JamesHigdon Posted January 29, 2005 Report Share Posted January 29, 2005 I've got a 350 ive just about given up on. I've ran compression tests which came out fine, reinstalled and resealed the intake manifold, run 3 diffrent carbs, 2 diffrent ignitions and 2 diffrent kinds of plugs. The motor was smoking at which point i reinstalled the intake, afterwards it began smoking and carbon fouling the plugs. It has continuously changed conditions and now it just randomly starts smoking at some point 5-10 minutes after start-up. It no longer fouls plugs but is still smoking. The smoke smells like a rich mixture but timing or carb tune has no effect on it. The motor is a late 350 roller block with a ZZZ hydralic roller cam, an edlebrock intake, headers, a cheap performance cat, an accel billetproof distributor with MSD HEI external coil conversion (blaster 2) and 6A box, avenger 670 carb and 993 heads that have been cleaned up with big valves. Any ideas at all, even any shot in dark ideas, because im stumped. James Higdon Link to comment Share on other sites More sharing options...
PAPA Posted January 29, 2005 Report Share Posted January 29, 2005 How does the engine run besides the smoking? Is it white smoke or black smoke? You said the exhaust smelled rich. That could be the carb loading up or is to rich on the idle side. Have you noticed if the choke is closed? Does the intake have a EGR valve? If so it could be bad. If your running a holley carb check the float setting to make sure its not to high.I bet the carb is the problem and its because its loading up. Link to comment Share on other sites More sharing options...
JamesHigdon Posted January 30, 2005 Author Report Share Posted January 30, 2005 The engine runs ok, it doesnt have any major misses or really serious problems, it does seem down on power. The smoke is between grey and blue, im not exactly sure which and its probably between them. The carb and choke where what we originally looked to. both the first were holleys, after the third which was an edelbrock with no change we ruled that out. The intake is a 3701- no EGR provision. I orignially rebuilt and retuned the first carb hoping that was it with no luck, then put the second holley on it and set the floats and everything with still no luck, i then put a fuel pressure regulator on it set to 5.5 and then 5psi and still no change, i then tried a edelbrock straight off another perfectly good running small block and still had no change. You seem to know a good deal about carbs though so how about this question, ive never noticed it before but the motor seems to have a whistle through the carb, whenever i put my hand over the primary side of the carb the noise is muffled so its obviously coming through there, is this normal? Also thank you for taking the time to help diagnose my heap. James Higdon Link to comment Share on other sites More sharing options...
SeanAugustus Posted January 30, 2005 Report Share Posted January 30, 2005 Just a shot in the dark. But you may want to check your air/fuel mixture. If its running to rich than the excess gas will exit the exaust pipes causing it to smoke. Just an Idea. sean Link to comment Share on other sites More sharing options...
supertx Posted January 31, 2005 Report Share Posted January 31, 2005 Check for vacum leaks Link to comment Share on other sites More sharing options...
1-Crew Posted January 31, 2005 Report Share Posted January 31, 2005 How much of the original emission control is still in the system? Is it automatic transmission? On the emission control side, I am wondering if you are drawing raw fuel in from the evaporative emission canister. This is the charcoal filled canister that is designed to concentrate fuel vapors from the fuel tank and keep them from being released to the air. After the engine starts engine vacuum pulls fresh air through the canister to purge the fuel vapors out. If the canister is full of fuel, it will suck a bunch of raw gas in and mimic the symptems you are describing. On the transmission side, it wouldn't be a rich condition but a bad vacuum modulator will let the engine suck transmission fluid up in to the engine while running. It will smoke like a train and otherwise, mimic the symptoms you are describing. Link to comment Share on other sites More sharing options...
JamesHigdon Posted January 31, 2005 Author Report Share Posted January 31, 2005 As far as carb issues weve just about totally ruled that after the third one. In relation to vacuum leaks, has anyone ever heard that a vacuum leak at valley side of the manifold will cause a whistle through the carb ? This motor has a kind of bizzare whistling noise through the carb that changes as the idle is adjusted with the primary throttle plates. The vehicle is almost totaly stripped of emmisions equipment excluding the cat and a simple charcol canister for the tanks that is not connected to the motor in any way. I have contimplated a bad vacuum module, there is some slight fluid buildup on where the modules vacuum line comes into the manifold. I guess the only way to diagnose this would be to remove and plug the vacuum line from the transmission and see if this fixxes the problem. As soon as it warms up some around here ill try that and if that doesnt stop the smoke the only other thing i can think of is to change to synthetic oil (which doesnt smoke when it burns) and see if that stops the smoke. Thanks for the ideas everyone and when and if i figure it out ill post whats going on. James Higdon Link to comment Share on other sites More sharing options...
