How does low oil pressure indicate bad bearings?
Guest
Posts: n/a
Re: How does low oil pressure indicate bad bearings?
Oil pumps have to have resistance to build up pressure or the oil just
flows free at 0 psi.
The oil channels lead to the bearings have a 'little' restriction, but
not much. The big restriction is at the bearing faces.
The biggest bearings are on the crank so when the bearing faces get
worn, the restriction goes away and the oil flows past faster and under
lower psi.
This makes for a lower pressure reading on a gauge in the system.
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
William Oliveri wrote:
>
> Mike mentioned this in another post and it's not coming through my little
> pea brain how that works. How does worn bearings produce low oil pressure?
> What's the relation?
>
> Thanks,
>
> Billo
flows free at 0 psi.
The oil channels lead to the bearings have a 'little' restriction, but
not much. The big restriction is at the bearing faces.
The biggest bearings are on the crank so when the bearing faces get
worn, the restriction goes away and the oil flows past faster and under
lower psi.
This makes for a lower pressure reading on a gauge in the system.
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
William Oliveri wrote:
>
> Mike mentioned this in another post and it's not coming through my little
> pea brain how that works. How does worn bearings produce low oil pressure?
> What's the relation?
>
> Thanks,
>
> Billo
Guest
Posts: n/a
Re: How does low oil pressure indicate bad bearings?
Oil pumps have to have resistance to build up pressure or the oil just
flows free at 0 psi.
The oil channels lead to the bearings have a 'little' restriction, but
not much. The big restriction is at the bearing faces.
The biggest bearings are on the crank so when the bearing faces get
worn, the restriction goes away and the oil flows past faster and under
lower psi.
This makes for a lower pressure reading on a gauge in the system.
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
William Oliveri wrote:
>
> Mike mentioned this in another post and it's not coming through my little
> pea brain how that works. How does worn bearings produce low oil pressure?
> What's the relation?
>
> Thanks,
>
> Billo
flows free at 0 psi.
The oil channels lead to the bearings have a 'little' restriction, but
not much. The big restriction is at the bearing faces.
The biggest bearings are on the crank so when the bearing faces get
worn, the restriction goes away and the oil flows past faster and under
lower psi.
This makes for a lower pressure reading on a gauge in the system.
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
William Oliveri wrote:
>
> Mike mentioned this in another post and it's not coming through my little
> pea brain how that works. How does worn bearings produce low oil pressure?
> What's the relation?
>
> Thanks,
>
> Billo
Guest
Posts: n/a
Re: How does low oil pressure indicate bad bearings?
Oil pumps have to have resistance to build up pressure or the oil just
flows free at 0 psi.
The oil channels lead to the bearings have a 'little' restriction, but
not much. The big restriction is at the bearing faces.
The biggest bearings are on the crank so when the bearing faces get
worn, the restriction goes away and the oil flows past faster and under
lower psi.
This makes for a lower pressure reading on a gauge in the system.
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
William Oliveri wrote:
>
> Mike mentioned this in another post and it's not coming through my little
> pea brain how that works. How does worn bearings produce low oil pressure?
> What's the relation?
>
> Thanks,
>
> Billo
flows free at 0 psi.
The oil channels lead to the bearings have a 'little' restriction, but
not much. The big restriction is at the bearing faces.
The biggest bearings are on the crank so when the bearing faces get
worn, the restriction goes away and the oil flows past faster and under
lower psi.
This makes for a lower pressure reading on a gauge in the system.
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
William Oliveri wrote:
>
> Mike mentioned this in another post and it's not coming through my little
> pea brain how that works. How does worn bearings produce low oil pressure?
> What's the relation?
>
> Thanks,
>
> Billo
Guest
Posts: n/a
Re: How does low oil pressure indicate bad bearings?
Think of the sprinklers out in your yard.
There is probably about 10 of them connected to a single valve, and you have
perhaps 6 valves to water the front and rear lawns, and the planter boxes.
There is something like 60 psi on the system, and if there are too many
sprinkler heads on a single line, then none of the sprinklers will spray
very well because the pressure at any one head will drop relative to the
pressure there would be if there were fewer heads. If one head blows off,
then the water flow through the remaining heads will drop.
