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Burning Oil
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#11
 
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Re: Burning Oil -
09-12-2009
, 12:48 AM
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On Sep 11, 8:41 pm, jim beam <m... (AT) privacy (DOT) net> wrote: here's something to consider - an old "trick of the trade" is to use some of that crappy "stop oil consumption" additive when a dealer sells a known dud car. it works fine for a while, then, once a few months have gone by and it's no longer a quick come-back, it breaks down and oil consumption rises again. I was not aware that such additives existed but I can certainly believe this is what happened and I got sold a car with a way worn engine. This may be a lesson of used car buying, even with a clean title and second owner status. Worst case I guess I may live with the oil consumption and then at some point chase down an engine to swap in. I will keep this thread updated. |
There are two types of additives to lower oil consumption. One
swells the valve seals; if you did the seal replacement right then you
can rule that out. The other kind thickens the oil to slow blow-by past
the rings. That would have been removed not long after the oil change.
You can do a simple test to see if it's worn rings: pull all the plugs
and the air filter, then run a compression test with the throttle wide
open. If you have worn rings OR valves, the compression will be low.
Then squirt about a tablespoon of higher-weight oil like SAE 80 or 90
into each cylinder and repeat the test. If the compression shoots up,
you have worn rings. It if only rises slightly or not at all it's worn
valves.
#12
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Elle wrote: On Sep 11, 8:41 pm, jim beam <m... (AT) privacy (DOT) net> wrote: here's something to consider - an old "trick of the trade" is to use some of that crappy "stop oil consumption" additive when a dealer sells a known dud car. it works fine for a while, then, once a few months have gone by and it's no longer a quick come-back, it breaks down and oil consumption rises again. I was not aware that such additives existed but I can certainly believe this is what happened and I got sold a car with a way worn engine. This may be a lesson of used car buying, even with a clean title and second owner status. Worst case I guess I may live with the oil consumption and then at some point chase down an engine to swap in. I will keep this thread updated. There are two types of additives to lower oil consumption. One swells the valve seals; if you did the seal replacement right then you can rule that out. The other kind thickens the oil to slow blow-by past the rings. That would have been removed not long after the oil change. You can do a simple test to see if it's worn rings: pull all the plugs and the air filter, then run a compression test with the throttle wide open. If you have worn rings OR valves, the compression will be low. Then squirt about a tablespoon of higher-weight oil like SAE 80 or 90 into each cylinder and repeat the test. If the compression shoots up, you have worn rings. It if only rises slightly or not at all it's worn valves. |
#13
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Leftie wrote: Elle wrote: On Sep 11, 8:41 pm, jim beam <m... (AT) privacy (DOT) net> wrote: here's something to consider - an old "trick of the trade" is to use some of that crappy "stop oil consumption" additive when a dealer sells a known dud car. it works fine for a while, then, once a few months have gone by and it's no longer a quick come-back, it breaks down and oil consumption rises again. I was not aware that such additives existed but I can certainly believe this is what happened and I got sold a car with a way worn engine. This may be a lesson of used car buying, even with a clean title and second owner status. Worst case I guess I may live with the oil consumption and then at some point chase down an engine to swap in. I will keep this thread updated. There are two types of additives to lower oil consumption. One swells the valve seals; if you did the seal replacement right then you can rule that out. The other kind thickens the oil to slow blow-by past the rings. That would have been removed not long after the oil change. You can do a simple test to see if it's worn rings: pull all the plugs and the air filter, then run a compression test with the throttle wide open. If you have worn rings OR valves, the compression will be low. Then squirt about a tablespoon of higher-weight oil like SAE 80 or 90 into each cylinder and repeat the test. If the compression shoots up, you have worn rings. It if only rises slightly or not at all it's worn valves. valves don't affect oil consumption. |
Valve seals do, however. I was assuming that worn valves would be
leaky as well, but maybe not.
