How much oil does your flathead use?

Old Henry

Old Henry

Well-known member
I'd be interested to know what anyone considers normal oil usage or what your oil usage actually is. Mine just went from a quart per 1,000 miles with 3 ring pistons to 3/4 quart per 1,000 miles with 4 ring pistons. What is yours and/or what do you think is "normal" and what do you think makes a difference in oil usage?
 
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My ole 35 doesn't use any oil from spring to spring changes and it is far from newly overhauled. Also to my old common sense mind, a 4th ring has to be adding close to 25%more drag than the 3 ring piston. The new design high power engines pistons are no thicker (or longer) than it takes hold a piston pin in and has only 3 or even 2 rings.
 
I change the oil in my '40 every 1000 miles or so, and have never had to add any between changes.
 
I guess I am sorta shy to admit it, but it takes me a while to tick off 1000 miles. I'm with Brendan, ours will leak a cup or less (1/4 qt) before it will burn it, that's how much it sits vs. drives. When I did 500 miles in four days last fall, there was no need to top off oil. Haven't topped it since. Last I checked, Tuesday, it was 1/4 qt. low. Will deal with that later. So from September, plus 500 miles, plus leakage, I'm less than 1 cup low. That's my experience.

Engine was in car when we got it 4 years ago so there's no way of knowing what I'm dealing with. But one of my minor problems is the existing engine runs so good I can't bear to put in the fresh rebuild we have ten feet away.

-VT/JeffH
 
My '40 burns a quart very 500 miles but does not smoke at all ! My car sat for many many years before I bought and may need rings, etc. I change oil every 1,500 miles though too. Never been on a long trip like Old Henry. Just around town etc.

Mike
 
We have 51,000 miles on our 46 and as far as I know the engine has never been out. We just put 570 miles on a trip, 85-90 degrees and mostly interstate travel (60-65 mph). dipstick level down 1/4" (maybe 1/4 qt). Burned less than a qt on a 1700 mile trip to Nova Scotia. I do change it every 2000 miles. (3 times a year). 20/50 Castrol and it stays more amber than black..
So, professor, give your engine more time before you worry about consumption. Besides, what's a qt of oil? Who cares?
John
 
keith oh said:
My ole 35 doesn't use any oil from spring to spring changes and it is far from newly overhauled. Also to my old common sense mind, a 4th ring has to be adding close to 25%more drag than the 3 ring piston. The new design high power engines pistons are no thicker (or longer) than it takes hold a piston pin in and has only 3 or even 2 rings.
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Hard to compare, tho. New engines have clearances that would cause a flathead to lock up, use low-tension thin-section rings, etc. The compression rings are the ones that really drag, and wear the cylinders.

Oil is the cheapest part of operating my flatmotor...
 
my rebuild is a 3 ringer. 3 years strong, still leeks, burns none......I like 3 rings more than 4.....I think there is less wear and tear with a 3 ringer.
 
oldford2 said:
. . . professor, give your engine more time before you worry about consumption. Besides, what's a qt of oil? Who cares?
John
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I buy oil by the 5 quart container as cheap as I can get it since all of my other cars leak it more than use it. (The flathead leaks nothing.)
 
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With my rear seal leaking on my 226 6 cylinder, I lost 2 quarts of oil from Racine, WI to Columbus, OH- 400 miles. I was wondering why people behind me were upset and had to wash their windshields. By the way, It took 2 quarts to get home also. The oil pressure and temp was good. I bet the 6 banger could have lost 3 quarts and still wouldn't have missed a beat. Looks like it's time to replace the seals.
 
Professor,
Those comments are not very kind. Pay no attention and go about driving Old Henry. I get Castrol at walmart 5 qts for $15.87. Good stuff.
John
 
keith oh said:
My ole 35 doesn't use any oil from spring to spring changes and it is far from newly overhauled. Also to my old common sense mind, a 4th ring has to be adding close to 25%more drag than the 3 ring piston. The new design high power engines pistons are no thicker (or longer) than it takes hold a piston pin in and has only 3 or even 2 rings.
Click to expand...
Keith,
Your statement means nothing unless you indicate how many miles you drive "spring to spring". And it doesn't use ANY???? Come on, I am smarter than I look.
John
 
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My '50 started the trip to Lake Tahoe with about 6000 miles on the rebuild and I never added oil when I changed it for the trip. I drove it 6520 miles cross country and added 1 1/2 qts oil and got a little over 19 mpg. I added no water.
 
I find if they run hot the oil gets black fast and it burns oil. Running cool in the 170 180 range the oil don't get black, just slightly dark yellow. My 39 ran hot, in the 200 range for a number of years and burnt a fair amount of oil. It now runs below 180 has over 115,000 miles is quiet and don't burn a drop of oil in 1.000 miles. G.M.
 
I don't understand why the term "scathing remark" When I asked why it would burn oil. One of the flatheads I built last year drove half way across Canada and back and never used any oil between oil changes of 2000 miles. Was not meant to hurt your feelings, just a question.
 
Mine just went from a quart per 1,000 miles with 3 ring pistons to 3/4 quart per 1,000 miles with 4 ring pistons.

Using this logic; if you used five ring pistons, you'd expect to use 1/2 quart oil, 6 ring pistons would halve that again. Rubbish!!
 
Just to put everything into perspective, when my engine died three months ago I was in deep despair not knowing who I was going to be able to get to fix it. I was profoundly grateful to find that the same person who rebuilt it 30,000 miles ago was still willing to do it again. I treasure every one of the 30,000 miles I was able to drive it after his previous rebuild before a piston came apart and I am now very grateful for every mile I'm driving it again. Oil usage is no big deal for me but does seem to be for some people. My '97 Camry with 270,00 miles leaks way more oil than Old Henry uses but I just keep driving it cause it still runs so great. I've driven cars that I had to add a quart of oil for every tank of gas and just kept driving them until they died. One year I gave away 4 cars that I'd used up. I'm just profoundly happy that Old Henry is on the road again, oil or no oil, no big deal for me. I was just curious.
 
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