Old School Oil Formulation - Castrol GTX Classic 20W-50 Conventional Motor Oil

[SID297]

I saw that Castrol recently introduced a new oil aimed at pre-emissions engines. The specs on this stuff looks great. I just wish they'd add a few more viscosities (10w30 and 15w40 sounds good to me. Here's what they have to ay about it:

Castrol GTX Classic is a high-performance engine oil for push-rod, flat tappet engines and performance cam applications. It’s specially formulated for classic/collector cars, muscle cars, hot rods and race cars. It’s high zinc and phosphorus content helps prevent premature aging, wear and metal fatigue on engines with high tension valve springs or performance modifications that create high contact pressure and extreme internal temperatures.​

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• Castrol Classic 20W-50 is suitable for use in automotive gasoline engines where the manufacturer recommends an API SJ or earlier specification 20W-50 lubricant. NOTE: NOT FOR USE IN MODERN ENGINES WITH CATALYTIC CONVERTERS OR WET CLUTCH APPLICATIONS
• Specialized additives containing high Zinc (1400 PPM Max) and Phosphorus for extreme wear protection
• Formulated to maintain tough and thick oil film even under severe conditions
• Minimal foaming and high resistance to thermal degradation
• Compatible with gasoline and alcohol-based fuels

If you're interested in it, you can pick some up here:

https://amzn.to/3XqBuui

Personally, I've had great luck with Castrol conventional. I ran it for 200,000 miles in my old Jeep XJ and that engine looked like brand new inside when I sold it. Thoughts?

 

[Rambro]

I’ve been thinking about switching to a 10w40 or 50 weight in the cobra for summertime. I’ll keep this in mind. The old 4.6 might like the high zinc and phosphorus?

 

[offroadkarter]

I’ve been thinking about switching to a 10w40 or 50 weight in the cobra for summertime. I’ll keep this in mind. The old 4.6 might like the high zinc and phosphorus?

I don't think a mod motor is in need of something like this, especially if you have cats.

 

[SID297]

Good vid on this oil:

 

[gimmie11s]

Good stuff

 

[ShelbyGT5HUN]

I got 300k miles on my beater Toyota back in the day using Castrol GTX! Sold it for $300. Guy put another 50k on it.

 

[railroad]

Rotella 15w- 40 fills the bill, also.

 

[98 svt]

My father worked as a service manager at a Ford Dealer for 35 years. He used to sweat by the original Castrol GTX oil. He used it in everything from the lawnmower to the family station wagon.

 

[SID297]

Rotella 15w- 40 fills the bill, also.

That is also not as good as it once was, but is still a solid choice.

 

[SID297]

My father worked as a service manager at a Ford Dealer for 35 years. He used to sweat by the original Castrol GTX oil. He used it in everything from the lawnmower to the family station wagon.

I used to exclusively run Castrol GTX 10w30 in my old Jeep XJ's 4.0. At 200,000 miles the inside of that engine still looked brand new. No deposits at all.

 

[FICannon]

I wonder if this would be ok to run in my 93 LX... I've read mixed reviews with this weight of oil.

 

[railroad]

Run the Castrol hot rod oil or Rotella in flat tappet engine. Syn will not protect the lifters and cam.
Roller cams can run anything, just use the right wt oil.
There are plenty of oils with zinc and zppd additives.

ZDDP Content Chart - High Zinc Oil List - Brand Breakdown

Our ZDDP oil list covers conventional, synthetic, and diesel oil zinc content levels to help you determine the best oil for your engine's needs.

www.speedwaymotors.com