Oil change intervals

Doublebase · October 1, 2018

19 hours ago, Grumpy Bear said:

Then this should amuse you.

http://www.sbintl.com/tech_library/articles/tlc_of_your_valves_temperatures_loads_and_corrosive_environment.pdf

(quote) Normal temperatures on intakes range from 600° to 800° F in the center of the head of a light duty job to 800°-1000° F for a heavy-duty application. At the seat face, those temperatures range from 200°-400° F on light duty engines, to 400°-600° F on heavy-duty engines. As with seat faces, the under head areas are relatively mild on both types — about 200°-300° F on light duty to 300°-400° F on heavy-duty jobs. (end quote)

We are not worried about the combustion side and as for the plenum side...well...not tough duty for Amsoil or Red Line.

Many on this site claim no concern at all for bulk oil temperatures over 235F. Which is it? Deal or no Deal?

http://www.sbintl.com

The article doesn't reference direct injection engines. Port injection engine will have fuel sprayed on the back of the valve dropping temperature, direct injection does not. When the back of the valve gets covered in carbon, the carbon acts as an insulator and the valves can get red hot...to the point of the heads popping off and dropping right into the cylinder. And keep in mind that the stem is also exposed through the intake port - and heat will travel up the stem - with no fuel being sprayed on that portion, carbon gathers even more. I'd say this is where the most accumulation occurs, even more so than the seat area (because the seat is cooler).

I'm reading that the number one concern with direct injection engines and oil, is NOACK. Dexos approved oil has to meet a specification regarding NOACK. I've read seven is ideal.

So with the goal of limiting oil burning on the back of valves and causing the problem of carbon buildup and sludge, I'd think a NOACK rating is important, no?

Edited October 1, 2018 by Doublebase

Grumpy Bear · October 2, 2018

4 hours ago, Doublebase said:

The article doesn't reference direct injection engines. Port injection engine will have fuel sprayed on the back of the valve dropping temperature, direct injection does not. When the back of the valve gets covered in carbon, the carbon acts as an insulator and the valves can get red hot...to the point of the heads popping off and dropping right into the cylinder. And keep in mind that the stem is also exposed through the intake port - and heat will travel up the stem - with no fuel being sprayed on that portion, carbon gathers even more. I'd say this is where the most accumulation occurs, even more so than the seat area (because the seat is cooler).

I'm reading that the number one concern with direct injection engines and oil, is NOACK. Dexos approved oil has to meet a specification regarding NOACK. I've read seven is ideal.

So with the goal of limiting oil burning on the back of valves and causing the problem of carbon buildup and sludge, I'd think a NOACK rating is important, no?

Because the fuel doesn't do much cooling. The air does. The heats your eluding to happen on the combustion chamber side of the valve. Most of a fuels ability to cool comes from...vaporization....which doesn't happen to any significant degree in a carbureted or port injection motors until after entry into the chamber. To that point it's a mist at WOT and at PT even though MAV is high the amount of fuel is low. Heat of vaporization. Ever see a "wet" flow bench? Russ Collins, sort of a fuel injection expert, pioneered them for this purpose.

FYI motor fuels end point is 430 F. That's the point the heaviest ends evaporate. Under heaviest loads then (WOT) the fuel which is at atmospheric pressure can't fully vaporize. At part throttle the load is so low there isn't enough sensible heat available to drive the valve temperatures very high. A point made in that post. Vaporized liquids are what make swamp coolers work. Your AC or Frig. Swirl and tumble got to be a big deal because fuel doesn't vaporize well in the intake system. It's the reason GDI pressures are so high. Thousands of pounds. Truth is less than 40% of the fuel is a vapor before entering the chamber and it is in the minority.

NOACK and oil 'burning' on valve backs. You do know this happens to carbureted motors as well right? Seen in at it's worst in motors with guide wear and/or shot seals that draw raw oil in past the inlet guides. Motors that smoke when you lift. Less a function of PVC systems. They continue to run for decades.

Here's the bottom line. IF NOACK was the issue then we would be saying that the vapor temperature (PCV introduced at the valves back side) at the bulk oil level is above 482F and in that case NOACK and valve deposits are the least of our worries. Your talking about oil in the vaporized state, right? Not a mist but literally a vapor like steam is to water. Above the boiling point of the lightest ends at that pressure. Not likely in NORMAL service which brings me to the last point.

People that write that drivel making a worst case statement and leaving that little fact out. It is worst case. I saw a 'news' story the other day on CNN. Quote" Will Cosby get the full 30 years?" News doesn't end with a question mark, sensationalization does. Your motor will die if you run unleaded gas in a motor with iron seats was a bust too. Only in extended high load conditions did it have ANY effect at all. For Joe Average is was a non-event. Sold allot of cars and useless machine work however.

Grumpy Bear · October 2, 2018

20 hours ago, Black02Silverado said:

If anyone is interested in some crazy oil change interval, check out this 40k mile oil change interval on a Honda with 393k miles on it. Yes the last oil change took 22qts make up which is about a qt in every 2k miles. But before that it was a qt in 10k miles. This guy is really wanting to see how things go to the extreme.

