Motor Oil

[Dale M.]

Disel Motor Oil

I have seen other concerns with using diesel motor oil in gas engines. Are there facts showing that diesel motor oil contains higher percentage of detergent and if so, what is the effect of this higher levels of detergent. Are there other additives that may effect a gasoline engine? If I remember correctly, the base oil is the same. Thanks for any enlightenment.

[Duke W.]

Re: Motor Oil

ZDDP is consumed with use, but more than 1400 ppm P initially can cause long term problems. The ideal amount of P to start with in vintage engines is about 1200 ppm with oil change intervals of no more than 5K miles. The P analysis of current CJ-4 oils is 1100-1200. SM is 600-800. I recommend avoiding any "boutique oils" that have more than 1200 P, and you don't need to add ZDDP supplements to CJ-4. A vintage engine does not need more than 1200 ppm P to start with and there are long term corrosion mechanisms that have been observed with very high levels of ZDDP.

The rate of ZDDP consumption is a function of internal engine sliding surface loading and engine condition. For example, gorilla valve springs and lots of low speed operation is going to consume ZDDP more rapidly than OE springs under the same operating conditions. The worst case for cam/lifter wear is idle because the low relative surface speed between the lobe an lifter generates the lowest hydrodynamic pressure. If this is not sufficient to support the spring load, rapid cam-lifter wear is likely.

Most modern DOHC designs use a roller trunnion rocker arm with a roller element against the cam lobe. GM's Ecotec engine is typical. Early direct acting DOHC valvetrains generally had low loading due to light valves and very mild springs that were adequate for 7000 RPM operation, so they so they can get away with less ZDDP, but, nevertheless, I use CJ-4 in my Cosworth Vega, which has a direct acting DOHC valvetrain. It just doesn't make any sense to use SM in any vintage engine, when CJ-4 is available at about the same price.

The CV valvetrain limiting speed is about 9000, and the dual springs yield a seat force of about 75 pounds and 195 pounds at max lift of .339". That's slightly less than the nominal closed/open forces of the 3911068 SB spring. The lobes bear against the hardened valve lash shims which are over 1" in diameter (wider than the Chev. V8 lifter, which is 0.842") with a wider lobe than on a SB, so loading is lower than on a SB and much lower than a BB, which uses the same lifter and lobe width as a SB cam, but has higher spring loading. CV cam lobes and shims usually mic within OE tolerance on these old engines, despite abuse and lack of proper maintenance.

You should reread the article, then go to the Web reference sites, take the online courses and download and read the API 1509 document.

Duke

[Duke W.]

Re: Disel Motor Oil

I have seen other concerns with using diesel motor oil in gas engines. Are there facts showing that diesel motor oil contains higher percentage of detergent and if so, what is the effect of this higher levels of detergent. Are there other additives that may effect a gasoline engine? If I remember correctly, the base oil is the same. Thanks for any enlightenment.

More myths and misinformation.

Prior to SL many oils were dual rated, but some primary C-category oils had more detergent/dispersant, which can cause more foaming, so more anti-foaming additive is required. It may have been adviseable to avoid high detergent levels in very high revving racing engines, but this is not applicable to road engines.

Detergent levels in both C-category and S-category oils may be less than ten years ago and C-category acid neutralizer concentration has been reduced because it is designed for use with low sulpher diesel fuel - comparable to the sulpher levels in gasoline.

The next time anyone comes up with "I heard" or "my engine builder says" ask them for sources - SAE or ASTM papers - some sort of bonafide scientific/engineering research. Or do you own research to see if any claims can be verified. I'm frankly getting tired of responding to all this BS, which often comes from Web bloggers who are at best, shadetree mechanics, and don't even know about API and oil certification or have any educational/professional background in engine design or lubrication.

Next time someone comes up with "I heard", state the source and what you have done to validate or refute the claim.

Duke

[Bill B.]

Re: Motor Oil

A good rule of thumb for non-roller camshafts is not to go over .485 lift and you will never have problem using any 1200 ppm ZDDP CJ-4. I personally would not use any 1400 ppm or higher oil in non-racing applications. There will be two or three new oils introduced in early May that will address the non-roller vintage engine enthusiast. Will keep you updated.

Bill



1961 Black/Silver/Red Int. 283/315 FI
power windows. Frame off 65% completed.
1989 hard top daily driver 165,000 miles

[Jim L.]

Re: Motor Oil

......and there are long term corrosion mechanisms that have been observed with very high levels of ZDDP.

How about explaining what these are and what constitutes "long term".

Thanks,

Jim

[Duke W.]

Re: Motor Oil

How about explaining what these are and what constitutes "long term".

Thanks,

Jim

I don't have any detailed information on them - read a reference to them in some papers/articles I looked at including one from a GM engineer. Maybe you or someone else can research it. I'm getting tired of being the only guy...

Long term would mean years, which would apply to most of us and our cars.

