The reason I am posting this message is because I am finding after letting my 73 Swinger with 225 sit for a few days, and then starting it cold, I find it takes some time for the oil light to go out. Prior to my last oil change, I don't remember this being an issue at all.

This got me to research information on this forum- but it has left me with many more questions than answers, which is why I am now posting this message.

My first two questions are my main questions.

Question #1 - The oil filter I use, and have used for many years, is the Purolator L14670. Is this a good oil filter to use or not?
It is commonly found in auto parts stores such as Advance and AutoZone.

I see most people here suggest using Wix oil filters, which I can get at O'Reilly's or NAPA. The Wix cross reference for this oil filter is #51068. However I see people suggest that I should use Wix 51515 or 51806 instead. However when I research Wix filter #51806, I come up with vehicles like Allis Chalmers, Caterpillar, Massey Ferguson, etc. i.e. not automotive applications. Filter #51515 does show Dodge/Plymouth vehicles from the 60s and 70s with slant 6s as well as V8s. I read the comments about the filter 51806 having an internal standpipe. Do I need a filter that has one if I already have one?

Question #2 - I have a standpipe mounted on the oil pump as I mentioned. Isn't this supposed to prevent oil drainback into the crank case? How is the oil draining back, judging from the 5 or so seconds it takes the oil light to go out upon cold start up, if I already have one of these?

I do not remember having an issue using Purolator L14670 before. Did I just get a bad filter this time, maybe?
Does the little screen in the standpipe need to be cleaned out, maybe?

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I began reading people's posts on oil and ZDDP additives also.
I use 10W-40 oil and people say not to use it, it leaves deposits in the oil pan. This is what I typically use.

Question #3 - why is 10W-40 a worse grade oil to use than say 10W-30 or 15W-40? Shouldn't the brand you use matter more than the grade, in terms of leaving deposits, or not? My reasoning for using 10W-40 oil is because 10W, when cold, should provide fast lubrication to the bearings. But I drive the car more in the summer when the weather is hot, so 40 weight should help on hot days and long highway trips. Am I right or wrong here? I would think 10W-30 would be too thin for an older engine with looser tolerances.

Question #4 - I see comments not to use STP oil treatment. I have been using this to add some ZDDP to the engine oil since modern oils no longer have it - but I saw comments that STP oil treatment is not good to use. Why not? If it's not good, what else should I use as a zinc additive?

The whole goal here is to create as little engine wear as possible to allow for long engine life.

Thank you.

Your oil filter choice is fine, but it's still an inexpensive mass produced item and you may have received one with a defective anti-drainback valve. It's an easy thing to substitute to see if your oil light behavior returns to normal.

The longer 51515 Wix filter gives increased oil and dirt capacity, but this is usually not an issue. Oil filters have been downsized as fuels, oils and engines have improved as these things generally lead to less oil contamination. The filter with the standpipe may help some people sleep better at night, but I've gotten good service from anti-drainback valves and therefore don't see a need.

All we know if your symptoms. Is oil really draining out of the filter? Could it be the oil suction pipe losing prime? Again, the easiest thing is to change the oil filter and re-test. The standpipe will keep the oil filter from being siphoned dry, but just to the level of the standpipe.

There is no screen in the standpipe. Just a little spring and plate.

10W-40 requires more viscosity index improvers to cover the broad range from SAE 10W to SAE 40. These are polymers and not lubricant. Old 10W-40 oils had a lot of these polymers and they appeared to have had a roll in deposit formation. Oils are better now and this is probably not the issue that it was. https://www.machinerylubrication.com/Re ... -improvers

Modern oils still have ZDDP. You can probably find your oil here and see just how much zinc and phosphorous were found in the test sample. https://pqia.org/passenger-car-motor-oil/ Only special-use cases need more ZDDP than a correctly formulated oil.

If you really want long engine life make sure the air filter is doing a good job. It's far more important than the oil filter. The carburetor and choke need to function correctly so that lubrication is not washed off the cylinder walls. The engine needs to run at a high enough temperature to drive condensation out of the oil. The PVC system needs to function to evacuate moisture and other contaminants from the crankcase.

