Oil changes with filter

[glenn in camino]

I change my oil in my Model As, without oil filters, every 500-600 miles. I'm putting an Afordable Model A oil filter on my sport coupe. How much can I extend my oil changes on that car with the filter?

[Kurt in NJ]

The only real way is to send off the oil for analysis

Detergent oil --or non detergent

Thermostat??

how rich do you keep your mixture

short trips driving slow?? or do you drive long enough to get the oil hot??

If you are using detergent oil, run a thermostat ,are getting 18+ mpg and drive more than 25 miles at highway speeds 1 out of 4 drives I would think 2-3000 miles or 1 time a year

If you use non detergent oil, don't have a thermostat, only drive 1 mile trips, get 8 mpg, and keep changing to hotter plugs to get rid of the black fluffies 500 miles may still be a good time

[ford1]

LOL, i see you have been told the Model A needs its oil changed every 500 miles or so, that was valid when the car was new and no paved roads so the cars were always in the dirt and the oil was not even good enough to oil farm plows, new cars go 5000 miles between oil changes at speeds the Model A never dared to approach, and the horse power is 5 times the Model A and the compression ratio is about 3 times that engine, modern oil, even big box stores oil is so much better than it was a 100 years ago with the engine working so much much less, there is no reason you cant change it every 5000 miles, especially with a filter, why spend $15 every 500 miles when its not necessary? and i bet you were told never to use detergent oil in the engine because it will destroy the babbit, modern bearings are lined with babbit and they go over 200,000 miles, think about it

[Kevin in NJ]

Ya at 500 miles you are throwing away good oil.
Based what I have read from oil engineers that have written on the subject here are the issues you need to consider about oils (this applies to all cars).

Oil when the A was built was poorly refined and had little or no additives to keep it stable and not have bad chemicals build up in the oil. One example is when the moisture from condensate mixes with sulfur compounds formed durning combustion to make sulfuric acid. I have seen holes in the oil pan from the acid.

So you have two or three issues to think about to determine when you really need to change the oil.
First, when have the minerals that make lubrication broken down. These days it takes quite a while unless you have real high temps- which the A just will not make. Synthetics go a REAL long time and supposedly never break down. So this is not a reason to change oil in the A.
Second, when the additives have worn out. There are only so many molecules per volume of new oil that can lock down the bad chemicals. When you run out then the bad stuff will start to build up. I pointed out about the moisture and acid. This is something that happens even with the car sitting. You run the car it makes the sulfur compounds. Hopefully you got the engine hot enough and it burned off the water laying around. Then you put the car away. While the car is sitting the temps change from day to night. When the metal is cool and the air warms up the moisture in the air will condense out. Over the months that you do not drive the car this builds up in the engine. Well you can see. If you are using a compression ignition oil (diesel engine) they tend to have more additives to prevent the sulfur build up.
Third, dirt in the engine. We are not always talking the dirt from the road. The particulate build up from combustion as well as what you get from the road. These are small particles that are kept in suspension by detergents and come out when you change the oil. The build up is worse when driving in harsh environments, city driving is more harsh then country driving.


The 500 mile numbers are remnants of the days when crappy oil and bad roads were the rule.
That is not today.
Be nice to the environment and your pocket book and go longer between changes.

[Arthur in AK]

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Originally Posted by Kevin in NJ

Ya at 500 miles you are throwing away good oil.
Based what I have read from oil engineers that have written on the subject here are the issues you need to consider about oils (this applies to all cars).

Oil when the A was built was poorly refined and had little or no additives to keep it stable and not have bad chemicals build up in the oil. One example is when the moisture from condensate mixes with sulfur compounds formed durning combustion to make sulfuric acid. I have seen holes in the oil pan from the acid.

So you have two or three issues to think about to determine when you really need to change the oil.
First, when have the minerals that make lubrication broken down. These days it takes quite a while unless you have real high temps- which the A just will not make. Synthetics go a REAL long time and supposedly never break down. So this is not a reason to change oil in the A.
Second, when the additives have worn out. There are only so many molecules per volume of new oil that can lock down the bad chemicals. When you run out then the bad stuff will start to build up. I pointed out about the moisture and acid. This is something that happens even with the car sitting. You run the car it makes the sulfur compounds. Hopefully you got the engine hot enough and it burned off the water laying around. Then you put the car away. While the car is sitting the temps change from day to night. When the metal is cool and the air warms up the moisture in the air will condense out. Over the months that you do not drive the car this builds up in the engine. Well you can see. If you are using a compression ignition oil (diesel engine) they tend to have more additives to prevent the sulfur build up.
Third, dirt in the engine. We are not always talking the dirt from the road. The particulate build up from combustion as well as what you get from the road. These are small particles that are kept in suspension by detergents and come out when you change the oil. The build up is worse when driving in harsh environments, city driving is more harsh then country driving.


The 500 mile numbers are remnants of the days when crappy oil and bad roads were the rule.
That is not today.
Be nice to the environment and your pocket book and go longer between changes.

Kevin: Does your mileage changing intervals take into account the use of the more primitive, non detergent SA or SB rated oils that are frequently used in antique cars today? Or is it mainly advice for those that use modern SM or SN rated oils?

-Rich