Was using Castrol 10W60 on my newly built engine, now 20k on it, all along.

Decided to change to Fuchs Titan Pro S 10W50 as it's a popular choice on here and ever since then there's a ticking sound, tick tick tick, under load. Can't hear it when boost comes on because air filter is too loud.

No ticking on idle, no ticking when I rev the car at idle, can't hear anything on boost, it's only under load from around 1k to 3k rpm.

Used engine flush, emptied old oil and changed the oil to Mobil 1 10W60 today and ticking still there.

Tappets were newly installed at the time of the build so don't think it's them, but I'm no expert.

I put Wynns hydraulic valve lifter treatment in too, still the same.

Heard that it could be pinking also but I don't know how to tell.

Haven't checked fuel pump voltage yet, that's tomorrow.

Anyone have any idea please?

Cheers,

Philip.