Important Oil Question

[fadingfastsd]

Hey guys, I've got a good one for you.

I searched and read all the oil threads but didn't find an answer to my question.

I did my first oil change in my 51 Concord since I've owned it (2 weeks), and I don't know what the old owner was using for oil.

I used 10W30 Valvoline High Mileage (75k miles +) Synthetic Blend in the car.

When I was first driving it before the oil change, I noticed the oil pressure gauge always stayed around 30-40 at idle, and 40-50 at freeway cruising RPM.

Since the oil change, I've noticed the pressure gauge shows 30-40 at idle when the car IS COLD. When It gets up to temperature (normal operating temp gauge about half way), I get about 40 on the OP gauge at freeway speeds, but it drops to 10 or so at idle.

If I let the car sit and cool down for 30min, start it up, it will idle at 30-40 oil pressure again.

Is this the wrong oil to be using in the car? Too thin?

Need some input on this one. I read about using the diesel oil in these flathead sixes...is that what you guys recommend?

Thanks for the help!

Evan

[48mirage]

The original spec for your oil was probably a straight 30 weight oil. Your 10w30 oil is actually a 10 weight oil with elastomers in it that give the oil properties of a 30 weight oil when it reaches operating temperatures. I don't think you are going to hurt anything. Many of us use a rule of thumb want to maintain 10 lbs per every 1000 rpm. Living in southern California with moderate temperatures year round you would probably be more comfortable with a heavier oil. The worst of todays oils are much better than the oils that were available when our cars were new. Next time you add or change oils use the wally world brand of a straight 30 weight oil and see if your pressure doesn't come up. And if you believe in snake oil (this product I do), Lucas oil stabilizer works for me.

[55 Fargo]

The original spec for your oil was probably a straight 30 weight oil. Your 10w30 oil is actually a 10 weight oil with elastomers in it that give the oil properties of a 30 weight oil when it reaches operating temperatures. I don't think you are going to hurt anything. Many of us use a rule of thumb want to maintain 10 lbs per every 1000 rpm. Living in southern California with moderate temperatures year round you would probably be more comfortable with a heavier oil. The worst of todays oils are much better than the oils that were available when our cars were new. Next time you add or change oils use the wally world brand of a straight 30 weight oil and see if your pressure doesn't come up. And if you believe in snake oil (this product I do), Lucas oil stabilizer works for me.

Not sure about Wallyworld staright 30 or 40, the Wallworld Tech or Supertech oil is re-refined oil, my experience with it was not good, it would thin out when warm, and mt flattie would puff blue.

Since switching back to Castrol 20 W 50, no issues, I like this oil and Rotella 15 W 40, for flatties.

I also have heard good things about Lucas oil additives, whether it's snake oil or not is to be seen...........Fred

[48mirage]

I don't know where you get the re-refined oil idea. I would suggest that the blue puff you are seeing is either bad rings or valve guides. If it was smoking all of the time rings, If on deceleration bad exhaust valve guide. The suggestion to try the wally world oil for the experiment would be to reduce his expenses not a recommendation of their product. I use different manufacturers in my different vehicles because I use them differently. I don't see how a modern API certified oil could harm his 57 year old engine.

[Plymouthy Adams]

property of oil does not break down, it does however get dirty with use and will lose it additives (detergents) over time...re-refined oil is filetered and the additives put back in..there is no reason not to use this oil..if that is what you want to buy..it does meet specifications. As for additives, on my engines with hydraulics lifters and at 75000 miles and up..a shot of Rislone is my recommended medicine

The scenario you described with the lower oil pressure is common using a multi weight oil..follow 48mirage's recommendation..you be ok..

[greg g]

I have been using 15-40 diesel oil from Tractor supply company. It is rated for all engines, is about 9 bucks for a 1 gallon container. I believe it still contains the ZDDP stuff, and it compares well o specifications to the Shell Rotela oil sitting on the shelf next to it. Mine runs 25 psi at idle hot and 45 going down the road. The rebuild has about 6K on it.