Your bearings are kinda similar. There are a number of particular sized
holes (gallies) that the oil will flow through. If a bearing wears, then the
oil pressure will drop because the amount of oil that can flow there will
increase. If the crank and bearings are in good shape, then the oil galley
is a known size. but, if the bearing or crank journal wears, then the galley
effectively becomes larger because oil can not fit in the space between the
crank and the bearing face. When this happens, there is less oil for some
location further down the line. Basically, the oil pressure is dependent
upon having specific sizes of oriffices to be pushed through, if one or more
of those oriffices can accomodate more oil that it is designed to, then the
remaining oriffices will get less oil because the amount of oil available is
fixed due to the capacity of the oil pump.
If the bearings wore a little bit, then theoritically one could install a
higher capacity pump to raise the amount of oil available. the problem with
that theory is that the worn parts will continue to wear, requiring
increasingly larger capacity pumps. At some point, the ability of the pump
to do its job would exceed the ability of the oil passages to carry oil, and
the pump would cavatate, and you would still have the worn bearings that
allowed the oil to bypass all of the other places that it ought to be going.
If you connected a fire hose to your sprinkler system that had lost a head,
the other heads might get some water, but the one that was broken would
still be broken and lots of water would be wasted. (there is a significant
difference in the oil pump and the fire hose, the pump is in a closed system
so there wouldn't be the waste, but what these have in common is that there
would be lots of oil in a place that couldn't benefit from it, and minimal
oil in a place that needs it badly.)
"William Oliveri" <wuji@bigvalley.net> wrote in message
news:c2am04$1qphp5$1@ID-193866.news.uni-berlin.de...
> Mike mentioned this in another post and it's not coming through my little
> pea brain how that works. How does worn bearings produce low oil
pressure?
> What's the relation?
>
>
> Thanks,
>
> Billo
>
>
There is probably about 10 of them connected to a single valve, and you have
perhaps 6 valves to water the front and rear lawns, and the planter boxes.
There is something like 60 psi on the system, and if there are too many
sprinkler heads on a single line, then none of the sprinklers will spray
very well because the pressure at any one head will drop relative to the
pressure there would be if there were fewer heads. If one head blows off,
then the water flow through the remaining heads will drop.
Your bearings are kinda similar. There are a number of particular sized
holes (gallies) that the oil will flow through. If a bearing wears, then the
oil pressure will drop because the amount of oil that can flow there will
increase. If the crank and bearings are in good shape, then the oil galley
is a known size. but, if the bearing or crank journal wears, then the galley
effectively becomes larger because oil can not fit in the space between the
crank and the bearing face. When this happens, there is less oil for some
location further down the line. Basically, the oil pressure is dependent
upon having specific sizes of oriffices to be pushed through, if one or more
of those oriffices can accomodate more oil that it is designed to, then the
remaining oriffices will get less oil because the amount of oil available is
fixed due to the capacity of the oil pump.
If the bearings wore a little bit, then theoritically one could install a
higher capacity pump to raise the amount of oil available. the problem with
that theory is that the worn parts will continue to wear, requiring
increasingly larger capacity pumps. At some point, the ability of the pump
to do its job would exceed the ability of the oil passages to carry oil, and
the pump would cavatate, and you would still have the worn bearings that
allowed the oil to bypass all of the other places that it ought to be going.
If you connected a fire hose to your sprinkler system that had lost a head,
the other heads might get some water, but the one that was broken would
still be broken and lots of water would be wasted. (there is a significant
difference in the oil pump and the fire hose, the pump is in a closed system
so there wouldn't be the waste, but what these have in common is that there
would be lots of oil in a place that couldn't benefit from it, and minimal
oil in a place that needs it badly.)
"William Oliveri" <wuji@bigvalley.net> wrote in message
news:c2am04$1qphp5$1@ID-193866.news.uni-berlin.de...
> Mike mentioned this in another post and it's not coming through my little
> pea brain how that works. How does worn bearings produce low oil
pressure?
> What's the relation?
>
>
> Thanks,
>
> Billo
>
>
Guest
Posts: n/a
Re: How does low oil pressure indicate bad bearings?
Think of the sprinklers out in your yard.
There is probably about 10 of them connected to a single valve, and you have
perhaps 6 valves to water the front and rear lawns, and the planter boxes.
There is something like 60 psi on the system, and if there are too many
sprinkler heads on a single line, then none of the sprinklers will spray
very well because the pressure at any one head will drop relative to the
pressure there would be if there were fewer heads. If one head blows off,
then the water flow through the remaining heads will drop.
