Engine smoke

[SteveR]

On my 230 Dodge engine, i have had a small amount of burnt oil from the exhaust. Will any of the stop smoke additives be of any use and will any of these additives cause damage to my engine? I have used these products on modern Ford cars with fair results but not on these old flathead engines. What are your thoughts?

[greg g]

Have you done a compression test, have you put a vacuum gauge on your engine?  When it is running are there visible fumes coming fr9m the oil filler pipe?  The results of a proper compression test procedure would be more indicative of what is causing the smoke.  If you don't know how to run this test, visit secondchancegarage.com to see the procedure detailed here.  They also have a procedural for using a vacuum gauge to interpret what the g auge is showing.  Run those tests, then post your results.

[keithb7]

Agree with above. Need to learn if it is piston sealing or valve guides letting oil in.  Proper compression test can help narrow down the culprit. 

Edited January 15 by keithb7

[SteveR]

Hopefully I'll let you all know tomorrow the results. It's going to be cold tomorrow with a high of 37F and I do not have a garage to work in.

The car is running fine and starts on the button even in 27f deg temps. For the most part, you do not see smoke just every once in a while. Thats why I was wondering about a no smoke additive. I don't want to ruin this old girl as being retired I can not afford a rebuilt engine.

[keithb7]

A couple more tips on the compression test and burning oil. A few quick things to look out for.

 

All spark plugs to be removed. Lay out each plug in order they were removed. Take a nice clear photo of all electrodes showing the porcelain color.

Darker, non mocha color indicates with cylinder is burning oil. Good cylinders are a nice coffee with creme color.

 

Take intake air filter off. Choke will manually need to be held wide open while cranking to get max air into cylinder on intake strokes. 

You should have a 6V charger 16a or better is preferred, on the battery while moving the compression gage to the next hole. Keep re-charging the battery between cranks. The battery will lose it's charge. Effecting cranking speed, especially at the cold temps you mentioned. Crank engine over with throttle wide open and choke wide open. Compression gauge will likely bump up 3x. Once no is longer climbing, stop cranking the engine over. Write down the reading. Repeat for all 6 cylinders. 6 measurements. These are the "dry" measurements. My recent engine rebuild netted bout 112 psi at 350M above sea level if I recall. Let's assume you get about 85-90 psi across your 6 cylinders, dry. 

 

Start back at cylinder 1. Add teaspoon of engine oil into the spark plug hole. Measure compression again. Same process as above. Record all 6 "wet" measurements. 

Expect some small increase in any engine when oil is introduced to the cylinder. Even a fresh nice rebuild. If you see a noticeable increase in compression, say now its 110 psi,  the good news is your valves are sealing well. The bad news is you have piston ring sealing issues. Could be worn, stuck, or broken rings. Or a scrape in the cylinder wall letting oil pass up to the top of pistons. Dirt introduced, excessive carbon build up or a piece of a broken piston ring could case such a cylinder wall scrape. A full engine rebuild may not necessarily be required. But a major engine intervention will be needed for sure. If your dry compression is quite good, say 95 psi and up, and  a wet test compression rest does not considerably change the compression psi, yet you are burning oil you likely have worn valve guides or valve stems. This allows for excessive valve guide to valve stem clearances. Oil mist in the crankcase gets sucked into the cylinder via the valve guide to valve clearances when the throttle is closed and your are coasting. The pistons are still making vacuum on the intake stroke, but the carb throttle is closed. Air wants to come in from somewhere.  The intake valve opens. Not enough air comes in to to fill the void in the cylinder as throttle is closed. It takes the next path of least resistance, the worn valve guides. Sucking in air now that is in your crankcase. It has a heavy oil mist in it. Then you burn it.