[55 Fargo]

I don't know where you get the re-refined oil idea. I would suggest that the blue puff you are seeing is either bad rings or valve guides. If it was smoking all of the time rings, If on deceleration bad exhaust valve guide. The suggestion to try the wally world oil for the experiment would be to reduce his expenses not a recommendation of their product. I use different manufacturers in my different vehicles because I use them differently. I don't see how a modern API certified oil could harm his 57 year old engine.

Phone Wal Mart and they will tell you, Wal Mart Tech or Super Tech oil, is re-refined in Chicago, by Safety Clean Products.

I have no issues since I have returned to Castrol GTX 20 W 50, I do not burn oil on acceleration or deceleration.

My engine compression is 105 to 110 across the board, oil pressure is 40 lbs at an idle, and 50 to 55 at highway speeds. The engine is not rebuilt, has miles on her, but when I removed the valve covers, next to no sludge.

I have used Wallyworld oil on other engines, but have since only used some better products.

Phone Wal Mart, ask them where the Tech or Super Tech oil is made, I am not talking about there synthetic line.

I have done this research last spring,sorry will not use Wallyworld house oil again, only my opinion.

As far as governement requirements and standards, well hopefully they are reliable, not sure how much I trust huge wealthy oil companies, but I suppose quality control is regulated.........

[55 Fargo]

property of oil does not break down, it does however get dirty with use and will lose it additives (detergents) over time...re-refined oil is filetered and the additives put back in..there is no reason not to use this oil..if that is what you want to buy..it does meet specifications. As for additives, on my engines with hydraulics lifters and at 75000 miles and up..a shot of Rislone is my recommended medicine

The scenario you described with the lower oil pressure is common using a multi weight oil..follow 48mirage's recommendation..you be ok..

Tim you use Risilone, so did I at times.

And Mirage you are absolutely right on the oil viscosities, he is certainly better off using the heavier oil you have recommended

[fadingfastsd]

Wow, thanks for all the responses and great discussion guys, I appreciate all the information.

I think I will go to a straight 30weight oil very soon, most likely Castrol GTX, as I have ran that in my motorcycles for years and have had good results.

I guess my main question now, is WHY is this happening?

What about this 10w30 is causing it to lower oil pressure at idle when it gets to normal operating temps? Does it being a synthetic blend or the "high mileage" specific oil have anything to do with this?

Or is it just too thin of an oil, and at higher operating temps it just cant build up higher pressure as it thins out?

Thanks again everybody!

Evan

[48mirage]

Rockwood and Tim Adams, I'm not sure I would have much faith in anything a wal-mart clerk would have to say about the technical aspects of any product. But let's give them the benefit of the doubt. The Supertech oils are distributed by Warren Distribution of Omaha. They buy in bulk from the low cost supplier and repackage the products. Look at there vendor line card and you will also see Castrol listed. As far as the re-refining process. In the '90's I worked at the then Texaco refinery in El Dorado Kansas. We processed used oil also. It was taken to the Coker unit where under high temperature and pressure the lighter elements were seperated and the heavier elements broken down into lighter elements by thermal cracking. The resulting products were lighter smaller hydrocarbon chains that were seperated and sent back to the different units for further processing and blending. The "leftovers" was what is called petroleum coke. This coke is used in the making of steel, glass and as a feedstock in electric generating units (my current employment). There is no filtering and there is no way to tell a re-refined molecule from a "virgin" molecule. Even if your entire feedstock was used oil the coking process would only give you hydrocarbons. Those are then seperated by their boiling points and used in millions of ways.

[Uncle-Pekka]

My engine is quite worn, I've had problems with oil pressure. When I ran 10W30 last summer the pressure was hardly even 20Ibs running 50mph road speed. Dropped to zero idling a hot motor. Since I only drive in summers I changed to old time 40 weight mineral this summer. Pressure is much better now: 35-40Ibs after starting cold almost any rev. 30Ibs at 50 mph hot motor, even will stay 5-10Ibs at low revs when hot.

