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Victor Borg
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Post by Victor Borg » Sat Mar 16, 2019 7:45 am

...I know there has been lotsa discussion on this topic but I need some info that I haven't seen covered: How much oil is correct in the engine??After running our '26 touring I check the oil on the after-market dipstick that some kind soul added and it reads scarily low.it eventually comes up to the "full" mark that registers 4 quarts which I'm told is the proper amount,but a search of all the books doesn't specify an exact amount...only that it should reach the top petcock on the crankcase.It doesn't say anything about how much is too much.Is there a peril in overfilling? I'm kinda a newby at this T business,and I don't want to do anything stupid but I have been soul-searching for a while about adding another half a quart or so because that low low oil reading on the dipstick immediately after engine shutdown gives me the jitters.Am I fretting due to ignorance,or is my concern valid?

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Re: oil

Post by Moxie26 » Sat Mar 16, 2019 8:21 am

That aftermarket dipstick is installed in the lower petcock position. Try waiting a few minutes after shutdown to check oil level on dipstick. Too much oil will be indicated by opening top petcock and showing a steady stream of oil coming out.

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Peter, Memphis TN
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Re: oil

Post by Peter, Memphis TN » Sat Mar 16, 2019 8:56 am

First, you need to know that the dipstick you mention was made by a modern car factory, for a modern car engine. Whoever put together your dipstick kit used one that approximates the levels in a Model T engine, but it isn't necessarily accurate in terms of the quantity needed to become "full."

What I did when I installed a dipstick on my engine, was to use the tried-and-true method of determining when the engine was full of oil - parked on a level place, I slowly added oil until a few drops dribbled out of the upper petcock (which I had determined was open and not clogged with gunk). Then I pulled the dipstick and marked where the level was, and made that mark my "full" position. I marked it by filing a notch on it.

The Model T engine is remarkably forgiving about the amount of oil in it. You see how far apart the two petcocks were built into the crankcase? Well, Henry's instructions simply said that if oil runs out of the lower one you have enough, and if it runs out of the upper one you have too much. That's a pretty wide and un-specific way to specify "how much oil?" But it's worked for 100 years or so.

Actually, I'm not aware of any damage done by over-filling. Maybe someone can chime in on that subject.

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Re: oil

Post by Oldav8tor » Sat Mar 16, 2019 11:07 am

Maybe someone who is more knowledgeable will chip in, but this is my take on Model T oil levels.

The model T is a whole different beast compared to modern engines inasmuch as it primarily distributes oil by splashing, not pumps and pressure. In aircraft engines (which I am more familiar with) the engine will keep circulating oil as long as the pickup tube is submerged in oil.... in an aircraft with a two gallon oil sump you can still maintain oil pressure down to a couple of quarts...what will be more noticeable will be a rise in temperature as there is less oil circulating to cool the engine. Not so in the model T. While it may be forgiving to some degree, letting the oil drop too much would result in less effective lubrication in my opinion. Frequent level checks and a couple of quarts under the seat is a must!

I'm sure you're also aware of the problem with the front main bearing being deprived of oil when a car is driven on a long uphill slope. That is why many cars have an aftermarket oil line installed to catch oil by the flywheel and deliver it to the front (see photo.) There is also the problem with under seat fuel tanks where too little fuel on a steep uphill slope can starve the engine of fuel...solution there is add fuel or go up the hill backwards.

I'm new to Model T's and learning something every day and I must tell you I've developed a healthy respect for what our ancestors had to deal with at the beginning of the automobile age... We have it so easy today by comparison.
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Re: oil

Post by Jugster » Sat Mar 16, 2019 11:28 am

Obviously, too little is no good, but too much is also not good. You need enough to keep that front engine bearing bathed, but if there's too much, the stuff will migrate down the drive shaft housing and make a mess of things. Not sure whether that can get into the differential, but if it can, it'll dilute the heavy oil in there and flow out through the axle housings and make a mess of the brakes. No, you don't want too much oil in there.

Okay, so how much is enough? Well, we know that Henry wanted the level to be kept between the two spigots, but what is the perfect ideal? Well, I slowly fill the crankcase until the top spigot begins to drip. That's when I stop pouring. My engine seems happy with that and nothing leaks excessively. I have an external oil line which, supposedly, does something to enhance lubricating that front engine bearing when going uphill. If it's a long hill, I might pull off to the side halfway up and drive a tight circle to get that oil back up front for the rest of the climb. Does that really do anything? I dunno. Couldn't hurt.
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Mark Gregush
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Re: oil

Post by Mark Gregush » Sat Mar 16, 2019 12:15 pm

I have found that it is 4 qt's "DRY" like after a rebuild. The dipper tray holds some, the bands get soaked and there is oil held in the transmission. On a oil change, I open the top petcock, put the 4 qt's in and let it settle by draining off any extra thru the open top petcock. When the engine is running most of the oil is in motion around the flywheel not in the sump. If the engine is over filled, there can be a lot flowing back to the 4th main which is not sealed and if not in good shape will be flooded and can lose oil there.
I would do as suggested, on draining the oil, refill with 3 qts let settle then check the dipstick and mark that level. Add the 4th qt and let the oil settle. Open the top petcock, let over fill drain. When any over fill gets to just a drip, close the petcock. Pull the dip stick, wipe off, reinsert and check the level. Compare to the full mark that may be on it and correct as needed. About half way between the two marks will should be in the safe range for most driving. Dripping out the top petcock is all that is needed, it does not need to flow out in a stream.
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Norman Kling
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Re: oil

Post by Norman Kling » Sat Mar 16, 2019 12:35 pm

You must remember that you pour the oil into the front of the engine and it runs back into the sump. So as you add oil, pour in a little and wait a few minutes. If no oil runs out the top spigot, pour in a little more and wait a few minutes.

If you are using multi grade oil, it will run back faster than 30 weight. When cold the 30 is thicker and runs more slowly. As stated above, if you have the oil too full it will run to the differential. So it is a good idea to remove the filler plug from the differential when you service the car and if too full let it drain out. This would be a problem with the earlier cars where the recommended oil level is below the filler plug. If the differential oil is too low, then of course, add some.

One way to keep less oil from running down the tube is to keep the universal joint and front driveshaft bearing completely packed full of grease.

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Victor Borg
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Re: oil

Post by Victor Borg » Sun Mar 17, 2019 3:52 pm

Thanks everybody...guess i'll calm down on adding extra oil.Henry musta known what he was doing since his creations are still ticking away!

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