Your bearings are kinda similar. There are a number of particular sized
holes (gallies) that the oil will flow through. If a bearing wears, then the
oil pressure will drop because the amount of oil that can flow there will
increase. If the crank and bearings are in good shape, then the oil galley
is a known size. but, if the bearing or crank journal wears, then the galley
effectively becomes larger because oil can not fit in the space between the
crank and the bearing face. When this happens, there is less oil for some
location further down the line. Basically, the oil pressure is dependent
upon having specific sizes of oriffices to be pushed through, if one or more
of those oriffices can accomodate more oil that it is designed to, then the
remaining oriffices will get less oil because the amount of oil available is
fixed due to the capacity of the oil pump.
If the bearings wore a little bit, then theoritically one could install a
higher capacity pump to raise the amount of oil available. the problem with
that theory is that the worn parts will continue to wear, requiring
increasingly larger capacity pumps. At some point, the ability of the pump
to do its job would exceed the ability of the oil passages to carry oil, and
the pump would cavatate, and you would still have the worn bearings that
allowed the oil to bypass all of the other places that it ought to be going.
If you connected a fire hose to your sprinkler system that had lost a head,
the other heads might get some water, but the one that was broken would
still be broken and lots of water would be wasted. (there is a significant
difference in the oil pump and the fire hose, the pump is in a closed system
so there wouldn't be the waste, but what these have in common is that there
would be lots of oil in a place that couldn't benefit from it, and minimal
oil in a place that needs it badly.)
"William Oliveri" <wuji@bigvalley.net> wrote in message
news:c2am04$1qphp5$1@ID-193866.news.uni-berlin.de...
> Mike mentioned this in another post and it's not coming through my little
> pea brain how that works. How does worn bearings produce low oil
pressure?
> What's the relation?
>
>
> Thanks,
>
> Billo
>
>
There is probably about 10 of them connected to a single valve, and you have
perhaps 6 valves to water the front and rear lawns, and the planter boxes.
There is something like 60 psi on the system, and if there are too many
sprinkler heads on a single line, then none of the sprinklers will spray
very well because the pressure at any one head will drop relative to the
pressure there would be if there were fewer heads. If one head blows off,
then the water flow through the remaining heads will drop.
Your bearings are kinda similar. There are a number of particular sized
holes (gallies) that the oil will flow through. If a bearing wears, then the
oil pressure will drop because the amount of oil that can flow there will
increase. If the crank and bearings are in good shape, then the oil galley
is a known size. but, if the bearing or crank journal wears, then the galley
effectively becomes larger because oil can not fit in the space between the
crank and the bearing face. When this happens, there is less oil for some
location further down the line. Basically, the oil pressure is dependent
upon having specific sizes of oriffices to be pushed through, if one or more
of those oriffices can accomodate more oil that it is designed to, then the
remaining oriffices will get less oil because the amount of oil available is
fixed due to the capacity of the oil pump.
If the bearings wore a little bit, then theoritically one could install a
higher capacity pump to raise the amount of oil available. the problem with
that theory is that the worn parts will continue to wear, requiring
increasingly larger capacity pumps. At some point, the ability of the pump
to do its job would exceed the ability of the oil passages to carry oil, and
the pump would cavatate, and you would still have the worn bearings that
allowed the oil to bypass all of the other places that it ought to be going.
If you connected a fire hose to your sprinkler system that had lost a head,
the other heads might get some water, but the one that was broken would
still be broken and lots of water would be wasted. (there is a significant
difference in the oil pump and the fire hose, the pump is in a closed system
so there wouldn't be the waste, but what these have in common is that there
would be lots of oil in a place that couldn't benefit from it, and minimal
oil in a place that needs it badly.)
"William Oliveri" <wuji@bigvalley.net> wrote in message
news:c2am04$1qphp5$1@ID-193866.news.uni-berlin.de...
> Mike mentioned this in another post and it's not coming through my little
> pea brain how that works. How does worn bearings produce low oil
pressure?
> What's the relation?
>
>
> Thanks,
>
> Billo
>
>
Guest
Posts: n/a
Re: How does low oil pressure indicate bad bearings?
Think of the sprinklers out in your yard.
There is probably about 10 of them connected to a single valve, and you have
perhaps 6 valves to water the front and rear lawns, and the planter boxes.
There is something like 60 psi on the system, and if there are too many
sprinkler heads on a single line, then none of the sprinklers will spray
very well because the pressure at any one head will drop relative to the
pressure there would be if there were fewer heads. If one head blows off,
then the water flow through the remaining heads will drop.
