I'm sure this has been asked about, but I wanted to know if I use a oil filter with a stand pipe and a anti drain back valve can I remove the stand pipe in the oil pump and drill out the 3/8 hole in the fitting that the filter screws to. I was wanting to increase oil volume. My slant turns right at 3 grand at 75 MPH

Answer to your question is "yes", but what indication do you have that you need to get more oil through that point in the system?

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Well I might be crazy for thinking this but my reason is the 500 mile trips I take to visit family I would think is hard on the engine. That's kind of why I asked. Would it not be better for the engine at those sustained rpms? Thanks Dan

My slant turns 3 grand at 60 mph, and runs that rpm for miles and miles and miles several hours at a whack traveling to different car shows through the boondocks of Maine nonstop. The engine could care less as long as there is sufficient good quality oil in its sump, and quality filter screwed on.

Back in the seventies when I didn’t mind long hours, cold weather, and running up and down steep hills, I worked winters while at university making snow nights at a local ski area. Water was sourced a quarter mile or more away, delivered via pipe from a stream to the hill by a propane fueled slant six driven pump. That thing was run at 3000 to 4000 rpm, I don’t recall exact speed, but it was cranked right up running for 12 hours nonstop every night; it never gave a problem for the several years I performed this job. I had to check three elderly finicky Cat powered compressors and this pump hourly, record oil pressure and coolant temperatures for these engines. The slant just mustered on unruffled on oil changes during season, and most likely a seasonal plug and point change along with a valve lash setting at the beginning of each season.

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67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

Wix filter and Rotella15/40 every 5 thousand miles. Thanks for the info I'll leave her alone and just keep on keeping on.

I run 10-30, change oil once a year which = around 3-4 K miles, and sometimes add a quart between changes.

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67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

I still have my original oil pump and standpipe but replaced the oil relief valve spring with a hemi spring (75 psi). For my last oil change, I used 15W-40 and my oil pressure is consistently at 75 psi above 2000 RPM (maybe even at lower RPM). I've been topping up with a 10W-30 HDEO (Rotella T) to bring the viscosity down. If you've got a stock relief valve spring, you are probably blowing-off back to the sump even more than I am. However, my owner's manual does recommend 20W-40 (similar to 15W-40) for ambient temperatures consistently above 32°F.

An oil pump is a positive displacement pump, which means that it pumps the same flow rate at a given RPM (except for a small amount of internal leakage around the gears) regardless of viscosity or standpipe configuration. Higher viscosity oil will develop more backpressure (what the oil pressure gauge and relief valve are sensing) due to higher flow resistance. Excessive pressure will cause some oil to flow back to the sump. For more flow to the bearings, I would use an oil grade that keeps the pressure below the relief valve setting.

Steady-speed highway driving is about the easiest operation of an engine. Short trips in cold weather are among the worst. As long as you have enough oil pressure, don't worry about visiting your family.

But this is 2012 and we have 2012 oils…this is not 1965 with 1965 oils (and thank god for that). For an engine in good mechanical condition with good (small) bearing clearances, 20W-anything is way too heavy; all it'll do is slow (way) down engine lubrication on startup, throw extra load on the oil pump (and thereby on the oil pump drive pinion/cam worm, and eat up gasoline and power unnecessarily. It will not offer you anything in return for these deleterious effects: no extra protection, no extra cooling, no extra margin of safety, nothing. Same for 15W-anything. If you've got a nice low-miles engine with nice tight bearing clearances, use 5w30 and get the benefit of fast engine lubrication on startup and reduced parasitic load. If the bearings are a skoshe looser than that, use 5w40. If they're a little looser than that, use 10w30. If you can't maintain proper oil pressure at hot idle with 10w30, then use 15w40.
Agreed! The above recommendations are general guidelines, but if you want to be precise and methodical about it, use a good mechanical oil pressure gauge to measure oil pressure with the engine hot and idling. Use the lightest-viscosity oil that gives proper oil pressure under those conditions.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

