Yanmar are crap.

[marshmat]

It sounds like you're just raring to get your hands on Takehito and Tadao Yamaoka here, Frosty. (Their president and chairman, respectively.) Perhaps a nicely phrased letter, politely expressing your extreme disappointment with the product itself and the service provided by the dealers, would accelerate things along somewhat.
These two have offices at:
1-32 Chayamachi, Kita-ku,
Osaka, Japan

[Fanie]

Something loose inside the exhaust by the sound of it.

[mark775]

It's the adaptor plate and a harmonic incompatability with the transmission. Yanmar doesn't want to tell you what plate to install. Your transmission company doesn't want to tell you which plate to install. It is a difficult scenario made more difficult by an unruly client. They want to be washed of you.
About all you can do is either try different plates (try Vulcan rubber of a recommended stiffness) or hire an independant torsional vibration analysis, or talk to Tony Athens (or someone like him), a moderator at Boatdiesel.com (like I said before) and get a recommendation.
I have tried the tack you are presently on and it soon runs out of water. You need a friend in your corner and to bear in mind that with all the talk about "this engine is better/worse than that" and such, SERVICE should be the first consideration when buying a diesel engine. Find a dealer with which you have something in common and develope said relationship or suffer.

[Frosty]

Yes homer I believe you are correct. That is why Yanmar is crap.

They knock together sooo many different variatiions of engines that they themselves don't know whats going on. So they just sell you something.

Ive replaced the rubber cush drive on the flywheel ---Sigh should I have to do this? it made no difference. They sell unknown engines just to get your money then run.

The rattle is harmonic vibrations shaking the transmission and there in the middle of the 2 is the "dark area"

Unruly client? 4 years trying unruly?

They probably think Oh he will get a few years out of it, and then he wont care or sell the boat, then we got away with it.

I hope you all wise up on Yanmar, they sell toys.

[mark775]

Frosty, really...the fact that your main point is simply that "Yanmar is crap" belies your professed desire to find an answer to your problem. Forget the past and try to forget how mad you are at Yanmar ( I went through this with Cat and feel uniquely qualified to empathize). Bleating about your injustice will not do anything. If you want even worse response utter the word "lawsuit".

[whoosh]

look,
this will take some time, but you could fit a clock dial to your flywheel and check the bell alignment,
When I rebuilt larger motors I would do this as routine
this would mean , taking off the boxes, yes well you know that

[Bigfoot1]

You dont say how long the engine rattles when you shut the engines down.
There is a valve that shuts fuel flow off when the ignition is turned off. If the engine turns more than say 10 or 15 revs before the compression brakes the momentum in the engines, then there could be fuel getting by the valve.

Re how long the engine must run from a cold start before the oil pressure comes up to guage.
I am not familiar with the guages, but most guages have a damper installed so that each small increment in oil pressure change does not vibrate the needle.
As an example, when you start a vehicle you can slowly watch the fuel guage reach the tanks fill position. Ie it is not instantaneous feedback.

The oil pump is positive displacement, when it turns the oil pressure starts at zero until the downstream resistance from the flow path offers resistance due the viscous shear of the oil. Ie if all of the oil is drained from all of the gallerys, which it should probably not happen, a few turns of the pump, the gallerys are filled, the resistance from the orfices and or clearances between the bearings create the pressure that the guage reads. Ie if you blew all the bearings, the guage would probably read zero or something small as the oil pump sees no resistance to build pressure.
A positive displacement pump will build pressure to whatever the input horsepower is driving it. At higher rpms, the pump will create more oil volume that the engine needs, and the extra volume will be bled off with a pressure relief valve in the oil pump.
I would not doubt that the pressure guage is just damped to give you a slow feedback.

But this should be a few minutes at worst, anything longer, who knows.
You are focused on the fact that the guage is giving you an accurate pressure picture. But I suspect that if you took a manual pressure gauge and screwed it into an oil pressure gallery port, that the pressure to whatever the pressure relief valve is set at the oil pump, would almost be instantaneous, while the guage at the helm is slowly coming up to specs.

