Possibly Changing Engine Oil from SAE30 to 10W30

shew01

shew01

Well-known member
The previous owner of the Model A that I just purchased told me that the engine was gone through 40 years ago, and only SAE 30 oil has been used in the crankcase.

Although the car has not been driven a lot since then, I'm thinking that there will likely be sludge buildup in the oil pan, correct?

If I drop the pan and clean it out, is there anything else I should do before swapping to 10W30 oil? Will any residual 30W oil elsewhere in the valve chamber, etc. tend to cause problems?

Or would I be better off just continuing to use 30W?
 
shew01 said:
The previous owner of the Model A that I just purchased told me that the engine was gone through 40 years ago, and only SAE 30 oil has been used in the crankcase.

Although the car has not been driven a lot since then, I'm thinking that there will likely be sludge buildup in the oil pan, correct?

If I drop the pan and clean it out, is there anything else I should do before swapping to 10W30 oil? Will any residual 30W oil elsewhere in the valve chamber, etc. tend to cause problems?

Or would I be better off just continuing to use 30W?
Click to expand...
Shew - There may or may not be sludge buildup in the crankcase, depending on how often the oil was changed in relation to how often it was driven. Sludge accumulates with used oil not getting circulated. Since getting the pan off with the engine in the car is not a trivial task, you might consider removing the side cover and checking for sludge in the valve chamber first. If there's not much sludge in the valve chamber there may not be much sludge in the pan. Regardless, checking for sludge, and cleaning it out if present, is an excellent first step for a new (to you) car.

No issue at all switching to 10W-30 from 30W. And I'd suggest that you go to 10W-30 synthetic, which just wasn't available 40 years ago but has far longer life and superior lubrication. If you do end up removing the pan and cleaning out the dipper tray as well as cleaning out the valve chamber, your replacement of the oil will be pretty much 100% the first time through!

Plenty of threads on the Barn about oil. FWIW, I use 10W-30 Mobil 1 as it's readily available, and I can get it on sale in 6-packs fairly often.

Consider new radiator hoses and cleaning out the cooling system as well...
 
Hello, the valve side cover may also be a source of sludge, dropping oil pan isn’t too bad ,removing the flywheel inspection cover helps and 1/4 drive socket and extension can be used for the front most bolts that the frame cross member covers.Kerosene or diesel fuel works to help clean out these areas. I Use 20 w 50 but this engine has some miles on it , don’t drive it if temperature under 60.
 
SAE 30 is very likely a "non-detergent" oil. It is what the Model A was designed to operate on with the full intention to use the lower sump to collect the majority of the sludge that forms in the oil (mostly blow-by from the cylinder.)

10W-30 or most any "modern" oil is likely "Detergent" oil - which was designed to keep the sludge in suspension so it could be "filtered out" in a modern oil filter.

The danger, of course is that detergent oil will "lift" any sludge and put it into suspension where, without a filter, it may find other places/passages to hang up.

You are correct in wanting to remove the sludge from the crank-case in your conversion. You ask about "other" places of your experience where sludge builds up. The answer is YES - best plan would be to have the engine disassembled and then "hot tanked" to remove ANY sludge.

But this is a lot of work, not to mention the possibility of damaging "babbit interstices" in the chemical process of hot tanking. (Babbitt like any metal, especially alloys, has a "grain," the gaps between grains being the interstice.)

Probably the best way to handle it is to "manually" clean what you can get to easily - and leave it at that. The interstices will continue to contain babbitt wear product and sludge just as they would have originally anyway.

Synthetic oil would be my choice too.

Joe K
 
If you can find 30 wt. fine, but more easily available will be 10-30.

Remember the most modern high tech oil is no different than a very expensive pair of running shoes for Grandpa. It's still Grandpa or with the Model A, a splash, gravity, non pressure lubrication system for bearings with clearances that could be measured with a yard stick.

Interesting in 1932 Ford suggested 20 wt. for under 32 degrees and 40wt for everything above. The old timer who poured the babbitt in my engine said 30wt. He thought 10-30 'might be a little thin, but where you live' referring to 'north' as opposed to his hot North Carolina.

You'll hear a lot of noise but all today's oil have the same quality. It's now about the frequency of oil changes that makes the difference.

My $.02, your mileage will differ. Enjoy the ride.
 
Just because the engine had SAE 30 doesn't mean it was nondetergent. I use SAE 30 detergent in my lawn mowers, have for years. DEFINITELY doesn't need to be hot dipped. Even if nondetergent was used previously, run detergent now, change oil often for a couple oil changes, then revert to regular intervals. It's a model A, it'll be fine.
 
In the summer, 10W-30 is the same as 30 wt. In the winter the oil is more like 10 wt until it gets warmed up then acts like 30 wt. Viscosity falls off with temperature. The 10W-30 just has a different curve so that it doesn't get as viscus in cold temperatures. It also does not get as thin as 30 wt oil at higher temperatures.
 