If anyone wants to buy a high priced non-API certified boutique oil with more than 1200 ppm P or add a ZDDP supplement to CJ-4 to drive the P analysis well above 1200 go ahead - it's your car, but keep in mind that over its life it never saw an oil with more than 1200.

I've spent waaaaaaaaaaaay more time than I should researching and writing about engine oil, and I'm tired of answering questions that people come up with from "engine builders" and every bubba out there in cyberspace. This subject has been absolutely beaten to death and I'm through.

Anyone who reads The Corvette Restorer including the Web educational references I offered in the article and this TDB should have enough knowledge to separate the wheat from the chaff and make their own decisions.

Duke

[Jim L.]

Re: Motor Oil

I don't have any detailed information on them - read a reference to them in some papers/articles I looked at including one from a GM engineer. Maybe you or someone else can research it. I'm getting tired of being the only guy...

OK, Duke, I'll try to track it down. Since you had mentioned that corrosion mechanism a couple of times, I thought you might know something about it.

Jim

[James W.]

Re: Motor Oil

Great discussion. The ZR-1 Net Registry has been at the fore of this discussion, as at least two members believe they have had cam failures due to the lack of ZDDP in their oils. I've talked to the Amsoil guys and seems like a good product, but ..................... the ZR-1 uses 10 qts every change and they are definitley a high priced item.

That being said, I ran across the two papers listed below. One talks about "oil myths" and the other s a product guide for Mobil 1 oils. It lists the ZDDP in each type of oil and the recommended application for each. Good reading. Based on what I have heard and read I am using Mobile 1 Diesel, which according to the chart attached, has about 1100 PPM. Sounds about right and the price is reasonable, not to mention that it is a known quantity.

Jim

http://www.zddpoiladditive.com/techbrief2.pdf

http://www.mobiloil.com/USA-English/MotorOil/Files/Mobil_1_Product_Guide.pdf

[James W.]

Re: Motor Oil

I've tried to post this earlier, so here goes again. There have been two ZR-1s that I know of that have suffered cam failures to what they think is oil failure. The ZR1netregistry has been talking about this for several weeks and have come up with some interesting information. I'm putting two links in. The first is an reference guide from Mobil giving all the amounts of ZDDP in all their oils and the suggested application. The second is an article discussing (Oil Myths"). Just some additional information.

Based on what I've seen and read I'm using Mobil 1 Diesel, which has 1100ppm ZDDP, which sounds about right, plus it is known to hold up over time.

My $0.02

Jim

http://www.mobiloil.com/USA-English/MotorOil/Files/Mobil_1_Product_Guide.pdf

http://www.zddpoiladditive.com/techbrief2.pdf

[Patrick H.]

Re: Motor Oil

I've tried to post this earlier, so here goes again.
Jim

Jim,

Not sure why you can't see it, but your previous post is sitting there right above this one....

Patrick

[Tom M.]

Re: Motor Oil

Great discussion. The ZR-1 Net Registry has been at the fore of this discussion, as at least two members believe they have had cam failures due to the lack of ZDDP in their oils. I've talked to the Amsoil guys and seems like a good product, but ..................... the ZR-1 uses 10 qts every change and they are definitley a high priced item.

That being said, I ran across the two papers listed below. One talks about "oil myths" and the other s a product guide for Mobil 1 oils. It lists the ZDDP in each type of oil and the recommended application for each. Good reading. Based on what I have heard and read I am using Mobile 1 Diesel, which according to the chart attached, has about 1100 PPM. Sounds about right and the price is reasonable, not to mention that it is a known quantity.

Jim

http://www.zddpoiladditive.com/techbrief2.pdf

http://www.mobiloil.com/USA-English/...duct_Guide.pdf

We talking about new 2009 ZR1 or 90-95 , 70-72 ?

regards Tom

[Tom M.]

Re: Motor Oil

I've tried to post this earlier, so here goes again. There have been two ZR-1s that I know of that have suffered cam failures to what they think is oil failure. The ZR1netregistry has been talking about this for several weeks and have come up with some interesting information. I'm putting two links in. The first is an reference guide from Mobil giving all the amounts of ZDDP in all their oils and the suggested application. The second is an article discussing (Oil Myths"). Just some additional information.

Based on what I've seen and read I'm using Mobil 1 Diesel, which has 1100ppm ZDDP, which sounds about right, plus it is known to hold up over time.

My $0.02

Jim

http://www.mobiloil.com/USA-English/MotorOil/Files/Mobil_1_Product_Guide.pdf

http://www.zddpoiladditive.com/techbrief2.pdf

OR THE 15W-50 SHOULD WORK FOR YOU ?? roller or flat tappet ?what year ZR1 ?
That is the same thing my engine builder was telling me too. they are taking some Zinc out of the newer oils to same money, all new engines are for the most part roller lifters, "SOME" not all flat tappet cams are having this problem, so it is very important that we use the correct oil for our cars

[Patrick H.]

