Over the 47 years I have had The Alfatross there are only two parts I've lost. One of them was the engine oil dipstick. Actually, I didn't lose it--the St. Louis-based miscreant posing as an Alfa mechanic who was supposed to rebuild my engine years ago (not DeWayne Samuels, this is the guy before him) "lost" it. He's the kind of "professional" who loans parts of your car out to his friends then can't remember who he gave them to.
It probably seemed trivial to him, but when you stop to think about it a dipstick is a pretty important part of your engine. Oil level is critical, but how do you check it when there is no dipstick, or when you have one but it isn't marked? And don't forget--you need two marks on the stick to determine the range between too much and too little. DeWayne fabricated a replacement dipstick for The Alfatross' engine, but left the marking up to me.
Before the Santa Fe Concorso I decided it was time to switch from break-in oil to regular use oil. I measured the volume of oil that came out, but then started to wonder if it represented the right amount. The service manual gives values for the volume of oil needed for a change along with the additional amount for a change of the oil filter--not in quarts but kilograms!
But what's the best way to convert from weight of oil to volume of oil? Do all engine oils weigh the same? Probably not, but if there is a difference it's probably irrelevant when dealing with quantities this small. So I weighed a quart of the 15W-50 oil DeWayne suggested I use and it came out to 0.882 Kg. When I realized that amounted to almost 9 quarts I was flabbergasted. That's a lot of oil for a little 2 liter 4 cylinder engine!
Still not satisfied, I put the oil I just drained out back in the engine. I ran a wire probe through the dipstick tube until it hit the bottom of the oil pan. It measured 22.5 inches from the top of the oil tube. Then I measured the length of the dipstick: 19.5 inches long from the inside of the cap that covers the top of the tube. With 6 quarts of oil in the pan the level showing on the dipstick is 18 1/8 inches from the inside of the dipstick cap. I reported this to Dan Allen and Giuseppe Maranghi. Dan checked it against an original tube and dipstick in his collection and replied "Dip sticks should go to the bottom of the pan, or close. Two inches is too far from the bottom. Rough measurements, you are filling one inch of the 2 3/4 top of the pan. Too little. Get at least another inch in the top section of the pan." And Giuseppe warned: "And, as on many other bialberos [twin cams], could be the difference between max level and low level on oil level check stick is not 1 liter as on the majority of vehicles, but 2 liters (2.1 qt)."
The image shows my rough measurements of the oil pan depths. If the overall depth from the top of the dipstick tube is 22 ½ inches and the present oil level is at 18 1/8 inches, then there is 4 3/8 inches of oil in the pan. This means that the oil level fills the sump and about 1 inch of the 2 ¾ inch deep pan. So present oil level is too low.
After this, I'll never look at a humble dipstick the way I used to. In a way, the item lost was kind of appropriate, given who lost it . . . .
It probably seemed trivial to him, but when you stop to think about it a dipstick is a pretty important part of your engine. Oil level is critical, but how do you check it when there is no dipstick, or when you have one but it isn't marked? And don't forget--you need two marks on the stick to determine the range between too much and too little. DeWayne fabricated a replacement dipstick for The Alfatross' engine, but left the marking up to me.
Before the Santa Fe Concorso I decided it was time to switch from break-in oil to regular use oil. I measured the volume of oil that came out, but then started to wonder if it represented the right amount. The service manual gives values for the volume of oil needed for a change along with the additional amount for a change of the oil filter--not in quarts but kilograms!
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| Engine oil quantities recommended in the 1957 repair manual for the 1900 TI and C engines: 6 kilograms (13.2 pounds) of oil plus another 0.75 pound for the filter: a total of almost 14 pounds. |
But what's the best way to convert from weight of oil to volume of oil? Do all engine oils weigh the same? Probably not, but if there is a difference it's probably irrelevant when dealing with quantities this small. So I weighed a quart of the 15W-50 oil DeWayne suggested I use and it came out to 0.882 Kg. When I realized that amounted to almost 9 quarts I was flabbergasted. That's a lot of oil for a little 2 liter 4 cylinder engine!
Still not satisfied, I put the oil I just drained out back in the engine. I ran a wire probe through the dipstick tube until it hit the bottom of the oil pan. It measured 22.5 inches from the top of the oil tube. Then I measured the length of the dipstick: 19.5 inches long from the inside of the cap that covers the top of the tube. With 6 quarts of oil in the pan the level showing on the dipstick is 18 1/8 inches from the inside of the dipstick cap. I reported this to Dan Allen and Giuseppe Maranghi. Dan checked it against an original tube and dipstick in his collection and replied "Dip sticks should go to the bottom of the pan, or close. Two inches is too far from the bottom. Rough measurements, you are filling one inch of the 2 3/4 top of the pan. Too little. Get at least another inch in the top section of the pan." And Giuseppe warned: "And, as on many other bialberos [twin cams], could be the difference between max level and low level on oil level check stick is not 1 liter as on the majority of vehicles, but 2 liters (2.1 qt)."
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| Dan's dipstick and tube. Note that the overall length of the stick is about 20 1/2 in. "High" and "low" levels are marked at about 16 in. and 18 1/2 in. Dan Allen. |
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| Dipstick tube is 255 mm (10 in) from mouth to the collar where it enters the block. The dipstick from tip to the collar where it enters the block is 430 mm (16.9 in). |
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| The Alfatross' oil pan and deep sump before restoration. The total depth is 159 mm (6 1/4 in). |
Based on this advice and measurements I decided to refill the sump and pan with seven quarts, mark the stick to show the "low" level, and add slightly less than 2 quarts to mark the "high" level. That's when I discovered how tough it is to mark a stainless dipstick with the kind of cross-hatching needed to accurately determine where the level is.
After this, I'll never look at a humble dipstick the way I used to. In a way, the item lost was kind of appropriate, given who lost it . . . .
