I hate to dip my toe into the tar pit of discussions on oil preferences, but I agree with Jose on Castrol 20W50. I use it in a number of older engines I have and am very happy with how it has been working. The one recommendation I have is to substitute one quart of the Castrol with a quart of Valvoline Racing Oil 20W50. It adds just enough anti-wear additive (ZDDP) to protect our engines.

 

This explains so much. It's good to discover/address this issue now rather than while I'm on a longer trip. All advice is welcome. Thank you all.

 

Castrol current 20w50 is "SN". This is not your fathers 20w50. It doesn't not have the additive pack for solid lifter flat tappets. A quart of something that is additized with ZDDP will mix, but it is only a guess if it is enough. A additive bottle of ZDDP might be a better guess. First best choice is a oil with enough ZDDP by design for solid lifters. I believe the spec is "SG". Unfortunately, Castrol is not in the "old car game".
Me: ten years in the Castrol division of BP, and still waving the flag high.

 

ok, so which 20W50 oil is good ?

 

Clyde, doesn't the Castrol Classic 20W/50 do the job ? It's SF spec and the literature says it should, but I can't find the ZDDP ratio's for it.

Millers classic 20W/50 is highly talked about here in the UK too, but I can't find the spec for that either other than it SJ spec.

What happens when an API classification become obsolete, it doesn't say on the API website, it just seems to get superseded by the next one ?

 

Jose,
Some 20w50's will say "meets SG" on the label, some will say additized with ZDDP for solid lifters or flat tappet cams.
From there, we get into "personal preferences", brand loyalty, and works great in my car.
I am currently using "Brad Penn Penn Grade 1 - 10w40 in my '77 XJ12L, engine is new with hydraulic roller cam. They also make various grades and carry endorsements of various cam manufactures.
20w50 is great to take up for wear and oil consumption. It is also what was used "back in the day" in a lot of muscle cars and sports cars. I've cut consumption, raised oil pressure, and quieted engines with 20w50.
Not a great idea for colder weather start ups.
https://m.summitracing.com/search/pr...de-1-motor-oil.
Next engine I'm building will have a solid roller. I am still searching what is out there in the shelf.

 

TilleyJon.
Yes on Castrol Classic. I Could not find it on the current Castrol USA Website. I may have not looked hard enough. I'll look again.

 

I looked again. It looks like it was pulled from the US marker.

 

Exactly in the obsolete. However label will say "meets", but not use the word "approved". Small detail.

 

god damn minefield !!

Guess it's down to doing the research and checking the details.

Thanks Clyde for that useful info, at least I can get Castrol and Millers here in the UK, I think Penrite do a good classic oil, but it's not readily available here, Australian product, not sure how available it is in the US

 

Well this is what I bought yesterday. I didn't see a specification. Hopefully I won't kill my car.

 

What you have to look out for is that modern oils have high levels of detergent, these can wash the rope- graphite - asbestos seals and they can start leaking. It also washes the pistons etc., and can cause pinking.

The Castrol GTX most probably falls into that category, the Valvoline being synthetic is probably just as bad.

In 2015 GTX was at a standard for API SG or earlier, as of last year it has jumped to SL or earlier spec. (that is from the data sheets, but the website says SG or earlier!!) Most older engines, if not reconditioned with newer seals etc do not like later spec oils as they don't agree with the high additive content.

Valvoline high mileage does have added zinc which does not show on the Castrol spec. but does have higher detergent levels and is although it is SN spec on the face of it is better than the Castrol.

What you do with this information I am not sure, the subject of oil is a minefield, with the oil manufacturers advertising not necessarily giving you all the information.

 

Aw crud, I totally missed where it said "synthetic blend" right on the front :P I saw where it was for cars over 75K miles and thought I was fine.

And I read where the Castrol said "sludge protection" and thought that was good. I did not see it as "High detergent"

Minefield is right! What do I look for?

 

Mineral, blend, synthetic, are not the issue. It's the missing ZDDP. Levels were lowered so cats would live 125,000 miles.
Detergent high in all new spec oils. Wash the seal, likely. Clean the pistons, maybe over time, cause ping, I doubt that one.

 

Grab a bottle of some ZDDP additive, & "run whatcha brung".

 

Where do you get ZDDP additive Clyde? I didn't see any in the car store I went to yesterday. Or do I have to ask at the counter? If they blink twice instead of answering I just need to go to the next place?

 

Advance auto parts shows rislone with zppp. ORileys shows hyper lube with zinc replacement. After that, summit racing, Eastwood, amazon.

 

Sigh. I wanted to get the oil changed this weekend, but I want to do the best for the car.

It's been a good weekend to catch up on house and yard stuff instead.

 

Go with Clyde's guidance, I am not familiar with what's available stateside.

I have to correct my wording, it's the washing of the pistons, and the resultant build up of metallic ash is the chambers and crowns that causes the pinking, not the actual washing itself, this is only an issue on high oil consumption engines where the oil is passing into the chambers.

 

Chuck, Clyde, Jose, Jon (Sorry if I've left anyone else out), I'm deeply humbled and ingratiated to you all for your concern for my car. It's obvious that you all want one more of these "rolling works of art" to be on the roads. I am just a hack; I will heed your advice.

I will do my best to do my part to get mine running well, and keep her purring. And, of course, I will keep you all updated. Now, I'm off to a car parts store(or 2)