240hoke Posted December 1, 2003 Share Posted December 1, 2003 hey guys, i went over to the Rockingham dragstrip for import day and got a few runs in. Every run was very dissapointing my best time being a 14.2 @ 103 mph, this was with the 1/8 mi being .3 seconds slower than my average at the local 1/8 track. Anyhow I'm not sure what was up but I think not being able to rev above 5K was really killing me. Had a little bit of light pinging at the end of the track (running 14psi on stock t3). Anyway on to the bad news... The engine is smoking very badly out of the vavle cover breather. It comes out around the hood and front when stopped and fills the cockpit when I take off, It is most noticible when accelerating from a stop. It has done this before after running it real hard but never this bad, and now it is constant. I was thinking maybe my vavle guides are messed up. Hopefully i will be able to do a compression check tomarrow and open here up. What are you guys ideas? This brings up another thing, i still cant rev over 5k. Several people have told be that it is a possibility that my valve springs are giving out at the high revs, i just shruged it off cuz they were new. If i decide to take the head off or have to to fix this how can i check the springs? Thanks -Austin Quote Link to comment Share on other sites More sharing options...
yo2001 Posted December 1, 2003 Share Posted December 1, 2003 May be a damaged ringland. I had a L6 smoke like yours before the block started knocking Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted December 1, 2003 Share Posted December 1, 2003 Is smoke coming out of the valve cover always a bad sign? What if it's just a little smoke? Mine has seemingly always smoked even after completely rebuilding the motor. Quote Link to comment Share on other sites More sharing options...
rags Posted December 1, 2003 Share Posted December 1, 2003 A small amout of smoke without a PCV valve is normal. When you have an excessive amount of smoke it usually means trouble. As yo suggested, broken ring land. Do a compression check, your not going to be happy. Joe Quote Link to comment Share on other sites More sharing options...
denny411 Posted December 1, 2003 Share Posted December 1, 2003 The possibility of the guides being bad enough to cause such a serious crankcase pressure problem is slim to none. I`m going to third the idea of a ring land or possibly a cracked ring. You are loosing compression to the crankcase which is why the problem worsens when the engine is under load or boost. Quote Link to comment Share on other sites More sharing options...
Guest Nic-Rebel450CA Posted December 1, 2003 Share Posted December 1, 2003 Is smoke coming out of the valve cover always a bad sign? Bastaad525, I think any time you ask "is it bad" it is! Only a very tiny amount is acceptable. This is only because it is impossible for a valve guide to have a 100% perfect seal and still get lubricated. Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted December 1, 2003 Share Posted December 1, 2003 yeah it's just a little bit... a puff here, a puff there Quote Link to comment Share on other sites More sharing options...
240hoke Posted December 1, 2003 Author Share Posted December 1, 2003 Well just ran a compression check. Cylinders 5-6 apear to be fine with reading in the 145 -150 range. Cylinder 1 is bad though with 90psi and it takes it a while to get there. Looks like im in for some new rings. I was thinking about having sunbelt do the job and let them check over the engine possibly redoing the head. Do you think its worth the extra time/money to have them do it, or should i just check for a place around here? -Austin Quote Link to comment Share on other sites More sharing options...
Ivan280zt Posted December 1, 2003 Share Posted December 1, 2003 Mine was always smoking just a little bit and i think that was normal but the night that i blew a headgasket thats when it just started sending freaking indian smoke signals lol mine was even coming out from that vent that goes to the block oh yeah it was bad.... Ivan Quote Link to comment Share on other sites More sharing options...
Guest Tim78zt Posted December 1, 2003 Share Posted December 1, 2003 Austin, save the $$ you are thinking of spending on rings. When my L6 turbo did this it was ringlands, not just rings, although the rings were broken into 3 pieces each on #1 piston. You are looking at replacing that motor, bud! That's what I did! It's cheaper to go with a junkyard motor than a new set of turbo pistons (forged, of course!). Running 14psi on a stock motor will definitely expose the weak link in a hurry!! Tim78zt Quote Link to comment Share on other sites More sharing options...
240hoke Posted December 2, 2003 Author Share Posted December 2, 2003 i just tore the engine apart to get a look at it. i cant really tell anything too much. cyl 1 was oilier then then others and had much less carbon, anyway heres teh pics, head gasket was perfect. This makes me sick it hasnt even been a year since i had the engine completely rebuilt. Ive got a friend with a rebuilt f54 block from an NA 280zx and a rebuilt p90 head, i may use it. But its going to cost me as much as a set of forged pistons since he wants the money back that he put in it. Im not sure what im going to do yet, dont really have anymoney rightnow. Sunbelt is out of the question 2500 for a basic rebuilt, yeah right! -Austin Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted December 2, 2003 Share Posted December 2, 2003 That sux dude only one year on the engine. You really can't mess around with turbo motors... you hear any pinging or anything like that you gotta back it off some. My motor overheated once from a failed water pump, it hadn't even gotten all the way to the red, it was like 3/4 of the way up, but before I noticed it was running hot, I got on it coming down the street, and thought I heard ONE ping. When I came to the next stop light my idle was lumpy and the motor was smoking like crazy. Usually from what I've read here stock efi will support 14psi intercooled, but NOT the stock fuel pump... is that what you were running? If so chances are the pump just couldn't keep up and you leaned way out at the top... Another possibility is a faulty injector... I seem to have problematic injectors all the time. I feel your pain dude trust me I only had my turbo motor for like a month before a valve got bent... I was just cruising down the street, wasn't even driving hard and blam... had the head rebuilt and then the rings were bad... engine smoking... then had to get the block rebuilt... I probably got to drive my car all of 2 weeks out of the first two months that I had the swap done. Quote Link to comment Share on other sites More sharing options...