Crewcheif21,73 Posted February 3, 2005 Report Share Posted February 3, 2005 The best way to find if your sucking air some where is screw your air/idle mixture screws all the way in and if the car dies then your intake and all that is sealed good. If it stays running then you have a problem with somthin not sealing and could lead to smoke. And what about your valve seals and guides did you raplace those when you had your heads redone. Link to comment Share on other sites More sharing options...
JamesHigdon Posted February 6, 2005 Author Report Share Posted February 6, 2005 I've attempted to change the noise with the idle screws but can not screw them even close to all the way in because the cam is so large it wont tolerate that, im pretty sure my next step is to change to a full synthetic oil when i can afford it and if that doesnt fix it then one by one im going to begin pulling parts off it till i find something that isnt right, oh and the valve guides and seals are supossed to be less then a year old. Thanks for all the help and when ( if ) i figure it out ill post on here what it was for future reference. James Higdon Link to comment Share on other sites More sharing options...
Truck99 Posted February 10, 2005 Report Share Posted February 10, 2005 James, I don't think switching to full synthetic will cure a smoking problem. If anything, it may make it worse. Full synthetic won't mask oil issues that are happening as a result of leaks or blowby, it will usually only make it worse. Keep on searchin' Link to comment Share on other sites More sharing options...
rsowell Posted February 10, 2005 Report Share Posted February 10, 2005 Did you disconnect that vaccum line from the tranny? You don't run any kind of header evac system or anything other than pcv valves do you? Had an engine that was sucking oil mist through some unbaffled breathers into the carb spacer vaccum port, causing it to burn some oil. Enough to smoke but not foul the plugs. Just a thought. Link to comment Share on other sites More sharing options...
JamesHigdon Posted February 11, 2005 Author Report Share Posted February 11, 2005 I have been pretty busy with the racecar at the school for the past week and havent even had a chance to look at my own car, weve got a race this weekend so probably middle of next week ill get to work on mine again. Also ss99, ive never tried this before but ive been told by many people that a full synthetic oil will not produce smoke when it burns so you can use it to diagnose a motor in this situation, have you tried this and not had it work because id hate to drop the money on a full synthetic and not have it make any difference at all. Thanks James Higdon Link to comment Share on other sites More sharing options...
supertx Posted February 12, 2005 Report Share Posted February 12, 2005 FASERace Don't believe that to be true look at the smoke when somebody loses a motor. I've been running Mobil 1 since the late 80's and it will smoke. Try starting the engine use like brake clean and spray around the intake, block around the top of the carb where it doesen't suck it in if there is a vaccum leak it will change the idle and sound . Link to comment Share on other sites More sharing options...
MIKE65 Posted February 16, 2005 Report Share Posted February 16, 2005 DID YOU PERFORM A LEAK DOWN TEST? YOU MAY WANT TO CHECK YOUR VALVE STEM SEALS AND OR VALVE GUIDES. ALSO IS THE CRANKCASE PROPERLY VENTED? ALSO COULD HAVE INTAKE LEAK FROM UNDER SIDE OF INTAKE PULLING THE OIL UP INTO THE CYLINDER. ALSO POSSIBLE TO HAVE SECOND GROVE RINGS UPSIDE DOWN. JUST SOME IDEALS. Link to comment Share on other sites More sharing options...
JamesHigdon Posted March 16, 2005 Author Report Share Posted March 16, 2005 We finally figured it out!!! In Edelbrock’s literature it says not to use metal core gaskets because they have “crushability issues”, and then goes on to say your supposed to use some special not paper but not metal core gasket. Well I used 3 of their special gasket sets, 2 Felpros and 1 Mr. Gasket, and none of them worked. The motor had been decked heavily and had some slight fitment issues which I guess these “special” gaskets couldn’t handle. After trying everything under the sun I was ready to yank to motor and figured before I did I might as well try these forbidden metal core gaskets. Well, torqued to 30 pounds they seal fine and there don’t seem to be any issues except that they seal. I would like to thank Larry Bendele for bringing the possible head issue to my attention and also everyone else that helped, now I can drive my 235 @.050 cammed 480 lift monster on the streets and not have it look like I’m trying to fog for mosquitoes. Thanks. James Link to comment Share on other sites More sharing options...
DIFFDOC Posted April 4, 2005 Report Share Posted April 4, 2005 if the car is an automatic with a modulator check for transfliud in the vacuum hose for the modulator Diffdoc Link to comment Share on other sites More sharing options...
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