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Post by metalbeast on Sept 6, 2005 14:50:02 GMT -5
O no i have replaced the pcv valve, but havent checked if the cranck case still puffs out smoke, if it only does this when i rev up then it has to be a rich problem....right? Its a gas thing i believe. And I put my hand over the crankcase and felt no sucking at all...i have a small vacumm leak but that i can hear from outside the car. And i believe its some hose to the tb. No. If you have excessive smoke puffing out the crankcase it has absolutely NOTHING to do with your car running rich. What happens is if you have a serious issue with your rings, cylinder gases"blow by" the piston rings and ends up trapped in the crankcase. The only way for the pressure to be relieved is thru the valve covers. I do think you are running rich and are in need of a tune based on some of your previous statements. If you are getting alot of vapor or smoke coming out of your crankcase, you need to have a cylinder compression test performed. |
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Post by the94z on Sept 6, 2005 15:01:51 GMT -5
well im having a leakdown test...are they the same thing?
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Post by Alex94TAGT on Sept 6, 2005 19:10:08 GMT -5
well im having a leakdown test...are they the same thing? No, they are not the same thing. You actually have to be careful if you're having a shop do it, because sometimes they dont even know the difference. They'll just do a compression test when you ask for a leak-down test. -In simplest terms, for a compression test, you're putting a compression tester (psi dial gauge) in place of the spark plug, and turning over the motor a few times to measure maximum compression put out by each cylinder. It's a pretty vague test -- it'll tell you if something is wrong, but it wont narrow down what is causing the problem. -For a leak-down test, you're hooking up compressed air & dial indicator, filling the combustion chamber with pressure, and seeing how much pressure is lost. You can also 'listen' for air escaping to determine what the problem is. If you feel/hear air or whooshing noises coming from the oil fill cap/crankcase, then that would signify bad piston rings. If you feel the same with the exhaust tailpipe, that'd be a leaking exhaust valve. If you hear it out of the intake manifold, that would be the intake valve. If presure comes out of the radiator, that would indicate a faulty head gasket. If you had a compression test that turned out OK, then I'm not really sure what you'll find with a leak-down test. If there were something major wrong, it would have shown up on the compression test as well, unless they somehow screwed up the test. However, if there is something wrong, the leak-down test is the way to go. |
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Post by metalbeast on Sept 6, 2005 19:25:09 GMT -5
No. They are similar, but 2 different test.
In a leak down test , you rotate the piston of a particular cylinder up to TDC (top dead center) with the intake and exhaust valve both closed. The leak down tester, which is inserted into the spark plug hole, then reads what % of air is leaking from the cylinders. 10% is normal leak down for a cylinder if I am not mistaken This is done for each cylinder.
In a compression test, you screw the air gauge into the spark plug hole of a particular cylinder. You disengage the ignition and fuel are disabled. You turn the engine over and see what the maximum pressure for that cylinder shoots up to. This is performed for each cylinder as well. Every cylinder should be within 10% of one another.
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Post by metalbeast on Sept 6, 2005 19:27:10 GMT -5
well im having a leakdown test...are they the same thing? No, they are not the same thing. You actually have to be careful if you're having a shop do it, because sometimes they dont even know the difference. They'll just do a compression test when you ask for a leak-down test. -In simplest terms, for a compression test, you're putting a compression tester (psi dial gauge) in place of the spark plug, and turning over the motor a few times to measure maximum compression put out by each cylinder. It's a pretty vague test -- it'll tell you if something is wrong, but it wont narrow down what is causing the problem. -For a leak-down test, you're hooking up compressed air & dial indicator, filling the combustion chamber with pressure, and seeing how much pressure is lost. You can also 'listen' for air escaping to determine what the problem is. If you feel/hear air or whooshing noises coming from the oil fill cap/crankcase, then that would signify bad piston rings. If you feel the same with the exhaust tailpipe, that'd be a leaking exhaust valve. If you hear it out of the intake manifold, that would be the intake valve. If presure comes out of the radiator, that would indicate a faulty head gasket. If you had a compression test that turned out OK, then I'm not really sure what you'll find with a leak-down test. If there were something major wrong, it would have shown up on the compression test as well, unless they somehow screwed up the test. However, if there is something wrong, the leak-down test is the way to go. You beat me to the punch Alex. Friggin dial up crap. ;D |
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Post by jdawgs94z on Sept 6, 2005 19:31:17 GMT -5
he is gonna have it done at a local performance shop all us in the san antonio f-body association use,the guy that owns it is real good ,and has built many of the engines in the club,ray can vouch for him,danny at lethal performance will figure out what is wrong,he's the only guy i would trust in town to build my engine and not have to worry about him ripping me off.
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Post by the94z on Sept 9, 2005 16:33:13 GMT -5
well guys we were all wrong leak test showed fine!!! Only my spark plugs/wires, and no tstat and no tne is doing it. Should be running perfect ready for tune by monday YES!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
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Post by 1bad2k2ta on Sept 9, 2005 16:42:24 GMT -5
well guys we were all wrong leak test showed fine!!! Only my spark plugs/wires, and no tstat and no tne is doing it. Should be running perfect ready for tune by monday YES!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Well, I will be the first to say it........glad I was wrong! Your weekend must be looking a lot better. |
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Post by Alex94TAGT on Sept 9, 2005 17:48:12 GMT -5
I'm sorry to have sent you in the wrong direction. But, at very least, it's reassuring to confirm the health of the motor. That's good news.
I still don't quite see how spark plug wires, a missing thermostat, or a bad tune can cause white and blue smoke out the exhaust. Black smoke due to a rich running condition, Ok, but blue and white doesn't make a whole lot of sense. It'll be interesting to see if the smoke disappears with the tune, but I still wouldn't rule out things such as valvestem seals or an intake manfold leak.
Keep us posted~
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Post by metalbeast on Sept 9, 2005 19:11:49 GMT -5
well guys we were all wrong leak test showed fine!!! Only my spark plugs/wires, and no tstat and no tne is doing it. Should be running perfect ready for tune by monday YES!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! I think most of us got confused by the color of the smoke. I told you it was probably a tuning issue though so I am glad I helped you at least to some degree. Hope everything works great! Keep us posted! |
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Post by the94z on Sept 9, 2005 21:12:07 GMT -5
well yeah i am happy when they do a leakdown test they check for head gasket, bad rings, valve stems and everything right? SO it has to be in good condition, and the plugs were fried!!!!
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Post by metalbeast on Sept 9, 2005 22:46:01 GMT -5
well yeah i am happy when they do a leakdown test they check for head gasket, bad rings, valve stems and everything right? SO it has to be in good condition, and the plugs were fried!!!! If your leak down and compression checks when great then you're probably OK as far as having problems with any blowby, ring damage, etc. When you said your spark plugs were fried, do you mean that they were worn out or were fouled due to a rich running condition? This would look like black soot on the electrode tip. If it is just a worn out, the electrode tip will look small and worn down. |
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Post by the94z on Sept 10, 2005 2:13:29 GMT -5
tips were gone!!!!(due to nitrous) getting msd 8.5 mm and ngk tr6's and 160 tstat!
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Post by metalbeast on Sept 10, 2005 14:10:46 GMT -5
tips were gone!!!!(due to nitrous) getting msd 8.5 mm and ngk tr6's and 160 tstat! Well, it looks like everything should be getting squared away soon! Let us know if you need anything else and keep us posted of the progress ;D |
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Post by turtle on Sept 11, 2005 20:23:03 GMT -5
worthless post, so I edited it  |
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