#14
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jim beam wrote: Leftie wrote: Elle wrote: On Sep 11, 8:41 pm, jim beam <m... (AT) privacy (DOT) net> wrote: here's something to consider - an old "trick of the trade" is to use some of that crappy "stop oil consumption" additive when a dealer sells a known dud car. it works fine for a while, then, once a few months have gone by and it's no longer a quick come-back, it breaks down and oil consumption rises again. I was not aware that such additives existed but I can certainly believe this is what happened and I got sold a car with a way worn engine. This may be a lesson of used car buying, even with a clean title and second owner status. Worst case I guess I may live with the oil consumption and then at some point chase down an engine to swap in. I will keep this thread updated. There are two types of additives to lower oil consumption. One swells the valve seals; if you did the seal replacement right then you can rule that out. The other kind thickens the oil to slow blow-by past the rings. That would have been removed not long after the oil change. You can do a simple test to see if it's worn rings: pull all the plugs and the air filter, then run a compression test with the throttle wide open. If you have worn rings OR valves, the compression will be low. Then squirt about a tablespoon of higher-weight oil like SAE 80 or 90 into each cylinder and repeat the test. If the compression shoots up, you have worn rings. It if only rises slightly or not at all it's worn valves. valves don't affect oil consumption. Valve seals do, however. I was assuming that worn valves would be leaky as well, but maybe not. |
#15
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also, do a common-sense blow-by test on the motor. *with the engine at working temp, carefully unscrew the oil filler cap. *if the engine's breathing right, and you don't have a compression/wear problem, you'll get a bit of chuff out of the hole, [and some oil spray]. *if there's something [badly] wrong, either the cap will want to shoot out of your hand as you get close to removal, or you can feel some vacuum if you have your hand over the hole. *what you /should/ feel is a reasonable degree of positive pressure. |
hand on the fill hole, there was a pulsing positive pressure--chuffing
as you wrote--and oil spraying/slopping onto my hand.
I gather this is not conclusive but a crude test for seriously bad
compression, right? I expect to get an inexpensive compression tester
soon and see what this yields.
#16
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On Sep 11, 7:18�pm, jim beam<m... (AT) privacy (DOT) net> wrote: also, do a common-sense blow-by test on the motor. �with the engine at working temp, carefully unscrew the oil filler cap. �if the engine's breathing right, and you don't have a compression/wear problem, you'll get a bit of chuff out of the hole, [and some oil spray]. �if there's something [badly] wrong, either the cap will want to shoot out of your hand as you get close to removal, or you can feel some vacuum if you have your hand over the hole. �what you /should/ feel is a reasonable degree of positive pressure. Did this test. No shooting of the cap at all, nor any vacuum. With my hand on the fill hole, there was a pulsing positive pressure--chuffing as you wrote--and oil spraying/slopping onto my hand. |
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I gather this is not conclusive but a crude test for seriously bad compression, right? |
Quote:
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I expect to get an inexpensive compression tester soon and see what this yields. |
breather system. fingers crossed on the latter.
this is not something i've tested, just suppose, but the oil consumption
in my d15 engine has dropped substantially compared to when i first got
it and after i'd fixed the leaks. my choice of oil has meant that
pretty much all of the gunk and deposits in the engine have dissolved
compared to the state it /was/ in. if this extends to the oil control
rings, which do tend to accumulate stuff like this, maybe they're free
to seal better, and thus reduce consumption? if that's true, and it is
oil rings, maybe you should stick with this engine for a while and see
what happens as your use of mobil 1 cleans things up.
#17
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jim beam wrote: On 09/13/2009 03:39 AM, Leftie wrote: jim beam wrote: Leftie wrote: Elle wrote: On Sep 11, 8:41 pm, jim beam <m... (AT) privacy (DOT) net> wrote: here's something to consider - an old "trick of the trade" is to use some of that crappy "stop oil consumption" additive when a dealer sells a known dud car. it works fine for a while, then, once a few months have gone by and it's no longer a quick come-back, it breaks down and oil consumption rises again. I was not aware that such additives existed but I can certainly believe this is what happened and I got sold a car with a way worn engine. This may be a lesson of used car buying, even with a clean title and second owner status. Worst case I guess I may live with the oil consumption and then at some point chase down an engine to swap in. I will keep this thread updated. There are two types of additives to lower oil consumption. One swells the valve seals; if you did the seal replacement right then you can rule that out. The other kind thickens the oil to slow blow-by past the rings. That would have been removed not long after the oil change. You can do a simple test to see if it's worn rings: pull all the plugs and the air filter, then run a compression test with the throttle wide open. If you have worn rings OR valves, the compression will be low. Then squirt about a tablespoon of higher-weight oil like SAE 80 or 90 into each cylinder and repeat the test. If the compression shoots up, you have worn rings. It if only rises slightly or not at all it's worn valves. valves don't affect oil consumption. Valve seals do, however. I was assuming that worn valves would be leaky as well, but maybe not. read the thread - they've been replaced already. Read my reply again: "One swells the valve seals; if you did the seal replacement right then you can rule that out." Ah, usenet... |
read the thread!