Your bearings are kinda similar. There are a number of particular sized
holes (gallies) that the oil will flow through. If a bearing wears, then the
oil pressure will drop because the amount of oil that can flow there will
increase. If the crank and bearings are in good shape, then the oil galley
is a known size. but, if the bearing or crank journal wears, then the galley
effectively becomes larger because oil can not fit in the space between the
crank and the bearing face. When this happens, there is less oil for some
location further down the line. Basically, the oil pressure is dependent
upon having specific sizes of oriffices to be pushed through, if one or more
of those oriffices can accomodate more oil that it is designed to, then the
remaining oriffices will get less oil because the amount of oil available is
fixed due to the capacity of the oil pump.
If the bearings wore a little bit, then theoritically one could install a
higher capacity pump to raise the amount of oil available. the problem with
that theory is that the worn parts will continue to wear, requiring
increasingly larger capacity pumps. At some point, the ability of the pump
to do its job would exceed the ability of the oil passages to carry oil, and
the pump would cavatate, and you would still have the worn bearings that
allowed the oil to bypass all of the other places that it ought to be going.
If you connected a fire hose to your sprinkler system that had lost a head,
the other heads might get some water, but the one that was broken would
still be broken and lots of water would be wasted. (there is a significant
difference in the oil pump and the fire hose, the pump is in a closed system
so there wouldn't be the waste, but what these have in common is that there
would be lots of oil in a place that couldn't benefit from it, and minimal
oil in a place that needs it badly.)
"William Oliveri" <wuji@bigvalley.net> wrote in message
news:c2am04$1qphp5$1@ID-193866.news.uni-berlin.de...
> Mike mentioned this in another post and it's not coming through my little
> pea brain how that works. How does worn bearings produce low oil
pressure?
> What's the relation?
>
>
> Thanks,
>
> Billo
>
>
There is probably about 10 of them connected to a single valve, and you have
perhaps 6 valves to water the front and rear lawns, and the planter boxes.
There is something like 60 psi on the system, and if there are too many
sprinkler heads on a single line, then none of the sprinklers will spray
very well because the pressure at any one head will drop relative to the
pressure there would be if there were fewer heads. If one head blows off,
then the water flow through the remaining heads will drop.
Your bearings are kinda similar. There are a number of particular sized
holes (gallies) that the oil will flow through. If a bearing wears, then the
oil pressure will drop because the amount of oil that can flow there will
increase. If the crank and bearings are in good shape, then the oil galley
is a known size. but, if the bearing or crank journal wears, then the galley
effectively becomes larger because oil can not fit in the space between the
crank and the bearing face. When this happens, there is less oil for some
location further down the line. Basically, the oil pressure is dependent
upon having specific sizes of oriffices to be pushed through, if one or more
of those oriffices can accomodate more oil that it is designed to, then the
remaining oriffices will get less oil because the amount of oil available is
fixed due to the capacity of the oil pump.
If the bearings wore a little bit, then theoritically one could install a
higher capacity pump to raise the amount of oil available. the problem with
that theory is that the worn parts will continue to wear, requiring
increasingly larger capacity pumps. At some point, the ability of the pump
to do its job would exceed the ability of the oil passages to carry oil, and
the pump would cavatate, and you would still have the worn bearings that
allowed the oil to bypass all of the other places that it ought to be going.
If you connected a fire hose to your sprinkler system that had lost a head,
the other heads might get some water, but the one that was broken would
still be broken and lots of water would be wasted. (there is a significant
difference in the oil pump and the fire hose, the pump is in a closed system
so there wouldn't be the waste, but what these have in common is that there
would be lots of oil in a place that couldn't benefit from it, and minimal
oil in a place that needs it badly.)
"William Oliveri" <wuji@bigvalley.net> wrote in message
news:c2am04$1qphp5$1@ID-193866.news.uni-berlin.de...
> Mike mentioned this in another post and it's not coming through my little
> pea brain how that works. How does worn bearings produce low oil
pressure?
> What's the relation?
>
>
> Thanks,
>
> Billo
>
>
Guest
Posts: n/a
Re: How does low oil pressure indicate bad bearings?
So, in my 98 TJ, my oil pressure at idle is pretty low compared to
what it used to be (I think). It seems to be down around 30psi at
idle, but at speed it is up around 50 or so. Is this the type of
indicator we are talking about for worn crank bearings, assuming of
course my pump and pressure sending unit are good. It only has 66k
miles on it (around there, would have to double check.)