240hoke Posted December 2, 2003 Author Share Posted December 2, 2003 Im running SDS EM4-6f, NPR i/c, MSD fuel pump, SVO 370cc injectors. heres a pic The problem im having is that i cant rev the car over 5 grand, at this point the ignition goes crazy tach bounces around, car engine starts to ping. I just pushed it to hard yesterday and i guess the detonation finally got to it. Im going to try and pull the block out tomarrow. Ive checked out almost everything on the engine about the 5k problem, even sent the ECU back to SDS for testing, so far i havent checked the vavle springs(which are supposably new). Im thinking, though, that there is a posibility that the crank pulley may be vibrating alot at 5k or my magnets arnt in a perfect circle. While the motor is out im going to check the valve springs and redo the magnets hopefully in a europully and have a machine shop mount them perfect. how can i test vavle springs? hopefully ill have some pictures of the damage by the end of the week, just have to get time to break down the bottom end. it will be back and better then ever even if i do go broke -Austin Quote Link to comment Share on other sites More sharing options...
wheelman Posted December 2, 2003 Share Posted December 2, 2003 240hoke, The tach jumping and the ignition going crazy has nothing to do with the valves and probably caused the pinging problem. I had a Subaru several years ago that started doing the same thing. It turned out the upper bushing on the distrbutor shaft was shot which allowed the shaft to wobble and which affected the electronic ignition pickup spacing. This caused the tach to jump around and screwed up the timing. This isn't exactly like your situation but sounds similar enough to maybe point you in the right direction. You might have a bad ignition module that fails when it reaches a certain RPM level. I don't know enough about your ignition system to really make an informed diagnosis but it sounds like something gets overloaded at the upper RPM range. Ken W. Quote Link to comment Share on other sites More sharing options...
yo2001 Posted December 2, 2003 Share Posted December 2, 2003 You might get a surprise when you pull the #1 piston out. I bet the ring land will fall out. This is second L6, that I know of, had a problem with #1 piston. The #1 must run leaner than others. O, don't spaned alot of money into a motor until the ignition problem is solved. My 2 cents Quote Link to comment Share on other sites More sharing options...
Guest Tim78zt Posted December 2, 2003 Share Posted December 2, 2003 Austin, you can actually remove the pistons without removing the block from the car. You already know how I know this!! I have been through 2 sets of pistons due to detonation before I got smart and went with a stock Nissan turbo long block. I also stopped going to tuners who believe 14:1 AFR is OK for a turbo street car. What is your air/fuel at, say. 5000 rpm? Since your motor is not stock you are looking at a tuning bug or a system malfunction like others have already mentioned. Good luck and happy hunting! Tim78zt Quote Link to comment Share on other sites More sharing options...
Sparky Posted December 2, 2003 Share Posted December 2, 2003 This is second L6' date=' that I know of, had a problem with #1 piston. The #1 must run leaner than others. [/quote'] From what Ive read, and heard through others with L6t's, the shape of the intake manifold (No 1 runner) causes a slight lean condition under boost, or at high RPMS. There was a guy from Missouri that went as fasr as to weld excess material onto the outside of the manifold, then port it out from the inside to smooth out and equally distribute the flow to each runner. anywho, Get that thing back together and check everything in your system! sure would hate to see it blown up again! Quote Link to comment Share on other sites More sharing options...
Guest Zcarsmakemyheadhurt Posted December 2, 2003 Share Posted December 2, 2003 What the hell happend to you Austin? If your running distributorless igniton or using the SDS crank pickup I would look there for the problems above 5K. Your engine sounds like its wasted, tear it apart and rering if your piston is not broken, also check the clearence in the cylinders, looking for excessive wear. My 189K mile motor was set up with crank ventalation and it kept things real clean but you must have a wrong tune to break that engine at 14psi. Good luck man hope you figure it out. Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted December 2, 2003 Share Posted December 2, 2003 That's odd... mine runs slightly more rich on the #1.... and I always... ALWAYS have problems on the #'s 5 and 6!! Bent valves and bad rings... ugh. And about pistons being pulled out w/o removing the engine... Me and a friend just did this recently... I say.. don't do it. It's backbreaking work, pain in the ass stuff... if you have the means, you will actually save yourself pain if you pull the motor out. I will NEVER go to the lengths to pull the pistons out again with the motor installed... not even with help... no way. Quote Link to comment Share on other sites More sharing options...
240hoke Posted December 2, 2003 Author Share Posted December 2, 2003 ive got the engine ready to pull. ive decided to just pull the whole engine. While its out im going to clean it real good and fix up my magnets so i Know they are perfect. I think i am going to go with stock turbo pistons i may be getting ahead of myself, still keeping my fingers crossed that its just a ring but.... Anybody have a set of pistons in good shape they would like to sell me? I could do with just one, but im worried there my be damage to the others. My goal for the motor is 300-350 hp. If set up right this is doable on the stock pistons correct? I'm hoping to save money on the pistons and possibly get a t3/t4 turbo while i've got the engine out. btw I know that the knocking was caused by my ignition problem. So my number one priority is to get that fixed while im getting this motor put back together. -Austin Quote Link to comment Share on other sites More sharing options...
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