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2 bad cylinders


Fleetwood Meadow

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If you follow my thread in Our Cars you will know I rebuilt the engine last year. It was my first one and I didn’t do all of the things I should have done, such as measure cylinders before ordering rings. However the car runs great. I parked it in November and started it up and let it run for a couple minutes every month until I took it out for a spin today. It shifted 1-4 perfectly, which is unusual for the first mile in that car, but it ran rough at idle and still a little rough driving. When I stopped the car at the garage there was light smoke coming from the driver’s side exhaust. I parked it and took out the spark plugs. 2,4,6,8 were all a uniform light brown color. 5,7 were the same light brown color except 7 was a little darker towards the threads. 1 was covered in oil, and 3 was caked up. What do I do about that? Do I need to disassemble those two cylinders and get larger rings? Could it have been from starting it and letting it only run a couple minutes without it getting to operating temperature? I do lose some oil out of it but I haven’t driven it enough to see how much, plus it leaks from the side of the oil pan so it’s tough to tell how much is going where. Pictures are from top to bottom: 1, 3, all of the rest. 

BF86DEEB-484E-428D-A567-34476EE9B2FF.jpeg

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14732350-A10D-4D98-B835-E2FAE4CF5857.jpeg

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I’m not exactly sure on the heads. The seller never touched the disassembled engine. He said that the heads had been rebuilt by the time he had bought it. I replaced the seals and the clips that hold the spring onto the valves. It was the first time I had rebuilt an engine so I didn’t try to jiggle the valves around to see if they moved. The engine only has about 200 miles on it since it was first started. 

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And as long as you have the plugs out, planning to put in new ones, record the compression of all cylinders. I don't know whether you have a new distributor cap and plug wires, but if not, good idea to get them now. You want to have good spark on all cylinders.   -  CC 

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No comment on your current problem, others have given plenty of direction.

 

But once you solve it, please discontinue immediately the starting the car each month during the winter and letting it run for a couple of minutes.  That is one of the must abusive things you can do to your engine.  If you start it, let it run long enough (20 minutes?) for all the fluids and components to reach normal operating temperature!!  If you aren't willing to do that, it's better if you don't start it at all.

Edited by Owen_Dyneto (see edit history)
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13 hours ago, cahartley said:

If you need to break in the engine you won't do it puttering around.

Find some hills and beat the snot out of the engine going up and coast down.

Repeat, repeat, repeat, repeat, and repeat.......literally.

Back when the Chev II came out the engines had rocker balls rather than rocker shafts.  Every one of them that we sold had to have the balls replaced, except for the one bought by one of our mechanics.  The day he took delivery he got a call that his father had been rushed to the hospital 150 miles away.  He took off and was there in just under two hours.  Totally against all rules about break in but his engine ran beautifully for years.

I have never let my engine idle to warm up.  Even in prairie winters as soon as the shifter would move we moved.

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So I took the car out and did the hill thing, and rougher driving as was suggested. The car ran great for about 20 minutes. Then i started hearing what sounded like a rod knock. So I headed home. Every time I stopped the car it stalled. When I parked the car and shut it off the carburetor kept dumping gas into the intake, which explains the hard start when I stopped to get gas along the ride. I took the covers off and assured that oil was getting up there. Then I saw it.. the broken valve spring. I wouldn’t have been so concerned about it because I didn’t replace them when I rebuilt the engine, except that is the second time that same spring has snapped. I also had noticed that the #2 spark plug wire hadn’t been reattached when I took them off the last time. That might explain the stalling, along with the frustrating carb that was dumping in fuel out of the forward ports. The broken spring was in the #3 cylinder, the same as the caked up spark plug. The #1 and 3 spark plugs looked great though.

 

It’s kind of hard to see the gas but it is shooting straight out of the port on the primary side of the carburetor, and the car is off..

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Edited by Meadowfleet
Indicated primary/secondary side for fuel coming out. (see edit history)
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Well it would appear that float needle isn't doing the job of stopping fuel flow when the carb bowl fills up.

 

So what's causing pressure build up when the engine has stopped, a number of possibilities exist:

  • do you have an electric fuel pump still running? 
  • Is there enough heat to cause fuel boiling?
  • some  carbs have an anti percolation system inbuilt to prevent residual heat causing too much carb bowl build up after shut down
  • Is it possible that the fuel cap vent is blocked, causing excessive tank pressures after shutdown?  

Putting aside the other problems you have encountered it surely won't run right until you get this sorted. 

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9 hours ago, Spinneyhill said:

Wouldn't this result in fuel being sucked back into the tank? Unless the pump pressurizes the tank...

 

Could be on a long run, but I get pressure from the cap often when I fuel up.

Gas expands with heat.

So I never fill to the brim when I am just going to park the car.

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On 3/30/2019 at 2:01 AM, hchris said:

Well it would appear that float needle isn't doing the job of stopping fuel flow when the carb bowl fills up.

