Oil leak..switch from 10w 30 to 20w 50? - Chevelle Tech
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post #1 of 11 (permalink) Old Jul 23rd, 14, 5:58 AM Thread Starter
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Oil leak..switch from 10w 30 to 20w 50?

Hey guys, I have been running castrol gtx 10w 30 for a year or so in my 327sb. I do not know the history/miles in this motor (but am assuming it's high milage)and have been considering moving up to a thicker oil. I live in SoCal by the coast so cold starts are a non issue for me. I also have a small leak I was thinking a thicker oil might remedy. Is this a good place for thicker 20 50? Also, I am assuming it has oe flattappitcam so what oil do you recommend or zinc additive I can add to regular gtx?

Any input would be greatly appreciated!
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post #2 of 11 (permalink) Old Jul 23rd, 14, 2:11 PM
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Derrick
 
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Re: Oil leak..switch from 10w 30 to 20w 50?

thicker oil won't stop a leak.

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post #3 of 11 (permalink) Old Jul 23rd, 14, 2:34 PM
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Re: Oil leak..switch from 10w 30 to 20w 50?

ditto, plus, if your rod and main clearances are not "oversized" for one reason or another, then dont run the 50 wt.
If you have a lot of miles and your oil pressure is running a little on the low side, then do it. It should raise it up a small amount.
wont stop a leak though.

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post #4 of 11 (permalink) Old Jul 23rd, 14, 3:21 PM Thread Starter
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Re: Oil leak..switch from 10w 30 to 20w 50?

The leak really isn't that bad, my main concern is just engine wear and what's best for te my old motor. Iv gone through a dozen posts and have concluded I don't want to go higher than 10w as that doesn't lube that well on start up. Would Somethin like a synthetic 0w 40 or 0w 50 (if they have a spread that large) be good for high milage engines? My oil is ready at a consistent 40-45 psi, idle or driving cold or hot so idk if that gauge can be trusted
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post #5 of 11 (permalink) Old Jul 23rd, 14, 4:44 PM
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Re: Oil leak..switch from 10w 30 to 20w 50?




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post #6 of 11 (permalink) Old Jul 23rd, 14, 5:15 PM
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Re: Oil leak..switch from 10w 30 to 20w 50?

I use 5w-30 Mobil1 High mileage in my 396.


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post #7 of 11 (permalink) Old Jul 24th, 14, 3:08 PM
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Re: Oil leak..switch from 10w 30 to 20w 50?

Quote:
Originally Posted by Bikebro View Post
Hey guys, I have been running castrol gtx 10w 30 for a year or so in my 327sb. I do not know the history/miles in this motor (but am assuming it's high milage)and have been considering moving up to a thicker oil. I live in SoCal by the coast so cold starts are a non issue for me. I also have a small leak I was thinking a thicker oil might remedy. Is this a good place for thicker 20 50? Also, I am assuming it has oe flattappitcam so what oil do you recommend or zinc additive I can add to regular gtx?

Any input would be greatly appreciated!
Do NOT assume using a high zinc oil is the best choice for a flat tappet cam. I've extensively tested over 130 different motor oils for their load carrying capacity which shows how well they prevent wear. I found that high zinc oils rank between number 4 and number 133, which VERY CLEARLY shows that simply having a high level of zinc is no guarantee of superior wear protection. If a high level of zinc was a guarantee of superior wear protection, then all high zinc oils would rank at the top of the list. But, that simply is NOT the case.

And if that itsn't bad enough, my testing clearly showed that adding aftermarket zinc additives actually makes an oil worse, NOT better. Many wiped flat tappet lobes COULD HAVE BEEN AVOIDED, including at break-in, if people had not blindly believed that all high zinc oils provide all the wear protection they need. Because nothing could be further from the truth. That whole line of thinking that you need high zinc oils for adequate wear protection has been completely debunked by Engineering tests, and is nothing more than an old wive's tale. See my Oil Testing Blog link below to see what oils really provide the best wear protection.

