Tony D Posted October 20, 2008 Share Posted October 20, 2008 Yeah, if the PCV is not functioning, and you are getting a high in-crankcase pressure the best seals in the world will not stop the oil from coming over past them. i'm not sure of the design of yours, wether it's carbon ring, or labyrinth, but both will be overcome easily by oil backup by even as much as a few inches of water pressure. The whole idea of the drain tube is that nothing really exists in the chamber under any pressure whatsoever. The seals are mere 'splash guards' at best. If you have any pressure they can be overwhelmed. Before you start spending money, check the drainage and pressure in the crankcase. A Magnahelic gauge and a fitting tapped into an old oil filler cap would work. Get something that reads to + and -5" H20, and if you peg the gauge positive....fix that first! Note on the testing: Make sure the high pressure reference lines originate on the oil cap, and the engine bay reading with one port uncovered in the passenger's compartment can skew the readings. Two pieces of tubing aren't that expensive! Copper Wire O-Ring of the exhaust flange works nice for a permanent leak-free gasket when combined with 736RTV (Red O2 Sensor Safe) Good to see you got the fumes nixed right away. Oh, and compression/leakdown tests will give you nothing on the condition of the valve seals Grumpy was talking about. Not much will. Again, they can be false diagnosed as 'bad' if you have compression blowby in sufficient amount to overwhelm the PCV system you are using. A pressure test of the crankcase pressure is the only way to know. more than 4" is probably going to cause a problem. Good Luck! Quote Link to comment Share on other sites More sharing options...
jt1 Posted October 20, 2008 Share Posted October 20, 2008 I don't see how Tom could be building any positive crankcase pressure. He doesn't have a PCV system, just a hose off the valve cover to a catch can with a breather on it, then a hose off the side of the block to another catch can and breather. It seems to me it has to be valve guides/seals, or maybe the turbo seals. jt Quote Link to comment Share on other sites More sharing options...
JMortensen Posted October 20, 2008 Share Posted October 20, 2008 I'd guess turbo or valve stem seals as well, but just to be sure, you might want to put a sniffer in the radiator. Either a smog sniffer or an A/C leak detector will show you HC's in the coolant. Quote Link to comment Share on other sites More sharing options...
Phantom Posted October 20, 2008 Share Posted October 20, 2008 Mayolives - a compression test WILL NOT tell you if you have worn valve guides or seals because your valves are closed and sealing the compression chamber from them. A compression test will only tell you if you have bad rings, valves or possibly a badly blown head gasket. Then you need to do as leak down test to see which one it is. Back to the original statement - you said white smoke? back smoke=fuel gray smoke=oil white smoke=water White smoke on decel would indicate a leaking head gasket or a crack in your block between the piston wall and water jacket. Better hope it's the former. Quote Link to comment Share on other sites More sharing options...
jt1 Posted October 21, 2008 Share Posted October 21, 2008 When Tom mentioned to me a while back the car was losing water and smoking on deccel, I figured it was getting water in the exhaust. But what condition would cause water in the combustion areas, but not allow compression into the cooling system when the engine was under load? Combustion pressures are far greater then vacuum under deccel. jt Quote Link to comment Share on other sites More sharing options...
Mayolives Posted October 21, 2008 Author Share Posted October 21, 2008 Phantom.....To my way of thinking; worn valve guides or valve seals should produce smoke at start up. I have none. Is my logic correct? There is no water in the oil. If my head gasket was bad, wouldn't that have show up during my leak down test? When I did the leak down, I purposly pumped about 125 psi into each cylinder and could not make the water move in the radiator. I would think that much pressure should have exposed any head leak or any crack in the block that would push water into the jackets. Am I missing something here? JT1.......Do I need to remove my head in order to check the guides and seals? Is there any other way. I'm really trying to avoid that. Just my lazy, slack ass speaking to me. Quote Link to comment Share on other sites More sharing options...