 

So what's causing pressure build up when the engine has stopped, a number of possibilities exist:

  • do you have an electric fuel pump still running? 
  • Is there enough heat to cause fuel boiling?
  • some  carbs have an anti percolation system inbuilt to prevent residual heat causing too much carb bowl build up after shut down
  • Is it possible that the fuel cap vent is blocked, causing excessive tank pressures after shutdown?  

Putting aside the other problems you have encountered it surely won't run right until you get this sorted. 

-It does have an electric fuel pump, I have now added a switch to use it only when needed. Haven’t installed the new springs yet to start it to see if the switch helps the carb not build up too much pressure, in the event that it is.

 

-The car is a 4 barrel Carter WCFB. I don’t know if it has an anti-percolation system or not. I can’t get the thing to adjust properly as it is. I can tighten both mixture screws and it still runs the same as if I had them open.  

 

-The gaskets under the carb are all new so I would like to think that the heat is ok. It can run and start every time so I don’t think there is a vapor lock or boil out issue. 

 

-The venting of the tank isn’t an issue. The vent tube isn’t sealed to the fillet neck fully so air can get in.

Edited by Meadowfleet (see edit history)
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4 hours ago, cahartley said:

You diagnosed part of your trouble when you said turning in the mixture screws have no effect.

There is/are plugged passages somewhere.

 

Well if it's flooding you are never going to get the mixtures right, so at this point I wouldn't assume that anything's blocked.

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On 3/31/2019 at 8:08 AM, Meadowfleet said:

I took a picture inside the cylinder that had the broken valve and this is stuck to the side of the wall. I don’t know what it is. The cylinders that I checked look great though, with the exception of whatever that is. 

13183D2F-A5BD-4F22-A211-CA6C07174DBD.jpeg

 

Gotta say that's most intriguing. 

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On 3/31/2019 at 12:32 PM, Meadowfleet said:

And this was in the #1 cylinder however the spark plug wasn’t covered in wet oil. It was dry. 

CF3F4A6F-649F-4580-B018-3BA7059C1945.jpeg

 

Looks to me like oil has run down an open valve whilst motor is staionary, good chance the valve guides are shot.

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I replaced the valve springs on the odd side. I know I’m not supposed to do a compression on a cold car but I did just to see where it stood:

#1 80

#2 90

#3 95

#4 120

When I did start it I ran it fast and checked to see that oil was getting to the rockers. Oil came out nicely as it should. 

What I find perplexing is that the engine idles and revs smoothly. 

 

I took the electric fuel pump wire off and ran the car strictly on the mechanical fuel pump. It ran great. Unfortunately I forgot to look and see if the carburetor was still shooting gas out when it was shut off. I will look the next time I run it. There was so much black smoke coming out of the tail pipes I couldn’t see clearly through it. I’m assuming after looking online a little that it is more of a carburetor issue more than it is an engine issue. It didn’t smoke like that before but perhaps that has to do with the weak springs that were on it and now that they are replaced the hidden issues came out. But it was definitely not encouraging to see all of that smoke. 

Edited by Meadowfleet
Added the last line after the compression numbers (see edit history)
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1 hour ago, Meadowfleet said:

I replaced the valve springs on the odd side. I know I’m not supposed to do a compression on a cold car but I did just to see where it stood:

#1 80

#2 90

#3 95

#4 120

When I did start it I ran it fast and checked to see that oil was getting to the rockers. Oil came out nicely as it should. 

What I find perplexing is that the engine idles and revs smoothly. 

 

I took the electric fuel pump wire off and ran the car strictly on the mechanical fuel pump. It ran great. Unfortunately I forgot to look and see if the carburetor was still shooting gas out when it was shut off. I will look the next time I run it. There was so much black smoke coming out of the tail pipes I couldn’t see clearly through it. I’m assuming after looking online a little that it is more of a carburetor issue more than it is an engine issue. It didn’t smoke like that before but perhaps that has to do with the weak springs that were on it and now that they are replaced the hidden issues came out. But it was definitely not encouraging to see all of that smoke. 

 

So there`s a big discrepancy between 1 and 4 despite the engine being cold, in fact other than 4 they all look sick, what do the other cylinders read ?

 

To ascertain whether compression leaks are valve or piston ring related, squirt a little oil into the cylinder being checked then do the test, if the pressure is significantly higher after the oil treatment then its indicating faulty rings, if the pressure reading remains much the same then there is a valve leak.

 

Given your opening comments about rings and heads being messed with, makes it rather difficult to give specific diagnosis; perhaps you need to start again ?? if it were my car, I would not be impressed with that much oil lying on top of the piston in photo 2.

 

With the carb fault, I would assume you had a lot of residual fuel lying in the manifold which is going to smoke until it all clears thru combustion.The reason I asked about the electric pump, is I suspect, that`s the cause of flooding, it`s simply overwhelming the float needle, so if you continue to use it you may need a regulator, in the first instance however I would try running without using it. 

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I haven’t read the other sides compression yet. I took the car around the block and it didn’t smoke and ran very well. When I shut it off the carburetor didn’t spit any gas when the engine was shut off. I guess that the electric fuel pump was creating too much pressure. It’s going to rain for a couple days. I’ll get the compression of all of them the next nice day after the engine is warm. 

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