It's been a while since i've posted anything but I had remembered something fom when my dart was still running. I had tuned it up and it was still idling rough. I had found the #4 cylinder spark plug covered in a thick black oily crust. I thought that I could use the steam cleaning trick to help remove crud from cylinder #4. I took a spritzer bottle and sprayed a mist of water over the carburetor it seems that the idle improved and the engine began to run smoothly. I am wondering what the thoughts on this are. I am very curious as to why.

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Leela: 1970 Dart 225 CID
Coulmn Shift TorqueFlite
7 1/4" Axle 2.76 Gears

Go ahead and save that weird car, the sedan, the 6 cylinder, the C-Body. If you want a big block musclecar and that's all you care about, your missing the point.

On the old piston airliners, that was called water injection. The water evaporates, cools the air, improves the air density, more power, less detonation. But I think the racing folks on this forum may have more pertinant info.

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"Louise", a 1976 Dart Custom project, (now sadly reverted to being just an "organ donor" to our other project Darts.)

hmm, interesting about the airplanes. It sounds like my engine is in a pretty bad state then(?)

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Leela: 1970 Dart 225 CID
Coulmn Shift TorqueFlite
7 1/4" Axle 2.76 Gears

Go ahead and save that weird car, the sedan, the 6 cylinder, the C-Body. If you want a big block musclecar and that's all you care about, your missing the point.

Start with the basics: valve adjustment, points, condenser, idle mixture, timing, vacuum leak, etc...

In general, the water vapor absorbs heat from the combustion process and moderates the burn rate, and limits detonation. The same happens with moist air in general; some research work was done back in the 80's and the report was that high humidity results in as much as the equivalent of 3-4 points of octane increase over dry air. More ignitionn advance can be run for better power/economy. Excess water vapor will result in steam and that may may loosen up some crud in the combustion chamber some.

Perhaps you have enough oil into the #4 combustion chamber that has created a lot of cruddy deposits and somehow is possibly causing preignition in that cylinder. The water might moderate that issue by cooling or by cleaning. But probably the oiled plug is just causing a simple plug misfire and you water cleaned something.....

I would be investiagating the reason for the oily deposits on that plug. If it is shiny oily all over, I would suspect a sticking, worn, or broken oil ring in that cylinder. Sticking rings may be fixable a MM Oil or Rislone treatment, or some other internal cleaning procedure. Next on the list would be bad vlave stem seals; much easier to replace.

Question: When you back off the throttle and coast to a stop and wait at a light or stop sign for a bit of time, do you see a large clouod of oil smoke from the exhaust when you accelerate from the stop? That is a good indicator of worn valve stem seals. Oil ring problems will tend to smoke more when at higher RPM's and power.

Have you taken off the valve cover to see how much sludge is in the engine?

The Dart no longer runs. the body was so rusty from driving in Illinois for 44 years non stop that it started to fall apart once I dug into the quarters and rockers. It was all bondoed up and it had Chebelle sheetmetal on it. I am just at the point to pull the engine out and take it to a local shop to see what is going on.

To answer your question, it only smoked if i let it sit 3 weeks or more without starting it up. It also only smoked if I floored it to use what the factory literature called "passing gear" or as we know a forced downshift. It always did this on the oval ramp at the end of IL 53 where it turns into Lake-Cook Rd. I would turn onto IL53 and come around on the highway at 30mph and step on it to 65mph and just as the power kicked on grey smoke came out of the tailpipe. It only was black once from a dirty air filter.

I have changed the oil & filter evey 3000 miles and adjusted valves every 6000 miles, I have cleaned the crankcase breather cap every 12000 miles. Timing has been checked every month and adjusted if needed. The last time the car ran was in June 2014 it was set to the following:

Idle speed w/vacuum advance disconnected 750 RPM in N w/high beams on and blower on hi, timing was TDC to 2 degrees BTDC also w/vacuum advance disconnected, idle mixture was 3 turns out from closed.
When the vacuum advance was reconnected the Idle was around 900 RPM and it would sputter and vibrate when put into D.