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Joshua

Actually, it's even easier than that. Wait until many hours have elapsed, unscrew the filter and look inside. Given the symptoms, I predict it will be bone dry, won't even drip down the engine when you unscrew. In which case, it's pretty much guaranteed you got a filter with a bad anti-drainback valve. Especially considering you report this never happened prior to the most recent oil change.
Important, yes. More important? I'll just quietly disagree. A nerve-wracking 5 seconds of running without oil, every morning, is going to turn a wonderful engine into an oil-smoking pig within a few tens of thousands of miles. I'd guess 40-60k, based on two experiences with Toyotas where the owners didn't realize that startup noise was a problem.

You've no doubt seen Russ Knize's tests, which are interesting especially for the conclusions about common manufacturers, but are now nearly 20 years old. I loved the Purolator PureOne but cannot find it anymore, so now I do Wix. I also just stumbled on this rebuttal. Lots to read.

Bottom line, get a good quality filter with a silicone anti-drainback valve. You are absolutely correct to cringe when an oil light is illuminated.

- Erik

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Lots of early Valiants and Barracudas have crossed my path.
Also a handful of other toys for variety now and then.

Yes, the oil filter is less important than the air filter. Far more vehicles were built without oil filters than air filters. Engines produce far fewer contaminants internally than they inhale from the atmosphere.

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Joshua

Guys

Thanks for your comments. I did take the filter off to see what was going on last night. The car had sat 3 or 4 days without being started.
And yes, you were right in that very little oil drained out when I took the filter off. However it wasn't like there wasn't any in there, there was some, just not a lot.

I've been trying to use shorter filters over the years, such as this one (Purolator L14670) or STP S16 (I think that's the right number) through the years because the filter is shorter, about the length of the standpipe, so there will be less drain back, which would lead to oil pressure coming up faster. Maybe it is not necessary to use shorter filters if the anti drainback valve works as it's supposed to.

I thought with the standpipe there, this situation couldn't happen. But as you suggested, maybe the suction pipe is losing prime.
And yes, I'll try another filter and re-test it and see. It's easy enough to do. Maybe a bad filter is all it is.

Thanks for your other comments also.

The short filter/drainback bit doesn't hold a lot of water.....

STP oil treatment? Well....in this day and age, the oils are so good you really don't need to treat them and it's probably not a good idea to do so.

I'm all for having good oil pressure on start-up. But....I also have to admit that even if it takes a second or two to build pressure, the net effect of that (with a Slant Six) is you will see a reduction in engine life of being able to reach only 575,000 miles instead of 600,000 miles.

As a side note, I was reading on some Indy engines and was interested by the fact that they are unable to start cold. Each engine must first be brought up to operating temperature with heated oil and heated coolant before they're ever started. I offer this in contrast to the Slant Six which can be started cold and run without a thermostat or oil for a few months.....

someone mentioned adding STP to get additional ZDDP

This video with lab test results says otherwise, in fact the SPT has less ZDDP than the store brand motor oil.
The video also has a clip of running (maybe ruining is a better word) a lawn mower on 100% STP,, I don't think anyone would ever recommend that.

https://www.youtube.com/watch?v=mqiUFklL_XI&t=3s

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Doo Ron Ron and the Duke of Earl are friends of mine.....
https://www.youtube.com/watch?v=uX8Nj8ABEI8

My thoughts on using STP as an oil additive were this:

I never used to use any oil additive when I changed my oil.

Then, I remember about 10 or so years ago there being a lot of discussion about how zinc was being taken out of modern oils because it inactivated the catalytic converters in new cars. Also newer (1990 and newer) cars typically have roller lifters, so the use of zinc was not necessary.

So, the engines of older cars that used non-roller lifters would experience higher engine wear if they used modern oils.

STP is readily available and doesn't cost an arm and a leg, and it has ZDDP, so at some point, I don't remember when exactly, maybe 5 years ago, I started using it in my older cars.

It was reading other people's posts on this forum that made me question my practices.

So you're saying ZDDP has not been removed from modern oils as I had heard ~10 years ago?

If STP does not help, then what is a good readily available ZDDP additive to use?

I take it you didn't look at the oil analysis results by PQIA. Go see how much zinc and phosphorus are in the oil you use. For stock slants it's usually plenty. If you want more you can use Chevron Delo LE that has more.

_________________
Joshua

I use STP mixed 50-50 with motor oil for assembly lube when I put motors together.

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Official Cookie and Mater Tormentor.

watch the video, STP has less ZDDP than the store brand oil, so by adding STP, by volume you are reducing the ZDDP content.