Re: Motor Oil

OR THE 15W-50 SHOULD WORK FOR YOU ?? roller or flat tappet ?what year ZR1 ?
That is the same thing my engine builder was telling me too. they are taking some Zinc out of the newer oils to same money, all new engines are for the most part roller lifters, "SOME" not all flat tappet cams are having this problem, so it is very important that we use the correct oil for our cars

My suspicion - and it's just that, having read a lot of these threads - is that some builders/owners/etc have "lost" flat tappet cams for a compilation of reasons. Over the past few years we've had poorly manufactured solid lifters, similar quality with some camshafts, changing oil specs, and quite a bit of poor planning when it comes to building an engine. Throw it all together and you have a recipe for disaster. I, too, know people (firsthand) who have had flat tappet cams "wiped out" on a new engine; one of my patients lost two in a row.

However, as many have pointed out, if you pay attention and plan well I do not think that anyone should be worried. If you pick quality products (especially lifters), choose a camshaft with solid specs and ramps that aren't beyond reason, select properly matched valvesprings, add some EOS or similar when breaking in a flat tappet cam and choose an oil with a proper (not too little and not too much) amount of ZDDP, you will do fine.

Unfortunately such guidelines are not always followed, or parts do not originate from a reliable source even when we think they do. So, problems arise and the blame gets spread around.

So in the case of your Torino, Tom, I doubt you need to change to a roller cam if you select reasonable springs and a reasonable cam profile. Your builder has probably been burned just like my patient was, and he too went to a roller cam for his 3rd try. However, I don't think it was necessary in his case and likely would not be in yours.

I am somewhat skeptical that a 1990-95 ZR-1 motor (LT-5) with original cams and valvetrain would have a camshaft destroyed by any "modern" oil. Even at the level of 800ppm of ZDDP (the lowest in Mobil1) I think they'd be fine since they should be well past the break in period. In addition, since they have catalysts they really don't want to go to a high ZDDP oil or they will run the risk of killing their cats.

Just my thoughts after reading a bazillion posts on this, as well as some of Duke's references.

Patrick

[Joe L.]

Re: Motor Oil

My suspicion - and it's just that, having read a lot of these threads - is that some builders/owners/etc have "lost" flat tappet cams for a compilation of reasons. Over the past few years we've had poorly manufactured solid lifters, similar quality with some camshafts, changing oil specs, and quite a bit of poor planning when it comes to building an engine. Throw it all together and you have a recipe for disaster. I, too, know people (firsthand) who have had flat tappet cams "wiped out" on a new engine; one of my patients lost two in a row.

However, as many have pointed out, if you pay attention and plan well I do not think that anyone should be worried. If you pick quality products (especially lifters), choose a camshaft with solid specs and ramps that aren't beyond reason, select properly matched valvesprings, add some EOS or similar when breaking in a flat tappet cam and choose an oil with a proper (not too little and not too much) amount of ZDDP, you will do fine.

Unfortunately such guidelines are not always followed, or parts do not originate from a reliable source even when we think they do. So, problems arise and the blame gets spread around.

So in the case of your Torino, Tom, I doubt you need to change to a roller cam if you select reasonable springs and a reasonable cam profile. Your builder has probably been burned just like my patient was, and he too went to a roller cam for his 3rd try. However, I don't think it was necessary in his case and likely would not be in yours.

I am somewhat skeptical that a 1990-95 ZR-1 motor (LT-5) with original cams and valvetrain would have a camshaft destroyed by any "modern" oil. Even at the level of 800ppm of ZDDP (the lowest in Mobil1) I think they'd be fine since they should be well past the break in period. In addition, since they have catalysts they really don't want to go to a high ZDDP oil or they will run the risk of killing their cats.

Just my thoughts after reading a bazillion posts on this, as well as some of Duke's references.

Patrick

Patrick----


I believe that 94-95 LT5's were factory-filled with Mobil 1.

[Duke W.]

Re: Motor Oil

I am somewhat skeptical that a 1990-95 ZR-1 motor (LT-5) with original cams and valvetrain would have a camshaft destroyed by any "modern" oil. Even at the level of 800ppm of ZDDP (the lowest in Mobil1) I think they'd be fine since they should be well past the break in period. In addition, since they have catalysts they really don't want to go to a high ZDDP oil or they will run the risk of killing their cats.


Patrick

I agree. Like my Cosworth Vega I believe the nineties ZR-1 DOHC engine has a direct acting valvetrain and loading is likely modest. As I said before, I have seen Cosworth Vega engines that have been abused beyond believe, but worn cam lobes are essentially unheard of.

BTW that's 800 ppm P, not ZDDP. P (phosphorous) is the surrogate element for measuring ZDDP concentration.

Once added, ZDDP cannot be directly determined, but spectroscopic analysis breaks down the molecule and the amount of phosphorous can be measured.

Duke