About to do the first oil change. Got a wix and 5 qts of Brad penn 20w50.

Question- Do I need to add an additional zinc additive?

 

Why 20/50 on fresh engine? No additional additives are required.

 

I agree with Eric, 10w30 should be fine for your car. Perhaps look for some oil that already has some zinc., 20w50 is a bit treacly for American iron, it is suitable for old British cars with the transmission effectively the engine oil pan.

Roger.

 

Awesome. Thats why I asked. I'll purchase the BP 10w30 then.

 

Huh?
If you have tight clearances then 10w30 is fine. If you're clearances are on the loose side then 15w-40 or 20w-50 is the right choice.

 

I'm guessing it will have close tolerances, if it's a post break in oil change I'm assuming the engine has been rebored.

Roger.

 

Curious, what would reboring have to do with bearing clearances?

 

Old cars didn't come from the factory with that thin of oil. 10w-40 should be as thin as you go. I run Shell Rotella 15w-40 and am happy.

 

I use Brad Penn 10W30 in everything I have that needs zinc. It has plenty of it. Semi-synthetic. Engines run smooth and quiet.

 

The term "Semi synthetic" is like the term " 3/4 race cam" What does it mean???

 

I'm guessing it means it isn't 100% synthetic.

 

Well I worked on the assumption that if it needed breaking in it had been rebuilt. So my thinking that bearings and journals would have been measured for wear and refurbished as required was an extrapolation.
Maybe the OP was just talking about a new camshaft and no other work.

All the information we have is he (or she) had 5 quarts of Brad Penn 20w50 and a Wix, and wanted to do a post break in oil change.

And imo an Oldsmobile that need 20w50 oil really needs a rebuild.

So there. Yah boo

Roger.

 

Ok I'm going to ask again, you specifically said reboring. So what would that have to do with bearing clearances in particular? Am I missing something here?
And any engine, if the bearing clearances are large enough, will require a heavier weight oil. Most all high performance builds include opening up the bearing clearances therefore warranting heavier oil. It has very little to do with it being worn out or not.

 

Your first choice was the better one. Brad Penn oils are all high zinc. I use the BP 15W50 in my performance engines & am happy with it.

 

My two cents is to use 10w30 or 15w40. I googled oil and zddp and found several sources, including a site where a guy compiled 20 brands of oil and their zddp content. From racing oils to off the shelf. Found that Shell Rotella T3 oils is formulated for flat tappet diesel engines with high zddp, had a bit higher than the Valvoline race one.
Priced it at the local O'Reilly's and other auto stores and found it very reasonable. Go to a farm and garden store and get it a bit cheaper yet in gallon jugs.

My initial Oil i put in a napa/valvoline 10w30, with STP. Also used break in lube on the cam lobes and journals when I installed it, and used stp additive on the crank main and rod bearings. I don't plan on running it overly long before I do the first change, as it has been started off and on for nearly two years while at the body shop...

Pics of my car on my profile for those that want to check it out.

 

I think you are. I clarified my earlier post with the second one.
Most all high performance build will also see close attention to maintenance and short intervals between teardowns. Like ten seconds running at full power for a top fuel motor. Maybe a million miles for a locomotive diesel.
For street applications I would use a high volume oil pump for loose bearing clearances.
I also recognise that you build fine engines, and your method works. Maybe a different approach can work just as well.

Roger.

 

Personally, I wouldn't run diesel oil, I had ring stick in two different 350's. One was 15w40 and the other was 5W30. 15W40 was dino and the other 5W30 was semi synthetic and both 1421 PPM Zinc. Maybe it was the cheap Coop brand was the problem but not doing that again. I used Kleenflo Combustion Chamber Cleaner, which I tried to buy on Friday at Acklands, works great to clean sparks and cylinders rings. I just bought a 5.9 magnum was going to shoot some in the cylinders. Told not for sale in Canada, has to go back. Dam hippies are taking over our country. I run 5W20 or 5W30 Quaker State Defy, buying up all the old formula SL oil, new stuff SM. Only other easy to find option is Mystic 0W40 or 10W40 SL motorbike/4 stroke skidoo oil.

 

Maybe? So you don't really know I take it. A high volume pump is a band aid, at best.

Let me explain something to you. When your bearing clearances are larger than normal flowing more oil thru them, even at a higher pressure has little to nothing to do with the film strength of the oil being used. Typically a 20w-50 will have better film strength, load capability or sheer resistance if you will, than a lighter oil. When the clearances are larger you need an oil to be able to fill the void and hold stabile for lack of a better term. Using a thinner oil with bigger clearances, even at higher pressure, is a disaster waiting to happen.

You're right, you do it your way, and I'll do it mine, which even as you stated, I KNOW works.

Thank you.

 

There are articles about that very topic concerning oil clearances and motor oil weight.My clearances are: .0030 mains 1-4 and .0035 on #5.Rods are .0025.I useCastrol 20/50.Surprised a lot of people don't realize the correlation,and how important it is.My oil pressure at cold startup is 65-70 psi,and drops to 35- 40 psi when hot. Idle is 750 rpm's.Full roller, aluminum heads,455F block .Car runs smooth and does see 5500-6000 rpm,from time to time.

 

Ok-
Couple things.

First, thanks for all the feedback I like the debates honestly, it gives you a point of view.

Second, I drive the car once/twice a week and I will drive it during the winter. I built it to burn rubber and to be thrashed from time to time.

third, I don't know what my clearances are as I didn't get a build sheet. I asked him to set piston to wall loose (.005) but deferred to his 30 years in the business everywhere else.

