850 T5 B5234T engine fault please help me!

I bought 1996 850 T5 ex-police expecting it to have been serviced
regular as clockwork, thus being well maintained and in good
condition.
But since i got the car it has had a terrible hot start problem and
now has a ticking noise. Local garage has ruled out cambelt,waterpump,
tensioners/rollers,power steering and alternator faults.
He did comment on several rocker bolts that are not standard so
advised me to do a compression check, my tester isnt accurate but is
consistent and here is what I found
1)9.3bar 2)6.6bar 3)6.6bar 4)9bar 5)8bar
So I presume from this that I have either a head fault or headgasket
fault between 2 and 3.
But before I replace the headgasket and test the head/skim I would
rather find out what this noise is(dont want to waste money)
Volvo says that it is a bent conrod(but tried to sell me an engine
privately)
Local garage says it is a hydraulic tappet(but he is a BMW
specialist).
I says I’m not sure.
The noise is apparent at tickover but gets worse but it isnt
consistent with the revs.
I noticed that at a steady 2000rpm,no matter what gear, the noise was
intermittent but it was speeding up and slowing down even though the
rpm was steady.
Can somebody help me please?
Many Thanks
Dale

 

Fraid this kind of fault is very difficult to diagnose without seeing and
hearing the car, however you elabourate alittle more- how does the car run,
does it misfire, does it start from cold ok on all cylinders, how is the
mpg, is the noise roughly at half engine speed or what???

As many details as possible please.

When you say its hard to start from hot, is it suffering from no fuel, too
much fuel, no speak what??

Tim..

 

He did comment on several rocker bolts that are not standard so

Bent conrods is a common fault on engines having run at higher boost than
original, above 1.1-1.3 bar.
Bent conrods might result in bad compression. You can test that if you can
measure how high up the pistons go on all cylinders.

Niels

 

Since posting I have taken the rocker cover off and noticed that some
of the holes have been sealed by an expert in kitchen sink sealing.
In reply to questions regarding the engine:-

Number 2 plug was black but not oily.
Starts fine from cold.
The noise is intermittent throughout the rev range, but more apparent
under load.
I havent noticed a misfire and its the first Volvo that I have
owned(was a BMW man) so I’m not sure what kind of niggles to look for
really.
MPG?? If taken easy then its not too bad, actually its better than
expected, but with all that power on tap and owning a very heavy right
foot I couldnt say for sure. I have put 48 litres in and done around
150 miles but quite a bit of that has been on tickover at the garage

How can you measure the stroke accurately without taking the head off?

Cheers
Dale