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Hey guys, my motor is using a quart of oil every 100 miles..
I ran a compression test and all cylinders read 130-135psi dry..wet they ran 150-155psi..
i changed out the pcv and hose..
adjusted all valves..
there is no oil in the breather cap or air filter..
No oil is dripping on the floor...
Valves seals?
I've always heard as a rule of thumb:
If it smokes on startup then not too bad - bad valve guides.
Smokes pretty much continuously - bad rings or scored cylinder/s.
Because of decent pressure, my guess is there is a scored cylinder/s.
Bert
valve seals is about all it could be, i didnt think valve seals would use that much oil though. if the motor is in as good a shape as you just described, it shouldnt be using that much oil. you sure its not a qt. every 1000 miles which wouldnt be bad. :confused:Quote:
Originally posted by bgrd
Hey guys, my motor is using a quart of oil every 100 miles..
I ran a compression test and all cylinders read 130-135psi dry..wet they ran 150-155psi..
i changed out the pcv and hose..
adjusted all valves..
there is no oil in the breather cap or air filter..
No oil is dripping on the floor...
Valves seals?
thanks for the info guys...
no it was quart for 100 miles...
smoking continuously, but not real heavy
all plugs were black and oily, after only 100 miles, number 2, and 8 cylinder had some carbon build up on the plugs
if the rings or a cylinder was bad it would show up in the wet, dry check or blow by out of the breather. 2 and 8 are on the same intake runner so id be looking at that a little closer if the pcv valve is running off of them. **) **)Quote:
Originally posted by bgrd
thanks for the info guys...
no it was quart for 100 miles...
smoking continuously, but not real heavy
all plugs were black and oily, after only 100 miles, number 2, and 8 cylinder had some carbon build up on the plugs
Quote:
Originally posted by lt1s10
if the rings or a cylinder was bad it would show up in the wet, dry check or blow by out of the breather. 2 and 8 are on the same intake runner so id be looking at that a little closer if the pcv valve is running off of them. **) **)
looks like the vac. is sucking the oil into the motor passed the intake gasket or pvc valve.
lt1s10, if it is a vacuum problem, how do i correct?
and may i add, it runs awesome...
Might be a warped intake manifold lettiing the oil out throught the valley. Do you have dual exhaust and if so is the smoke coming from both pipes on start up when engine is cold and then lets up when engine warms up?
Had any work been done to the motor prior to this happening??
Did it happen over time,,,or all of a sudden??
Thunderbucket Had any work been done to the motor prior to this happening??
Did it happen over time,,,or all of a sudden??
Just gradually over the last 45 days or 300 miles
chevy 37 Might be a warped intake manifold lettiing the oil out throught the valley. Do you have dual exhaust and if so is the smoke coming from both pipes on start up when engine is cold and then lets up when engine warms up?
No sir, starts smoking right from the start, smokes about the same even after it's warmed up...
take the pcv valve out of the valve cover and let it run and see if it stops. if it dont clear up in about 5 min. thats not what it is. you can pull the valve cover and see if the drain holes are stoped up also. it shoulnt be the rings they check to good. :cool:Quote:
Originally posted by bgrd
lt1s10, if it is a vacuum problem, how do i correct?
You said in the last 45 day's 300 miles,,,,,,i also asked if any work had been done to the motor,,,,,may have a direct relationship to the smoking problem.
As it is,,,valve seals and guides usualy show signs of wear gradualy,,,,you would have noticed oil usage before this point if that were the case,,,so i dont think it's valve seal's,,,,,how about a missed shift??
Has the motor been revved to high,,,even for a second,,,before it started smoking??
If not,,,,you can start looking at crankcase ventilation,,,and bypassed vaccume at the intake manifold ( difficult to check ) but usualy manifold problems occur after overheating,,,or gasket replacement.
Quote:
Originally posted by bgrd
Thunderbucket Had any work been done to the motor prior to this happening??
Did it happen over time,,,or all of a sudden??
Just gradually over the last 45 days or 300 miles
chevy 37 Might be a warped intake manifold lettiing the oil out throught the valley. Do you have dual exhaust and if so is the smoke coming from both pipes on start up when engine is cold and then lets up when engine warms up?
No sir, starts smoking right from the start, smokes about the same even after it's warmed up...
lt1s10, i will check the pcv valve when i get home this evening, Thanks
Thunderbucket You said in the last 45 day's 300 miles,,,,,,i also asked if any work had been done to the motor,,,,,may have a direct relationship to the smoking problem.
