Ways to diagnose rings as source of oil consumption

[zwede]

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.

[Belgian1979]

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.

[zwede]

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

[engineguyBill]

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?

[engineguyBill]

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?

[Belgian1979]

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.

[zwede]

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.

[zwede]

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.

[pamotorman]

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.

[gnicholson]

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

[Belgian1979]

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.

[BOOT]

Forgot to ask if your rocker studs go into the intake runner and if so they gotta be sealed.

[hoodeng]

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"

Cheers.

[MadBill]

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.

[zwede]

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.