The second number (40) in an SAE grade is more important than the first (15W or 20W) once the engine is warm. The advantage in using a 40-weight oil over a 30-weight oil is that 40-weight oils have a stronger fluid film (measured by their HTHS rating). HTHS (High Temperature / High Shear) is a measure of an oil's ability to maintain its viscosity under load. The minimum HTHS viscosity for various SAE grades are:

• 2.6 cP - SAE 20 (all)
• 2.9 cP - SAE 30 (all)
• 3.5 cP - SAE 0W-40, 5W-40, 10W-40
• 3.7 cP - SAE 15W-40, 20W-40, 25W-40, 40
• 3.7 cP - SAE 50 (all)
• 3.7 cP - SAE 60 (all)

The higher the HTHS viscosity, the stronger the fluid film in the bearings. If you're going to tow a heavy load at low RPM, HTHS viscosity will help to protect your bearings. Lower HTHS viscosity will provide better fuel economy.

Quite true. Check the calendar, though; we're heading into the time of year when we have to think about genuinely cold, cold starts.
Yahbut, it's important that doesn't mean a 40 is necessarily better than a 30 in general or in particular. There are other (very) important performance characteristics of engine oil beside fluid film strength. Sludge resistance, viscosity maintenance, pour point, etc. For years, petroleum 10w40 was a bad choice because it tended to exhibit poor sludge and viscosity-maintenance characteristics -- to pick one example. Today's 10w40s, particularly synthetics, are certainly better.

Still, I wouldn't pick a 40 over a 30 for an engine in good shape with tight bearing clearances being used for anything like normal service; the theoretical benefit of a higher film strength would be countervailed by greater parasitic drag and greater wear with every cold-engine startup, waiting for oil circulation.

Extreme-duty service (heavy hauling/towing), yes, go for the higher film strength. The problem is a lot of people don't realise that what's best for heavy-duty service is not best (or better) for standard service.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

The important thing is to have enough film strength and more than enough just wastes fuel. I just used 15W-40 last oil change because I had no other use for it.

That's why it's important to have a lawnmower even if you have no lawn.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Unless you have a roller cam in your slant you should be useing 15w-40 oil, 15w-40 is a diesel rated oil and has the zinc additive that keeps our flat tappet cams from wearing, from what I have read the new 5-30,10- 30,10-40 oils don't have the zinc in them, the zinc was pluging up the catalytic converters so the oil companies removed it. This was when the manufactuers went to roller cams, if you use the lighter oil I beleive there is a additive you can add to the oil, I use w15-40 in any engine I service with a flat tappet cam

Nope, I disagree -- and there are a great many slant-6 engines represented on this board alone that are doing just fine in the long (long long) term on oils other than unnecessarily-thick 15w40.
Not only is that not categorically true, but it's also old info. Outdated. No longer correct.

If it'll make you all warm and fuzzy to use a special oil you believe to have special protective powers, go for it, but please see previous discussions here and here.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

I ran 30W diesel oil in my old worn out slant. It helped keep the oil pressure from taking a nose dive during the 100* summers we have down here in GA. But of course this was with a well worn 270,000 mile engine in a truck. Before that my uncle had always ran Quaker State 10W-40 in the truck so it was full of crap and sludge. I had to short change the oil and filter a couple of times after switching to diesel oil because of all the stuff that was being broke loose inside the engine, as well as drop the pan and clean the crap out of the bottom.

That engine is currently being rebuilt, so after the break in period I plan on going to 30W synthetic or 10W-30 synthetic. If I lived in a colder climate I could get away with 5W-30.

One plus to diesel oil is that it's really loaded with detergents. It looks super nasty when you change it but the inside of the engine stays clean. This is when it pays to have a good oil filter.

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82 D150-225/727
02 Dakota-3.9/5 speed
87 GMC C7000-8.2 Detroit Diesel/5+2