And like Josh mentioned, know what you are buying, he posted the links to additive package analysis....

_________________
Doo Ron Ron and the Duke of Earl are friends of mine.....
https://www.youtube.com/watch?v=uX8Nj8ABEI8

and that is probably OK for old school motors like slant sixes,,but I use genuine old school assembly lube.

https://www.lubriplate.com/Products/Gre ... es/NO-105/

the engine assembly plant the I hired into in 1972 had 55 gallon drums of Lubriplate 105 all around the engine assembly area.
It was slathered on everywhere.
By the time I retired in 2016, there was virtually no assemble lube used in the new engine assembly process.
The only place where lube was applied was at the station where the intake and exhaust valves were inserted.
And there it was a very light mist. And that was to apply a fix for trucks that would set for months at a time on a dealer lot and
very occasionally have a sticky exhaust valve, due to the engine only being ran for a very short time and then getting condensation up into
the valve guides. Just a drop of oil in the guides fixed that.
Of course, by 2016 the parts surface finish, profile and cleanliness were vastly improved. There was also a dry film rust inhibitor on all the iron and aluminum parts,,,
But really everything was super clean and made to close tolerances that fit together.

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Doo Ron Ron and the Duke of Earl are friends of mine.....
https://www.youtube.com/watch?v=uX8Nj8ABEI8

I thought I posted in here, was poking at my phone on my lunch hour, I don't see it.....
I also use 10w40 year round in everything. No synthetic. Change every 4k miles, always have, very rarely go over on miles by very much.
If I ever get something newer than what I will call "318/360 technology" I'll probably go thinner on oil/ with overhead cams and such....
I also am a fan of the biggest filter I can use.... I know what everyone says about modern day Fram (and i haven't used one in years) but many tend to use their numbering system....
I believe the Purolator equivalent to a PH8A (the old "long" filter) is a L30001. Most Mopars that we normally talk about on a forum like this one now call for a PH16, or a Wix 1085.
the 1068 is like the old Fram PH43. A little longer than the PH16 but shorter than the 8A. As long as frame and body allow any of these can be used interchangeably.
I am in the camp of "use the biggest one of the list that there is room for" It costs exactly the same, and whether the extra capacity is "needed" or not, it probably isn't. But for no extra expense, nothing hurt, and extra filter capacity it definitely can't hurt.
On the 10w40 causing sludge.... I dont see any on my engines..... unless it was badly neglected by a past owner. I have heard that 10w30 actually has more of the "bad" additive in it than 10w40 does. But I am not a chemist. Just what I remember reading somewhere. I don't use STP type additives. But I have used straight STP as assembly lube before.
I have also heard that "Quaker State motors" (ones whose owners regularly used QS as their oil of choice) had more sludge issues than "Pennzoil Motors". I dunno. Just what I remember from guys of my Dad's generation of gearheads.

I have a couple Fram HP1 filters sitting around...now those are filters for manly engines!

I did look at the video actually.

What he is saying in the video may be true - but this is different than what I heard about zinc being removed from engine oils starting around 10 or 12 years ago.

What I was saying was I started using STP ~5 years ago because I heard you should make sure you have zinc in your engine oil on engines without roller lifters - and what I had heard at the time was STP was a good choice. So maybe what I heard is not true, and maybe STP is not the thing to use.

But this is the reason I'm asking - to see what other people use and what they think.

So this isn't true that the oil companies started taking Zinc out of the oil ~10 or 12 years ago due to the zinc inactivating the catalysts in the converters on newer cars? The advice I heard about this is wrong? Currently available motor oils still have the same amount of Zinc they used to have?

It seems to me if I want to add ZDDP, I should add something else. Someone mentioned a Chevron product which I'll look into.

In terms of filters, I used to use Purolator L30001. I also used to use Motorcraft FL-1A. At some point I switched to smaller filters.
I thought the larger ones weren't really necessary. I don't put a lot of miles on my Slant 6s since they are not my daily drivers.
I don't even put 3000 miles a year on them. Maybe 2000. But after a year I change the oil because I think it's time.

I was able to find WIX 51515 at the auto parts store last night, so I plan to try that one next.

I compared it to the Purolator L14670. If I look into the hole where it mounts on the standpipe, the WIX has what looks like an extra rubber gasket and even an extra piece of steel inside that the L14670 doesn't have. I take it this is the anti-drainback valve??