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Smokes after 8 minutes of running


acasey64

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1949 Chrysler Windsor (C45) with flathead 6. The car sat for 12 years. Five valves were stuck open. After a few weeks of patiently working with them, I finally got them all free. Because I put so much lightweight oil (Marvel Mystery, ATF/acetone, WD-40) on the valves, I changed the oil before I tried to start it. The car is now running.  Of course, it smoked to high heaven when I first started it. Now that I am past that there is a definite pattern and it is as follows: When the car is first started, the exhaust runs clean for about 7-8 minutes. Then it starts to smoke. The carb has been rebuilt. The plugs do have black soot on them, so some adjustments need to be made. I am concerned about compression. Compression is as follows: four cylinders at 80, one at 75, and one at 85. That is better than when I tested them before it was running; however, The car has had a total running time of 80-90 minutes now. If I read the manual correctly, it should be 120-150. Thoughts? Also, while working with the valves, I pulled the head. I put on a new gasket and tightened according to proper order and torque. I have attached a picture of a leak. It is the bolt the throttle linkage sets upon. I assume I need to take it out, put joint compound on it and tighten it back down. Or, is this more serious than I think? I checked my oil, it looks great! No antifreeze in oil.

Leak.jpg

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100 psi is fine on these low compression ratio engines.

You had stuck valves it sat 12 years and your compression is s bit low but at least its fairly uniform.

Get this car out and driving get those rings seating again.

If its burning oil after it warms up things get loose and maybe the cylinders and rings are worn.

Run it on the highway for a while and see if things improve.

120 psi maybe when fresh and new, 150 psi thats a much higher compression than stock.

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Before my engine rebuild I had 2 cylinders that had a compression of 5, one had 10, one 15, one 35, and one at 60.  It was so bad that we checked them 3 times with 2 different guages.  Got the same readings every time.  Drove the car that WHOLE SUMMER and put over 3,000 miles on it; never broke down or had a major issue.  I was putting a quart of oil in every 125 miles though.  Turned out that 5 of the 6 piston's top compression rings just fell apart when we disassembled the engine.  So I look at your compression readings and automatically think "that's not too bad" LOL

Oh, plus I was getting over 20mpg with no compression.   Now I get between 15 and 17. ?

Edited by Worden18
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" ... I pulled the head. I put on a new gasket and tightened according to proper order and torque. I have attached a picture of a leak. It is the bolt the throttle linkage sets upon. I assume I need to take it out, put joint compound on it and tighten it back down.  ..."        Several of the head bolts go into the water jacket , so if you haven't put sealer on the head bolts , you need to do that . Then retighten the bolts after warm up . I retighten mine several times . 

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It takes over an hour of running to burn the oil out of a muffler and it runs clean for about 10 minutes until the muffler gets hot.

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6 minutes ago, dpollo said:

It takes over an hour of running to burn the oil out of a muffler and it runs clean for about 10 minutes until the muffler gets hot.

Good info here. I would keep running it and more than likely the smoking will let up. I once removed a Chevrolet v8 cylinder head and some of the coolant that remained it the head ran down into the exhaust pipe. When the car was back together, it took a good part of the morning to completely stop smoking. It was someone else' s car and I was really happy that that was all it was. Good luck to you.

John R

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