 

If your compression is low right from the start of your 'dry" measuring  you should investigate further to ensure your valves are properly sealing before jumping to any conclusions. I'd do that by opening up the engine valve covers first. Ensure you have tappet clearance when each cylinder is at TDC of compression stroke. While in this position, have a friend introduce compressed air into the spark plug hole. Somehow seal up the entry at sparkplug hole if you can. 30 psi or so should be enough. Put your ear to the exhaust pipe, then the carb venturi. Are you hearing air hissing out? This is an indicator of leaky valves. Leaky exhaust valve is the usual culprit if tappet clearances are not maintained. Also,take the engine oil fill cap off. Put your ear to the fill tube. While your friend is inserting the compressed air, do you hear air howling in your crankcase? This is an indication of piston ring sealing issues. Repeat this 6x so you check all 6 cylinders for leakage.

 

Go for a drive, if you can down a long hill. Gear down to 2nd, do not apply any throttle.  The engine compression will be be holding your speed back. At the bottom of the 

hill punch the throttle and speed up in second and 3rd. Watch for puffs of blue smoke in your rearview mirror.  This blue smoke that builds up in your engine while coasting

with throttle closed comes from worn valve guides. 

 

Have a friend rev up the fully engine a bit while in neutral. Go back and watch the tail pipe. If blue smoke is exiting while revving up you likely have piston ring sealing issues.

 

Edited January 16 by keithb7

[Dan Hiebert]

So, no answer yet to your no-smoke additive question.  As above, the best thing to do is find out why your car is smoking and fix that.  As to your question and maybe get some discussion going, I don't technically know how a no-smoke additive works, I only vaguely recall seeing some advertisements in the past, but common sense tells me that it does not work by magically keeping any contaminates in the air/fuel mixture from burning, that it stops the smoking by plugging up any gaps where oil may be entering that mixture, whether that be the valve guides or piston rings/cylinder walls.  So, to me, (and what the others are alluding to), it is not a fix but a temporary solution that may lead to future problems due to whatever affects the additive has on the rest of the oiling system.  I think sludge would become a problem, and you'll still need to eventually fix the initial problem anyway.  The fact that this stuff works in more modern engines doesn't change the notion that the problem hasn't been fixed, just delayed.  So, I don't think it will hurt these engines, they tend to be rather robust, but you'll still have whatever issue is creating the smoking, it just won't be smoking for a while.  The valve guides are worn in our D24, I leave a cloud of blue smoke on deceleration everywhere I go, I imagine it annoys everyone behind us, but until I fix it, I chalk it up as "character". 

[FarmerJon]

Steve-

Do the diagnostic procedures laid out by Keith and others.

 

As far as additives- no 'mechanic in a bottle' is going to fix worn or broken parts. 

 

BUT! They can alleviate carbon and grime build up on the valves, piston crowns and rings. This can be a big help to old engines like these. If you are only seeing small amounts of smoke, and tests indicate that there is no major problems, additives, used correctly, might be just what you need.

Like Dan, I am not familiar with how the "No Smoke" products work, but I have used seafoam, marvel mystery oil, and a spray bottle of plain water to rejuvenate good but dirty engines.

Both MMO and Seafoam detail how to use them to "soak" or fog the cylinders. I will usually start with this, as well as the recommended amount in oil and gas. I usually alternate between the two products in my fuel, for several tanks of regular driving, as well as a few spirited WOT blasts, for the sake of forcing rings and valves to break free of the old gunk and reseat. 

 

 

 

 

[greg g]

Does the car use a lot of oil?  Can you drive 100 miles without adding oil?  What product are you planning to use?

[keithb7]

I didn’t discuss the oil additive as I am skeptical about it. In some instances it might help. For example if it breaks down carbon packed in behind and around piston rings. It could assist maybe in filling a score in a cylinder wall. At least for a while.
 

 I don’t understand how it could help worn valve guides.  Perhaps overhead valve engines, valve stem seals might become enlarged and help re-seal for a while. That won’t work in a flathead. 

[keithb7]

Deleted. Double post. 

