Castrol GTX classic Motor oil 20-50 weight

[desoto1939]

I was doing some searching on motor oil for our old flat head with tappets. Alot of discussion has been posted over the years about the lack of Phosphorus and ZDDP in the motor oil and alot of owners are worried about the camshft lobes and flat tappets get excessive wear.

 

Castrol has recently started a new product for our classic cars call CASTROL GTX CLASSIC 20-50 weight. I wrote to the Castrol Company and was asking for the amount of ZDDP and Phosphorus that is in each quart. They did indicate the parts per million for each.

 

So if you are worried about the lack of these two products then you can use this newer product.  I have found out that some Walmart stores carry the Castrol GTX classic product. The average cost is around $23 for a 5 quart container. Suggest that you either singon to the web page for each store and search for the product or go to your closest store.

 

I have attached a copy of the information that they sent me.  Please note that this oil SHOULD NOT BEUSED IN ANY OF OUR MODERN CARS THAT HAVE A CATALYTIC CONVERTOR.

 

Rich Hartung

Desoto1939@aol.com

Castrol GTX classic 20-50 oil zddp & Phosphorus.pdfCastrol GTX classic 20-50 oil zddp & Phosphorus.pdfCastrol GTX classic 20-50 oil zddp & Phosphorus.pdfCastrol GTX classic 20-50 oil zddp & Phosphorus.pdfCastrol GTX classic 20-50 oil zddp & Phosphorus.pdf

[Sam Buchanan]

Yep, my go-to oil for the past couple of years. I have it dropped on my porch by Amazon. ?

 

[junkers72]

Thank you for the heads up. My ol’ DeSoto is due soon for a change . 

[greg g]

This specifically mentions, push rods, performance camshafts, high pressure valve springs, my car has none of these things.  In all of the discussion and gnashing of teeth over this zinc issue, not once do I recall any source mentioning what year that zinc became part of the additive package added to motor oil.  This wasn't an issue till we got to hotrodders swaping factory stuff for aftermarket cams and lifters made offshore with questionable  metallurgy standards.  Soft cams and lifters wearing almost instantly after rebuilds with high lift long duration cams and dual heavy pressure valve springs.  Things that are useless for street cars.

 

Does anyone have a source that specifies when zinc was added, if so please share that info and source.  I am betting it wasn't till the mid fifties when manufacturers entered into the horsepower wars.  When engines went to high compression, short stroke, high rpm designs that had push rods, high spring pressure valve springs and high lift cams, from the factory.  I have seen one Motor Trend article that backs this up, suggesting that it was put in to ease friction wear specifically at start up when oil not yet a complete  cushion between rotating parts.

Edited August 11, 2022 by greg g

[Sam Buchanan]

I don't have strong feelings pro or con about the need for elevated zinc in our old flatties but when a respected brand like Castrol offers their "Classic" oil I find it an attractive option. I first became aware of reduced zinc in modern oil while in the aircooled VW community and started using Valvoline VR1 Racing oil since it was highly recommended for the Beetle's flat tappet engines with no need for additive. But Castrol Classic is considerably less expensive while carrying the extra zinc load.....no brainer. I also use Castrol in the Triumph TR6 where it might be a more useful application with higher spring pressures. But I can't think of any downside to using Classic in our flatheads unless someone just doesn't want to run 20W-50.

[desoto1939]

At the same time I was talking with the Zerex vavoline rep we also talked about the VR1 motor oil. He stated that the VR1 was developed for the more high powered cars,  hotrod that everyone is switching to and for the performance engines. They added the extra protection becasue of the wear with added protection. He basically stated that with our low rpm flat head engine and with the average speeds that we drive them at and the low acceleration factor that the use of the ZDDP and Phospohous was not really needed.  The regular oils of today do have stronger anti wear additives that are 100% better in quality than what was used back in the 1920 and later uptil the 1950's.  So basically we even dicussed that the Walmart branded oil is of great quality and was entirely better than the oils when our cars were produced.

 

My point that I am trying to get across to the owners is that you no longer have to go out and purchase ZDDP in a bottle as an extra additive.  The Castrol GTX Classic now has it mixed in with the oil.  So baiscally you will spend around 20 dollar for 5 qts of regular oil so why not spend the extra few dollars and th eoil will include the ZDDP and Phos additives.

 

Yes this has been dicussed many time so basically it is personal choice for each car owner to determine if they want to use it. I am not getting any endorsment fees.  Just rying to pass along new product info to the members as to inform them of the motor oil product that they can use.

