Ways to diagnose rings as source of oil consumption

General engine tech -- Drag Racing to Circle Track

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zwede
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Re: Ways to diagnose rings as source of oil consumption

Post by zwede » Wed Jan 03, 2018 3:56 pm

joe 90 wrote:
Wed Jan 03, 2018 3:52 pm
6 of your cylinders are burning oil.
2 are not.
You should be able to work it out?

1 of them is running extremely lean.
Sorry if it was unclear, both pics are of the driver's side plugs, 1-3-5-7. Just taken at different times showing they are looking better with time.

Also, both set of plugs were only in the car for 200 miles. I would expect them to look pretty much new/white after so few miles if all was well in the engine.

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Re: Ways to diagnose rings as source of oil consumption

Post by Belgian1979 » Wed Jan 03, 2018 4:25 pm

You could hook up a map sensor to the crankcase somehow and see what it does while driving. If it increases a lot with throttle and decreases a lot while decelerating you could get an idea about the condition of the rings. I haven't done this myself as I don't have a suitable way to connect the map to the crankcase.

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Re: Ways to diagnose rings as source of oil consumption

Post by zwede » Wed Jan 03, 2018 4:32 pm

I think the compression rings are good as I get an even 200 PSI cranking which is pretty high for only 10:1 CR.

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Re: Ways to diagnose rings as source of oil consumption

Post by engineguyBill » Wed Jan 03, 2018 4:36 pm

Did you break-in the engine with conventional oil or synthetic? Non-synthetic break-in oil should be used for any engine that is built, usually for at least the first 500 miles. What kind of rings are you running? Cylinders honed with a torque plate?
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Re: Ways to diagnose rings as source of oil consumption

Post by engineguyBill » Wed Jan 03, 2018 4:39 pm

Even though one quart of oil in 700 miles is excessive, your spark plugs do not appear to be in bad shape at all. Is there any oil evident at the exhaust pipes?
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Re: Ways to diagnose rings as source of oil consumption

Post by Belgian1979 » Wed Jan 03, 2018 4:41 pm

engineguyBill wrote:
Wed Jan 03, 2018 4:39 pm
Even though one quart of oil in 700 miles is excessive, your spark plugs do not appear to be in bad shape at all. Is there any oil evident at the exhaust pipes?
A quart every 700 miles has got to go somewhere. Unless a major leak the only other way would be through the tailpipe.

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Re: Ways to diagnose rings as source of oil consumption

Post by zwede » Wed Jan 03, 2018 5:03 pm

engineguyBill wrote:
Wed Jan 03, 2018 4:36 pm
Did you break-in the engine with conventional oil or synthetic? Non-synthetic break-in oil should be used for any engine that is built, usually for at least the first 500 miles. What kind of rings are you running? Cylinders honed with a torque plate?
Broken in on synthetic, which could well the the root of all this. I now know better.
Honing was done with torque plates.
Don't remember what the rings were. The builder picked them and he knew this was a street deal. I'll look through my receipts tonight and see if I can find the ring info. The builder gapped the rings and I checked them when I assembled it and they were spot on.

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Re: Ways to diagnose rings as source of oil consumption

Post by zwede » Wed Jan 03, 2018 5:05 pm

engineguyBill wrote:
Wed Jan 03, 2018 4:39 pm
Even though one quart of oil in 700 miles is excessive, your spark plugs do not appear to be in bad shape at all. Is there any oil evident at the exhaust pipes?
No signs of oil in the exhaust, just dry soot.

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Re: Ways to diagnose rings as source of oil consumption

Post by pamotorman » Wed Jan 03, 2018 5:14 pm

have you run the car hard to get back pressure on the rings you have to load the engine to get the ring to seat.

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Re: Ways to diagnose rings as source of oil consumption

Post by gnicholson » Wed Jan 03, 2018 5:29 pm

Rings need to seat allmost immediately after 1st starting or they burnish in and they may take 10k miles to seat. Over oiling on engine assy, synthetic oil ,incorrect cyl wall finish. In my experience the most common problem as long as the cyl wall finish , ring pack, clearances etc are good is over oiling the cyl walls during assy. You have to have friction to seat the rings. I use a drop or 2 of oil on the skirts and total seal dry assy powder. Since ive started this practice i havent had any more problems with oil burning due to oil rings not seating

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Re: Ways to diagnose rings as source of oil consumption

Post by Belgian1979 » Wed Jan 03, 2018 5:49 pm

gnicholson wrote:
Wed Jan 03, 2018 5:29 pm
Rings need to seat allmost immediately after 1st starting or they burnish in and they may take 10k miles to seat. Over oiling on engine assy, synthetic oil ,incorrect cyl wall finish. In my experience the most common problem as long as the cyl wall finish , ring pack, clearances etc are good is over oiling the cyl walls during assy. You have to have friction to seat the rings. I use a drop or 2 of oil on the skirts and total seal dry assy powder. Since ive started this practice i havent had any more problems with oil burning due to oil rings not seating
I have also seen other comments, where scuffed pistons were attributed to not enough oil on assembly. I think it was big joe's comment back then.

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Re: Ways to diagnose rings as source of oil consumption

Post by BOOT » Wed Jan 03, 2018 5:50 pm

Forgot to ask if your rocker studs go into the intake runner and if so they gotta be sealed.
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Re: Ways to diagnose rings as source of oil consumption

Post by hoodeng » Wed Jan 03, 2018 6:17 pm

Your picture of the piston is showing oil wash around the o/d , when oil passes the ring set it dissolves the crown residue closest the bore leaving a distinctive bare/clean crown band. If contamination is coming past the guides the piston crown will have an even residue deposit.
Oil deposits tend to be ash like and rough ,fuel deposits tend to be black ,smooth ,and sometimes a bit flakey, after extended use where residues become fixed [my observations only ,as i only work with pretty much one brand of engine]

EFI does not necessarily guarantee no combustion residue on the crowns/chambers ,usage like town ,short trips may not generate the temperatures required to clean surfaces,and even after a long drive or a good thrash the residue may not clean off due to fixed adhesion to the crown.{although water injection will keep the internals spotless!}.

Plug readings today are hard to pick with modern pump fuels but one thing does not change and that is the plugs ability to self clean {if the right range is installed } ,the porcelain has to reach 500-700°C for self cleaning to take place ,below 450°fouling can take place , above 800° plug induced pre-ignition is highly likely.

Previous sentence about plug temps is quoted from K Gough's book "The Vital Spark"

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Re: Ways to diagnose rings as source of oil consumption

Post by MadBill » Wed Jan 03, 2018 6:47 pm

Per Belgian's suggestion, a simple way to check crankcase pressure in a wet sump engine is to hook up a vacuum gauge to the dipstick tube. For an SB/BB Chev with deleted mechanical fuel pump, drilling and tapping the blank off plate is a simple approach. Also for most SBCs, there is a bolt hole in the front face passenger side of the block that is drilled through. (the one you can use to hold the pushrod in place during pump install). Likewise any other bolt-on access cover or if all else fails, many intake manifolds seal the valley area and can accept a vacuum fitting.
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Re: Ways to diagnose rings as source of oil consumption

Post by zwede » Wed Jan 03, 2018 7:12 pm

BOOT wrote:
Wed Jan 03, 2018 5:50 pm
Forgot to ask if your rocker studs go into the intake runner and if so they gotta be sealed.
I put RTV on the rocker stud threads.

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