As it is,,,valve seals and guides usualy show signs of wear gradualy,,,,you would have noticed oil usage before this point if that were the case,,,so i dont think it's valve seal's,,,,,how about a missed shift??
Has the motor been revved to high,,,even for a second,,,before it started smoking??
If not,,,,you can start looking at crankcase ventilation,,,and bypassed vaccume at the intake manifold ( difficult to check ) but usualy manifold problems occur after overheating,,,or gasket replacement.
yes, i over revved twice in the last 30 days, missed second gear... hmmmmm
you should have elimated any thing there with the compression check.Quote:
Originally posted by bgrd
lt1s10, i will check the pcv valve when i get home this evening, Thanks
Thunderbucket You said in the last 45 day's 300 miles,,,,,,i also asked if any work had been done to the motor,,,,,may have a direct relationship to the smoking problem.
As it is,,,valve seals and guides usualy show signs of wear gradualy,,,,you would have noticed oil usage before this point if that were the case,,,so i dont think it's valve seal's,,,,,how about a missed shift??
Has the motor been revved to high,,,even for a second,,,before it started smoking??
If not,,,,you can start looking at crankcase ventilation,,,and bypassed vaccume at the intake manifold ( difficult to check ) but usualy manifold problems occur after overheating,,,or gasket replacement.
yes, i over revved twice in the last 30 days, missed second gear... hmmmmm
lt1s10 quote:
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Originally posted by bgrd
lt1s10, if it is a vacuum problem, how do i correct?
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take the pcv valve out of the valve cover and let it run and see if it stops. if it dont clear up in about 5 min. thats not what it is. you can pull the valve cover and see if the drain holes are stoped up also. it shoulnt be the rings they check to good.
it1s10, no change when i took the pcv valve out...
also, pulled the covers again, drain holes were clear...
guess i might have to pull the heads...
Quote:
Originally posted by bgrd
lt1s10 quote:
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Originally posted by bgrd
lt1s10, if it is a vacuum problem, how do i correct?
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take the pcv valve out of the valve cover and let it run and see if it stops. if it dont clear up in about 5 min. thats not what it is. you can pull the valve cover and see if the drain holes are stoped up also. it shoulnt be the rings they check to good.
it1s10, no change when i took the pcv valve out...
also, pulled the covers again, drain holes were clear...
guess i might have to pull the heads...
I ran a compression test and all cylinders read 130-135psi dry..wet they ran 150-155psi..
i dont see how it could be the rings, the valve guides must be totally worn out. a qt. of oil every 100 miles is a lot of oil. :confused:
if the intake was sucking oil from the bottom side then i dought if it would idle good.
lt1s10, that's what so puzzling... it idles fine and runs good...
it just uses way too much oil and smokes
I dont know if the lt1 uses o-ring or umbrella seals but it sounds to me that the valve seals are shot, does it smoke at an idle as well as at high rpm? Typically smoking at an idle would indicate an oil ring problem regardless of compression. If it is valve seals the smoke would be much more pronounced at a higher rpm due to flooding of the head galley.
i dont know you never said how many miles it had and if you cant find anything else i guess it pull down time. :CRY:Quote:
Originally posted by bgrd
lt1s10, that's what so puzzling... it idles fine and runs good...
it just uses way too much oil and smokes
lt1s10 quote:
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Originally posted by bgrd
lt1s10, that's what so puzzling... it idles fine and runs good...
it just uses way too much oil and smokes
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i dont know you never said how many miles it had and if you cant find anything else i guess it pull down time.
It1s10, the motor is in a 63 nova i bought a few months back, the guy who is fairly reputable (sp) said there was about 1,500 miles on the motor, the internals of the engine are clean as a whistle...
Plumb-evil 514 I dont know if the lt1 uses o-ring or umbrella seals but it sounds to me that the valve seals are shot, does it smoke at an idle as well as at high rpm? Typically smoking at an idle would indicate an oil ring problem regardless of compression. If it is valve seals the smoke would be much more pronounced at a higher rpm due to flooding of the head galley.
Plumb, it does smoke lightly at idle, but a lot more at higher revs...
Quote:
Originally posted by bgrd
lt1s10 quote:
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Originally posted by bgrd
lt1s10, that's what so puzzling... it idles fine and runs good...
it just uses way too much oil and smokes
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i dont know you never said how many miles it had and if you cant find anything else i guess it pull down time.
It1s10, the motor is in a 63 nova i bought a few months back, the guy who is fairly reputable (sp) said there was about 1,500 miles on the motor, the internals of the engine are clean as a whistle...
