| Author | Message | ||
     Jack Higginbotham Experienced User Username: jhinmd Post Number: 16 Registered: 11-2017 |
Hello all, I’ve read, seemingly forever, of pros and cons of using or not using synthetic oil in older cars. I have a SC II and a 25/30 Wraith, and would like to do full fluid changes on both. I race old-Ish sportscars and have gone between using diesel oils, racing oils and normal mobil1 with no definitive difference between them....except with diesel, it hurts my soul a little less to change between each event. It seems with the passing of time, the hysteria around synthetic in classics is dimenishing online. Opinions please! | ||
| Robert Noel Reddington Grand Master Username: bob_uk Post Number: 1645 Registered: 5-2015 |
When new both synthetic and normal oils perform about the same. As the miles build normal oils deteriorate faster and by say 6000 miles the normal oil will be worn out. Both of the cars you have were designed with normal oils of the correct grade and spec I would suggest GTX 20/50 for both cars and change every 3000 to 4000 miles. Buy 5 gallon drum. Racing engines are not a good guide to road cars because the oil is changed at very low miles | ||
| ross kowalski Grand Master Username: cdfpw Post Number: 679 Registered: 11-2015 |
Jack, Castrol 20/50 is a good call, also remembr to add a ZDDP rich addative because you have flat tappets. | ||
| Jack Higginbotham Experienced User Username: jhinmd Post Number: 17 Registered: 11-2017 |
Castrol 20/50 with zddp additive it is....many thanks for the advice, Merry Christmas! | ||
| Mark Aldridge Grand Master Username: mark_aldridge Post Number: 490 Registered: 10-2008 |
Jack, check the oil specs, there are 20/50 oils with high ZDP , then additives are not necessary. Lucas Racing only, Penrite, Millars, to name a few. Mark | ||
| Patrick Francis Prolific User Username: jackpot Post Number: 212 Registered: 11-2016 |
Anybody know what the ideal zddp % should be? I read that too much can also be detrimental? Is that true? I use the Castrol 20/50 Classic oil which I presume has the required amount of zddp, but the more I read, the more muddled I get! HAPPY 2018 TO ALL | ||
| ross kowalski Grand Master Username: cdfpw Post Number: 685 Registered: 11-2015 |
Patrick F, Anything running flat tappets needs more ZDDP than modern oils provide. Oil traditionally had .15% or more ZDDP. Modern oils run .08% or less. I use the red can of STP per 5 quarts but there's probably better formulas. EAA had a good article on this. Unlike most internet information, they test it and have a dog in the race, if you are wrong you die. FYI they had a good article on leaded gasoline and it's effects on valve failure as well. | ||
| Maxwell Heazlewood Prolific User Username: tasbent Post Number: 140 Registered: 9-2017 |
Patrick and everybody....look up the Penrite web site which will give you full details about ZDDP requirements....they have one of the best technical sections. penrite.com.au | ||
| Christian S. Hansen Grand Master Username: enquiring_mind Post Number: 675 Registered: 4-2015 |
Ross... I would be interested in the noted articles, but first, what is EAA? | ||
| ross kowalski Grand Master Username: cdfpw Post Number: 687 Registered: 11-2015 |
Christian, The EAA is the Experimental Aviation Association. They are the people who run AirVenture in Oshkosh WI USA. Not to toot it's horn, but a pretty neat deal. Relating to gas, they were the ones that pushed to get automobile gas certified for some engines. I just went to find the article on leaded fuels and valves and found this book online. https://books.google.com/books?id=mklN1ROzc5kC the FAA worked with the EAA to figure out running automotive gasoline in planes. Basically, run rebuilt motors on leaded fuels before switching to low lead to treat the valves in a way that permanently prevents sticking and also, no alcohol in and fuel used in a plane. I couldn't find the EAA article online I might have to look through paper. In a nutshell, FAA commercial certified engines run precious little additive packages in their oil. FAA oil has some spec just like the avgas. The EAA folks running all sorts of car powerplants in their airplanes do use flat tappets all over the place and run zddp oils. Here's an internet page on Corvair engines where a guy ran Areo oil in a car engined aircraft and lost a cam. Ooops. https://flycorvair.net/2013/06/26/notes-on-corvair-flight-engine-oils/ | ||
| Randy Roberson Grand Master Username: wascator Post Number: 801 Registered: 5-2009 |
Can't help but think that, with any old machinery, there will be failures and issues which people will tend to blame on something besides old age and wear and tear. Oil and coolant seem to take the brunt of it. |
