Burning Oil - Any thoughts?

[bruces1]

I have a '75 with a Weber Carb that I recently converted to a daily driver because it was running well, and quite frankly, I needed it. I put about 200 miles on it a week. The past month or so I've noticed it goes thru a quart of oil a week. Any thoughts on what this could be, or am I just heaping too much abuse on a sweet old car. The odometer reads 99,xxx, and I don't know if it's about to go over 100K, 200, or whatever.

Any clues would be great. The car still runs fine and there are no obvious signs like blue smoke out the tail pipe or leaks on the floor of my garage.

Thanks, Bruce

[PSloan]

Get it up to about 5 k rpms and then shift. Then you'll see some blue smoke.

[winstontj]

your oil has to be going somewhere. either out the tailpipe or on the ground. U sure there's no leaks near the timing covers or maybe an exhaust manifold screw? How about what PSloan said... when you're on the highway downshift to third and take your foot off the gas to decel (best to do this around an off-ramp or on a quiet stretch)... let it come down about 20mph (not to 20 but from say70- 50mph) and look in the rearview. If there's nothing then shift... hit the gas... Anything?

Oil can go through gaskets, rings, valve seals and bolt/threadded passegways but no matter where it goes there will be a trail.

[bruces1]

Yep, you guys are both right when I do what you said, blue or white (can't really tell which) smoke. Now what?

[winstontj]

smoke on accel = rings

smoke on decel = valves (valve seals)

Time for a whole lot of how much can you stand??? Only way to fix is to replace valve seals, gotta pull the head to do that. Pull the head and you might as well do a valve job, clean things up, change the eccentrics, a standard head job. Do a head job & you're going to notice that you will soon need rings. Best thing is to let things be, keep your engine in tune and get ALL your ducks in a row for a full rebuild.

Do you have a garage? You can get a second longblock (complete M10) for cheap - cheap - cheap... so get yourself a spare and rebuild that. New honing in the cylinders, main & rod bearings, oil pump shims, timing chain gaskets, head work, etc. & you're good to go. You can do it for under $1,000 for a "refresh" type job.

[bruces1]

Are you talking $1,000 for the rebuild, or for buying another engine and rebuilding that? The second engine is not an option for me as I am neither mechanically oriented or inclined. How long can I go with my engine as it is?

[c.d.iesel]

change the motor oil (good and hot),

replace the filter with a BMW 059 or one of these quality filters,

and refill with 20w/50, 15w/50 oil of your choice.

Change the oil and filter again after 1000 miles.

report back

Do not over-fill ever because that will cause higher consumption.

1 quart in 1000 miles is acceptable consumption.

only check the oil level on level groung AFTER driving, oil is HOT, and, after waiting 5-minutes for oil drain down- before measuring . Do Not top Up A Cold Motor!

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[bruces1]

Thanks, I'll let you know how it goes. BTW, consumption is currently 1 quart for every 200 miles.

[pkbinplano]

and drive drive drive. Just drive it till it's blowing a quart a day out the crank case vent. Then worry about it.

[ingraham]

But a quart a week is a LOT cheaper than a rebuild, even over several years.

[ingraham]

(nt)

[bruces1]

Anybody know what the best weight to use is? I use 20/50. And also, does the specially formulated high mileage oil help?