Yanmar are crap.

[masalai]

Waiting for you to finish typing and post something... CYA later, time to clean up ready for dinner...

[murdomack]

Frosty,

I think you are right, you can do what you want without a spring loaded reservoir or orifices. On your 3/8" line you will probably have a starter signal operated solenoid valve. You will by-pass this valve to recharge the tank. and

You could try a pressure switch signaled solenoid valve and a non-return valve in line on your by-pass and see how that works. You could also rig up pressure switches so that you know that your bottles are charged before you hit the starter.

Your system will have to be bigger than a spring loaded reservoir as it will only half-empty before the rising engine oil back pressure stops the flow. Maybe you need to add an air bladder in your extinquisher Still, good luck, hope you get a result.

[Frosty]

Murdo, The solenoid valve will be manually operated, I mean switched by me.

I don't understand why you think that the bottles will charge up before I hit the starter?

Obtained the bottles,-- 4 inch by 17 exactly the same size as the pre lubes suggested size of 4 quarts. Co2 fire extinguishers.

I just released them at the back of the airport it made a lot of smokey stuff. I thought I might have had security running after me. I could have chosen a better place I suppose.

Next job, mountings and valves.

From accusumps pictures,-and pre lube its easy to sea the valve they use. It is a diaphrgm type, this type is of quick discharge ie 1 1inch flow hole making me wonder if yellowbutt is right or not.

[murdomack]

I did not mean that the bottles would charge up before you hit the starter, you have explained that you will charge them up when the engine is running on its previous run. I am merely suggesting to you that you could have more controls to tell you that the bottles had pressure (i.e. oil) in them before you open your valve.

Valves tend to leak over time, and if that happened and you were not aware of it your alarm would be going again, and your open valved bottle would be taking oil pressure away and not supplying it at the crucial time.

You are concerned about the large valve, and this is why I suggested a by-pass round this valve for re-filling. You could have a mini-bore solenoid valve powered from the engine pressure switch that would remain open while the engine was running. An in-line non-return valve on this by-pass would ensure that you got the maximum pressure in your bottle.

[apex1]

[quote=Bigfoot1;291756]

It is dynamic balancing of all of the reciprocating components AND more importantly the effect that uneven loading of the crankshaft due to the forces that are imposed upon the crankshaft due to compression of the mixture which loads the crank, ........So it is dynamic balancing that I am speaking here.

That was exactly what I understood and referred to. There was no confusion.

And I doubt that there is a different terminology in use either side of the pond.

When you imagine to hold this in your hands:


you would feel the "rotating mass forces" vibrating your hand. These are "free masses of the first order", the vibration is caused by the resulting "free forces of the first order". Whereas this:

has a balanced rotating mass and no "free forces" that vibrate your hand.

But now we have a piston and conrod:


and the latter has two masses, a rotating one and a oscillating one. The former can be balanced by increasing the counterweight, the latter can be balanced to a certain extend only and therefore there are "free masses of the first order" remaining. This balance would look like this:


A simple two cyl. 2 stroke engine has these masses balanced:


But now, due to the assymetric movement of the pistons we have "free mass moments of the first order" which let the engine "wobble" on its centerline.
To compensate that we could use a 2 cy. 4 stroke like this one:

Now we do´nt have free moments, but twice as strong free forces.
With a four cyl. 4 stroke we have solved that problem.


Thats why they are so common.

But now we have the "second order"! A strange phenomenon. And surprisingly we have the fact that the pistons are NOT moving with the same speed!?! Hahh seems unbelievable yahh? But it is a fact! Look here:




You clearly see that the upper piston has moved a longer distance than the lower one! (of course at the end of the stroke both have moved the same distance at the same speed)
To calculate that phenomenon you can use pure geometry:

where the multiplication of the acceleration with the piston mass results in a force (our free mass force) the first part of the formula shows the first, the second part the (much smaller) second order (and so on).

The six cyl. in line balances these forces perfectly.


The Boxer engine has no free forces or moments as long as you can divide the cyl. nrs. by two.



We now could go on with ignition angles and cyl. bank angles and the like until the final elimination of any unbalanced force, but that would cost me too much time typing here. But maybe I find some text to copy.

So, to quote you:

Bigfoot: hope this clears things up some of the confusion

and Frosty:

some people know,-- some just demand that they know.

Well, so it is Frosty, well observed! And when you question someone make sure you know whom and on which topic.

