Originally Posted by pbmaise
A very frustrating aspect of what should be a simple exercise is I have the complete "Workshop Manual" for my Isuzu Engine
Zero mention of a damper plate is made and zero dimensions of the flywheel are shown.
The best thing the manual told me is my engine
is 5.785 liters.
The manual shows me a drawing of the flywheel and I see 12 bolt holes. Many images
I see of damper plates only show 8 bolt holes.
Obviously the triangular version doesn't use all bolt holes available.
One interestingly tidbit I gained was from the website I was directed towards
" Today's marine
diesels are designed with lightweight flywheels which do not create the inertia of an older heavy flywheel. The lighter flywheels result in gear
chatter or rattle at low RPM's. This rattle translates into gear
wear and damage to the drivetrain. Our damper plates eliminate this problem."
In other words the damper plate according to above us nothing more than weight hung onto the flywheel to help reduce chatter at low revs.
Well golly gee! I already have a damper plate on my engine so the weight is currently present and obviously not doing its job well. Pulling its weight. Ha, ha.
This website shows a round one with 12 holes.
-- PYI Inc. Max-Prop PSS Shaft Seal Seaview Radar Mounts R&D --
It introduced two new terms too.
"A "Hammer Head" damper plate is designed for general use where motoring at low Rpm's is common."
It is common for me to be at low revs to conserve fuel
" A "High Deflection" damper plate is designed for use in vessels where low RPM
engine use is the norm as in work boats or where gear noise
is being experienced."
Well that is me too. Groan.
This brings me back to the central problem. I am obviously here because of noise
at low revs and a worry the transmission
guy told me I should replace the disc soon.
A "high deflection" damper plate sounds like the thing for me. I bet it is expensive.
I filled in their form and was given 403Error reply. The form indeed asked for wide range of information that I don't have despite having manuals
for both engine and transmission
# of holes is a guess of 12 based on drawing
Max revs... hmm low
Flywheel diameter unkown
of holes...don't even know what that is
Hole diameters... unkown
All these questions and people keep telling I have one of most popular engines and transmissions.
This is frustrating fast. Well actually slow I have been carefully reading manuals
cover to cover for information not present.
Probably the best place to find the information you're looking for is in the model and serial
number specific parts
manual from Isuzu. The parts
manual should have a list of all the plates supplied with the engine and their part numbers, along with, if you're lucky, dimensions and applications. The manuals are available on line, though I couldn't find a free one.
Usually the drive plate is supplied by the engine manufacturer, though they are often manufactured by another company. Sometimes the engine manufacturer sells the engine to an equipment
supplier with the flywheel machined to their spec; Mercruiser and Twin Disc come to mind. If this is the case, then Four Winds discovery that Borg Warner supplies discs is the proper resource.
There are of course aftermarket specialists who provide a multitude of replacement discs, with a wide variety of real and imagined 'improvements'. A reputable aftermarket supplier will be able to cross reference the manufacturers part number with their part number in order to give the closest match.
This of course doesn't mean that it will solve your problem. If there was a specing issue originally, replacing the old plate with the same new plate will just repeat the issue. There are idiosyncratic issues with every installation
, a boat is probably one of the most problematic because of, among other things, their somewhat flexible nature and the lack of a large consumer base on which to ferret out problems.
The 'high deflection' disc on the PYI website looks like it might solve your problem, though on the other hand a lot of flexibility might allow the induction of some kind of vibration. A lot of times it really can seem to be a crap shoot. Often a call to the disc manufacturer or their representative makes things a whole lot easier...the aftermarket suppliers have seen a lot more problems of the sort you seem to be describing.
All the information required, except the rpm
and maybe the pitch
, should be in the parts manual. They probably want maximum rpm, though operating rpm may be asked for also. The bolt pitch is most likely 360 divided by the number of holes, i.e. 360 divided by 4 = 90 degree bolt pitch, 360 divided by 12 = 30, etc.
shaft size and spline will come from the box manufacturer, and is also model and serial
number specific, but the plate manufacturer will know what they are if you give them that information.