4th- Cold start is 60 Psi, 38ish hot.

Finally- How about a 15w40 BP? Not quite 20w50 but not as thin as 10w-30

 

I mentioned my build has a hyd roller cam.If you are running a flat tappet make sure your oil has plenty of the necessary additives needed to prevent wiping out the cam.I stop using my car around November.I would like to know myself just how light an oil I could use in my build when it gets colder out if I wanted to use it in colder weather.A lot of different opinions.I live on the East coast,winters do get cold.And 20/50 might be too heavy at start up.1BOSS83...Your builder should know your oil clearance specs.

 

As does mine.

Roger.

 

Yanked this from another thread oldscutlass commented on:
https://540ratblog.wordpress.com/
Lengthy but very thought provoking. Couple things stood out to me.
1. If I am reading it correctly (I got through the top 15) the walmart 5w30 synthetics provide the best wear protection. That is great but just shocking because these are

 

My point in asking why the 20/50 I believe is a valid one. The most wear is produced when you start a cold engine. I agree that clearances are the #1 issue for determining what viscosity oil to use. The other issues are temperature, type of usage (racing or heavy towing), type of cam (flat tappet or roller), etc... Oil pressure is not one of them with the exception of older worn engines where 20/50 is used as a band aide. The old rule of thumb, 10# per 1000 rpm, still applies. IMHO, which do you want, high pressure and low flow of a thick oil. Or, a bit lower pressure and higher flow. Its a balance, oil is also used to not only lubricate but to cool moving part surfaces. Main bearing clearances are not the only place where lubrication is essential. The cam/lifter relationship has become really critical in the past few years, I think there are some cases of oil viscosity preventing lifters from spinning properly in their bores causing some of this wear damage.
The argument over pressure, viscosity, and protection has been on going for years. I for one try and use the lower viscosity and a reasonable oil pressure.

 

For whatever reason- The lengthy response I had last night would not populate in its entirety. Whats the story with synthetic use in these flat tapper rebuild situations? yay or nay? My mechanic runs synthetic in a 75 chevy 350, 64 chevy 327 and late model ls motor (same oil in all of them) and has given me a no-nonsense explanation several times as to try and debunk the dogma surrounding oil choices. I am just looking for the right set up for my application. The study listed suggests a modern big brand synthetic coupled with an additive will product the best results.

 

In the article it suggests the additive produced better results than without, however if you read further that additive with other products made the results worse. Some people swear by synthetics and others by dino, its personal preference. Which synthetic does your mechanic use?

If you have 38#s oil pressure hot, I'm assuming with the 30wt breakin oil, I would continue with a 10-30 in winter and see how it does.

 

Oil isn't a one size fits all device, particularly with todays sophisticated engines.
What is the condition of your engine?, newly totally rebuilt or recently fitted with new rings because it's showing signs of wear?.
Is it a weekend strip warrior or a tug for your trailerhome or fishing boat?.
Do you make long trips or just short trips to the Friday cruise in?.
All factors that might affect your final choice.

I prefer to use the thinnest oil that gives good oil pressures, but opinions are like a##holes, everybody has one.

Roger.

 

200 miles on rebuild- New cam, pistons, rings, bearings, crack was cut, .030 overbore, deck squared.

I thrash on it and take highway trips.

 

What is your oil pressure with the break in oil in it?

 

The motor as broken in with 20w50 and zinc additive. The oil was then changed to Valvoline 20w50 at the speed shop. On sat I'll get numbers at:
Cold idle-
Hot idle-
cruise-
Accell-

 

What does the speed shop recommend?

 

That place did a hack job. I picked the car up and the TV cable was so out of wack that I was on a course to burn up my transmission, engine had 44* of total in it. Quoted me a week and it took a month and they were 33% over budget. I reached out to the builder and I'll get his input as well.

 

Assuming the machining wasn't screwed up I think 20w50 is too heavy.
In your position I would use 5w30 or 10w30.
Also, I have never used a specified "break in" oil, way back when I used to fit reconditioned engines I simply used regular oil and changed the oil and filter at 500 miles. Plenty of those engines made 80-100k miles, similar mileages to the factory originals. Like I said, this was way back.

Roger.

 

http://www.bobistheoilguy.com/motor-oil-101/

If you have the time and really want to know about oils these are the articles to read. There are 12 of them.
I think you'll all find that what you thought was correct isn't. It's eye opening but complicated.
Basically what you're going to learn is that all 'engine' oils are designed to flow the same at what's considered normal operating temperature by the automotive industry, 212*F. Start up is a whole different story and using thicker oils can be detrimental on a cold engine at start up where most of that oil is probably going through the by-pass and back into your oil pan than through the engine oil passages.

 

I'll have a read. I read Eric's article too. I really enjoy the articles. Thanks Trip.

 

Thank you.

 

If I read correctly, you said that "you couldn't buy break in oil if you tried". Is that correct?

 

Good question but that's not really what I meant.
What I did mean was that even those oils are different than todays. And more often than not guys aren't installing stock cams back in them either. With faster ramps and higher spring pressure the need for better oil is even greater.
Basically he contended that larger clearances were normally a "mistake". Not true, some builds now require them.

 

Cold Start- 45 psi
Warm idle in gear- 35psi
low rpm cruise- 55psi
acceleration- 60 psi +

 

Id try the 10w30, your pressures will come down a little but your flow will go up.