Car was running on 93 octane and I swithced it to 87 octane and it seems to have improved the smoothness of the engine, but MPG has been way down originally it was 19-23 and it took a dump to about 12.

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Leela: 1970 Dart 225 CID
Coulmn Shift TorqueFlite
7 1/4" Axle 2.76 Gears

Go ahead and save that weird car, the sedan, the 6 cylinder, the C-Body. If you want a big block musclecar and that's all you care about, your missing the point.

Misting water into the carb at idle was an old timer trick for removing carbon deposits from the chambers and piston tops.

Another method was revving the motor some and dribbling it in from a pop bottle.

Basically a poor man's steam cleaner for the inside of the motor.

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Official Cookie and Mater Tormentor.

Romping on the gas on the on ramp and getting grey or even black smoke is about normal for OEM pre-1974 cars. (White smoke is water- bad) You are going to near full power and full fuel flow- dumping extra gas down the throat, giving "rich' smoke. But blue smoke- not good. Best test I've done for that is to coast down a long hill in gear, stop at the bottom, then watch your smoke as you accelerate from a stop. Blue smoke is valve guides or rings. that's my 2 cents.

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"Louise", a 1976 Dart Custom project, (now sadly reverted to being just an "organ donor" to our other project Darts.)

I think I'll take it to the engine builder I know, and have him pull it on the dyno to see where it's at, and then it will get probably get rebuilt.

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Leela: 1970 Dart 225 CID
Coulmn Shift TorqueFlite
7 1/4" Axle 2.76 Gears

Go ahead and save that weird car, the sedan, the 6 cylinder, the C-Body. If you want a big block musclecar and that's all you care about, your missing the point.

Last time I had an engine that smoked under power like that, the compression rings were shot and the bores well worn. Buuut, with your low gas mileage, I would think about a carb problem. Grey smoke is somewhat indeterminant as to fuel issue or a lot of blowby. Too bad you could not have run a compression test on it earlier; but sounds like you have a plan to check it.

I do have a plan I plan to restore my car and drive it until it needs to be restored again. I had a compression checked before and all were at 100psi, but the carb was not at WOT. Engine is the original engine, and only has 89k.

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Leela: 1970 Dart 225 CID
Coulmn Shift TorqueFlite
7 1/4" Axle 2.76 Gears

Go ahead and save that weird car, the sedan, the 6 cylinder, the C-Body. If you want a big block musclecar and that's all you care about, your missing the point.

100 psi is low from all I have read in the specs and even on my engine with the worn/stuck oil rings (that I just rebuilt); it was 115-130 psi before and had over .020" bore wear in #1. I never saw the carb being open or closed to make a whole lot of difference in general on a variety of engines; but it does keep gas from being pulled into the intake as much.....might have to check out the difference one of these days.

What he is saying is one should have throttle held wide open during compression test.

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67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

from what I understand that is ALWAYS the correct method for carburetted and Fi vehicles. I have alway been told that it is to provide maximum air flow as to not get a false reading on the gauge.

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Leela: 1970 Dart 225 CID
Coulmn Shift TorqueFlite
7 1/4" Axle 2.76 Gears

Go ahead and save that weird car, the sedan, the 6 cylinder, the C-Body. If you want a big block musclecar and that's all you care about, your missing the point.

Yes, I understand. I have done it both ways on non -/6 eingnes and not seen much difference, and not nearly enough to drop from 130-140 psi down to 100 psi across the board.....So I am doubtful that not testing with WOT is the reason you saw 100 psi readings; I would suspect worn compression rings and/or bores, especially with the WOT smoking going on while it was in operation.

With 100 psi readings, I would be pulling the head and checking the bore wear. If you ever encounter low compression, squirt some oil into the spark plug hole, rotate the engine a few times, and then re-test to see if the compression reading jumps up due to the oil sealing up worn compression rings.

I really need to brave the cold and re-test my fresh rebuilt engine with the throttle open to see the difference on a /6; I just tested a few days ago with throttle closed and got 130 psi +/- a few psi across the board. Used stock type cast pistons, maybe a .4 compression increase due to head shaving, partly countered by a mild torque cam.)