As for viscosity to use, 20W50 is way too thick. Consider the benefits of using thinner oil:

• Thinner oil flows quicker at cold start-up to begin lubricating critical engine components much more quickly than thicker oil can. Most engine wear takes place during cold start-up before oil flow can reach all the components. So, quicker flowing thinner oil will help reduce start-up engine wear, which is actually reducing wear overall.

• The more free flowing thinner oil at cold start-up, is also much less likely to cause the oil filter bypass to open up, compared to thicker oil. Of course if the bypass opened up, that would allow unfiltered oil to be pumped through the engine. The colder the ambient temperature, and the more rpm used when the engine is cold, the more important this becomes.

• Thinner oil also flows more at normal operating temperatures. And oil FLOW is lubrication, but oil pressure is NOT lubrication. Oil pressure is only a measurement of resistance to flow. Running thicker oil just to up the oil pressure is the wrong thing to do, because that only reduces oil flow/lubrication. Oil pressure in and of itself, is NOT what we are after.

• The more free flowing thinner oil will also drain back to the oil pan quicker than thicker oil. So, thinner oil can help maintain a higher oil level in the oil pan during operation, which keeps the oil pump pickup from possibly sucking air during braking and cornering.

• The old rule of thumb that we should have at least 10 psi for every 1,000 rpm is perfectly fine. Running thicker oil to achieve more pressure than that, will simply reduce oil flow for no good reason. It is best to run the thinnest oil we can, that will still maintain at least the rule of thumb oil pressure. And one of the benefits of running a high volume oil pump, is that it will allow us to enjoy all the benefits of running thinner oil, while still maintaining sufficient oil pressure. A high volume oil pump/thinner oil combo is preferred over running a standard volume oil pump/thicker oil combo. Because oil “flow” is our goal for ideal oiling, NOT simply high oil pressure.

• Oil flow is what carries heat away from internal engine components. Those engine components are DIRECTLY oil cooled, but only INdirectly water cooled. And better flowing thinner oil will keep critical engine components cooler because it carries heat away faster. If you run thicker oil than needed, you will drive up engine component temps. For example: Plain bearings, such as rod and main bearings are lubricated by oil flow, not by oil pressure. Oil pressure is NOT what keeps these parts separated. Oil pressure serves only to supply the oil to this interface. The parts are kept apart by the incompressible hydrodynamic liquid oil wedge that is formed as the liquid oil is pulled in between the spinning parts. As long as sufficient oil is supplied, no wear can occur. In addition to this, the flow of oil through the bearings is what cools them. Here are some comparison numbers from an 830 HP road race engine on the track:

15W50 oil = 80 psi = 265* oil sump temperature

5W20 oil = 65 psi = 240* oil sump temperature

Here you can see how the thicker oil flowed more slowly through the bearings, thus getting hotter, driving up bearing temperatures and increasing sump temperatures. And the thinner oil flowed more freely and quickly through the bearings, thus cooling and lubricating them better than thicker oil, while also reducing sump temperatures. If an engine is running hot, use a thinner oil to increase flow, increase internal component cooling, and help keep sump temperatures down. Keeping oil temps down is important to help keep oil below the threshold of thermal breakdown.

• Thinner oil will typically increase HP because of less viscous drag and reduced pumping losses, compared to thicker oils. That is why very serious Race efforts will generally use watery thin oils in their engines. But, an exception to this increase in HP would be in high rpm hydraulic lifter engines, where thinner oil can allow the lifters to malfunction at very high rpm. In everyday street vehicles, where fuel consumption is a consideration, thinner oils will also typically increase fuel economy. The majority of new cars sold in the U.S. now call for 5W20 specifically for increased fuel economy. And now Diesel trucks are increasingly calling for 5W30, also for fuel economy improvement.

• With the exception of high rpm hydraulic lifter engines, almost no engine should ever need to run oil thicker than a multi-viscosity 30 weight. The lower the first number cold viscosity rating, the better the cold flow. For example, 0W30 flows WAY better cold than 20W50. And 0W30 flows WAY better cold than straight 30wt, which is horrible for cold start-up flow and should be avoided at all cost. And the lower the second number hot viscosity rating, the better the hot flow. For example, 0W30 flows WAY better hot than 20W50.