#18
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On Sep 11, 7:18*pm, jim beam <m... (AT) privacy (DOT) net> wrote: also, do a common-sense blow-by test on the motor. *with the engine at working temp, carefully unscrew the oil filler cap. *if the engine's breathing right, and you don't have a compression/wear problem, you'll get a bit of chuff out of the hole, [and some oil spray]. *if there's something [badly] wrong, either the cap will want to shoot out of your hand as you get close to removal, or you can feel some vacuum if you have your hand over the hole. *what you /should/ feel is a reasonable degree of positive pressure. Did this test. No shooting of the cap at all, nor any vacuum. With my hand on the fill hole, there was a pulsing positive pressure--chuffing as you wrote--and oil spraying/slopping onto my hand. I gather this is not conclusive but a crude test for seriously bad compression, right? I expect to get an inexpensive compression tester soon and see what this yields. |
Air jetting from the oil filler cap tells you nothing, I'm afraid. Even a
brand-new engine, freshly broken in and at max oil life will exhibit
/considerable/ jetting from the oil filler cap. From oil filler neck
emissions alone, it's hard to tell the difference between the blowby of a
worn engine and a new one.
You need to have a garage perform wet and dry compression tests. Keep in
mind even these are only analogs for oil ring condition. It is possible to
have good oil rings and poor compression rings, and vice versa.
--
Tegger
The Unofficial Honda/Acura FAQ
www.tegger.com/hondafaq/
#19
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On 09/13/2009 03:39 AM, Leftie wrote: jim beam wrote: Leftie wrote: Elle wrote: On Sep 11, 8:41 pm, jim beam <m... (AT) privacy (DOT) net> wrote: here's something to consider - an old "trick of the trade" is to use some of that crappy "stop oil consumption" additive when a dealer sells a known dud car. it works fine for a while, then, once a few months have gone by and it's no longer a quick come-back, it breaks down and oil consumption rises again. I was not aware that such additives existed but I can certainly believe this is what happened and I got sold a car with a way worn engine. This may be a lesson of used car buying, even with a clean title and second owner status. Worst case I guess I may live with the oil consumption and then at some point chase down an engine to swap in. I will keep this thread updated. There are two types of additives to lower oil consumption. One swells the valve seals; if you did the seal replacement right then you can rule that out. The other kind thickens the oil to slow blow-by past the rings. That would have been removed not long after the oil change. You can do a simple test to see if it's worn rings: pull all the plugs and the air filter, then run a compression test with the throttle wide open. If you have worn rings OR valves, the compression will be low. Then squirt about a tablespoon of higher-weight oil like SAE 80 or 90 into each cylinder and repeat the test. If the compression shoots up, you have worn rings. It if only rises slightly or not at all it's worn valves. valves don't affect oil consumption. Valve seals do, however. I was assuming that worn valves would be leaky as well, but maybe not. read the thread - they've been replaced already. |
seal replacement right then you can rule that out." Ah, usenet...
#20
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Elle<honda.lioness (AT) gmail (DOT) com> wrote in news:630825e6-6d37-4ea9-a3e5- 0d9ec77dc3b9 (AT) e12g2000yqi (DOT) googlegroups.com: On Sep 11, 7:18�pm, jim beam<m... (AT) privacy (DOT) net> wrote: also, do a common-sense blow-by test on the motor. �with the engine at working temp, carefully unscrew the oil filler cap. �if the engine's breathing right, and you don't have a compression/wear problem, you'll get a bit of chuff out of the hole, [and some oil spray]. �if there's something [badly] wrong, either the cap will want to shoot out of your hand as you get close to removal, or you can feel some vacuum if you have your hand over the hole. �what you /should/ feel is a reasonable degree of positive pressure. Did this test. No shooting of the cap at all, nor any vacuum. With my hand on the fill hole, there was a pulsing positive pressure--chuffing as you wrote--and oil spraying/slopping onto my hand. I gather this is not conclusive but a crude test for seriously bad compression, right? I expect to get an inexpensive compression tester soon and see what this yields. Air jetting from the oil filler cap tells you nothing, I'm afraid. Even a brand-new engine, freshly broken in and at max oil life will exhibit /considerable/ jetting from the oil filler cap. From oil filler neck emissions alone, it's hard to tell the difference between the blowby of a worn engine and a new one. |
difference between worn and not worn is very much apparent from that test.
Quote:
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You need to have a garage perform wet and dry compression tests. Keep in mind even these are only analogs for oil ring condition. |
Quote:
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It is possible to have good oil rings and poor compression rings, and vice versa. |
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