proxlamus© Posted October 21, 2008 Share Posted October 21, 2008 I started a thread titled L series - Positive Crank Case Pressure, too much http://forums.hybridz.org/showthread.php?t=121590&highlight=Positive+Crank+Case+Pressure read me!! Here is what I have concluded with my L28 turbo.. when I am not running a PCV setup.. (ie open valve cover breather and open crank case breather) there is too much pressure in the crank case.. there is so much pressure, this stops the oil from draining out of the turbo into the pan. because of this, the oil backs out of the oil seals and burns in the exhaust!! I ran the car for months without this issue.. but one day it just appeared. I fixed this problem by adding a PCV setup connected to the intake. If you have a catch can, connect it to a vacuum source. I have a strong strong strong feeling this is your problem. Quote Link to comment Share on other sites More sharing options...
jt1 Posted October 21, 2008 Share Posted October 21, 2008 Tom, you can remove the rockers, retainers, springs, and check the guides and seals with the head still on the car. You will need a valve spring compressor that works with the head on the block. If the guides are bad, the head will have to come off. You can replace the seals with the head on. Maybe you should try a PCV system. It wouldn't cost a lot or take a lot of time to rig one up and give it a try. If it helps, you could build it to Redbird standards. All you would need to do is run hoses from the two breathers to the intake somewhere pre turbo. I will let you borrow some duct tape and zip ties. jt Quote Link to comment Share on other sites More sharing options...
bjhines Posted October 21, 2008 Share Posted October 21, 2008 My first posts on this site were about the crankcase breather systems on the L-series engines. I used PCV and an exhaust venturi to pull vacuum at all speeds and throttle positions. It was a fairly complex system and it included a vapor separator, fuel tank vent line, and purge valve. I never had oil consumption problems on that car. Tom, I was behind you in a couple of hard left handers after big braking zones and I saw the smoke up close. It had a puff of black that quickly turned to a dark brown mass of fuel smoke. I remember the white smoke either before or after the dark smoke. I think the white smoke was more prevalent when the fuel smoke wasn't so thick. Quote Link to comment Share on other sites More sharing options...
Phantom Posted October 22, 2008 Share Posted October 22, 2008 Mayolives - After re-reading your first post there is another possibility here. Your turbo oil seal may be leaking slightly. If so, it would pull small amounts of oil on decel that, with the high temperatures at that location would cause the oil to burn a whitish color rather than blue. You are correct in assuming that bad valve guides or seals would result in a puff of smoke at start-up. That is considered a primary sympton of that problem. You can go in through the top of the head to check that but, if you're not blowing a puff of smoke at start-up, I wouldn't bother. I can't argue your logic on the water loss and compression pressures vs vacuum on decel but I do know that most professional mechanics will point to a water leak of some kind if you have white smoke on decelleration. I remember one of my habits when I was running an L28 - if it was doing something strange - but nothing that seemed serious I would just watch it until in finaly got bad enought to identify itself. It's a tough motor but it can be a pretty frustrating one periodically. Quote Link to comment Share on other sites More sharing options...
Tony D Posted October 22, 2008 Share Posted October 22, 2008 I started a thread titled L series - Positive Crank Case Pressure, too muchhttp://forums.hybridz.org/showthread.php?t=121590&highlight=Positive+Crank+Case+Pressure read me!! Damn, I sound likea broken record after reading my posts in that thread! Quote Link to comment Share on other sites More sharing options...
proxlamus© Posted October 23, 2008 Share Posted October 23, 2008 lol.. i have such a strong suspicion that a proper PCV setup will fix Mayolives issue!! Quote Link to comment Share on other sites More sharing options...
Mayolives Posted December 2, 2008 Author Share Posted December 2, 2008 UPDATE: Smoking On Deceleration. I decided to pull the head and do a valve job and have the turbo checked by Garrett. The turbo was still at factory spec and didn't need anything. The head work was not a bad idea but really didn't need to be done except as routine maintenance. I was using some coolant and the new Kameari head gasket seemed to take care of the water issue. After a little tuning on the dyno and looking at the Electromotive system, we discovered a bad throttle position sensor that was sending false readings and dumping lots of fuel into the system on deceleration. The smooking and eye burning exhaust fumes are gone! Quote Link to comment Share on other sites More sharing options...
dr_hunt Posted December 2, 2008 Share Posted December 2, 2008 Cool! Quote Link to comment Share on other sites More sharing options...
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