I am an american here in the Philippines, and I have been looking to buy a car. I found a really clean 1984 mitsubisihi lancer,
but the idle is a little rough, and when I hold a dollar bill to the tail pipe it alternates between being blown out and sucked back in. The idle does smooth out some as the engine is revved.
But, I am guessing it has a burned exhaust valve. Any doper mechanics out there that tell me if that is true.
I believe it is a 1.4 liter rear wheel drive.
Used cars are actually expensive here, and I don’t want the hassle of a problem engine.
IANA(mechanic), but that indicates a valve or seal problem. You’re basically wasting energy by not having the piston transfer the energy for that cylinder fully. See if you can hold your hand over the tailpipe once it first starts and you might be able to kill the engine. A healthy normal car will force your hand away from the tailpipe. I’d say don’t get the car. An '84 with engine problems doesn’t sound like a happy thing to deal with in the future.
(IWALM). I’ve seen this sort of thing happen due to really bad ignition timing, and due to a car where the timing belt had jumped a couple of teeth. The fact that the idle smooths out upon being revved sounds like that could be the issue, and it’s not too difficult to test for.
Also, a really, really bad idle mixture can do this sort of thing as well. And, it would be interesting to know, what is the idle speed? Some cars simply, due to their harmonics of the pressure-waves produced by the exhaust gases, do not like idling at the level where the emissions people like them to idle. My Subaru 3-cylinder, for example, always sounded bad, both from an engine harmonic and in its exhaust note until I raised the idle from 500 rpm to 900 rpm. Sure, it wasted a little gas, but at least it wasn’t shaking me to pieces at every stop light.