Last edited:
eagle said:
Just because the engine had SAE 30 doesn't mean it was nondetergent. Even if nondetergent was used previously, run detergent now, change oil often for a couple oil changes, then revert to regular intervals. It's a model A, it'll be fine.
Click to expand...

Ditto

40 years ago puts the rebuild around 1984, by then most oils were "detergent".
Did the PO say non-detergent oil was used?
 
Last edited:
My Dad faithfully used SAE30 but I have used 10W30 syn. since I resurrected the car and all is well.
 
katy said:
Ditto

40 years ago puts the rebuild around 1984, by then most oils were "detergent".
Did the PO say non-detergent oil was used?
Click to expand...

I think you can buy SAE 30 in non-detergent, detergent, or synthetic.

The cheapest would be detergent. Non-detergent would be considered "specialty" (i.e. more money) and likewise synthetic.

IIRC, the last SAE30 detergent/non-synthetic I bought was for lawnmower use, and reading the package still indicated was "part synthetic."

Blend is probably more common than most people realize. Production of synthetic oil does allow the sellers to "taylor" the selling stock to a specific standard, curve, or "lubricity." (or production cost.)

The whole point of "refining" is to minimize the "dregs" left over.

Joe K
 
Do not take any covers off or drop the oil pan. When you drain the 30W oil, observe what is in the drain plug. Also stick your index finger into the drain hole and feel for sludge. Frankly, I would go with 10W40 because at 160F operating temperature, the viscosity of the 10W40 will be about 30. The detergents in modern oil will clean-out any light deposits leftover from the 30W. I strongly suggest that you use a high mileage multi-viscosity oil that is a synthetic blend.
 

Attachments

  • Engine Oil Dip Stick 171kb.jpg
    Engine Oil Dip Stick 171kb.jpg
    58.3 KB · Views: 39
  • Oil Analysis 239kb.jpg
    Oil Analysis 239kb.jpg
    82.8 KB · Views: 33
All oils will loose viscosity as they get warmer. The multiweight oils just loose less viscosity as they warm. They also do not get as thick at the lower temperature. The following graph from https://www.tdxltd.co.nz/blog/multi-grade-oil

Regarding high mileage oils: If you change your oil every 500 miles, the high mileage oils are a waste of money. However, if you have a full flow filter and change oil every 3,000 miles, then the high mileage oils may be for you.



MULTIGRADEoilpng7becbd.png
 
Shew - what’s the oil on the dip stick look like, smell like? My A was supposedly driven less than 50 miles in the last 18 years. No idea when/if engine may have been rebuilt before then. Oil was clear and golden brown - no fuel or burnt smell. When I dumped the oil from the oil pan it was also clear and light brown. I have no idea what oil was in it, but like my three other pre-war cars she’s flowing Castrol 10-40 now.
I had to replace a drooped exhaust manifold, so I removed the valve cover - amazingly clean in the chamber. I don’t plan to pull the oil pan unless I need to. If you dump the current oil and it looks good, I’d go with Bob’s Bidonde’s suggestions.
 
A tip to make life easier when you drop the pan: Turn the steering wheel all the way to the right so that the tie rod moves out of the way when trying to get a 1/2" socket over the front four bolts. It's a tight squeeze between the pan and the front crossmember and you'll need a straight upwards shot at those bolts. Without moving the tie rod out of the way, you might not be able to get a socket over them. 'Just did this today on a friend's Model A so that I could adjust the rods and mains. No way could I get a socket up there without turning the steering wheel to full right lock.
Marshall
 
Marshall V. Daut said:
A tip to make life easier when you drop the pan: Turn the steering wheel all the way to the right so that the tie rod moves out of the way when trying to get a 1/2" socket over the front four bolts. It's a tight squeeze between the pan and the front crossmember and you'll need a straight upwards shot at those bolts. Without moving the tie rod out of the way, you might not be able to get a socket over them. 'Just did this today on a friend's Model A so that I could adjust the rods and mains. No way could I get a socket up there without turning the steering wheel to full right lock.
Marshall
Click to expand...

I find that a 1/4” drive extension and socket works best on the pan bolts.
 
I use 10w30 in my a on a regular basis, I change it when it gets dark, and never had a problem with it. straight grade 30 and 10w30 have the same viscosity at room temperature, it's at low temps in the winter that it behaves like a 10 weight. I prefer multi-weight oils for that reason. As far as detergent oil vs non, if you have a stock babbitted engine, either is fine, but on an insert engine you need nondetergent or an oil filter if you run detergent. Babbitt can take detergent since any dirt that gets into the bearing is glazed over. Inserts can't do that, and you'll eventually score up the bearing and the crank.
 
You must log in or register to reply here.
Back
Top