• Thicker oil DOES NOT automatically provide better wear protection than thinner oils. Extensive “dynamic wear testing under load” of over 100 motor oils, has shown that the base oil and its additive package “as a whole”, is what determines an oil’s wear protection capability, NOT its viscosity. For example, some 5W20 oils have proven to provide OUTSTANDING wear protection, while some 15W50 oils have only been able to provide MODEST wear protection. So, do not run thicker oil under the false assumption that it can provide better wear protection for our engines.

• BOTTOM LINE: Thinner oils are better for most engine lubrication needs.

540 RAT

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To see my entire 130+ motor oil “Wear Protection Ranking List”, along with additional motor oil tech FACTS (with over 40,000 “views” worldwide), here’s a link:

http://540ratblog.wordpress.com/

Last edited by 540 RAT; Jul 24th, 14 at 3:28 PM.
post #8 of 11 (permalink) Old Jul 24th, 14, 3:26 PM
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Re: Oil leak..switch from 10w 30 to 20w 50?

Manufacturers recommend high zinc oils for flat tappet cam breakin. Warranty is bad enough even when using their recommendations but I'm pretty certain if it were not used any warranty would be out the window for certain. Wht's a guy going to do?

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post #9 of 11 (permalink) Old Jul 24th, 14, 3:28 PM
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Re: Oil leak..switch from 10w 30 to 20w 50?

Quote:
Originally Posted by 71454Chevelle View Post


As long as your engine's requirements don't exceed that oil's load carrying capacity, you'll be fine using that oil. But, just because your engine hasn't blown up while using a certain oil, that doesn't mean it is a great oil to use or recommend. Because you may well have a very small reserve protection capability with that oil, meaning if things go bump in the night and your engine's loading goes up, your oil may not be able to save your engine. And that's precisely why I started performing motor oil wear testing, so that I could find out which oils truly provided the best wear protection.

Consider the following:
An oval track dirt racer (his class is extremely competitive, so he asked that his name be left out) on the SpeedTalk Forum runs a 7200 rpm, solid flat tappet, 358ci Small Block Chevy motor, with valve spring pressures of about 160 on the seat and 400 open, that are shimmed to .060” from coil bind. The rules and the combination of parts, were causing him to experience repeated cam failures while using high zinc, semi-synthetic 10W30 Brad Penn, Penn Grade 1 motor oil. Lab Report Data from testing performed by Professional Lab, “ALS Tribology” in Sparks, Nevada, showed that this oil contains 1557 ppm zinc, 1651 ppm phosphorus, and 3 ppm moly. In spite of this being a high zinc oil, that most folks would “assume” provides excellent wear protection, he experienced wiped lobe cam failure about every 22 to 25 races.

A race consists of one 8 lap (a lap is typically 3/8 mile) heat race and one 20 lap feature race, plus any caution laps. If you add it all up, 25 races only total about 281 miles at the point of cam failure. So, that is a perfect example of what I’ve been saying all along about high zinc levels being absolutely NO GUARANTEE of adequate wear protection. And my test data on this 10W30 Brad Penn, Penn Grade 1 motor oil, shows that it produces a wear protection capability of only 71,206 psi, which puts it in the MODEST wear protection category, and it ranks a very disappointing 100th out of 133 oils tested so far. That means of course that there are 99 different oils I’ve tested that provide better wear protection.

So, my test data ACCURATELY PREDICTED EXACTLY what he experienced during racing. And that is, that this oil does not provide high enough wear protection capability to provide a sufficient margin of safety for this engine’s operating conditions. Looking at my “Wear Protection Ranking List” and choosing a much higher ranked oil, would have prevented all those cam failures. Repeatedly suffering cam failures in motors with so little time on them, may have been considered by some folks to be a normal consumption of parts back in the ‘60’s or ‘70’s. But, in the 21st Century that we live in now, by any measure, that is for sure premature failure. We no longer have to accept that as the cost of doing business, because we can do far better now.