Plumb-evil 514 I dont know if the lt1 uses o-ring or umbrella seals but it sounds to me that the valve seals are shot, does it smoke at an idle as well as at high rpm? Typically smoking at an idle would indicate an oil ring problem regardless of compression. If it is valve seals the smoke would be much more pronounced at a higher rpm due to flooding of the head galley.
Plumb, it does smoke lightly at idle, but a lot more at higher revs...
well that's where me and plumb disagree. I never seen a motor with that kind of compression smoke no way. if the compression rings is that good I don't see how the oil is getting pass then. most of the time a motor using that much oil it should be blowing oil everywhere. I still think the vac. is sucking the oil through the intake somehow. all the oil ring do is scrape the oil off of the cylinder wall. most of the time when a motor use a lot of oil its blow by that blows it out of the motor and on the late model the pcv valve picks up the blow by and sends it into the intake and re burn it. the motor sounds like its to solid to be using that much oil, but you got to start some where. if its not a vac. problem then the only choice you got it to put new valves seals or new rings or both. its your call. :whacked: **)
how much oil are you putting in the cylinder when you are doing your wet test? if you use to much it can give you a false reading.
how much oil are you putting in the cylinder when you are doing your wet test? if you use to much it can give you a false reading.
lt1s10, i used 4 squirts of the oil can or about a teaspoon a cylinder... sure hate too tear it down because it runs so good...
oh well, guess i will start with the heads and go from there... Gentleman, I appreciate all of your input... Anybody know a good machinst around Waco or Austin Texas?
Another suggestion (easy to find, easy to fix):
A long time ago, a fellow (me) built a 350. Being hot outside, I kept myself lubricated during the assembly. Not being able to think clearly, I used RTV on the intake gaskets. Truck ran great. Started using oil in large quantities soon after. Ran compression check, everything was fine. Pulled PCV, no smoke. Did notice that if I plugged the line going to the carb, there was suction on pcv line.......took manifold off and saw that gasket had slipped on bottom of ports (several) so that engine was sucking oil from the valley. Put new gasket in, threw RTV in dumpster, bought more lubrication. Lived happily ever after. RTV is easy to spot.
mike
robot, very interesting, i will check the intake gaskets once i get the manifold off.. Thanks
JUST KIDDING!!!!
I am no engine building expert by any means with regards to autos, but have rebuilt many many single cylinder motorcycle engines.
Reason I say this is becuase on may occasions compression will be up to spec., if not even higher on an engine that needs a rebuild. This was especially apprarnet on big bore 600cc single cylinder 4 strokes. The rings would be shot, and the top of the piston would look like it was shot with a bb gun 100 times. The top front and rear of the piston at the intake and exhaust post would present as if they were taken to a stone grinding wheel; and the compression would still be up to spec.
IMO you can definately have tired cylinders and rings and still show adequate compression. Just my .02
auto. motors dont work that way. **)Quote:
Originally posted by 30-A Rider
I am no engine building expert by any means with regards to autos, but have rebuilt many many single cylinder motorcycle engines.
Reason I say this is becuase on may occasions compression will be up to spec., if not even higher on an engine that needs a rebuild. This was especially apprarnet on big bore 600cc single cylinder 4 strokes. The rings would be shot, and the top of the piston would look like it was shot with a bb gun 100 times. The top front and rear of the piston at the intake and exhaust post would present as if they were taken to a stone grinding wheel; and the compression would still be up to spec.
IMO you can definately have tired cylinders and rings and still show adequate compression. Just my .02
If you think the intake gasket is the problem, a quick wat to check it is to plug the breather and pcv ports in your valve covers. Remove the dipstick, place a vacuum gauge on the tube, and run it. You sould see pressure, not vacuum.
Could someone post a link to a chart ,which has all the torque specs. for a 350 sbc... TIA
Quote:
Originally posted by bgrd
Could someone post a link to a chart ,which has all the torque specs. for a 350 sbc... TIA
is this what you need?
http://www.hotrodshack.com/torque_settings.htm
:cool:
Quote:
Originally posted by tpiini
Maybe I'm the dummy here, so feel free to ignore me. But wouldn't a 20-point difference in wet & dry compression tests tell you that your rings are exactly the problem?
these # are high but the the dif. from dry and wet is ok.
Ready to Test Compression
Connect a compression gauge to the engine—Screw the compression gauge fitting into the spark plug hole. You don't have to worry about torque here. As long as the rubber O-ring on the compression gauge gets compressed, you'll get accurate readings. See photo at right.