Another issue I heard from a fellow who has loads of experience on pre-war engines: The told the valve lubrication on most flatheads is based on vaporized oil. He said that modern syntethic or semi- oil is "too good" as it does not turn to vapor even in high temperatures, thus actually it is lacking á feature that is necessary for the flathead "health"...

[55 Fargo]

Rockwood and Tim Adams, I'm not sure I would have much faith in anything a wal-mart clerk would have to say about the technical aspects of any product. But let's give them the benefit of the doubt. The Supertech oils are distributed by Warren Distribution of Omaha. They buy in bulk from the low cost supplier and repackage the products. Look at there vendor line card and you will also see Castrol listed. As far as the re-refining process. In the '90's I worked at the then Texaco refinery in El Dorado Kansas. We processed used oil also. It was taken to the Coker unit where under high temperature and pressure the lighter elements were seperated and the heavier elements broken down into lighter elements by thermal cracking. The resulting products were lighter smaller hydrocarbon chains that were seperated and sent back to the different units for further processing and blending. The "leftovers" was what is called petroleum coke. This coke is used in the making of steel, glass and as a feedstock in electric generating units (my current employment). There is no filtering and there is no way to tell a re-refined molecule from a "virgin" molecule. Even if your entire feedstock was used oil the coking process would only give you hydrocarbons. Those are then seperated by their boiling points and used in millions of ways.

Mirage, the Tech oil inthe USA may come from a different source/location than in Canada, I did not get this information from a clerk, I got the info from the Wal Mart of Canada head of Automotive Services Canadian Division In Toronto, he then directed me to Safety Clean, I then spoke with the Manager of the oil refinery in Chicago, this is when and how I got this info on what and how Super Tech/Tech oil is manufactured, at least for the Canadian market..........Fred

[greg g]

There is a factor that needs to be cosidered for optimum lubrication. The rotating parts of engines rely on a cushion of oil that fills the tolerence area between bearings and crankshafts. That cushion of oil relies on fluid flow and not necessarily pressure. If your oil pump is worn, it may be indeed building pressure against the thicker oil, but because of this may not be providing the quantity of oil to insure the cushion is maintained. High oil pressure is not an accurate measure of the oiling systems performance.

It's is an important part, but in a worn engine it may not be the most improtant.

[Uncle-Pekka]

There is a factor that needs to be cosidered for optimum lubrication. The rotating parts of engines rely on a cushion of oil that fills the tolerence area between bearings and crankshafts. That cushion of oil relies on fluid flow and not necessarily pressure. If your oil pump is worn, it may be indeed building pressure against the thicker oil, but because of this may not be providing the quantity of oil to insure the cushion is maintained. High oil pressure is not an accurate measure of the oiling systems performance.

True - but... I've checked my oil pump. The pump has been replaced, it is tight and producing flow. The problem are worn main bearings. The oil pressure is low because there is much more space for the oil to run through than spec allows. In the hydrodynamic theory, however, main factors are speed, viscosity and area. In the case of worn engine (crosscut area grown) it is easiest to work with the viscosity of oil.

[Young Ed]

I believe the flatheads loose oil pressure first from worn cam bearings. Then worn rod and mains follows.

[RobertKB]

I run 20w50 in all three of my flatties. One is a fairly recent rebuild and two are a little tired. In the tired engines I also add a can of STP if I see any sign of the oil pressure dropping when the engines idles hot. I have put tens of thousands of miles on these engines and they all run great. My two cents worth.

[Don Coatney]

I believe the flatheads loose oil pressure first from worn cam bearings. Then worn rod and mains follows.

You are correct Ed;

Just another reason you should be the POC President

[Plymouthy Adams]

As oil pressure is the loss of resistance to flow, loss of pressure would be first indicator of the wear in main bearing..now I will agree that in this condition the first sign of this (other than flutter on start up cold engine) would be loss of oil to hydraulic lifters in modern engine and their rattle, ticking being first indicator..the cam is fed from the crank as are the rod bearings...