--
--
Joe Pribe
NC
jpribe 'at' nc.rr.com <you know the drill
jegp 'at' hotmail.com < at is really @
---- I Love My O|||||||O TJ
"CRWLR" <beerman@yahoo.com> wrote in message
news:104hrntpkjur30b@corp.supernews.com...
| Think of the sprinklers out in your yard.
|
| There is probably about 10 of them connected to a single valve, and
you have
| perhaps 6 valves to water the front and rear lawns, and the planter
boxes.
| There is something like 60 psi on the system, and if there are too
many
| sprinkler heads on a single line, then none of the sprinklers will
spray
| very well because the pressure at any one head will drop relative to
the
| pressure there would be if there were fewer heads. If one head blows
off,
| then the water flow through the remaining heads will drop.
|
| Your bearings are kinda similar. There are a number of particular
sized
| holes (gallies) that the oil will flow through. If a bearing wears,
then the
| oil pressure will drop because the amount of oil that can flow there
will
| increase. If the crank and bearings are in good shape, then the oil
galley
| is a known size. but, if the bearing or crank journal wears, then
the galley
| effectively becomes larger because oil can not fit in the space
between the
| crank and the bearing face. When this happens, there is less oil for
some
| location further down the line. Basically, the oil pressure is
dependent
| upon having specific sizes of oriffices to be pushed through, if one
or more
| of those oriffices can accomodate more oil that it is designed to,
then the
| remaining oriffices will get less oil because the amount of oil
available is
| fixed due to the capacity of the oil pump.
|
| If the bearings wore a little bit, then theoritically one could
install a
| higher capacity pump to raise the amount of oil available. the
problem with
| that theory is that the worn parts will continue to wear, requiring
| increasingly larger capacity pumps. At some point, the ability of
the pump
| to do its job would exceed the ability of the oil passages to carry
oil, and
| the pump would cavatate, and you would still have the worn bearings
that
| allowed the oil to bypass all of the other places that it ought to
be going.
| If you connected a fire hose to your sprinkler system that had lost
a head,
| the other heads might get some water, but the one that was broken
would
| still be broken and lots of water would be wasted. (there is a
significant
| difference in the oil pump and the fire hose, the pump is in a
closed system
| so there wouldn't be the waste, but what these have in common is
that there
| would be lots of oil in a place that couldn't benefit from it, and
minimal
| oil in a place that needs it badly.)
|
|
|
|
|
| "William Oliveri" <wuji@bigvalley.net> wrote in message
| news:c2am04$1qphp5$1@ID-193866.news.uni-berlin.de...
| > Mike mentioned this in another post and it's not coming through my
little
| > pea brain how that works. How does worn bearings produce low oil
| pressure?
| > What's the relation?
| >
| >
| > Thanks,
| >
| > Billo
| >
| >
|
what it used to be (I think). It seems to be down around 30psi at
idle, but at speed it is up around 50 or so. Is this the type of
indicator we are talking about for worn crank bearings, assuming of
course my pump and pressure sending unit are good. It only has 66k
miles on it (around there, would have to double check.)
--
--
Joe Pribe
NC
jpribe 'at' nc.rr.com <you know the drill
jegp 'at' hotmail.com < at is really @
---- I Love My O|||||||O TJ
"CRWLR" <beerman@yahoo.com> wrote in message
news:104hrntpkjur30b@corp.supernews.com...
| Think of the sprinklers out in your yard.
|
| There is probably about 10 of them connected to a single valve, and
you have
| perhaps 6 valves to water the front and rear lawns, and the planter
boxes.
| There is something like 60 psi on the system, and if there are too
many
| sprinkler heads on a single line, then none of the sprinklers will
spray
| very well because the pressure at any one head will drop relative to
the
| pressure there would be if there were fewer heads. If one head blows
off,
| then the water flow through the remaining heads will drop.
|
| Your bearings are kinda similar. There are a number of particular
sized
| holes (gallies) that the oil will flow through. If a bearing wears,
then the
| oil pressure will drop because the amount of oil that can flow there
will
| increase. If the crank and bearings are in good shape, then the oil
galley
| is a known size. but, if the bearing or crank journal wears, then
the galley
| effectively becomes larger because oil can not fit in the space
between the
| crank and the bearing face. When this happens, there is less oil for
some
| location further down the line. Basically, the oil pressure is
dependent
| upon having specific sizes of oriffices to be pushed through, if one
or more
| of those oriffices can accomodate more oil that it is designed to,
then the
| remaining oriffices will get less oil because the amount of oil
available is
| fixed due to the capacity of the oil pump.
|
| If the bearings wore a little bit, then theoritically one could
install a
| higher capacity pump to raise the amount of oil available. the
problem with
| that theory is that the worn parts will continue to wear, requiring
| increasingly larger capacity pumps. At some point, the ability of
the pump
| to do its job would exceed the ability of the oil passages to carry
oil, and
| the pump would cavatate, and you would still have the worn bearings
that
| allowed the oil to bypass all of the other places that it ought to
be going.