Edited January 16 by keithb7

[keithb7]

I didn’t discuss the oil additive as I am skeptical about it. In some instances it might help. For example if it breaks down carbon packed in behind and around piston rings. It could assist maybe in filling a score in a cylinder wall. At least for a while.
 

 I don’t understand how it could help worn valve guides.  Perhaps overhead valve engines, valve stem seals might become enlarged and help re-seal for a while. That won’t work in a flathead. 

[SteveR]

Ok Thats done now that my hands are frozen. Here are my results

1) 100

2)  75

3)  85

4)  75

5)  85

6)  93

after putting in the oil they pretty much stayed the same. This last summer I adjusted the valves as I had a ticking on one of them. The ticking is gone now. I am using 10w40 detergent oil in the engine. That's what the owner before me used and he dropped the pan several times to check for clumps and sludge.

Like I said I do not notice any smoke out the exhaust but then my exhaust ends just behind the front seat. It is more I can smell it and I do go through a small amount of oil. Maybe 1 quart a year. 

 

[Sam Buchanan]

1 hour ago, SteveR said:

Ok Thats done now that my hands are frozen. Here are my results

1) 100

2)  75

3)  85

4)  75

5)  85

6)  93

after putting in the oil they pretty much stayed the same. This last summer I adjusted the valves as I had a ticking on one of them. The ticking is gone now. I am using 10w40 detergent oil in the engine. That's what the owner before me used and he dropped the pan several times to check for clumps and sludge.

Like I said I do not notice any smoke out the exhaust but then my exhaust ends just behind the front seat. It is more I can smell it and I do go through a small amount of oil. Maybe 1 quart a year. 

 

 

So what is the problem??   ?

 

Sounds like a longer exhaust pipe will be the solution.

[SteveR]

15 hours ago, Sam Buchanan said:

 

So what is the problem?? 

My question was because there is some wear on this engine would a 'stop-smoke' additive help with the longevity of my engine? What about other additives? As I am retired my funds do not include any engine rebuilds.

I only mentioned no-smoke because my engine does use a small amount of oil.

[chris 48 P15]

those numbers are good 

the best thing to do to help save engine is to change oil frequently

the new oils have detergents in them they help to keep the inside clean

the additives wont fix a problem if there is one

 

[Sam Buchanan]

5 hours ago, SteveR said:

My question was because there is some wear on this engine would a 'stop-smoke' additive help with the longevity of my engine? What about other additives? As I am retired my funds do not include any engine rebuilds.

I only mentioned no-smoke because my engine does use a small amount of oil.

 

I suspect these old engines always used a small amount of oil, they are pretty "loose". Mine leaks more than it uses!  ?

 

I appreciate your desire to make the engine last as long as possible but your compression numbers indicate an engine that is in pretty good health. Driving it regularly is probably the best medicine you can give it. 

[keithb7]

The engine as it is today doesn’t need to be addressed. Unless your are personally looking for a project enjoy the car,  drive it. 
 

There is typical wear going on. The variations between cylinders (from 100 down to 75) could be further diagnosed. It’s enough for me to go in for a valve lap.  If you were in my town, I’d say bring it by. Lets get it done! 

General question for the group: Why does number 1 always seem better than the rest? First to get the coolest water from the rad and water pump?

 

Edited January 17 by keithb7

[SteveR]

2 hours ago, keithb7 said:

It’s enough for me to go in for a valve lap.

I have thought of that but I am deathly afraid of snapping a bolt off in the head. This engine has never been opened up and is a 51 model year

[Los_Control]

A old trick a guy showed me was the dollar bill trick.

If you lay a bill over the end of the tail pipe while it is running, the exhaust should blow the bill straight out.

 

If the bill flaps back and forth, you will have some valves that are not seating. And you would be losing some compression through the valves.

I will tell you I did this with my truck, I did not have a dollar bill so just used notebook paper. It flapped back & forth so quickly it ripped the paper in 1/2.

My truck sat for years in a field and sure there were a few valves open and some rust on the valve seats.