Ok, so we have to go further:

The V8 in its simplest form, it is basically two straight-4 engines sharing a common crankshaft. However, this simple configuration, with a single-plane crankshaft, has the same secondary dynamic imbalance problems as two straight-4s, resulting in vibrations in large engine displacements. As a result, since the 1920s most V8s have used the somewhat more complex crossplane crankshaft with heavy counterweights to eliminate the vibrations. This results in an engine which is smoother than a V6, while being considerably less expensive than a V12 engine. Racing V8s (Ferrari Testarossa) continue to use the single plane crankshaft because it allows faster acceleration and more efficient exhaust system designs

The cross-plane or two-plane crankshaft is the configuration used in most V8 road cars. The first and last of the four crank pins are at 180° with respect to each other as are the second and third, with each pair at 90° to the other, so that viewed from the end the crankshaft forms a cross. The cross-plane can achieve very good balance but requires heavy counterweights on the crankshaft. This makes the cross-plane V8 a slow-revving engine that cannot speed up or slow down very quickly compared to other designs, because of the greater rotating mass. While the firing of the cross-plane V8 is regular overall, the firing pattern of each bank is LRLLRLRR. In cars with dual exhausts, this results in the typical V8 burble sound that many people have come to associate with American V8s, In all-out racing cars it leads to the need to connect exhaust pipes between the two banks to design an optimal exhaust system, resulting in an exhaust system that resembles a bundle of snakes as in the Ford GT40.

The flat-plane or single-plane crankshaft has crank pins at 180°. They are imperfectly balanced and thus produce vibrations unless balance shafts are used, with a counter rotating pair flanking the crankshaft to counter second order vibration transverse to the crankshaft centerline. As it does not require counterweights, the crankshaft has less mass and thus inertia, allowing higher rpm and quicker acceleration. The design was popularized in modern racing with the Coventry Climax 1.5 L (~92 cu in) V8 that evolved from a cross-plane to a flat-plane configuration. Flat-plane V8s on road cars come from Ferrari, (every V8 model they ever made, from the 1973 308 GT4, to today's F430 and California), Lotus (the Esprit V8), and TVR (the Speed Eight). This design is popular in racing engines, the most famous example being the Cosworth DFV.
So, how so ever we look at it, the V8 is not in balance.

Torsional vibration is a concern in the crankshafts of internal combustion engines because of several factors.

1) Alternating torques are generated by the slider-crank mechanism of the crankshaft, connecting rod, and piston.
2) The motion of the piston mass and connecting rod mass generate alternating torques often referred to as "inertia" torques
3) The cylinder pressure due to combustion is not constant through the combustion cycle.
4) The slider-crank mechanism does not output a smooth torque even if the pressure is constant
5) The piston speed is not constant

The well balanced 6cyl. has the least torsional issues due to the fact that the crankshaft has more bearings per cyl. than any V engine.

Firing pattern and bank angle.
To achieve the smoothest possible engine the common firing pattern is 720° (referring to crankshaft circle) divided by cyl. numbers. Therefore a V6 has a common cyl bank angle of 120°, a V8 90° leading to imbalanced masses on either side of the center compared with a straight 4 or 6 where the masses are vertically balanced.


Regards
Richard

[masalai]

Waaaarrrk I was so pleased with your efforts I tried to award some positive rep but "You must spread some Reputation around before giving it to apex1 again." seems I gave just recently so am inhibited ....... ....... ....... Have some psuedo points instead .......... ..........

[apex1]

Originally Posted by masalai

Waaaarrrk I was so pleased with your efforts I tried to award some positive rep but "You must spread some Reputation around before giving it to apex1 again." seems I gave just recently so am inhibited ....... ....... ....... Have some psuedo points instead .......... ..........

Thanks MAS I took them as given......................

[Frosty]

Lovely pictures --moving as well, very nice, but we were talking about tortional vibration.

You know what torsional vibration is don't you?

That is the frequenecy of the cycles of power from power strokes or compressions resulting in erratic rotating moment of the crankshaft.

I dont think anyone disagreed on the balance.

It is tortional vibration that was making the gearbox rattle.

[Frosty]

There are no Accessories more than an alternator as standard. Engines are out of the box plug ins.

Engines are separate in every way even fuel.

Yanmar have said that the rattling gearboxes are normal on the 6LP. There is a new drive plate available and is expensive at thier own admission.

It is only when stopping the engines, so if the housing was out it would make noise all the time. The noise is just the crank stopping and rattling the drive because of torsional vibration from the 6 cylinder engine.