| If you connected a fire hose to your sprinkler system that had lost
a head,
| the other heads might get some water, but the one that was broken
would
| still be broken and lots of water would be wasted. (there is a
significant
| difference in the oil pump and the fire hose, the pump is in a
closed system
| so there wouldn't be the waste, but what these have in common is
that there
| would be lots of oil in a place that couldn't benefit from it, and
minimal
| oil in a place that needs it badly.)
|
|
|
|
|
| "William Oliveri" <wuji@bigvalley.net> wrote in message
| news:c2am04$1qphp5$1@ID-193866.news.uni-berlin.de...
| > Mike mentioned this in another post and it's not coming through my
little
| > pea brain how that works. How does worn bearings produce low oil
| pressure?
| > What's the relation?
| >
| >
| > Thanks,
| >
| > Billo
| >
| >
|
Guest
Posts: n/a
Re: How does low oil pressure indicate bad bearings?
So, in my 98 TJ, my oil pressure at idle is pretty low compared to
what it used to be (I think). It seems to be down around 30psi at
idle, but at speed it is up around 50 or so. Is this the type of
indicator we are talking about for worn crank bearings, assuming of
course my pump and pressure sending unit are good. It only has 66k
miles on it (around there, would have to double check.)
--
--
Joe Pribe
NC
jpribe 'at' nc.rr.com <you know the drill
jegp 'at' hotmail.com < at is really @
---- I Love My O|||||||O TJ
"CRWLR" <beerman@yahoo.com> wrote in message
news:104hrntpkjur30b@corp.supernews.com...
| Think of the sprinklers out in your yard.
|
| There is probably about 10 of them connected to a single valve, and
you have
| perhaps 6 valves to water the front and rear lawns, and the planter
boxes.
| There is something like 60 psi on the system, and if there are too
many
| sprinkler heads on a single line, then none of the sprinklers will
spray
| very well because the pressure at any one head will drop relative to
the
| pressure there would be if there were fewer heads. If one head blows
off,
| then the water flow through the remaining heads will drop.
|
| Your bearings are kinda similar. There are a number of particular
sized
| holes (gallies) that the oil will flow through. If a bearing wears,
then the
| oil pressure will drop because the amount of oil that can flow there
will
| increase. If the crank and bearings are in good shape, then the oil
galley
| is a known size. but, if the bearing or crank journal wears, then
the galley
| effectively becomes larger because oil can not fit in the space
between the
| crank and the bearing face. When this happens, there is less oil for
some
| location further down the line. Basically, the oil pressure is
dependent
| upon having specific sizes of oriffices to be pushed through, if one
or more
| of those oriffices can accomodate more oil that it is designed to,
then the
| remaining oriffices will get less oil because the amount of oil
available is
| fixed due to the capacity of the oil pump.
|
| If the bearings wore a little bit, then theoritically one could
install a
| higher capacity pump to raise the amount of oil available. the
problem with
| that theory is that the worn parts will continue to wear, requiring
| increasingly larger capacity pumps. At some point, the ability of
the pump
| to do its job would exceed the ability of the oil passages to carry
oil, and
| the pump would cavatate, and you would still have the worn bearings
that
| allowed the oil to bypass all of the other places that it ought to
be going.
| If you connected a fire hose to your sprinkler system that had lost
a head,
| the other heads might get some water, but the one that was broken
would
| still be broken and lots of water would be wasted. (there is a
significant
| difference in the oil pump and the fire hose, the pump is in a
closed system
| so there wouldn't be the waste, but what these have in common is
that there
| would be lots of oil in a place that couldn't benefit from it, and
minimal
| oil in a place that needs it badly.)
|
|
|
|
|
| "William Oliveri" <wuji@bigvalley.net> wrote in message
| news:c2am04$1qphp5$1@ID-193866.news.uni-berlin.de...
| > Mike mentioned this in another post and it's not coming through my
little
| > pea brain how that works. How does worn bearings produce low oil
| pressure?
| > What's the relation?
| >
| >
| > Thanks,
| >
| > Billo
| >
| >
|
what it used to be (I think). It seems to be down around 30psi at
idle, but at speed it is up around 50 or so. Is this the type of
indicator we are talking about for worn crank bearings, assuming of
course my pump and pressure sending unit are good. It only has 66k
miles on it (around there, would have to double check.)
