[Amel Yacht Owners] Re: Volvo Turbos


Stephan Regulinski
 

Ian and Judy,

Good grief! I didn't realize that the belt change tool kit was so
expensive! You may try ofering to "rent" the tools from your local
Volvo mechanic. This could work for both of you. Good luck on your
first change.

By the way, as to the question of 1000 versus 2000 hours, this is
usually settled on two pieces of data. First is the point at which a
significant number of failures begin to occur. When the engine is
first developed, it is estimated based on prior experience with
similar engines plus engineering "judgement". In time, this estimate
is updated using data from the actual engine.

"Significant" in this case is a function of the cost of repairing in
the event of running to failure as compared to the cost of replacing
the belt prior to failure. Since the engine overhaul is likely to
cost on the order of ten times the cost of a belt change,
a "signifcant" number of failures would be anything greater than ten
percent of the belts failing between 1000 and 2000 hours under normal
use.

The second piece of data is the effectiveness of inspection. If
inspections were perfectly effective in identifying belts that will
fail before the next inspection, than you would have no "hard time"
limit on the belt. Instead, you would inspect on the interval and
replace only when the belt failed inspection.

With things that slowly wear out and then catostrophically fail, we
mix the two ideas and inspect through the part of the life where
failure is unlikely and then as the probability of failure increases,
we replace the part and start over.

Stainless steel is a good example of substance that does not yield to
visual inspection. It is hard to observe minute cracks in stainless
and it fails quickly after the formation of small cracks. Belts,
however, seem to be of the other sort. Evidence of belt wear is easy
to observe and failure happens well after the first signs of belt
degradation.

I am inclined to believe that the original maintenance program is
correct. But remember it has two parts: Inspection and
replacement. Inspecting the belt requires that the inspection port
is opened and the belt is rotated through its entire circumference.
You are looking for "teeth wear and damage" and "cracks in the belt
and oil contamination" (from the maintenance manual). Oil degrades
the belt material and causes the fibers in the belt to begin to pull
apart.

Jay, who wrote in earlier (759 and 762) may shed some light on the
question of whether belt inspections are useful if he can tell us
what was observed when his belts were inspected prior to their
failure.

Stephan G. Regulinski


--- In amelyachtowners@..., "Ian & Judy Jenkins"
<ianjudyjenkins@h...> wrote:
Dear Stephan, What a useful note. I was hoping to change the belt
myself
until I found out the price of the belt tension guage ( somewhere
in the
region of $6-800).Interestingly, my prophet on the mountain in La
R. , M.
Selo, has recently emailed me that 2,000 hours before a change was
OK,
whilst cautioning that an amateur attempt to change should not be
undertaken
lightly.I have noticed a few Volvo trucks on(and off)the road in
Ecuador so
I am now hunting down a knowledgeable Jose to lend me his tools and
ride
shotgun on my very cautious first change
Marine Express Parts recomend 1000 hours, which I think is in
the latest
handbook. They also say that in their experience unless there is
something
wrong with the fuel pump they would not check it when changing the
cam belt.
Ian

From: "Stephan Regulinski" <stephreg@y...>
Reply-To: amelyachtowners@...
To: amelyachtowners@...
Subject: [Amel Yacht Owners] Re: Volvo Turbos
Date: Mon, 22 Sep 2003 17:53:01 -0000

Ian, Joel, Jay, etc.,

My copy of the Instruction Book ("Instruction Book 22 Series",
Volvo-
Penta, 1998) page 28 says that the timing gear belt (also called
the
cam belt) should be inspected every 200 hours and replaced every
2000
hours. This is twice the interval recommended by Joel.

I have just replaced my belt at 2000 hours and found no excessive
wear. I would like to know more about Jay's experience,
particularly
the maintenance findings on the last belt inspection prior to
failure. It would be nice to know whether the 200 hour inspection
is
capable of picking up premature belt wear in time to replace the
belt. I am not surprised that he has to adopt a more rigorous
maintenance program (he reports belt failure at just over 1000
hours)
given he is operating under more extreme conditions. The question
is
whether this program is necessary for the rest of us. A timing
belt
change is neither cheap or fast.

For those interested in doing this job yourself, you will need a
new
belt ($40 in Gibraltar), a workshop manual or copy of the relevant
pages, a belt tension guage, two locator pins and two locator
bolts.
I was able to borrow all of the above from a cooperative Volvo
shop.
The were made more cooperative by the fact that I had just spent a
large sum of money repairing the rigging and we were arguing about
the bill. I agreed to pay the bill in full and the shop manager
agreed to loan me the manual, the tools, and a chat with his Volvo
mechanic. Now we both think that the other is a perfect gentleman.

