hot running

[chippys323]

hi, can anyone help, my 323 runs great cold but once warm it lack power and runs uneavan.
dont know were to start.
andy

[zaust]

Compression test...

[chippys323]

and what will that terll me ?
sorry to apear thick !
andy

[Treeman612]

Compression test will tell you 1) If piston rings/bore are worn 2) If cylinders have very different compression readings, it will tell you which ones are most worn 3) if valves are worn/not seating properly (hmmm - maybe it's leakdown test that checks this ?)
Anyway, if you have worn pistons/rings/bore, the engine may well run ok when cold, because the oil is still relatively thick, and may disguise bore wear. Also,piston to bore clearance is less when engine is cold. When the engine warms up, the oil gets thinner, and worn rings/bore means compression is lost past the rings, resulting in poor performance. The uneven running may be that one cylinder is particularly bad, possibly misfiring. Take the plugs out - is one or more oily? - if so, there are problems with this cylinder.
totally agree with zaust - compression test is first route after basic plug check.
One last thing - is there any white/cream coloured slime on oil filler cap, or visible around oil filler hole? Or is the coolant in the expansion tank got same stuff?
If so, this could indicate cylinder head gasket failure - both oil and water circulate from block to head and back - if c.h. gasket fails, oil could be leaking in to water passages and vice-versa. This could also cause compression loss if gasket has failed, resulting in the symptoms you describe. (Gasket may hold compression when engine cold, but thermal expansion causes leaking)
HTH

[Brianmoooore]

Don't know too much about these early engine, but I would look at the cold start enrichment arrangements, which I guess is an extra injector. Pull the plug on it once the engine is hot.