--
--
Joe Pribe
NC
jpribe 'at' nc.rr.com <you know the drill
jegp 'at' hotmail.com < at is really @
---- I Love My O|||||||O TJ
"CRWLR" <beerman@yahoo.com> wrote in message
news:104hrntpkjur30b@corp.supernews.com...
| Think of the sprinklers out in your yard.
|
| There is probably about 10 of them connected to a single valve, and
you have
| perhaps 6 valves to water the front and rear lawns, and the planter
boxes.
| There is something like 60 psi on the system, and if there are too
many
| sprinkler heads on a single line, then none of the sprinklers will
spray
| very well because the pressure at any one head will drop relative to
the
| pressure there would be if there were fewer heads. If one head blows
off,
| then the water flow through the remaining heads will drop.
|
| Your bearings are kinda similar. There are a number of particular
sized
| holes (gallies) that the oil will flow through. If a bearing wears,
then the
| oil pressure will drop because the amount of oil that can flow there
will
| increase. If the crank and bearings are in good shape, then the oil
galley
| is a known size. but, if the bearing or crank journal wears, then
the galley
| effectively becomes larger because oil can not fit in the space
between the
| crank and the bearing face. When this happens, there is less oil for
some
| location further down the line. Basically, the oil pressure is
dependent
| upon having specific sizes of oriffices to be pushed through, if one
or more
| of those oriffices can accomodate more oil that it is designed to,
then the
| remaining oriffices will get less oil because the amount of oil
available is
| fixed due to the capacity of the oil pump.
|
| If the bearings wore a little bit, then theoritically one could
install a
| higher capacity pump to raise the amount of oil available. the
problem with
| that theory is that the worn parts will continue to wear, requiring
| increasingly larger capacity pumps. At some point, the ability of
the pump
| to do its job would exceed the ability of the oil passages to carry
oil, and
| the pump would cavatate, and you would still have the worn bearings
that
| allowed the oil to bypass all of the other places that it ought to
be going.
| If you connected a fire hose to your sprinkler system that had lost
a head,
| the other heads might get some water, but the one that was broken
would
| still be broken and lots of water would be wasted. (there is a
significant
| difference in the oil pump and the fire hose, the pump is in a
closed system
| so there wouldn't be the waste, but what these have in common is
that there
| would be lots of oil in a place that couldn't benefit from it, and
minimal
| oil in a place that needs it badly.)
|
|
|
|
|
| "William Oliveri" <wuji@bigvalley.net> wrote in message
| news:c2am04$1qphp5$1@ID-193866.news.uni-berlin.de...
| > Mike mentioned this in another post and it's not coming through my
little
| > pea brain how that works. How does worn bearings produce low oil
| pressure?
| > What's the relation?
| >
| >
| > Thanks,
| >
| > Billo
| >
| >
|
Guest
Posts: n/a
Re: How does low oil pressure indicate bad bearings?
So, in my 98 TJ, my oil pressure at idle is pretty low compared to
what it used to be (I think). It seems to be down around 30psi at
idle, but at speed it is up around 50 or so. Is this the type of
indicator we are talking about for worn crank bearings, assuming of
course my pump and pressure sending unit are good. It only has 66k
miles on it (around there, would have to double check.)
--
--
Joe Pribe
NC
jpribe 'at' nc.rr.com <you know the drill
jegp 'at' hotmail.com < at is really @
---- I Love My O|||||||O TJ
"CRWLR" <beerman@yahoo.com> wrote in message
news:104hrntpkjur30b@corp.supernews.com...
| Think of the sprinklers out in your yard.
|
| There is probably about 10 of them connected to a single valve, and
you have
| perhaps 6 valves to water the front and rear lawns, and the planter
boxes.
| There is something like 60 psi on the system, and if there are too
many
| sprinkler heads on a single line, then none of the sprinklers will
spray
| very well because the pressure at any one head will drop relative to
the
| pressure there would be if there were fewer heads. If one head blows
off,
| then the water flow through the remaining heads will drop.
|
| Your bearings are kinda similar. There are a number of particular
sized
| holes (gallies) that the oil will flow through. If a bearing wears,
then the
| oil pressure will drop because the amount of oil that can flow there
will
| increase. If the crank and bearings are in good shape, then the oil
galley
| is a known size. but, if the bearing or crank journal wears, then
the galley
| effectively becomes larger because oil can not fit in the space
between the
| crank and the bearing face. When this happens, there is less oil for
some
| location further down the line. Basically, the oil pressure is
dependent
| upon having specific sizes of oriffices to be pushed through, if one
or more
| of those oriffices can accomodate more oil that it is designed to,
then the
| remaining oriffices will get less oil because the amount of oil
available is
| fixed due to the capacity of the oil pump.