So, he switched to the super micro polished billet lifters from PPPC and the cam life went up to 40 races, which was an improvement since he could now go 450 miles between failures. But, that was still clearly unacceptable. Then 2 years ago he started using “Oil Extreme Concentrate” as an additive to the 10W30 Brad Penn, and he’s never lost a lobe on a cam since. Adding the “Oil Extreme Concentrate” completely eliminated his premature wiped lobe cam failures. Now the motor has now gone 70+ Races without issue, and is still doing fine. This “Oil Extreme Concentrate” is one additive that actually works as advertised, and makes low ranked oils far better than they were to begin with. And that is PRECISELY WHAT MY MOTOR OIL TEST DATA PREDICTED as well.

Here’s how. I also added “Oil Extreme Concentrate” to 10W30 Brad Penn, Penn Grade 1 semi-synthetic, as part of my motor oil “Dynamic Wear Testing Under Load” research. And with 2.0 OZ of “Oil Extreme Concentrate” added per qt, which is the amount intended for racing, its wear protection capability shot up by a BREATH TAKING 56%, to an amazing 111,061psi, which puts it in the INCREDIBLE wear protection category, and now ranks it a jaw dropping 6th out of 133 oils tested so far. So, it moved up a whopping 94 ranking positions, just by adding the “Oil Extreme Concentrate”. This totally accounts for the reason all his cam lobe failures were eliminated, and clearly proves that my oil test data predicts what we can expect from a motor oil.

But, I don't generally recommend that people use any additives at all. I recommend that they choose an oil that provides excellent wear protection right out of the bottle.

540 RAT

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To see my entire 130+ motor oil “Wear Protection Ranking List”, along with additional motor oil tech FACTS (with over 40,000 “views” worldwide), here’s a link:

http://540ratblog.wordpress.com/
post #10 of 11 (permalink) Old Jul 24th, 14, 4:50 PM
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Re: Oil leak..switch from 10w 30 to 20w 50?

One thing missing is the challenge against your findings from an oil manufacturer. I do find this interesting. You have clearly stated your findings but the question remains as to the ceritfication of your specific method of testing. If it were to become to industry standard it would validate your claims. I'm not suggesting your method to be bad or good, I just wonder which method the oil industry uses for their testing.

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post #11 of 11 (permalink) Old Jul 24th, 14, 8:11 PM
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Re: Oil leak..switch from 10w 30 to 20w 50?

I don't want to argue with RAT540 as his testing is fine for ball bearings and their loads. He uses the three ball steel to steel test. But, the 327 we are talking about has other issues. If high mileage and wear are in the mix, there is need for cushion in the growing clearances.

The cam is well past break-in and running stock springs (?), so the pressures are not likely enough to cause a problem. It's run this long ...

Synthetics have a drain-off issue when sitting for even a few days. Start a high mileage motor on synthetic after 4 days of sitting and you will hear every bearing clatter until full flow is re-established. That's why I quit synthetics on any motor over 100K.

I use Delo400, Rotella, or Delvac 15-40 on all high mileage motors in my mini-fleet. I have OEM engines well over 200K and they are running just fine. They pass smog inspections, have reasonable fuel mileage and just keep going. And they do not rattle on cold start when sitting for weeks.

On a new tight motor where pressure points might develop during break-in, I have no problem with more modern oils, syn-blends, etc. But once you cross 100K, things are different ...

And on the Zinc additive - RAT540 has been dosing his tests with full doses per the additive MFG recommendations. That would be fine if the base oils did not have any, but they do. So his tests have been over dosed. I add ZDDP to in small doses (one or 2 oz depending on the oil at hand) to get back up to a 1500 PPM level and I have had very good luck with this approach for years now.

So let's bring this discussion back to the OP's motor - high mileage with leaks. Why put $6~10 a qt oil in such a motor. Fleet oils will get it to the logical end of it's life just fine. Better investment is a good oil filter and slightly more frequent changes.

If he wants to know if there is immanent bearing failure or something, send an oil sample off for analysis and know for sure ...
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