dhoughland | -- 08-12-2018 @ 8:53 AM |
I have a 1940 with a flathead that hadn't been started in quite a few years. I lubricated the combustion chambers prior to starting, runs/sounds great but it smokes. Is there a way to reseat the piston rings?
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dandy32 | -- 08-12-2018 @ 9:06 AM |
maybe just intake valve seals are shot from sitting
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40 Coupe | -- 08-12-2018 @ 10:51 AM |
Put Marvel Mystery Oil in the crankcase, follow label directions or slightly less MMO, with your oil and drive the car.
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shogun1940 | -- 08-13-2018 @ 11:17 AM |
When does it smoke? All the time or on start up? Most smokers were caused by worn bearings not rings. If you think that it is the rings i would take the plugs out and spray pb blaster in ther for few times and see if that helps. How is the oil pressure? The last resort is to advance the timing until it pings and see if you can shake the rings loose. Goodluck
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supereal | -- 08-21-2018 @ 1:06 PM |
It is likely the rings are stuck in the piston grooves from sitting for years. Sometimes putting lube thru the spark plug holes can help, but it is a long shot unless the oil has plenty of time to seep down. It may be that the engine was badly worn and replaced long ago when it smoked.
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kubes40 | -- 08-22-2018 @ 5:57 AM |
How can a bearing cause an engine to smoke? Mike "Kube" Kubarth
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cliftford | -- 08-22-2018 @ 8:10 AM |
Worn bearings can cause excess oil on the cylinder walls, more than the oil rings can handle.
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kubes40 | -- 08-22-2018 @ 2:21 PM |
Worn bearings can cause excess oil on the cylinder walls, more than the oil rings can handle. Really? New one on me. Mike "Kube" Kubarth
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TomO | -- 08-23-2018 @ 8:17 AM |
Me too. Tom
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shogun1940 | -- 08-23-2018 @ 10:08 AM |
There was a test where you removed the oil pan and pressurized the engine with oil and counted the drips from each bearing. If ni remember correctly the max was 150 on the average car.
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cliftford | -- 08-23-2018 @ 3:56 PM |
This is how it was explained to me. The oil control rings are just that. They scr*pe off the excess oil thrown on the cylinder walls by the spinning crankshaft and it drains out the holes in the lower piston groove. If the rod bearings are loose and throw too much oil, it will get by the oil ring and compression rings and into the combustion chamber.
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kubes40 | -- 08-23-2018 @ 4:21 PM |
That may very well be how it was explained to you. However, perhaps you can explain to me how a loose rod bearing can possibly throw more oil than a "snug" bearing. I know I only graduated from GM school decades ago and was ASE certified for many years but this one just has me perplexed. Mike "Kube" Kubarth
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cliftford | -- 08-23-2018 @ 6:34 PM |
Since the rod bearings [and mains] are pressure oiled through the crankshaft, the greater the bearing clearance, the more oil will be pushed out.
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kubes40 | -- 08-24-2018 @ 9:14 AM |
QUOTE: Since the rod bearings [and mains] are pressure oiled through the crankshaft, the greater the bearing clearance, the more oil will be pushed out. Yeah, I get that part of your theory. What I can't make the jump to, is just how this little "extra" being pushed out of the bearing area is going to manage to get on the cylinder walls in any amount that would effect oil consumption. Now, over filling the crankcase can cause too much rod splash but worn bearings? Really? Mike "Kube" Kubarth
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kubes40 | -- 08-24-2018 @ 9:16 AM |
Quote: There was a test where you removed the oil pan and pressurized the engine with oil and counted the drips from each bearing. If ni remember correctly the max was 150 on the average car. What is an "average" car? And what exactly di this "test" attempt to show? Mike "Kube" Kubarth
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cliftford | -- 08-24-2018 @ 11:43 AM |
I'm signing off on this subject. I would like to hear Ol Ron, Supereal, or others who care to address this.
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kubes40 | -- 08-24-2018 @ 12:13 PM |
Quote: I'm signing off on this subject. I would like to hear Ol Ron, Supereal, or others who care to address this. Me too. I am always willing to learn new things. Mike "Kube" Kubarth
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TomO | -- 08-25-2018 @ 9:33 AM |
I have never heard the theory that worn bearings can cause oil consumption. Here is a link to an article that supports what I have been taught and believe about oil consumption. https://highwayandheavyparts.com/n-12786-excessive-oil-consumption-explained.html Tom
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kubes40 | -- 08-25-2018 @ 9:44 AM |
Tom, That article, although brief, is well worth reading, especially by those so interested in learning bit more on this subject. Mike "Kube" Kubarth
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shogun1940 | -- 08-25-2018 @ 7:24 PM |
If you read the whole article it ends at the bottom by saying that too high of oil pressure will cause oil to be slung onto the cylinder walls and the oil control ring can not wipe the cylinder down properly. So if you get .004 thousnds of clearances rather than .001 to .002 it is possible to get too much oil on the cylinder wall.
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TomO | -- 08-26-2018 @ 8:40 AM |
I always thought that the most common cause of low oil pressure is worn bearings. So if the bearings are worn, then the oil pressure should be less. The article was written within the last 25 years and pertains mostly to overhead valve engines Using the theory that excessive oil pressure causes oil consumption works very well with an overhead valve engine, but very poorly with a flathead engine. In an overhead valve engine, excessive oil pressure would deliver too much oil to the valve system, causing oil to pool on the heads and valves and then be burned. As the last word that I want to add is for the original poster. There have been many "snake oil" products introduced over the year to reduce oil consumption ans I do not know of any that worked. If your smoke looks blue, it is oil consumption. A good detergent oil may free the rings after many thousands of miles and MMO could do the same, but I would go with a 20w-50 synthetic oil until you decide to rebuild the engine. If your smoke is black, have your carburetor rebuilt. If your smoke is white, you have a leak of coolant into the combustion chamber and you will have to find the source and fix it. Tom
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supereal | -- 08-28-2018 @ 12:15 PM |
Excess bearing clearance is a sure sign that the engine is worn in more places, and a rebuild is coming up. High oil consumption can usually come from two places: leaks and worn parts. As most old Fords do leak, it is often hard to determine what is excessive. Blue smoke is always a sign of internal consumption. Another neglected place is the oil filler cap on the fuel pump stand. It contains metal mesh, and should be soaked in solvent to clear it occasionally. It doesn't take much blow by buildup to push oil from many places.
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