Hi all, I'm hoping to get some help diagnosing a problem with a friends LA360. It's a built motor with 10.5 to 1 compression, big solid camshaft (unsure of specs), extensively ported j heads etc and is regularly spun hard to 7500rpm. The motor was built about 8 years ago but it has not seen much use and is still very tight. After a recent pass, it has developed a knock that sounds like its coming from the centre of the engine (definitely not a big end or crankshaft bearing knock) which can only be heard over 3000 rpm. Its has 60 psi oil pressure when cold but it drops away to 10 psi when warmed up. It runs fine until the revs are brought up to 3000 and the noise can be heard then refuses to idle afterwards. I'm wondering if it is possible for the camshaft retaining plate to fail or come loose allowing the camshaft to float (move forwards) as I'm thinking this could explain the loss of oil pressure and poor idle as it could also cause the distributer to retard slightly. Has anybody experienced anything like this before? Is this even possible? Just not in a position to pull the motor at this stage and hoping it's something that can be fixed in car.
Thanks in advance,
Andy