I've had an overheating problem with a new/other engine (1991) for 3 years now. Some time back I discovered that there was a misfire on cylinder 1 and maybe an intermittent misfire on cylinder 4. I've read that a misfire can cause overheating. I've done everything i can to ensure that the timing and spark are in good order. Compression is very good and consistent across all 4 cylinders. Also on turning engine over with ignition disconnected and a naked flame applied to spark plug port produces a big pop proving i believe that fuel is available to cylinder. Gas was applied all around inlet manifold, carb and head gasket seems and no increase in revs was observed as a result of air leakage.

So i removed the head and cant see a problem with any valves. I've restored the head and had it skimmed (7 thou out of flat?) And am about ready to put everything back together dismayed that i've still not found the source of the problem.

Is it possible that a rag, collapsed silencer or some other type of restriction in the exhaust could be the cause of these symptoms? The exhaust gas appears to my untrained eye to have reasonable flow but fails the dollar bill test producing a flutter I believe in keeping with a sticky valve.

Is there a test to check if the exhaust is functioning ok with çylinder head removed?

Austin morris/leyland sherpa 230. 1700cc "o" series engine.


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