2.0 EFI pinto smoking under load

[megadodo]

When I built my 2B I didn't do anything to the engine apart from change the valve oil seals as it smoked on the over-run and at idle. It ran very well with no noises so I just dropped into the 2B. Its ran absolutely fine for 3.5k miles but over the weekend it started to blow smoke out of the exhaust under load. At the same time its developed a slight misfire under light throttle. I'm no Pinto expert but I'm thinking a ring has let loose possibly? There are no mods to the engine, its set up as it was in its donor Sierra Sapphire.

[richyb66]

Compression test would be the first thing I'd try.

[Sparepart]

The obviouse diagnostic would be to use a compression gauge and look at how good each cylinder is. The manual says that at starter motor speed the pressure should be between 11-13 bar (all except engine code NAE) or 10-12 bar ( NAE code). Most people can't just open their toolbox and whip out a compression gauge though. Does a lot of air/smoke come out of the oil filler hole on the cam cover, which would indicate excess combustion gasses passing some ring(s). Unlikely but there might be too much oil in the engine. Does the smoke coming from the exhast small "oily" or "petroly"  i.e. is the smoke just too rich a petrol mixture because say the float in the carb is leaky. Is there a petroly smell under the bonnet. Is any oil weeping out of the top of the dipstick tube, blown up by too much pressure in the crank case from poor ring(s). Also the "Crankcase Ventilation System" (manual say check every 12 thousand miles) could be inspected to see if the vent valve is blocked or the oil separator is all gunked up with oil.

Edited November 30, 2021 by Sparepart
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[Jonty Wild]

Was it an unleaded head?