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Guest
Guest
I can\'t tell you about Comma Oil ...
for fear of being lynched !!!
It's great lawnmower oil .....
for fear of being lynched !!!
It's great lawnmower oil .....
SAE30
- Thread starter Phoenix of Hamble
- Start date
sailorman
Well-Known Member
Re: I can\'t tell you about Comma Oil ...
[ QUOTE ]
for fear of being lynched !!!
It's great lawnmower oil .....
[/ QUOTE ]
should be just the thing 4 the Honda 4stroke
o/bds then /forums/images/graemlins/blush.gif
[ QUOTE ]
for fear of being lynched !!!
It's great lawnmower oil .....
[/ QUOTE ]
should be just the thing 4 the Honda 4stroke
o/bds then /forums/images/graemlins/blush.gif
tyce
Well-Known Member
Re: I can\'t tell you about Comma Oil ...
marine engines, such as yanmar 1gm10, are old design engines.
they do not have the tight tolerances of for example car engines, and are bordering on being agricultural.
synthetics therefore will not create a good seal between ring and liner and will have a high oil consumption rate.
these engines do not need the additives found in synthetics and are more than happy with bog standard oil as long as its the correct grade
marine engines, such as yanmar 1gm10, are old design engines.
they do not have the tight tolerances of for example car engines, and are bordering on being agricultural.
synthetics therefore will not create a good seal between ring and liner and will have a high oil consumption rate.
these engines do not need the additives found in synthetics and are more than happy with bog standard oil as long as its the correct grade
Avocet
Well-Known Member
I thought the great thing about synthetics was that they DIDN'T thin out as much as mineral oils when they got hot - have I missed something?
Also, if it's not too daft a question, why do boat gearboxes have clutches in them anyway? I know mine is connected to the flywheel via a small single plate dry clutch but there is no way of disengaging it. I assumed it was just there to act as a "weak link" in the event of the prop getting fouled. Is it more of an issue with bigger engines producing more torque?
Also, if it's not too daft a question, why do boat gearboxes have clutches in them anyway? I know mine is connected to the flywheel via a small single plate dry clutch but there is no way of disengaging it. I assumed it was just there to act as a "weak link" in the event of the prop getting fouled. Is it more of an issue with bigger engines producing more torque?
nealeb
Active Member
[ QUOTE ]
Also, if it's not too daft a question, why do boat gearboxes have clutches in them anyway?
[/ QUOTE ]
Because there is a bit of slip as they engage to reduce shock loads? Dropping it into gear would be a bit sudden, even if the prop would slip through the water a little more easily than tyres on a road.
Also, if it's not too daft a question, why do boat gearboxes have clutches in them anyway?
[/ QUOTE ]
Because there is a bit of slip as they engage to reduce shock loads? Dropping it into gear would be a bit sudden, even if the prop would slip through the water a little more easily than tyres on a road.
sailorman
Well-Known Member
i have a hydraulic box + max prop.
less gearbox noise + more reliable
less gearbox noise + more reliable
cliff
Well-Known Member
Re: I can\'t tell you about Comma Oil ...
[ QUOTE ]
for fear of being lynched !!!
It's great lawnmower oil .....
[/ QUOTE ]Having totally wrecked 3 car engines using Comma oil (lubrication failure), I would not even use it in a lawnmower.
4th engine was run on Duckhams from "new" and was still going strong after >100,000 miles.
-----------
“Artificial intelligence is no match for natural stupidity”
Skype id:cliffillupo
[ QUOTE ]
for fear of being lynched !!!
It's great lawnmower oil .....
[/ QUOTE ]Having totally wrecked 3 car engines using Comma oil (lubrication failure), I would not even use it in a lawnmower.
4th engine was run on Duckhams from "new" and was still going strong after >100,000 miles.
-----------
Skype id:cliffillupo
G
Guest
Guest
Re: I can\'t tell you about Comma Oil ...
Mmmmmmmmmm --- did I say I liked Comma Oil ????
I am a Duckhams man ............ never liked Castrol GTX
And I don't like recycled oil for cars etc.
I buy Tesco's / local shop special for boat - even though it is recycled !! but use good stuff in cars ... Not Comma or GTX .... but thats my opinion ....
Out here we have about 100 ltrs a week come into our lab ... so I don't know nuffin offiser !!!
/forums/images/graemlins/grin.gif
Mmmmmmmmmm --- did I say I liked Comma Oil ????
I am a Duckhams man ............ never liked Castrol GTX
And I don't like recycled oil for cars etc.
