So I am to get the engine running one of these days, as soon as I get it all back together (pic below). My neighbor (a former diesel mechanic) walks over, compliments me on the engine, and tells me that I should use a non-detergent/additive oil for the initial start-up and even for the first few hundred miles. I go to the parts store and was told they don't even have anything without a detergent these days but I should look elsewhere. My neighbors reasoning for the use of such oil was that it would ultimately improve the break-in process and would allow the parts to wear-in sooner.
Has anyone ever heard of this?

 

I'd use a standard, mineral oil based, detergent SAE 20W or 20 for break in. The detergents are only going to help keep the smaller particles in suspension so the filter can trap them. Any larger particulates are going to end up in the sump. and particles too small to be caught in the filter are also going to be suspended by a straight mineral oil by the sheer flow rates at break-in RPM.

I doubt that you'll find an SAE-graded oil that doesn't have some detergent additives any more. Even Delvac has detergents, even though it is not specifically mentioned on the containers or drums. About the only way to get a non-detergent oil would be to use a base stock from an industrial lubricant supplier, and even those will have rust and oxidation inhibitors blended in. And of course, none of those use the antiquated SAE viscosity grading system.

 

i doubt if you can find any API rated oil for your car/engine that's not detergent, it'd been many many years since i've seen any. i've used 30w dino oil for years to break in new engines with no problems.

 

Ditto ditto. That's a leftover from the days of flat head straight 8s. Modern engine components don't need that. Thank him politely for the helpful tip (in case you could use his expertise later), but don't follow it.

Use a good quality straight 30 weight oil, change it after 500-1000 miles, and again at 3000; after that you can use synthetic if you want, I sure would, 10W-30.

 

sells a non detergent motor oil its marked ND but i forget who makes it i think its kendal but the only weught i seen it in was 30 and 50

 

OK, thanks for the tips. I think I'll go with a decent 30w for the initial start up. I am going to change it after the first 30 minutes but leave the filter.
Now, 30w or 10w-30 for the first 500 miles? I don't understand the point of using a non-variable viscosity oil for break-in versus a variable oil for long term (after break-in) use. A quick explanation would be appreciated.

Thanks and happy Memorial Day!

-Balázs

 

The more "viscosity modifiers" (to produce the spread in the rating) there are in your fixed 5-quart fill, the less oil there is. That's why a single-weight oil is better for break-in. After that, treat it the same as you would a new factory motor.

 

Hyper,

Sorry about the typo in my first post. I meant it to read "SAE 20W or 30", not "20W or 20" (duh).

Anyway, do yourself a grand favor and don't change oil without changing the filter. If you're into saving money, at the very least do it the other way around - change the filter and not the oil. This isn't the time to save $4 on a filter.

As for the single-viscosity versus the multigrade, I'd vote for the straight 30, especially in your climate. Just allow a minute or two for warmup to establish oil flow. 10W30 multigrade is simply 10W base oil with fortifiers that enhance the high temperature viscosity of the oil, so that it acts more like an SAE 30 at higher temperatures. Those fortifiers (polymers) are the first thing to break down in the oil, and add to the sludge, as well as rendering the high temperature characteristics useless. You really don't want an inadequate lubricant right now. Synthetis are a completely different game, but we'll get into that later if you decide to use the better product once the engine is broken in.

Happy Memorial Day to you as well.

 

I'd like to add one point here. And this may be an "old wives tale" too.

I was told in automotive school (10 years ago) that the reason for using straight weight is what Vader and RB said; it's the real deal -no addatives to break down or "displace" real oil.

As for the Non-detergent I was told that this is to be used because DETERGENT oil will "wash" the pre-assembly lube off the parts quicker, and specifically my teacher was talking about the camshaft lobes on a flat tappet cam. This would also apply to any oil run following a flat tappet cam swap.

I suspect you are running a roller cam, which would make this a mute point, but I just wanted to throw in what I "know".