Thumper Posted August 26, 2005 Share Posted August 26, 2005 Well I think I need new valve seals but wanted your guys opinions. Here are the symptons. Car smokes out of exhaust and alittle bit out of the valve cover breather upon deceleration. When idleing or accelerating no smoke. When you first start the car no smoke comes out. When the car is cold very little to no smoke. The smoke is very blue. The vacuum gauge shows 16 with little movement. The smoke gets worse the warmer the car gets. The pcv valve is in good shape. Any inputs or questions? Thanks Quote Link to comment Share on other sites More sharing options...
S30TRBO Posted August 26, 2005 Share Posted August 26, 2005 Well I think I need new valve seals but wanted your guys opinions. Here are the symptons. Car smokes out of exhaust and alittle bit out of the valve cover breather upon deceleration. When idleing or accelerating no smoke. When you first start the car no smoke comes out. When the car is cold very little to no smoke. The smoke is very blue. The vacuum gauge shows 16 with little movement. The smoke gets worse the warmer the car gets. The pcv valve is in good shape. Any inputs or questions? Thanks Welcome to the club, it's either stem seals or oil ring. I have the same symptoms on my 240Z's original motor not for much longer hehehee L28ET... Quote Link to comment Share on other sites More sharing options...
HadesOmega Posted August 28, 2005 Share Posted August 28, 2005 yep sounds like valve stem seals to me, my eclipse had the same problem the vacuum needle would kinda vibrate. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted August 28, 2005 Share Posted August 28, 2005 Sounds like oil rings to me. Stem seals usually cause smoke at startup IME, but yours doesn't smoke at startup becaue the seals are fine and the oil is too cold and thick to get past the rings. My $.02. Quote Link to comment Share on other sites More sharing options...
Here comes trouble Posted August 29, 2005 Share Posted August 29, 2005 If absolutely no smoke at start-up.. I will go along with Jon on oil rings.. I have had engines that would smoke intermittenly on start-up since just one or two valve seals were bad draining oil past an open valve to cylinder.. Valve seals are easy to change and relatively cheap. I would look for wet plugs and do a compression test...16 inches of vaccum is not that high (20 would be great) but a good acceptable vaccum. .........slight vibration at 16 is not an indicator of a valve train problem ......dramatic fluctuations of vaccum would indicate a valve train problem. add two cans of STP and see what happens. (plenty of rest stops and a good night's sleep) Quote Link to comment Share on other sites More sharing options...
PeterZ Posted August 29, 2005 Share Posted August 29, 2005 Make that $.06. I agree, smoke at start-up = valve stem seal problem. Smoke on decel only is probably an oil ring problem. Compression or cylinder leakage tests may not show any problems because you are testing mostly the compression ring. The increased manifold vacuum on decel will pull oil past the control rings and you see the smoke. Like HCT I recommend checking spark plugs. Stem seals are cheap and easy but sounds like you gotta go deeper. If the engine is really old the oil drain holes inside the piston can plug up with carbon and sludge. Also, an excessively rich fuel system can wash the oil film from your cylinder walls and speed up wear. As a side comment I recommend against these 5 minute engine flush chemicals for similar lubrication issues. By the way, are the engine crankcase vent hoses and baffles in good shape and not puddling an accumulation of breather oil? Quote Link to comment Share on other sites More sharing options...
Guest 73Turbo240z Posted August 29, 2005 Share Posted August 29, 2005 on the subject of gummed up piston drains... idea... what if he threw in 4 quarts of cheap oil and 1 qt of atf, ran it for 50 miles then swapped back, should help clean the system out a bit? Quote Link to comment Share on other sites More sharing options...
Here comes trouble Posted August 30, 2005 Share Posted August 30, 2005 To clean an engine.. I drain oil pan and put in a gallon + of diesel fuel...run for 10 minutes and let set over night. Run engine for 10 mintes and drain oil pan. Engine vital signs should be monitored closely with this country boy method. Replace oil filter and fill with 5 qts Chevron Dello 400- 30 WT. It usually takes a week for the new oil to be dark enough to be easily seen on a dipstick. Quote Link to comment Share on other sites More sharing options...
Guest 73Turbo240z Posted August 30, 2005 Share Posted August 30, 2005 To clean an engine.. I drain oil pan and put in a gallon + of diesel fuel...run for 10 minutes and let set over night. Run engine for 10 mintes and drain oil pan. Engine vital signs should be monitored closely with this country boy method. Replace oil filter and fill with 5 qts Chevron Dello 400- 30 WT. It usually takes a week for the new oil to be dark enough to be easily seen on a dipstick. no issues w/ bearing scoring using the thinner diesel fuel as your bearing lubrication? Quote Link to comment Share on other sites More sharing options...
proxlamus© Posted August 30, 2005 Share Posted August 30, 2005 check the PCV too.. make sure it's breathing properly... mine did the same thing.. but i had too much positive pressure inside the block.. and the oil was not draining.. which meant it came out of the turbo and into the exhuast and burned... on start up.. got worse as it warmed up... bad valve seals will smoke bad when sitting for a few hours.. and the oil drips onto the cylinders and burns on start up.. bad seals also means it smokes on deceleration... but so did my bad PCV setup. Quote Link to comment Share on other sites More sharing options...
Thumper Posted August 31, 2005 Author Share Posted August 31, 2005 Well I found out my turbo was going out. It wasn't quite that gone but it was starting to lose boost. I went out and found a rebuilt one for a good price. Finished installing it and no more smoke at all. My concern now is why the first one went bad. I believe its an oil pressure problem so i'll see if I can find out where my problem is. I know the turbo is getting oil, since I removed the feed line while the car was running and oil came out. It was only a drip at idle but as soon as I reved the engine it came pouring out. We will see. Maybe clogged pick up screen or ... Quote Link to comment Share on other sites More sharing options...
innerware Posted September 19, 2005 Share Posted September 19, 2005 Just to add to the thread and ask a question. It sounds like my daily driver has bad valve guides, or going bad anyway. It smokes like a mother when I start it when it is cold and cool. Once it warms up though it goes away completely. The smoke is light grey almost whitish. This is what I thought was coolant a little bit ago but now think it is oil. I just passed smog in CA too about three weeks ago and it did this right before it was smogged. So, if it smokes apon startup and goes away apon warm up then most likely valve guides aye? I need to do a compression test I know. I've been real busy. Thanks all, Kyle Quote Link to comment Share on other sites More sharing options...
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