I buy Tesco's / local shop special for boat - even though it is recycled !! but use good stuff in cars ... Not Comma or GTX .... but thats my opinion ....
Out here we have about 100 ltrs a week come into our lab ... so I don't know nuffin offiser !!!
/forums/images/graemlins/grin.gif
Avocet
Well-Known Member
Not sure, The "clutch" plate on mine has spring in it just like a baby car clutch plate and when you take the gearbox off, you can certainly see the marks where the springs have moved each time a gear is engaged. I therefore think that (at least in my box) the springs are there to take out the shock loads when initially engaging a gear but that the clutch isn't supposed to slip at all in normal use. Does anyone know if the Hurth HBW 50 has any internal clutches (cone or otherwise)?
oldharry
Well-Known Member
[ QUOTE ]
, why do boat gearboxes have clutches in them anyway?
[/ QUOTE ].
On mechanical gearboxes cone clutches are a common way of engaging the mechanisms for forward and reversing gears, also providing a convenient 'neutral' disengagment. The alternative would involve a synchromesh system similar to that on a car, which is more complex. Usually cone clutches are directly controlled by the external gear shift lever which is arranged to move the cones in and out of engagement.
Other mechanical boxes may use a small dry plate clutch to disengage the power train, ensuring the box is 'off load' to prevent damage to the gear teeth by ensuring the gearwheels are properly engaged before power is applied
Parsons and Stuart Turner boxes used a planetary gear arrangement to acheive reversing. The entire reversing mechanism would rotate as part of the forward drive train until the 'clutch' was engaged. This locked the body of the reversing train causing the power to pass through the planetary gears which rotated the shaft in the oppsite direction. I believe Albin used a similar arrangement. Stuarts had a cone clutch to acheive this, which was quite easily damaged if incorrectly adjusted, while Parsons used a brake band which clamped down on to the exterior of the reverser drum to bring it into use. Friction modifiers, like Molyslip, or synthetic oils would cause the band to slip and burn out in service on the Parsons. The way it was designed meant that if the band failed the box was trying to transmit power forward and reverse at the same time! The end result was power loss, no neutral, nasty burning smells and some mighty dodgy manoevering at close quarters!
Hydraulic boxes work on entirely different principles, but still need the right oils to function properly.
, why do boat gearboxes have clutches in them anyway?
[/ QUOTE ].
On mechanical gearboxes cone clutches are a common way of engaging the mechanisms for forward and reversing gears, also providing a convenient 'neutral' disengagment. The alternative would involve a synchromesh system similar to that on a car, which is more complex. Usually cone clutches are directly controlled by the external gear shift lever which is arranged to move the cones in and out of engagement.
Other mechanical boxes may use a small dry plate clutch to disengage the power train, ensuring the box is 'off load' to prevent damage to the gear teeth by ensuring the gearwheels are properly engaged before power is applied
Parsons and Stuart Turner boxes used a planetary gear arrangement to acheive reversing. The entire reversing mechanism would rotate as part of the forward drive train until the 'clutch' was engaged. This locked the body of the reversing train causing the power to pass through the planetary gears which rotated the shaft in the oppsite direction. I believe Albin used a similar arrangement. Stuarts had a cone clutch to acheive this, which was quite easily damaged if incorrectly adjusted, while Parsons used a brake band which clamped down on to the exterior of the reverser drum to bring it into use. Friction modifiers, like Molyslip, or synthetic oils would cause the band to slip and burn out in service on the Parsons. The way it was designed meant that if the band failed the box was trying to transmit power forward and reverse at the same time! The end result was power loss, no neutral, nasty burning smells and some mighty dodgy manoevering at close quarters!
Hydraulic boxes work on entirely different principles, but still need the right oils to function properly.
ex-Gladys
Well-Known Member
...and what does synchromesh have? clutches between the gears....
oldharry
Well-Known Member
Although I may know what happens inside - i didn't design the things, so it isnt my fault.... /forums/images/graemlins/grin.gif
G
Guest
Guest
Synchromesh ...
I was always told that this was a system where the 'cogs' were kept spinning in relation to each other so that they SYNCHRO meshed without crashing .... removing the need to double D clutch and spin up up the shafts / cogs ???
/forums/images/graemlins/confused.gif
I was always told that this was a system where the 'cogs' were kept spinning in relation to each other so that they SYNCHRO meshed without crashing .... removing the need to double D clutch and spin up up the shafts / cogs ???
/forums/images/graemlins/confused.gif