Guest 2slo4u Posted November 28, 2004 Share Posted November 28, 2004 Man, just can't seem to get a break for long on my engine. After getting the valve job, most of the valve seals popped off. I replaced them with ANOTHER new set and they all lasted until yesterday, when I noticed a small puff of oil smoke at startup. What could keep popping them off? I am running about 10psi and sometimes the boost spikes up substantially higher when it's cold outside. Could the excessive boost cause them to come off? The guy who did the valve job told me it would take over 40psi to do this but I'm sure my boost isn't spiking that high. Any suggestions to keep them on. I'm planning on doing it only one more time. It's my brother's car now, and I don't want him to have to deal with it (or me for that matter). Any help guys and gals? 81280zxturbo with 300zxecuandMAS, etc. Quote Link to comment Share on other sites More sharing options...
Tony D Posted November 28, 2004 Share Posted November 28, 2004 Excessive valve guide wear could, in theory, allow pressures to pop them off--but since it's been rebuilt recently, then that shouldn't be a problem... If they are the correct seals for the application then I suggest the following: Top of guide must be cleaned SCRUPULOUSLY with absolutely NO residue. A NEW set of seals is procured, and with them DRY, use contact cement, gasket adhesive, hell SUPERGLUE on them. This will keep them in place, but I have run well over 17psi and mine don't blow off. Which is why I am suspect of proper application. Good Luck. Quote Link to comment Share on other sites More sharing options...
RB26powered74zcar Posted November 29, 2004 Share Posted November 29, 2004 buy a set for the "A" serirs motors. They have a metal jacket around them, which will not pop off (even when you try to remove them) Brian, I have one at my house still in the Nissan bag, so you can get the part# from it. Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted November 29, 2004 Share Posted November 29, 2004 You only saw a puff of smoke when you started the car? I wouldn't think this is an indicator of unseated valve seals.... if they had come off I'd think you'd get a lot of smoke and more than just at start up. My motor is also recently rebuilt, and I almost always get a small puff of smoke on startup, but never any other time. It used to bother me, but if I remember right like every car I've owned has done this. The oil level has stayed fine, I top it off maybe once between 3000 mile oil changes, if at all. But there's always that puff..... Quote Link to comment Share on other sites More sharing options...
Guest 2slo4u Posted November 30, 2004 Share Posted November 30, 2004 Thanks, Joel. I'll stop by when I get a chance. I'd like to see how your rb project is going. Yeah, Bastaad. It happened to me before when I first had the valve job done. After installing another new set, it stopped. When it did it this time, I knew without a doubt. I checked it today and a couple are off. It also makes the engine run just a little rougher at idle, but runs perfectly during boost and at all other times. Layta y'all. Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted November 30, 2004 Share Posted November 30, 2004 heh so uh.. okay now I'm worried. Sounds like I have the same symptoms as you... never even thought to suspect loose valve seals. I get that little puff of smoke almost every time I start her up, and I have always had a slightly rough idle with a bit of misfire... which I long ago gave up trying to figure out after trying just about everything I could think of to fix it. I'm just not gonna worry about it for now... I really really don't feel like pulling off all the valve springs to try to find out. At least not for now Guys, what are other possible reasons on a rebuilt motor, for the little puff of greyish/whitish smoke on almost every startup? Is it something I should worry about? What if I check the valve seals and they are all fine? I get no smoking any other time. Could one or more loose valve seals also be responsible for smoke coming from the valve cover vent (blowby)? Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted December 2, 2004 Share Posted December 2, 2004 Anyone? not to try to extend what may already be a dead post, but I'm seriously wondering if I should be worrying about these puffs of smoke...... Quote Link to comment Share on other sites More sharing options...
Guest 2slo4u Posted December 2, 2004 Share Posted December 2, 2004 Pull the valve cover off and look through the sides of the valve springs. You will be able to see if a seal has popped off. It will be higher than the others. You may have to spin the motor a couple of times to make some of the valve springs decompress so you can check them all. (Just remember to disconnect the spark or you may get splashed with oil) Quote Link to comment Share on other sites More sharing options...
JMortensen Posted December 2, 2004 Share Posted December 2, 2004 Just wanted to make sure you saw this. Your local auto parts store probably has these on the shelf and they run ~$20... http://hybridz.org/phpbb2/viewtopic.php?t=31967 Quote Link to comment Share on other sites More sharing options...
Guest 2slo4u Posted December 3, 2004 Share Posted December 3, 2004 Thanks for the input guys. I'll be ordering some tomorrow. Hopefully I can get them on without destroying half of 'em! Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted December 4, 2004 Share Posted December 4, 2004 Well... I keep putting it off but I REALLY need to readjust my valve lash anyways... haven't really been driving the car much, too collllllld out really, and I hate driving the Z with the windows up so Well I'll definately take a look at the seals when I get around to it. It will suck if one or more of them are loose, but at the same time it will be a relief to be such an 'easy' fix as well, if it gets rid of my misfire! 2sloforu - one question for you, in your case with the misfiring or rough running idle when the seals come off, do you notice ANY change in this roughness in relation to the temperature of the engine? For instance, mine misfires a lot when stone cold, then when it gets to it's regular idle running temp, runs very smooth, with little or no miss, then if it heats up, like after a spirited drive or on a hot day, it starts getting worse again. Does yours do this? Quote Link to comment Share on other sites More sharing options...
Guest 2slo4u Posted December 4, 2004 Share Posted December 4, 2004 Mine actually runs smoother when cold, it is only noticeable when warm. The misses are more noticeable though after the seal(s) come(s) off. I have a slightly different setup, stock fuel regulator and pump. I also don't have the egr, aac, and I have an early 300zx mas and crank angle sensor in the distributor. It's really helped it run better. I went to advance auto parts today and got the seals that jmortensen mentioned above. They are green and shorter than stock. I hope they will actually grab the valve stem, I didn't notice any kind of locking inner lip, only several smaller ridges. Quote Link to comment Share on other sites More sharing options...
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