The job took me five hours and would take an experienced mechanic
half that (assuming an Amel were engine access is good). Here are
a
few hints:

(1) Have handy: a full set of sockets including two wrenches, a
31/32 socket, a strap wrench to hold the water-pump pulley while
loosening and tightening screws, and a crow bar or equivalent to
help
tighten alternator belts. An assistant wouldn't hurt to hand tools
and read the manual.

(2) After removing the alternator belts and the water-pump pulley,
the timing-belt cover can be removed with gentle twisting.

(3) The maintenance manual calls for removing the starter motor
and
inserting an anti-rotation tool. My mechanic advised me that this
was not necessary. I did not find it necessary.

(4) Fitting the timing pins into the camshaft and into the
flywheel
is a little tricky. Use a socket wrench with 31/32 socket to turn
the drive shaft, and listen for a little "click" on the pin in the
camshaft hole. It took me six or seven revolutions to convince
myself I had found it. Then kneel beside the engine (next to the
genset) and hold the pin in the flywheel hole. Wiggle the drive
shaft and see if the flywheel pin sets. It will do so firmly and
fully. If not, rotate the drive shaft one half turn (the camshaft
will turn one full turn) and the pin should set. Beware of setting
the flywheel pin in a place where the camshaft pin is not set. I
think there is a second hole, but couldn't swear to it.

(5) Set the two bolts in the pulley of the fuel injection pump.
All
is well if the "B" on this pulley lines up with the notch in the
housing.

(6) The manual says to remove the belt tensioner pulley and the
idler pulley. I did and found that I had to put them back before I
could get the new belt on. My mechanic later said that he doesn't
remove them at all. However, check the bearing on the idler
pulley.
I am told that it can seize and that early evidence is a failure to
turn smoothly.

(7) Replace the belt. Cut the old belt in two so that it cannot
be
reused and dispose.

(8) When tensioning the belt. My mechanic suggested rotating the
tensioner pulley (actually it is a cam) counter-clockwise to
tension
so that the belt, which rotates clockwise, pulls the pulley into
itself thereby increasing tension.

(9) My mechanic advised that he did not adjusted the timing of the
fuel pump as part of a belt replacement, despite this being a step
in
the maintenance procedure. I did not attempt this operation.

(9) Follow the manual in all other circumstances.

(10) Finally, before starting the engine, remember that prayer is
an
important part of any good maintenance program.

Stephan G. Regulinski
Delos (SMM #303)


--- In amelyachtowners@..., "Joel F. Potter"
<jfpottercys@a...> wrote:
Hello Ian,

Joel Potter here. The turbo boost pop-off valve really needs A
LOT
of
requested power to function. To check:

1. Go about 3-4 KTS in reverse
2. Gently go to neutral, then forward to idle speed.
3. Wait 3 seconds then wide open throttle in forward. WIDE
OPEN.

You will see the rod move ever so briefly. The engine is
governed
and you
will never get into the boost limit in cruise power conditions.
Only when
asking for more than you should, like at avoiding a crash. Hope
this helps.

All the best,
Joel F. Potter, Hull #400

P.S. Change your cam belt every 1000 hours. Trust me, this is
important.
-----Original Message-----
From: Ian & Judy Jenkins [mailto:ianjudyjenkins@h...]
Sent: Wednesday, July 23, 2003 1:36 PM
To: amelyachtowners@...
Subject: [Amel Yacht Owners] Volvo Turbos




I have SM 302 with the Volvo/Perkins TMD22p. No complaints
after
800
hours,
other than replacing the key switch and the engine hour meter
and
rev
counter, both at crazy Volvo prices.Power output is fine and I
take care
to
open up the revs every few hours to ensure the Turbo is
properly
exercised.
When the revs are high and the turbo is really being used
there
is a
pressure control valve that opens up if the turbo pressure
gets
too
high.As
I understand it the rod attached to this valve moves back
against
the
resistance of a spring.I have been advised to move this rod
back
manually
from time to time ( with engine switched off) to ensure that
it
is free
moving and it has always been free when I have moved it.
However, when I use full revs there is no discernible
movement on
this rod
(
possibly 1/2 mm but it's difficult to guage when the engine is
flat
out).It
has been suggested to me that as Amel govern the output to
60hp
the turbo
pressure doesnt reach the point where the valve opens.( this
wouldn't
prevent the turbo from working ok as mine seems to be)
Has anyone any experience to suggest that the rod should or
should not be
seen to move at full revs, and if it does move is this a
momentary and
occasional movement or should the the valve be seen to stay
open
above
certain revs?
Ian Jenkins

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