Ok folks. My 4x4 cozy spun a shell cupla year ago which obv req a full rebuild. Car has been spot on untill i put it off road for winter last year i started hearing i kinda slight rattle/knocking when cold. Not constant,it cums and goes,almost like a fuckd bucket. Then when its ran for cupla mins its ok. When its making the noisd it doesnt do it when reving,its only on idle. Oil presure seems ok as i have a guage in car and its a new genuine 1 fitted wen rebuilt. So the other day i removed the sump,took the big end caps off for inspection and ther still like brand new. Also tryd to check for play in a small end by gently movin rod up n down but all seems good! Im baffled with it! Can anyone suggest i check anythn else b4 building back up? I thot about checking the spray jets 2mora incase 1 of thems blockd and not feeding the small end/bore walls when cold. Hard to even tell if its defo cuming from bottom,its like centre of the engine! Its a strange 1.... Help

 

Thats ment to say genuine oil pump fitted on rebuild. Oops

 

I think the gearbox mainshaft(I think) can make a noise,not sure how to diagnose it tho, hope you find what's causing rattle

 

When you say the noise comes and goes it does sound like a hydraulic follower 'warming up'. Mine does it , no noise at first few seconds then a rattly follower (one) kicking in and out then quiet again .

Post up a video of it on cold start as a follower is fairly distinctive noise.

 

Sounds like lifters to me, both from the noise and the start of symptoms. When it's left unused over winter, dirty oil can clog them up a bit. They may recover with use, or they may not...you could try changing the oils and driving it around a bit. You could've made sure of the location with a mechanics stethoscope when the engine was running, that's how I pinpointed the noise to the head on mine.
Was afraid of big ends or piston slap too, but the long winter was just too much for the hydraulic lifters. May have to change them since the noise doesn't seem to go away.