Know what you call a motor that uses that much oil with todays ring and valve seal technology? JUNK! Yea, yea. GM says a quart in a thousand is NORMAL. Use to be during the days of the 454 they denied motor claims until it got worse than a quart in 400 miles. that was normal too. A quart in 10K before and he sees no issue? I wonder what it would take to get his attention?

KARNUT · October 2, 2018

My 92 truck engine uses a qt every 500 miles. Has for the eight years I’ve owned it. I’ve had decided early on to play it out to see what happens. No smoke to speak of no leaks. The cats must come into play. Has always run great, 5 or 10 lbs of boost. Synthetic or reg oil the same. Two other vehicles used oil every 2500 miles 94 Z28, 99 Ford p/u. The Ford had a S/C installed no change for the worst. All lasted past 100K miles. Both of those fell under normal usage according to the manufacturer.

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Doublebase · October 2, 2018

19 hours ago, Grumpy Bear said:

Because the fuel doesn't do much cooling. The air does. The heats your eluding to happen on the combustion chamber side of the valve. Most of a fuels ability to cool comes from...vaporization....which doesn't happen to any significant degree in a carbureted or port injection motors until after entry into the chamber. To that point it's a mist at WOT and at PT even though MAV is high the amount of fuel is low. Heat of vaporization. Ever see a "wet" flow bench? Russ Collins, sort of a fuel injection expert, pioneered them for this purpose.

FYI motor fuels end point is 430 F. That's the point the heaviest ends evaporate. Under heaviest loads then (WOT) the fuel which is at atmospheric pressure can't fully vaporize. At part throttle the load is so low there isn't enough sensible heat available to drive the valve temperatures very high. A point made in that post. Vaporized liquids are what make swamp coolers work. Your AC or Frig. Swirl and tumble got to be a big deal because fuel doesn't vaporize well in the intake system. It's the reason GDI pressures are so high. Thousands of pounds. Truth is less than 40% of the fuel is a vapor before entering the chamber and it is in the minority.

NOACK and oil 'burning' on valve backs. You do know this happens to carbureted motors as well right? Seen in at it's worst in motors with guide wear and/or shot seals that draw raw oil in past the inlet guides. Motors that smoke when you lift. Less a function of PVC systems. They continue to run for decades.

Here's the bottom line. IF NOACK was the issue then we would be saying that the vapor temperature (PCV introduced at the valves back side) at the bulk oil level is above 482F and in that case NOACK and valve deposits are the least of our worries. Your talking about oil in the vaporized state, right? Not a mist but literally a vapor like steam is to water. Above the boiling point of the lightest ends at that pressure. Not likely in NORMAL service which brings me to the last point.

People that write that drivel making a worst case statement and leaving that little fact out. It is worst case. I saw a 'news' story the other day on CNN. Quote" Will Cosby get the full 30 years?" News doesn't end with a question mark, sensationalization does. Your motor will die if you run unleaded gas in a motor with iron seats was a bust too. Only in extended high load conditions did it have ANY effect at all. For Joe Average is was a non-event. Sold allot of cars and useless machine work however.

I guess I'm confused at the point you're trying to make. Are you saying NOACK won't help in keeping oil from burning on the back of valves? Are you saying that direct injection engines do not have this problem at all? Or are you saying that it just doesn't matter, nothing you do will help the situation? Because engines - GM engines specifically in the Equinox and others - very much have a problem with oil/carbon/ deposits on the back of their valves. Some as little as at 30,000 miles. Then it hardens. Then it can break off and goes into the cylinder.

The fuel doesn't do much cooling? That goes against everything I've ever heard.

https://www.sae.org/publications/technical-papers/content/971729/

Aside from this ^^^small, short article, just yesterday I read that fuel does most of the cooling and air does very little in the intake to cool the valves.

http://www.enginebuildermag.com/2017/10/solving-gasoline-direct-injection-issues-facts-fictions-gdi/

Gasolone is cold to the touch, it will instantly absorb the heat from your hand. A fuel injector will spray a fine mist - I've never seen an injector do anything but - it's not a stream it's a mist. Then it atomizes.

And PCV systems are very much a huge contributor to oil entering intakes. I'd say more so than valve guide wear nowadays. The PCV systems have become almost an afterthought by manufacturers lately. Just yesterday I was reading this. One system - a GM - has the oil return from the head (where it drops down back into the crankcase) right over where the PCV exits the crankcase. Oil gets sucked right out and into the intake.

Have you ever taken a throttle body off and taken a look inside an intake on some of these engines today? There is so much oil tracking and pooling in these things that it's ridiculous. Even my Silverado with 14,000 miles on it has a very noticeable amount of oil pooling inside my intake manifold. Blowby isn't helping - and that's a DI issue, along with oil consumption - the fuel is sprayed right into that cylinder at high pressure and the fuel is mixing with the oil on the cylinder walls and it's burning it...and then the blowby is heavier...the oil mist carried out with the PCV is heavier, then it condenses right in that intake (or catch can if you have one). Then wam! Here comes the back of the valves and it fries like it's been left on the stove too long. The contradiction is once those deposits are formed, heat (excessive heat) will do a much better job at removing a deposit. But heat - the initial heat and oil contact - will fry it on there.