 

This is what the forum should be all about. Providing updates and links to information to keep our cars running and new products.

 

Comments are always welcomed.

 

Rich Hartung

Desoto1939@aol.com

[Los_Control]

I have been using castrol GTX  5-30 in my daily drivers .... 1993 Dodge caravan ... 1991 chebby truck sbc 350. I have 10-30 Castrol in my pilothouse.

 

The Caravan had 150k miles on it before my FIL bought it and switched oil to Castrol. At 186k the engine failed with a broken piston at the wrist pin. When I dissembled the engine 2 pistons had broken rings. This engine was in terrible condition.

Granted I think it was the original caretaker who put the first 150k on it (poor maintenance) where it got the damage ..... I can not blame Castrol GTX for the last 36k miles put on it.

 

I recently learned from another forum from a retired Chrysler employee .... Castrol GTX meets 3 of 5 SAE requirements for a 1993 Dodge 3.3 .... It simply does not fill the bill.

I can not help but wonder if Castrol did not help to the demise of my engine?

 

Just how I have come to my personal choices about engine oil .... If Castrol GTX does not meet requirements for a 30 year old Dodge V6 engine .... probably not good enough for my flathead 6 either.

 

 

I change my oil by Fall & spring twice a year regardless of miles. My 3 vehicles all have Castrol GTX in them now. Last week on our trip to walmart I picked up walmart super tech brand oil preparing for my upcoming Fall oil change.

Seems it is either made by Mobil or Exxon, just depends what area you live in and what is delivered to your store ..... meets all SAE requirements.

I'm done with Castrol myself.

[desoto1939]

los-control: is there any way that you could post the comments from your chrysler guy as to stating what and what not the Castrol Gtx is not meeting for the SAE requirements.  I know that on the SAE information the label on the bottle also states which other requiremnets that the oil covers and you should always check these against what your specific requirements are for your engine.

 

Rich Hartung

Desoto1939@aol.com

[kencombs]

1 hour ago, greg g said:

This specifically mentions, push rods, performance camshafts, high pressure valve springs, my car has none of these things.  In all of the discussion and gnashing of teeth over this zinc issue, not once do I recall any source mentioning what year that zinc became part of the additive package added to motor oil.  This wasn't an issue till we got to hotrodders swaping factory stuff for aftermarket cams and lifters made offshore with questionable  metallurgy standards.  Soft cams and lifters wearing almost instantly after rebuilds with high lift long duration cams and dual heavy pressure valve springs.  Things that are useless for street cars.

 

Does anyone have a source that specifies when zinc was added, if so please share that info and source.  I am betting it wasn't till the mid fifties when manufacturers entered into the horsepower wars.  When engines went to high compression, short stroke, high rpm designs that had push rods, high spring pressure valve springs and high lift cams, from the factory.  I have seen one Motor Trend article that backs this up, suggesting that it was put in to ease friction wear specifically at start up when oil not yet a complete  cushion between rotating parts.

I don't want to list all the references, but a quick search of the question will turn up dozens, if not hundreds of sources.  All state in some way that zinc was first added to engine oil in the 50s to enhance starting lubrication with the new-fangled OHV engines.  

 

I've referenced this in a few post but normally stay out of the discussions.

 

Suffice to say that my flattie won't be getting any special additives or high zinc oils. 

 

If the sources are correct millions of pre 50s flatheads ran there entire life without it.  I've never seen a worn (other than rust-caused) flathead cam in any make.  

[Los_Control]

@desoto1939 I will have to search back to find the post. 

This was on the ALLPAR forums .... The context was someone asking what they use in their cars. I posted what I use.

 

 

I posted what I use for my engine ...... That is where I got a reply from a  moderator from Allpar warning the original poster that the oil did not meet SAE.

 

Now I admit to being a bit gullible to accepting their word for it, If I ask the person they will flood me with a book full of information on the subject.

While I'm willing to accept their word on it, I should offer proof when making a statement like I have done .....

 

 

Like this forum here ..... If @Plymouthy Adamsgave me advice on paint .... I would not 2nd guess them I know they are pro with their experience.

If @Sniper gave me some advice on electrical .... I would say thank you and not 2nd guess them

Same thing with this Gentleman who drives older 60's Chrysler's & assist with the latest 2022 vehicles  .... has books on all years and offers digital photos & information on all Mopar products ..... I trust his word, just the same as I would trust a few others in this forum.

 

Oil is simply nothing but a opinion .... I'm going to stir up a bee hive in allpar asking about Castrol oil ..... let's see the answers we get.

