the breather vent on top of the valve cover, out of the intake, or out of the exhaust (worn valves, seats, or guides), or from the block by air exiting the breather pipe on the side of the block (worn rings, cylinder walls out of round, broken ring lands, etc) Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted September 23, 2003 Share Posted September 23, 2003 Got me dude that's how I was told to do the test... engine should be hot so that the rings/pistons/cylinders are expanded to their normal running shape, and you want the throttle open to let air in unrestricted. I did it with all the spark plugs removed at the same time, and cranked the engine over five times per cylinder, which is about when the PSI would peak anyways.. the last 2 strokes really didn't increase the reading much at all. I was going to do a leakdown test but then a whole new set of variables comes into play. For instance, you can have damage on the cylinder walls down near the bottom of the pistons travel, but it wouldn't show because the leakdown test only tests with the pistons at TDC. I'm sure if Afshin reads this he will get on my case now that I'm not running out to do a leakdown test asap (if you're wondering I AM just kidding). At any rate it wouldn't matter... the engine will be apart in less than a week, the head will be examined by a good machine shop, and the pistons will get new rings and bearings and the cylinders will be honed. I'm really looking for ideas of what else if anything could be causing the smoke... I just have this bad feeling with my luck, after new rings and the head checks out okay... we'll put it all back together and somehow there's still gonna be smoke. Ah well we'll find out soon enough... hopefully NicRebel will be right and I'll get to finally post a YAY thread real soon. Quote Link to comment Share on other sites More sharing options...
Jersey Posted September 23, 2003 Share Posted September 23, 2003 525 - cant type much - too many drinks but, i ripped my cousins '83zxt down and it's his T3 that' s wasted. Godda go. Quote Link to comment Share on other sites More sharing options...
Afshin Posted September 23, 2003 Share Posted September 23, 2003 Hi Bastaad, well the whole thing is certainly confusing. At this point without seing the car it's difficult to make any further calls. The problem is still by far most consistent with leaking seals for the same reasons as before, which were, pattern of smoke (at start up, after idling, not during cruising.), and happened immediately after the head rebuilt.. Also it seems more likely that faulty seals may leak more and less at different times based on how they are seated, accounting for the variable amount of oil on the plugs (as opposed to failed oil rings). Off course I can't explain why the seals you looked at seemed OK. We know it's not the turbo, it certainly does not seem like rings which is further confirmed by the nice compression numbers you got (don't worry, the leak down test would be needed if the compression was low ) nor does it seem related to ventilation/pressure. It doesn't seem like you need a bottom end rebuilt, but then if the guy is willing to do it , why not ( assuming that you are planning on keeping the car for a long time). Unfortunately, nothing makes perfect sense, but overall leaking seals make the most sense (I don't even know if the sentence makes any sense). If you get the chance try asking a couple of engine shops/rebuilders for their opinion before you pull the bottom end apart, maybee there is some trick for checking seals or we are forgetting to consider something. Also make sure you get the nice seals that Tim offered. Hopefully this saga will end soon. Quote Link to comment Share on other sites More sharing options...
rags Posted September 23, 2003 Share Posted September 23, 2003 Have you checked the obvious like a high oil level and bad PCV valve? The plugs are showing oil contamination, it's not just blowing smoke? If it's blowing smoke and not showing on the plugs you could be passing oil to the exhaust side of the turbo from the center section. Joe Quote Link to comment Share on other sites More sharing options...
TimZ Posted September 23, 2003 Share Posted September 23, 2003 Have you checked the obvious like a high oil level and bad PCV valve? The plugs are showing oil contamination' date=' it's not just blowing smoke? If it's blowing smoke and not showing on the plugs you could be passing oil to the exhaust side of the turbo from the center section. Joe[/quote'] To expand on this, are the plugs showing oil at the elecrode/center insulator, or do they just have oil on the threads (you probably already said, but I don't have time to read all five pages right now)? Also, be careful on drawing conclusions based on whether or not it still smokes after changing something - if you have blown oil into the exhaust (which you almost certainly have), it can take a really long time for it all to burn out - like ten or fifiteen miles of freeway driving. Quote Link to comment Share on other sites More sharing options...
