Hi Guys, before I go ahead and shoot my 51 Cadillac with an AK47 I would like to pick your brains. My problem is I have an intermittent misfire and a smoking problem, its a 51 Cadillac with a 331ci motor, some days the car runs sweet and others it has a misfire and smokes a bit bot intermittently. I've fitted new plugs, leads, cap and rotor also runs pertronix electronic ignition and coil. Someone suggested stuck rings as the car had sat for a while over the winter, so I treated the car with Marvel mystery oil in the bores to soak etc. I've used the car over the summer and sometimes its fine and other times it has this misfire and smokes at the same time. Compression test done and were all between 108-115 psi. Heads were also rebuilt about 4000 miles ago. Any ideas as I am lost on what to do now ? Cheers Kev
what is the smoke like? is it black, or light blue? Black means the mixture is too rich, like if the choke were stuck "on". Light blue is from oil burning. What about the misfire? is it random, like a blubbering, or does it act like one cylinder is always missing?
The smoke is a blue colour and smells of burning oil, im wondering if there is a valve issue? I think the misfire is on one cylinder as the plug seems to always be wet and you can hear that cylinders not performing correctly, like a chuffing sound if that makes sense ?
Joined: Nov 8, 2014 Posts: 31 Profile Page Clean Kev Member from United Kingdom The smoke is a blue colour and smells of burning oil, im wondering if there is a valve issue? I think the misfire is on one cylinder as the plug seems to always be wet and you can hear that cylinders not performing correctly, like a chuffing sound if that makes sense ?
Greetings Kev!...congrats on getting a ak into the Uk!...don't shoot the caddy, put the hottest plug you can get that has the same thread, length etc. in the offending cylnder....if that doesn't work there are "anti fowl" devices that thread onto the plug that often work surprisingly well but ultimately it needs valve seals or guides or a total rebuild If it is oil on the plug...start with compression test, pull valve cover and peak between the valve springs and see if it still has valve seals(sometimes they get brittle and crack off!)..
Hi King Ford thanks for your reply, ive done a compression test and all cylinders are between 108-115 psi, I will pull the valve cover off and take a look to see what I can see. It doesn't smoke all the time that's the pain so I just kept using it through the summer but now its started the misfire and run crap which is also not all the time. So frustrating its hurting my head lol.
I cant help but wonder if this is a sticky valve. I would consider running an engine oil flush through before an oil change to see if you can remove some accumulated junk. There are lots of stories of engine flush doing bad things but I have never had a problem....it has however solved issues a couple of times for me. Make sure you use quality oil.
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