£2k won't buy much...apart from trouble and expense.....
And as JJ says...the engine is the weakest point on a 450.
The later 700cc engines (04 onwards) are far stronger and have a better exhaust
manifold that is less prone to cracking than the 600cc. And no...the manifolds are not
interchangable. If the manifold cracks you have to buy a turbo and manifold as a unit
as the manifolds were not available separately.
One of the most common failures is a valve burns out, and lots of unscrupulous folk
will sell or do you a re-con for around £1100 to £1500. And the 'Con' from re-con
is about the operative word. These characters will do a top end rebuild and replace
just the parts that are knackered..in other words a valve. A lot of money to do just
a valve eh ? But here's where the 'con' comes in....the reason the valve burns out is
cos the pistons rings have become imobile or cracked. More oil then passes up by them
into the cylinder head, and as oil burns at a higher temperature it 'eats' the valve
head. So 6 months or so later, the same problem returns.....thank you very much.
And any guarantee they give is not worth the paper it's written on as they'll have a
'get out' clause written into it anyway.
The only answer is a complete rebuild using all new parts...pistons, bearings,
valves, filters, etc etc...built to within manufacturers tolerance. Oh and while apart
it is pointless not fitting a complete new clutch at the same time...so include that too.
Total cost including labour/fitting......circa £1900 - £2000.
To keep that in perespective..just a new engine from MB would set you back £3000+
So....if you think you have seen or found a good one for sale...get it checked over
thoroughly by a reliable 'indie'...
And finally...the way to make any of those engines 'last' is to have it serviced
regularly, and never drive off till the autochoke has cut out, never rev past 3k until
the engine has got up to operating temp (2 blobs on temp gauge).....and always,
but always....when you get within 5 miles of home, cut all speed and use as few revs
as possible, and finally when you pull up at home, let the engine tick over for a few
minutes.....that will allow the oil to 'soak up' the heat from the turbo therby saving
the engine and your wallet.