 

These engines it was common to have just the rings replaced or just a valve job done. .... Low oil pressure you would want to install new bearings.

I believe the rings are cast iron, they just wear quickly compared to modern rings.

This was in a way just considered general maintenance. ..... Question is, how many times have your rings been replaced or valves lapped over the years already?

Pulling the head to measure the cylinders and inspecting the valves could be done.

 

Everyone here seems happy with your compression numbers ..... I feel it may run for years just as it is also.

 

I think it is useful to keep track of the compression, it will tell you a story.

When I first got the truck delivered from sitting in a field for 20 years ...  the compression was 115  60  75  85  75  90

I checked it awhile back and was better ..... Now it is 125 85 125 100 120 110 ..... best reading yet but still troublesome.

#2 cylinder is way lower then the rest, I'm afraid I may have a stuck ring frozen to the piston and not rotating/sealing like it should.

I will most likely pull the head and drop the pan and figure out whats going on .... I will not pull the engine for this though.

 

 100, 75, 85, 75, 85, 93 .... I've heard as a rule of thumb, anything over 60 should fire ... barely. Sure would be better to see all of them around 100 in my book.

If you are physically able, you can spend a little $$ for a engine gasket set, a new set of rings and lap the valves .... just freshen it up.

Replace the bearings if you think they look bad .... This is totally mickey mouse by todays standards with modern engines running over 300k miles.

But is exactly how these engines were maintained in that time period.

 

 

I bet you might break a bolt along the way and will be a challenge ..... Either accept it as it is, or open it up and have fun with it.

[Dan Hiebert]

No-smoke additive will not increase the longevity of an engine.  All it does is cover up whatever issue is causing it to smoke, the only prolonging it could conceivably provide is with the need to fix something.  I agree with the good folk here, I don't see any issues with your compression numbers, and while a little smoke could still be annoying to some, it really isn't indicative of any issues - as noted, these engines aren't as "tight" as more modern ones.  One thing to keep in mind when ruing a valve job is that these engines were intended to have regular maintenance done on the valves, every 10,000 miles I believe is the factory recommendation, so you do have to open it up once in a while.  A valve job on these is relatively easy.

[Kilgore47]

On 1/16/2024 at 10:17 AM, SteveR said:

Maybe 1 quart a year. 

If you only use one quart a year I wouldn't worry about it.  How many miles is that?  Next I'm going to say something that will probably get me several comments.  But since you are using a 10 \ 40 oil - you might consider using a 20 \ 50 oil instead of an additive.  It's your car and from what you have described - if you don't change anything your car should be fine.

[keithb7]

I like 20W50 too for seasonal driving in warm weather. Not as readily available on store shelves around here. 

[FarmerJon]

On 1/17/2024 at 12:20 PM, SteveR said:

I have thought of that but I am deathly afraid of snapping a bolt off in the head. This engine has never been opened up and is a 51 model year

If you are thinking of pulling the head for a valve job, I would spray all the bolt heads with a quality penetrating oil several times, over a few weeks. Add it cold, and when engine is hot.

You can also start by tightening the head bolts to the recommended torque spec. This usually helps break them loose from whatever corrosion has built up, but is much less likely to break them off. 

 

[kencombs]

My advice to anyone pulling a head is to use an impact wrench.   Set on lower power and forward first, the reverse.   The rat-a-tat is much less likely to break a bolt that a straight pull with hand tools.  

 

Most, if not all, air impacts have no way to lower reverse power, only forward.  The reason the fwd/rev is to assist in breaking the adhesion of threads to block without subjecting the bolt to full power.   I have a couple of composite impacts (3/8 & 1/2) that I really like, Ingersoll-Rand.   Light weight, both with titanium hammer cases,  and LOTS of power. 

[OUTFXD]

Are you sure it is oil smoke?   Rule of thumb,  Black is Fuel,  White is steam,  Blue is Oil.

 

Just putting in my 2 cents