Engine Smoking Information
Attention!
Most engine fluids are toxic (they can kill you) and flammable. Antifreeze tops the list and has a sweet odor so it attracts kids and animals. Please clean any antifreeze right away; a small amount can/will turn your day bad in a hurry. Be safe with your engine chemicals and all chemicals for that matter. Do not get antifreeze or other engine chemicals on your skin.
1) Black smoke is raw gasoline burning. A rich condition can be the cause by a faulty or poorly adjusted float, a choke stuck shut, a bad oxygen sensor, a bad map sensor, a bad fuel pressure regulator, a plugged up air filter or a bad injector, too much fuel pressure or any other function that may cause excessive fuel to be ingested into the motor including a bad tune. Typically, if you only get black smoke first thing in the morning, it has to do with the choke or the fuel enrichment portion of your fuel injection system. If you get black smoke all the time, get it fixed soon or you run the risk of ruining the catalytic converter and doubling your repair bill.
Testing=check plugs for color and odor, check fuel system components
2) Blue smoke is oil burning. The tailpipe will either smoke all the time or just once, first thing in the morning. If you get blue smoke all the time, that is a sign of impeding doom. That is the first sign of the beginning of the end. Broken rings, bad pistons, damaged cylinder walls, all high dollar items.
On the other hand, if all you get is a puff or two first thing in the morning and never again throughout the day, then your problem is probably bad value guides or value guide seals, never assume that seals alone will totally fix this problem, if the engine has 100k miles plus just rebuild it. Blue smoke can also be caused by oil in the converter (After installing a new engine onto old catalytic converter(s) that were previously attached to a worn motor.)
Testing = Check plugs for color and odor. Compression check, find low cylinder add a few drops of oil in plug hole, then recheck. If compression rises bad rings are at fault. If no rise in compression, seals are probably bad. If no cylinders are bad, don’t tear the motor down until you have checked the pcv valve and other possible functions first.
3) Gray smoke can really be black or blue. You can usually tell which is it by the odor or by matching other symptoms you have to the color of the smoke.
4) White smoke is either;
- A) The transmission shift modulator is bad and allowing the engine to suck and burn transmission fluid.
- B) White smoke could also be coolant or antifreeze that is either leaking, or being forced into the combustion chambers and being burned. The exhaust will look wet and have a sweet smell to it.
- C) A bad head gasket (most common)
- D) a broken/cracked head
- E) a broken/cracked cylinder wall
Testing = Check plugs for color and odor, check oil for water intrusion (brown muddy oil), check radiator for excessive bubbles or motor oil. Warm engine and perform a pressure check on the radiator. Compression check.
Thrust Bearing Failures
This is written for small block Ford thrust bearing issues using automatic transmissions.
Some of the best thrust bearing articles I found are here;
http://www.atra.com/crankshaft/
http://www.4secondsflat.com/Thrust_bearing_failures.html
http://www.gnttype.org/techarea/transmission/trantsb.html
I ran a 363 cubic inch all aluminum 8.2 deck height small block Ford with twin 80mm turbos. I was killing thrust bearings (and steel billet crankshafts) every 5-9 quarter mile passes. Spending over $2300 a pop for cranks it got real serious real fast.
The cause of thrust bearing failures in my case was attributed to improper torque converter clearance and a “soft” thrust bearing. What I learned in the process was you need at least .120 thousands between the end of the crankshaft and the snout of the torque converter when the converter is bolted to the flywheel and .140 thousands between the converter and the transmission. These measurements are critical and should net be exceeded by more than .040 or so. You will often times hear about people solving the thrust bearing problem by changing the converter. This is more often due to the differing torque converter physical measurements than manufacturer (unless there is an actual problem with the converter, i. e. ballooning or spline lock). I also found different crankshaft manufacturers leave varying amounts of material on the back of the crankshaft (the metal lip around the pilot hole on the back of the crankshaft) affecting the converter clearance measurements.
If you would like to be fairly sure to solve your thrust bearing issues, these items will help:
1) Reduce the pump volume to the converter from a ¼ inch hole to 1/8 inch hole (have a trans person do this one).
2) Change the main bearing to a harder material bearing that will take more heat.
(No, not Clevite or Federal Mogal)
3) Modify (chamfer) the thrust bearing per one of the articles listed above.
4) Make sure your trans yoke is not bottoming out during launch.
5) Make sure you have the correct clearance when installing the trans/converter.
6) I found approx .006 thrust clearance proved to be optimal for small block fords.
7) When working with a good deal of horsepower in turbo applications a crankshaft with the center crankshaft weights is of great help with crankshaft flex.
If you follow the above listed items you should solve your thrust bearing issues assuming the converter itself is not bad, the crankshaft is machined properly and the engine is assembled/machined correctly.
Please read the articles that are referenced above, they have great information and are accurate.
These items worked for me when I was pulling my hair out trying to find the thrust bearing issue on a 1700+ hp race motor. Additionally, thrust bearing failures require a “combination” of the listed items. One listed “fix” by itself may have a positive effect however the “combination fixes” have a much higher success/longevity rate and are not detrimental to performance what-so-ever.
Some of the information contained in this short paper was obtained from various race parts manufacturers; converter manufacturers, transmission shops, race bearing manufacturers, engine machine shops, and race only engine shops. The basis and core of the information contained in this short paper was learned by experience and various parts failures and analysis.
Disclaimer: I assume no liability for anything. Race motors, transmissions and converters and automotive parts in general are often abused and may fail due to numerous reasons.
Hope this helps.
John Wall
|