Do I think NOACK is a scam? Hell I don't know but why not take a look into it and give it consideration? DEXOS certifications seem to be giving it consideration. Hell, Valvoline just put a new oil on the shelves designed specifically for DI engines.

This video discusses the importance of NOACK and ways to combat carbon buildup on valves due to direct injection. It's in the later portion of the video, right after the catch can segment.

Edited October 2, 2018 by Doublebase

Grumpy Bear · October 3, 2018

WOLF!

There are three GDI motors on this property. All GM and all 2014 or newer. Two with over 75K on them. Yes I had a look inside and down the runners of the 4.3 around 50K as saw nothing I haven't seen in those same places in healthy motors for the past 50 years that I routinely drive to a quarter million. So here's what I'm saying:

"Known to be an issue" is not the same as "Know it WILL BE an issue".

Well...and I'm doing something obviously wrong if I don't have the same issues that are certain to happen. Wonder what that might be?

gone_fishing · October 3, 2018

1 hour ago, Grumpy Bear said:

Yes I had a look inside and down the runners of the 4.3 around 50K as saw nothing I haven't seen in those same places in healthy motors for the past 50 years that I routinely drive to a quarter million.

I'm just curious how you did that? Endoscope camera?

Grumpy Bear · October 3, 2018

2 hours ago, gone_fishing said:

I'm just curious how you did that? Endoscope camera?

Yes.

gone_fishing · October 3, 2018

3 minutes ago, Grumpy Bear said:

Yes.

Thanks. Might have to try this on my Sierra.

Crobinson16 · October 4, 2018

Grumpy bear , what oil do you use?

Grumpy Bear · October 4, 2018

2 hours ago, Crobinson16 said:

Grumpy bear , what oil do you use?

Red Line High Performance.

Crobinson16 · October 4, 2018

7 hours ago, Grumpy Bear said:

Red Line High Performance.

What weight?

Grumpy Bear · October 4, 2018

19 hours ago, gone_fishing said:

Thanks. Might have to try this on my Sierra.

I would be interested in your observations please.

1 hour ago, Crobinson16 said:

What weight?

0W20 but if I were not running extra cooling (180 F thermostat) it would be 5W30.

Edited October 4, 2018 by Grumpy Bear

gone_fishing · October 4, 2018

Just now, Grumpy Bear said:

I would be interested in your observations please.

For sure. I think it will be at least a few weeks but I plan to remove the TB and clean it as it's been awhile. I have one of those USB endoscopes that hook to your phone. I'll see if I can get it to snake through the intake manifold and down to the ports. I have 142,000 miles on my 5.3 with a catch can on since about 21,000 miles.

Doublebase · October 6, 2018

On 10/3/2018 at 9:46 AM, Grumpy Bear said:

WOLF!

There are three GDI motors on this property. All GM and all 2014 or newer. Two with over 75K on them. Yes I had a look inside and down the runners of the 4.3 around 50K as saw nothing I haven't seen in those same places in healthy motors for the past 50 years that I routinely drive to a quarter million. So here's what I'm saying:

"Known to be an issue" is not the same as "Know it WILL BE an issue".

Well...and I'm doing something obviously wrong if I don't have the same issues that are certain to happen. Wonder what that might be?

So what you're saying is, is that carbon buildup on DI engines either doesn't happen, or is not an issue. And you're saying that issues with DI engines do not exist.

I find that to be a very interesting statement/opinion. It goes against the grain of everything I've read, and heard from people in the industry. I work in the industry, I teach automotive and I'm the department chair of several trades (metal fab, culinary, autobody, automotive), but my background is automotive. Therefore I have to stay current in the industry. I mentioned your opinion at an advisory board dinner the other night to a few factory reps and shop foremans...that carbon buildup and DI issues don't exist. They replied, "like hell it doesn't". Where did you hear that? Now at this point I was a little embarrassed because I had to tell them, from a guy on the internet in one of these forums I frequent. Which is ok because I think there is valid information on forums, and I have read your stuff and feel as if you have good opinions. And to be honest...I think forums have some of the best and latest industry trends (if you sift through and find it).

Now perhaps Silverados are getting away without carbon deposit issues? I think it's too early to say. And there's a difference between "dirty" and causing problems (misfires, check engine lights, power loss). However I have read that other GM vehicles have had their issues. And based off the testaments from people I talked to the other night; Audi, Mercedes, BMW and VW, all are having serious, expensive issues.

I would not let oil go past 7,000 miles on an interval with DI. These guys are telling me that the particulates they are finding in the ring lands because of direct injection is worse than they see on Diesel engines. The rings are getting stuck and the consumption is through the roof. And they are very much participating in intake removal and valve cleaning, due to misfires, power loss...from carbon build up.

Edited October 6, 2018 by Doublebase