Fuel guages are an easy example of this dampening as if it guage changed instantly with every wave the guage would be jumping around all over the place.

[mark775]

I forgot about the oil pressure aspect of your problem but the above describes things perfectly.

[Jimbo1490]

You are focused on the fact that the guage is giving you an accurate pressure picture.

I think he's rather focused on the sound of connecting rods knocking loudly on start-up as their shell bearings are not 'floating' on a film of oil under pressure as they should be, and that this knocking is going on WAY too long, like 10 seconds or so while the engine has already started. He already knows the reason for this: The 'upside down' oil filter installation coupled with a less-than-perfect anti-drainback (check) valve in the spin-on filter allows the filters to drain dry, causing an excessively long dry start every time. This is definitely not good as dry starting is responsible for most of the wear in a typical engine. Doubling or more the dry start time has GOT to be very hard on (especially) the con rod bearings.

I would be very unhappy with a $50K engine that pulled shenanigans like this, and a supposedly reputable company that refuses to provide a remedy!

Jimbo

[wardd]

prelube pump?

[Jimbo1490]

BTW, I've thought of a remedy, and it's relatively cheap and simple.

The upside down filters are the root cause. The anti-drainback valve in a typical spin-on oil filter is really not a 'perfect' valve as valves go; after all, an oil filter costs only a few dollars (yeah, Frosty, I know; for what Yanmar charges they ought to be gold plated ) so they don't really build a proper check valve into it, it's really just a rubber disc backed up by a metal disc and a spring. But they usually only have to cope with siphon (negative) pressure, which actually aids the valve closing. The problem arises when this less-than-perfect valve is used in an 'upside-down' install where they have to cope with steady positive pressure, so that even if they leak only a little tiny bit, the filters will empty out, which is no good.

What you need is a PROPER check valve installed as a 'sandwich adapter' between the spin-on oil filter and the factory filter adapter (engine block). Since this will become a permanent part of the engine, it can be well-made and designed to not leak AT ALL. No more drainback; problem solved.

I see a cool aftermarket product offering, as well

Jimbo

[globaldude]

Talked to a friend 20 years marine engineer .
" Oh yeah, thats typical from those engines , often its the centrifical oil filter rapidly slowing down on shut down " and the 7 - 10 seconds for oil preasure ?
" not uncomon, don't forget marine engines often have remote filters and oil coolers whereas automotive don't ,that's a lot of area to preasureise , a lot of the "delay" could be in the time it takes to get to the gauge !, does it actually rattle ?, I doubt it would , he should check the presure at the engine to see the speed at start up ".

For what its worth .
Id like to know if you find out what it is making the rattle or if the oil presure readings at the engine are a few second different .

Interesting you are replacing this and that and it's " making no diference" then say why should I have to do this [ or words to that effect .
Need I point out the obvious , ahh, If it made no difference , No, you didn't "have to do this" .

How do your " crappy " engines preform ? . apart from the two " problems " are they otherwise good ? [ don't let your problems colour your frosty opinion

[Frosty]

Globaldude, there is no mention in my post of gauges, I said alarms, we have 2 engines in one boat and both are identical in the problems.

These engine do not have centrifugal filters or remote, they are Toyota 1HD engines from a Landcruiser.

It is not big end bearings that are rattling it is harmonic shudder through the transmission when the engines are turned off. Read the posts again.

[Jimbo1490]

His engines DO NOT have remote filters, rather the filter is installed 'upside-down'.

And what does performance have to do with a situation that's causing rapid wear? You don't imagine that such a situation would affect performance, do you? The engines might be 'performing' just fine and dandy but destined for a 1000 hour service life, which would be completely unacceptable. Worn out connecting rod bearing will have no effect on performance at all, right up to the moment the 'rapid disassembly' occurs.

Jimbo

[whoosh]

for you who are interested
to trouble shoot bearings BEFORE they cause trouble, take out the filter element
cut in half with hack saw , spread out the filtrate(paper) and you can READ the engine This was common practice when i was field service mech for cummins
And BEFORE someone shots down Cummins) most breakages were caused by overspeed( letting the load push the truck over rated rpm, ) and poor maintenence