Thanks Clift_d an excellent insight and advice into performance etc! Baxters link also very interesting and comprehensive, he knows his stuff!
I have done the basics, oil and filters, new glow plugs. Fuel tank off, cleaned refitted plus fuel filter. New air cleaner, so she is drinking and breathing well. Changed gearbox oil and seals as well on this unknown bus.
Drove a 200km trip (with some rain) and returned to find rear end lagged up with streaky black carbon deposits from the exhaust, something aint right
Will have to follow Baxters Bible
Also, I noted a few drops of black oil around the first joint of the silencer? That can't be good?
The youtube link from Titus was also very useful, reassuring to 'hear' another JX running as noisy as mine, bag of nails comes to mind
The bus had a nappy/tinware/splash guard when I purchased around/under the engine, a real bugger to get off, fiddly rusty bolts and screws. Had to come off to see the engine underside. Nappy was the right description, the inch thick soundproof cladding was soaked in black oil, a real s--t job to clean off.
If I replace the 'nappy' I have learned there is a product called 'fat mat' which is a very good alternative sound proof lining.
Re the Turbo, there is no perceived kick in at 2000 rpm!? maybe there are other engine issues (as in Baxters post) that mask the turbos proper function!?