Crank the engine over five or six times—And...
Note the readings on the gauge—If you're doing the test by yourself, that's the best you can do. Crank the engine five or six times and read the gauge. If you have a helper, though, have him (or her) crank the engine while you watch the gauge. It's best if you can see what the compression reading is on each turn of the engine, to get an idea of how quickly it comes up to its maximum reading. Then...
Repeat for the other four cylinders—This will give you a set of measurements of your engine's ability to compress the air/fuel mixture.
What's It Mean?
The compression specifications for a Vigor engine are...
...at 250 rpm (cranking speed) and wide open throttle (that's why we blocked the throttle plate open) ...
206 psi (nominal)
135 psi (minimum)
28 psi (maximum variation)
Note: All pressure values in this article are given in pounds per square inch. That's because the author is a typically arrogant and lazy American. If your compression gauge reads only in kilo Pascals, click here. A converter will open in a new window.
See? He's not that lazy!
This means that a new (or near new) engine should have 206 psi of compression. There should not be more than 28 psi difference between the highest and lowest cylinder. All cylinders should have more than 135 psi of compression.
A low reading on the first stroke followed by gradually increasing readings on successive strokes usually indicates worn rings. That's why it's sometimes helpful to be able to watch the gauge while the engine is being cranked.
Probably the most important consideration is the difference between the highest and lowest cylinders. Let's say you've got readings of 169, 165, 135, 168, and 171. Hmmm. One cylinder is significantly lower than the others. That tells us there's a compression problem in that cylinder—but that's all that it tells us.
Let's back off here for a minute. If the readings were 169, 125, 131, 168, and 171, we could make an immediate deduction. If any two adjacent cylinders have a significantly low reading, that usually indicates a blown head gasket—the gasket has broken down between the two cylinders and they're leaking into one another.
But what if only one cylinder has a low reading? We can assume for the moment that the head gasket is probably okay, so the most likely culprit is a different leak, either at a valve or at the rings. We'll have to do another check to narrow it down. This is the time to do a...
Wet Compression Test
This involves squirting a few teaspoons of oil into the spark plug hole and then re-testing the compression of the suspect cylinder. The oil will (temporarily) coat and seal the compression rings. NOTE: do NOT squirt too much oil into the cylinder, or you'll get false results. With excessive oil in the cylinder, compression readings will go up even if the rings are in good condition.
If the new compression readings are significantly higher, then that indicates the compression rings (or the cylinder walls) are worn and need replacement and/or repair. It's time for new rings or cylinder service. Cylinder service entails either boring the cylinders to a larger diameter (with corresponding oversized rings and/or pistons) or re-sleeving the cylinder to its original geometry. Either way, you may as well do all the cylinders.
If the wet compression readings don't change appreciably, then that cylinder's valves aren't sealing properly, or the head gasket has a leak. Either way, it's time to pull the head and see what's going on. Most likely, it'll be a bad (burned) valve or a bad valve seal or valve seat. In other words, it's time for a valve job.
Variation vs. Absolute Results
The variation of one (or two) cylinders from the others tells us there's a definite problem with a head gasket or with one cylinder's valves or rings. But what if the absolute numbers are all on the low side?
That depends on how low the numbers are. It tells us that the engine is wearing out. But it's wearing out evenly. In other words, the engine is getting old, but there's no real problem unless they're all near or below the minimum of 135 psi.
Bottom line—as long as the numbers are above 135 and within 28 psi of each other, don't worry about it. You've probably got plenty of other things to worry about. Give them your attention instead.
these # are a little on the high side, 135 is good compression on a st. motor. it shouldnt be using a qt. of oil every 100 miles no way. that much oil cant get by the rings without oil being blown all over everything. :HMMM: :confused:
lt1s10 quote:
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Originally posted by bgrd
Could someone post a link to a chart ,which has all the torque specs. for a 350 sbc... TIA
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is this what you need?
http://www.hotrodshack.com/torque_settings.htm
Thanks lt1s10, for the settings and the oil usage was coming from the valve seals...
never thought it was the rings and thats a lot of oil going by the valves, but all that counts is you got it fixed. :cool:Quote:
Originally posted by bgrd
lt1s10 quote:
--------------------------------------------------------------------------------
Originally posted by bgrd
Could someone post a link to a chart ,which has all the torque specs. for a 350 sbc... TIA
--------------------------------------------------------------------------------
is this what you need?
http://www.hotrodshack.com/torque_settings.htm
Thanks lt1s10, for the settings and the oil usage was coming from the valve seals...