There Expert and teacher at Yanmar Australia has said that it is common also for the filters to drain on the 6LP?????? now that I don;t understand as said these engines are Toyota and you would not put up with that in your car.

They don't know and don't want to know, they have my money and warranty is long gone.

They no longer use the Toyota engine for this leasure boat class but have moved over to a BMW derivative. I wonder why?

[whoosh]

well cant you search a drive plate from another manufacturer same spline same drill pattern, or get a blank, have it drilled?

[Frosty]

Its a special plate made by Centa, when I took mine out it seemed then 4 years ago to be the right one, ie it was by Centa, Im confused to be honest what it needs. Yanmar seem reluctant to tell me what I need ,i suppose in case it does'nt cure it. The one I have has big rubber bushes in and not the spring type that we are all used to. Yanmar dont know what I have in mine yet they built up the motor for delivery to me.

As you can probably tell I am tired of the whole thing and will have to live with the rattle and tell future buyers that it is normal.

But I will email Yanmar and ask the part number of the Centa that is supposed to cure the prob.

[apex1]

Originally Posted by Frosty

Lovely pictures --moving as well, very nice, but we were talking about tortional vibration.
It is tortional vibration that was making the gearbox rattle.

Frosty, if you would have read my text (not only look at the pictures) you would have noticed that I mentioned inertia when referring to motion of the piston mass and connecting rod mass generating alternating torques. Though I used the correct term forces.


And I edited my post above

[Frosty]

Hey Murdo Ive been thinking about what you said. You mean fit 2 valves one slow for charging the bottle and one fast for priming the engine!!! not a bad idea.

Actually over the days that I have been locating parts I have come up with a few mods myself, for instance the valve can be right on the engine not necessarily on the bottle. I even thought of a manual valve for long term storage T'd off to 2 valves.

Maybe getting a bit overboard but thanks for the idea.

Pssst by the way,-- Yanmar are talking again.

[Yellowjacket]

Originally Posted by murdo

You are concerned about the large valve, and this is why I suggested a by-pass round this valve for re-filling..

A separate fill/dump valving is what was suggested way back in post 25...

Maybe a one way valve with a small restrction orifice in it on the inlet side and a dump valve on the outlet would work.

No need to use a solenoid valve for the input circuit, a simple check valve will work just fine. In fact you could use a 15 psi preloaded check valve (parker makes them) and that would be about right. Then the valve wouldn't crack open until you get 15 psi in the gallery (giving you fast ramp up of pressure to 15 psi) and when you had 30 psi the gallery you would have a half a gallon of oil in the one gallon tank (which should be plenty of oil for the next pre-lube). That way you only need to control the dump, which would be on a momentary switch, and the only time it is working is when it is dumping. To start, hit the momentary dump switch, wait 15 seconds, release the dump switch and start the engine. Forget about it after that.

Much more simple than using different valves, and trying to figure out when to open and when to shut them and what size and restriction you need, more reliable and cheaper too.......

So now we find that your accumulator is twice as big as even I was assuming. Double the size, more than double the time to increase the pressure in the galleries. If you aren't careful here you can do more harm than good....

From accusumps pictures,-and pre lube its easy to sea the valve they use. It is a diaphrgm type, this type is of quick discharge ie 1 1inch flow hole making me wonder if yellowbutt is right or not.

Well, as Homer Simson would often say.... DOH!!!!

It's about time you started thinking. Some folks here are trying to help you and you seem to want give all of them a bad time. Sounds more like you don't want to really solve any problems, you just want to gripe out loud....

As you finally noticed, Accusump sytem has a big flow capacity and that is actually good for your particular application. If you don't move a good bit of fluid you aren't going to purge the filter. If you just dribble oil into the gallery upstream of the filter, the filter, being upside down, will still have an air pocket in it and all of the work you are doing won't do you a lot of good. The alarms will go off sooner, but you will end up delivering a shot of air to the bearings just after the engine is running, which may or may not be an issue, but if you are going to all this trouble, why not do it right....

You need to send a slug of oil into the filter to purge the air in it. Hence a good size valve and delivery tube in the dump side of your system, and a smaller restricted inlet side to control filling is the best approach.

[captim]

Hello Frosty,

Who are you dealing with in Australia?? I have just installed a set of 6CX-GTE2 -500hpengines in my boat and have 25hrs on the engines. I read with interest your problems.

Hopefully I wont recieve the same when I develope a problem and go looking for help.
My choice for Yanmar was made because a friend of mine has a set in a boat the same as mine with 6000 hrs with not a spanner on them. I'm looking for the same result. Time will tell.