[desoto1939]

Los-Control: Thanks for trying to get the information. I always thought that if an oil has been rated as an SAE oil it had to meet the standards and requirements to be approved. So am i wrong in this opinion or is the rating system incorrect. Oils also have an API stamp and log on the bottles so now it gets even  more confusing.  I always look for the modern oil to meet the requirements for the specific car manufactures requirements. Had a Foord 500 and they had their requirements and i alwasy looked to verify if the oil I was using meet the ford standards to insure that the oil could be used without any potential motor issues.

 

When our older cars were produced they used the SAE system:  Here is what is printed in my 938-39 Master service and repair manual for my 39 Desoto under Lubrication:

 

Oil used in the engine should always be a high grade, well-refined oil. The recommendations made in the Lubrication Section are based on the S.A.E. viscosity numbering system. The numbers used indicate the viscosity of the oil only and do not take into consideration the quality of the oil.   

 

So I am assuming from the gentlemans statement that the SAE oil made by Castrol and the GTX product might not be meeting specific requirements for specific car manufactures to insure that that specific brand has the appropriate properties.

 

So basically the SAE ratting is either a straight weight, mutit weight, blended or full synthetic that we can now purchase at the stores..

The above screen print is the definition for the S.A.E

 

 

Rich Hartung

Desoto1939@aol.com

Edited August 11, 2022 by desoto1939

[Sniper]

There are two classifications for every oil made.

 

SAE, such as 10w30

 

They refer two two different things.  The SAE is. essentially, a viscosity indication.  There are two temperatures they measure at to get the two numbers in a multi grade oil.  If it is a single number then it uses the higher temp only.  The high is always 212°F, the low temp varies.

 

API, such as SN

 

This refers to, essentially, the additives package.  This is the zinc, Phosphorus, etc in the bottle

 

Los' 1993 example vehicle called for API SH, we are up to SP now.  The Catrol GT Ultraclean he's using meets SP specifications, now why it may be bad for his ride, I dunno.  Can;t seem to find a specification for SH to compare to SP. 

[Los_Control]

https://www.hemmings.com/stories/2012/10/18/tech-101-zinc-in-oil-and-its-effects-on-older-engines

[Sam Buchanan]

22 minutes ago, Los_Control said:

https://www.hemmings.com/stories/2012/10/18/tech-101-zinc-in-oil-and-its-effects-on-older-engines

This link makes Castrol Classic look even better.

 

Per Rich’s original attachment from Castrol:

P 1199

Zn 1310

Edited August 11, 2022 by Sam Buchanan

[desoto1939]

22 minutes ago, Sam Buchanan said:

This link makes Castrol Classic look even better.

 

Per Rich’s original attachment from Castrol:

P 1199

Zn 1310

Sam:  i just read the article that Hemmings had written regarding the motor oil.  I also compared the amt of zddp and Ph and the Castrol GTX Classic is what I also saw along with  what you just stated.

 

So the questin for any car owner is if they want to use the product or not.

 

Again I just posted the information to let the other owners know that we can get a modern oil that has these additives.

 

Felt as if the messenger was being shot but that is par for the course in our current times.

 

Information is always appreciated by some and not by others.

 

Rich

[Sam Buchanan]

This is good info Rich, thanks for the starting the thread, it's always good to be able to make informed decisions.

 

 

[Los_Control]

Lets be honest, I posted the link because it is what was sent to me ..... My mistake because it really does not specify Castrol GTX .... Just talks about oil performance.

 

I really messed up when I posted it without a link to Castrol GTX  .... I have no idea why others are happy with Castrol .... I made a bad decision with my link.

 ..... It does not mention Castrol, only the reasons to use zinc.

 So Yes we can talk about shooting the messenger ..... where do we talk about the quality of Castrol GTX?

 

I personally do not care what oil anyone chooses to use .... I made a choice and Castrol is not it.

 

 

[desoto1939]

Los Control: you did nothing wrong. It forced all of us to look deeper into the SAE and API information on each bottle of motor oil.

 

I am not a chemical engineer, so I do not have the qualifications to officially endorse or not endorse any specific brand of motor oil. All I was trying to do was indicate that there isa a brand of motor oil that now contain a significant amount of ZDDP and Phosphorus already in the bottle of oil.

 

I know that Castrol is a major player in the automotive oil products world. So I was just trying to pass along the info.

 

So if anyone can make qualified documented breakdown of the Castrol then they are welcome to supply the information and also compare it to the other brands.

