My searches online indicate that Castrol GTX 20w50 has more ZDDP than most other oils out on the market, but I can't determine whether it's completely sufficient, or just better than other oils. (BTW, other variants in the GTX line - 10w30 and 10w40, for example - appear to not have as much ZDDP as 20w50. Something to keep in mind particularly if any of us switch over to a different grade for cold whether driving - something that you So Cal folks don't have to worry about, I imagine.)
From what I've gathered, we need to keep an eye on this situation, as the oil companies can theoretically alter formulations at any time (responding to government guidelines). (Another thing I've discovered is that more ZDDP is needed to combat wear after a rebuild, at least until parts wear-in.)
To be safe, I'm probably going to add ZDDPlus to Castrol GTX 20w50 at oil changes, but probably only about 1/4 to 1/3 of the recommended amount - since GTX 20w50 supposedly has more ZDDP than most other oils nowadays. The desired amount of ZDDP for older engines with solid tappets is 1200 to 1800 parts per million. If GTX 20w50 is in the safe range, but is at the lower end - one Australian article I read that was several years old indicated that GTX 20w50 has around 1200 PPM of ZDDP - I figure that adding a smaller amount of ZDDPlus can't hurt. But if the amount of ZDDP is a bit lower than 1200 PPM, I figure it could place the wear factor solidly into the "safe" range.
Unfortunately, the oil companies typically don't give out numbers as to the ZDDP content of their oils. The only thing they actually do is to label the oils with significantly-reduced ZDDP levels as "Resource Conserving". (They've done this to prolong the life of catalytic converters, what can be degraded faster from the use of ZDDP in higher proportions.) From what I've read, we should never put any oil labelled as "Resource Conserving" in our older engines without also using a ZDDP additive.
Call me a worry wort, but given the lack of replacement parts for our Honda 600 engines, I'd rather have an added layer of wear protection.
Richard
--- In
anzhonda600owners@yahoogroups.com
, Tad Clark wrote:
> I have been driving 600's since 73 and have always used Castrol GTX. There should be no need to add aditional ZDDP to the oil. The car I currently am driving has had continuous use since 1984 and has never had any problems. I also drive the crap out of it. It never gets babied. 300,000 miles and counting.
> From: richmccolman
> To:
anzhonda600owners@yahoogroups.com
> Sent: Saturday, September 29, 2012 5:19 PM
> Subject: [anzhonda600owners] Re: oil
> Thanks for alerting us to the ZDDP issue. I was previously unaware.
> Investigation I've done online appears to indicate that Castrol GTX 20w50 still has an appreciable amount of ZDDP, though I'm not 100% convinced it's in the "safe" range. I ordered some ZDDPlus to add in at oil changes, just to be sure. (I've read that too much ZDDP can cause problems, so I'll likely put in a bit less than the average recommended amount, since the Castrol 20w50 supposedly has more ZDDP than many other oils.)
> I contemplated going with Amsoil or Royal Purple, but since I don't put gobs of miles on the car between six-month oil changes (I mainly just drive it around a little on weekends), and since I'm not sure about the condition of the engine's seals or whether the synthetic oil will tend to leak past the seals more than conventional oils, I figured I'd not spring for the synthetics at this time.
> Thanks again,
> Richard
> --- In mailto:anzhonda600owners%40yahoogroups.com, "John" wrote:
> > Brad, Yes I have researched and found the same, ZDDp is still needed for multiple reasons. I also used to believe Valvoline was tops and I have ran it for years in many engines fom classic muscle to modern muscle and marine and about everything in between. I have ran Valvoline in convention, synthetic, and racing formulas. I have found the same results on many motors reguardless of oil or engine brand or brand of parts in the engine. First all the engines I have ran valvoline in that have hydraulic lifters wont hold their prime when shut off no matter age or condition of the lifters and are inconsistent on valve lash, which we dont have to worry about with 600's. Next I have had numerous engines of different uses and brands end up needing new oil rings and valve seals I believe way before they should have. The government also removed the ZDDP out of all diesel oils now too unfortunate for us who used them for the ZDDP as now all diesel engines are full
> emmision controlled too. I know many people who use Amsoil and Royal Purple and have done so for years and have never had the issues I have had and they mantain their engines the same as I have, I know use royal purple and have for a couple years and my engines love it including my wife's 600 with some added ZDDPLUS.
> > --- In mailto:anzhonda600owners%40yahoogroups.com, "John" wrote:
> > > Yes I have researched and ran a lot of different engines and what you all are saying is true, all our classic and older engines prior to 1996 need extra ZDDP. I like the product ZDDPLUS you can buy it from amazon.com or clarkscorvairs.com. I also will not ever run Valvoline oil in anything again as I along with other rodders in my area believe it is not good in any engine any more. Good luck to all.
> > > --- In mailto:anzhonda600owners%40yahoogroups.com, T W S wrote:
> > > > this is something i just wanted to pass along to anyone that might be more
> > > > knowledgable about oils in engines. I have an ultralight airplane with a half VW
> > > > engine in it and one of the gurus that builds these things had this to say
> > > > about the oil: This message is to inform you about a problem with the new motor
> > > > oils. There is a lot of information around about the reduction of ZDDP in oil
> > > > formulations. ZDDP is an extreme lubricant additive. The oil companies are
> > > > lowering the amounnt of it because of its effects on exhaust emissions. The VW
> > > > engine needs the extra lubricant that ZDDP provides. With traditional oil
> > > > formulations, I have had no problems reaching 1.000 hours time on an engine. I
> > > > now have had two engines with approximately 350 hours wear out bearings. From
> > > > what i see, its not a lack of oil pressure because both engines had good oil
> > > > pressure and oil temperature. It just looks like the oil is not lubricating
> > > > enough. What I am recomending is using either a diesel grade oil or a racing
> > > > oil. Both have higher amounts of ZDDP. There are ZDDP additives also. Synthetic
> > > > oils are not much better. I am by no means an expert scientist on this subject,
> > > > but this is the only answer i have to hteis problem. Scott Casler, Hummel
> > > > Engines I know he was writing this about VW engines but was
> > > > wondering if it might be applies with the 600s? Tim