13/60 Knock On Starting

[cbjroms]

Just got my 13/60 back on the road and have noticed that the bottom end has started to knock for the first few revolutions when the engine starts.

Wondering whether the oil pump is at fault or whether an oil additive could save the day? Would measuring the oil pressure be of any help at this stage?

If it is the oil pump then might I as well replace the bottom end bearings or is a major rebuild inevitable?

What would you guys advise? 

[RobPearce]

A little bit of knocking on the first few revolutions - or even the first few seconds - after start is actually fairly normal for these engines. It's caused by the oil draining back into the sump so that the pump takes a while to get the pressure back up. This can be due to wear in the pump but is largely caused by the filter design. Because the filter is fitted pointing "upwards" it is important that a filter with the correct non-return flap is used. Most cheap filters do not have this, or have a design that doesn't work too well.

That said, as long as the knocking stops within a few seconds and doesn't return when the engine is hot, and if you take care to wait for the knocking to stop before revving or pressing the clutch, then it probably isn't doing any harm and isn't anything to worry about.

[sparky_spit]

My 1296 engine does the same.  I'm lucky in that the car will not start from cold without choke, so I keep the engine turning over on the starter until the oil warning light goes out and then pull the choke out to start the car properly. It needs a decent battery to do this but seems to work okay to stop the engine "death rattle".

[Rosbif]

My 13/60 does the same. I give it a moment without the choke initially, when the engine is cold of course. Once the engine has been running there isn't the knock on restarts. I agree, don't move off or rev the engine until the knock stops, it should only be a few seconds just until the oil light goes out in fact.

[Antonnick]

My 13/60 used to do this but after regrinding of the Crankshaft and refitting, it does not do this any more. Moreover the oil pressure is phenomenal.