 

But according to the Hemmings document it explains the amount of zddp and phos contained in the various API grades of oil and then you have to use the appropriate SAE weight for your antique or modern car.

 

Lets keep the discussion open and keep digging to get more info for the guys in the P15D25 forum.

 

Any Chemical Engineers out there in the group that can provide some input please chime in on the discussion.

 

Rich Hartung

desoto1939@aol.com

[kencombs]

When I want solid oil info I spend some time at  bobistheoilguy.com.  Lots of time!!   More info there than I can possibly absorb.  But, seems to be factual.  Even some fairly good info on what the API designations mean.

 

Edit to add:   this is a link to a concise list of API info.

 

https://penriteoil.com.au/knowledge-centre/Specifications/194/api-service-classifications/363

 

It's important to note that early in this article the point is made that newer classifications are backward compatible.  IOW, newer meets all older specs +.

Edited August 12, 2022 by kencombs

[desoto1939]

question for the group?

 

So the API ratings for the motor oils have changed over the years. Who is under th eimpression that all of the ZDDP and the Phosphorus protection elements have been removed from our modern engine oils?

 

Plese come back with your thoughts on this part of the motor oil discussion. After getting some replies I willthen post some facts for everyone to view regarding current motor oils.

 

Rich Hartung

Desoto1939@aol.com

[chris 48 P15]

here is some info i found

i don't know how they loaded make sure to read them in order

[kencombs]

3 hours ago, desoto1939 said:

question for the group?

 

So the API ratings for the motor oils have changed over the years. Who is under th eimpression that all of the ZDDP and the Phosphorus protection elements have been removed from our modern engine oils?

 

Plese come back with your thoughts on this part of the motor oil discussion. After getting some replies I willthen post some facts for everyone to view regarding current motor oils.

 

Rich Hartung

Desoto1939@aol.com

Reduced, not completely removed in most.  Due to incompatibility with modern catalytic converts is what I understand.  It is also my understanding that that is immaterial for our flathead sixes as those where not present at the time they were designed or for the most part during their lifetime. 

 

Now if I were running a 56 V8 (or any OHV) especially with non-stock valve springs, I'd have a different view.  (and I wish I was but Hemis or Polys are just to expensive to build).

[Los_Control]

My opinion has been more solidified just asking myself questions about the oil I use.

I have a engine with unknown past maintenance. (Possible the school teacher took it for regular oil changes) We got it at 150k miles & failed at 187k.

A lot of miles for any engine but not uncommon to reach 300k miles with these engines.

 

What I found when I diagnosed the engine failure, A piston broke at the wrist pin. The rod destroyed the block ... total destruction.
I also found 2 other pistons when I removed them, the top ring was broke .... just fell off the piston when removed from the hole.
Just saying it was a time bomb waiting to explode.

My thinking is, possibly the piston broke because of improper lubrication at the wrist pin? ..... Just a WAG but not too far fetched.
How long will a engine run with a broken ring? This engine leaked 1/4 quart of oil in 3k miles, no smoke.
I would suspect after a few thousand miles with the rings "loose" flopping up and down, possibly breaking a ring landing eventually just destroy the whole cylinder.

So that's the question I'm asking myself. .... Did those rings break before the engine had 150k miles on it? ..... Or was it in the past 36k miles after it was switched to Castrol?
I just find it hard to believe the engine would run for over 40k miles with 2 pistons with broken rings. .... I could be wrong though.

 

I have no solid proof that Castrol caused this issue.

I certainly feel it did not help the situation at the very least.

[Sniper]

4 hours ago, desoto1939 said:

After getting some replies I willthen post some facts for everyone to view regarding current motor oils.

 

Why not just post the facts and not play games?

[desoto1939]

Here is the info taken from the article  Tech 101: Zinc in oil and its effec on older engine.  As a quick answer zinc, phosphorus and boron are all contain in our modern oil. Yes it has been reduced over the year but has not been eliminated.  So from my reading I do not think the use of Castrol oil would have casued the rings to break and the broken piston pin. The prior owner did not state what oil he had used but the current owner stated he switch over to Castrol.  So its a crap shoot to determine what caused the issue.

 

Thefirst column is the API product rating such as SL then the P=phosphorus the ZN = Zinc and the B = Boron.

 

So when our otiginal motor oils were being produced  the API use back in 1947 only state  Regular, Premium andn Heavy Duty motor oils. And the quality of the motor oil was a crap shoot. In 1952  the API was starting to be put on the bottles and this has continued up to the current time frame.

 

Rich HArtung

Desoto1939@aol.com