zbuild Posted September 23, 2003 Share Posted September 23, 2003 Many years ago I had a hot VW golf that for no apparent reason started to smoke very badly, foul plugs in all cylinders just like yours. I came a hairs breath from having the motor rebuilt, but couldn't afford it right then. Then I went out and got a new tank of gas. . . .. bingo. . .fixed. Apparently when the gas stations tanks get low, you sometimes pic up a tank full of very oily fuel. ... .have you got a tank of gas lately??? Cheers Zbuild Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted September 24, 2003 Share Posted September 24, 2003 Jersey - kewl you found out what it was I wish the turbo had been my issue would have probably been the easiest fix. You know... I still think that it's a possibility.... Afshin - I agree that the seals still seem to make the most sense as the culprit for the reasons you listed. That's why I'm gonna get a second oppinion from another head shop when we get the head off. For all I know they could be .1mm too big or something. I did email TimZ and hopefully he can get those brown seals out to me before it's time to put everything back together. I was going to end up changing the seals either way just for peace of mind. I dont really mind getting new rings and bearings on the block at this point anyways. I figure... i already did the head, and yeah I do plan on keeping this car for a long time... I'll feel better knowing the entire engine is fresh. And it's not costing too much anyways so why not. But like you I still kinda think the rings are not the problem and that little voice in the back of my head says it's not gonna fix the smoking and that's bothering me.... okay I'm gonna ask this again, does anyone know what the pattern of smoke is if the turbo seal is bad? I.E. does it smoke all the time? Only at WOT? Only at idle? If the turbo seal is bad will there definately be a lot of oil built up in the J-pipe? Rags - The oil level is okay, and has gone down some in the last couple weeks. Getting really close to the 'low' mark on the stick. I eliminated the PCV valve from the system entirely. The engine is now just vented into the intake before the turbo... I also ran the car with both the block and valve cover breathers open to atmosphere but it would stink up the car really bad. OH and one thing I keep forgetting to mention!!!!! When the valve cover breather was vented to atmosphere a lot of smoke came out of it! That's blowby right? Oh and rags yeah theres oil on all six spark plugs... though sometimes there isn't! But 3 out of 4 times that I've checked them they have all had oil on them. TimZ - the plugs have oil on the electrode, insulator, threads.... They are pretty thoroughly drenched. I drive 40 miles to work and back everyday so every change I've made at work has had plenty of opportunity to make a difference. Hey by the way Tim did you get my email? Zbuild - I believe I'm on my 5th tank of gas since the head rebuild. Quote Link to comment Share on other sites More sharing options...
Afshin Posted September 24, 2003 Share Posted September 24, 2003 what the pattern of smoke is if the turbo seal is bad? I.E. does it smoke all the time? Only at WOT? Only at idle? As far as I know when turbo seals leak, there is no smoke at start up, none at idle (or some if the seal is really shot) and the smoking increases dramatically under boost/spool. If the turbo seal is bad will there definitely be a lot of oil built up in the J-pipe? Not necessarily I believe more often the seal leaks oil into the exhaust causing smoke as opposed to into the J pipe. I know of failing seals (one z, one supra and a saab) causing lots of smoke with minimal oil in the J pipe and no oil whatsoever on the plugs, which were resolved with new/rebuild turbos. All 3 only smoked under boost Quote Link to comment Share on other sites More sharing options...
Jersey Posted September 24, 2003 Share Posted September 24, 2003 525 - my cousins '83ZXT, that just started smoking seemingly out of the "blue" and found out the other night that his T3 is shot, would not really smoke at cold start up. I think because the oil was thicker and the T3 doesn;t even spin at idle. After it warmed up a bit and spun the T3 a little, it would start to smoke a little at idle, little more when giving it throttle, and when you backed off after holding it at like 2krpm for a minute or so, it would cloud. It really wouldn't smoke too much at idle after sittle there for a bit, probably because the T3 isn't pushing any air in to the intake at this rpm...but bring the R's up a little and a nice blue cloud would appear! J-pipe itself had a slight film of oil on it but not really that much. I'm guessing the air/oil mixture was passing through it so quickly, it didn't cling. I took the AFM to T3 boot off, grabbed the compresor shaft and it had lots of side to side movement and instantly knew that it was the cause. Just for S&G's, we disconnected the T3 oil feed line on the passenger side of the L28, where it T's off, plugged the hole so no oil would come shooting out of the block and ran it...guess what, no smoke. No oil to burn past the seal in the T3, no smoke. Maybe you could try this test. Not that hard to do and would tell you whether it's the T3 seals or not. One more thing to eliminate from the saga Quote Link to comment Share on other sites More sharing options...
Brad-ManQ45 Posted September 24, 2003 Share Posted September 24, 2003 I'd put the PCV back in the system. When you are boosing with the turbo you may tend to draw more oil from the crankcase. Quote Link to comment Share on other sites More sharing options...
mobythevan Posted September 24, 2003 Share Posted September 24, 2003 You could try that, but I've been running for several weeks with the crankcase and valve cover vented to atmosphere and no signs of burning any oil. Quote Link to comment Share on other sites More sharing options...
Afshin Posted September 24, 2003 Share Posted September 24, 2003 we disconnected the T3 oil feed line on the passenger side of the L28 even if real brief, wouldn't that ruin the bearings on a good turbo ? i never tried running a turbo without oil to know how long it would take to burn the bearings (my guess not very long), but I certainly would not advise it unless you know for sure that it can be safely done ( I really really doubt it). Don't do it, unless you need a excuse to buy a T3/T4 Quote Link to comment Share on other sites More sharing options...
mobythevan Posted September 24, 2003 Share Posted September 24, 2003 Don't do it, unless you need a excuse to buy a T3/T4 hmmm.... Quote Link to comment Share on other sites More sharing options...
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