|
| If the bearings wore a little bit, then theoritically one could
install a
| higher capacity pump to raise the amount of oil available. the
problem with
| that theory is that the worn parts will continue to wear, requiring
| increasingly larger capacity pumps. At some point, the ability of
the pump
| to do its job would exceed the ability of the oil passages to carry
oil, and
| the pump would cavatate, and you would still have the worn bearings
that
| allowed the oil to bypass all of the other places that it ought to
be going.
| If you connected a fire hose to your sprinkler system that had lost
a head,
| the other heads might get some water, but the one that was broken
would
| still be broken and lots of water would be wasted. (there is a
significant
| difference in the oil pump and the fire hose, the pump is in a
closed system
| so there wouldn't be the waste, but what these have in common is
that there
| would be lots of oil in a place that couldn't benefit from it, and
minimal
| oil in a place that needs it badly.)
|
|
|
|
|
| "William Oliveri" <wuji@bigvalley.net> wrote in message
| news:c2am04$1qphp5$1@ID-193866.news.uni-berlin.de...
| > Mike mentioned this in another post and it's not coming through my
little
| > pea brain how that works. How does worn bearings produce low oil
| pressure?
| > What's the relation?
| >
| >
| > Thanks,
| >
| > Billo
| >
| >
|
what it used to be (I think). It seems to be down around 30psi at
idle, but at speed it is up around 50 or so. Is this the type of
indicator we are talking about for worn crank bearings, assuming of
course my pump and pressure sending unit are good. It only has 66k
miles on it (around there, would have to double check.)
--
--
Joe Pribe
NC
jpribe 'at' nc.rr.com <you know the drill
jegp 'at' hotmail.com < at is really @
---- I Love My O|||||||O TJ
"CRWLR" <beerman@yahoo.com> wrote in message
news:104hrntpkjur30b@corp.supernews.com...
| Think of the sprinklers out in your yard.
|
| There is probably about 10 of them connected to a single valve, and
you have
| perhaps 6 valves to water the front and rear lawns, and the planter
boxes.
| There is something like 60 psi on the system, and if there are too
many
| sprinkler heads on a single line, then none of the sprinklers will
spray
| very well because the pressure at any one head will drop relative to
the
| pressure there would be if there were fewer heads. If one head blows
off,
| then the water flow through the remaining heads will drop.
|
| Your bearings are kinda similar. There are a number of particular
sized
| holes (gallies) that the oil will flow through. If a bearing wears,
then the
| oil pressure will drop because the amount of oil that can flow there
will
| increase. If the crank and bearings are in good shape, then the oil
galley
| is a known size. but, if the bearing or crank journal wears, then
the galley
| effectively becomes larger because oil can not fit in the space
between the
| crank and the bearing face. When this happens, there is less oil for
some
| location further down the line. Basically, the oil pressure is
dependent
| upon having specific sizes of oriffices to be pushed through, if one
or more
| of those oriffices can accomodate more oil that it is designed to,
then the
| remaining oriffices will get less oil because the amount of oil
available is
| fixed due to the capacity of the oil pump.
|
| If the bearings wore a little bit, then theoritically one could
install a
| higher capacity pump to raise the amount of oil available. the
problem with
| that theory is that the worn parts will continue to wear, requiring
| increasingly larger capacity pumps. At some point, the ability of
the pump
| to do its job would exceed the ability of the oil passages to carry
oil, and
| the pump would cavatate, and you would still have the worn bearings
that
| allowed the oil to bypass all of the other places that it ought to
be going.
| If you connected a fire hose to your sprinkler system that had lost
a head,
| the other heads might get some water, but the one that was broken
would
| still be broken and lots of water would be wasted. (there is a
significant
| difference in the oil pump and the fire hose, the pump is in a
closed system
| so there wouldn't be the waste, but what these have in common is
that there
| would be lots of oil in a place that couldn't benefit from it, and
minimal
| oil in a place that needs it badly.)
|
|
|
|
|
| "William Oliveri" <wuji@bigvalley.net> wrote in message
| news:c2am04$1qphp5$1@ID-193866.news.uni-berlin.de...
| > Mike mentioned this in another post and it's not coming through my
little
| > pea brain how that works. How does worn bearings produce low oil
| pressure?
| > What's the relation?
| >
| >
| > Thanks,
| >
| > Billo
| >
| >
|