MERCMAN
07-15-2010, 03:33 PM
Found this on Thunderbirdnest.com
Good info here :up:
Since some members here are selling older vehicles and some are buying them I thought I would put this out for the benefit of those who may not be aware that that today’s oils may not be the best thing for yesterday’s cars. When the Thunderbird was re-introduced the North American standard for passenger car motor oil was SL GF-3. In 2004 the standard became SM GF-4 and later this year the standard will be SN GF-5 with Honda, Toyota, Nissan, and GM having their own individual standards. When a new standard comes out it is supposed to be backwards compatible with the previous standard and that is true to a point but are today’s oils backwards compatible to cars made in say the 50’s or 60’s? Not really.
To meet ever increasing emissions standards the levels of Zinc dialkyldithiophosphates (ZDDP) decreased in the SL standard and fell off a cliff in the SM standard for passenger car motor oil. Modern engines with overhead cams or engines with roller lifters and rockers arguably do not need a healthy dose of ZDDP. However, older flat tappet engines do. Modern oils do not have a ZDDP replacement in their formulation that provides the lubrication necessary in a flat tappet engine.
Older flat tappet engines need about 1300 to 1500 parts per million (PPM) of ZDDP to keep the cam and lifters from self destructing. This is especially true in higher compression “muscle” car engines of the 60’s and early 70’s but applies to engines made before that as well as up to the point where manufactures converted flat tappet configurations to roller.
So, what oil do you place in your classic treasure to give it the protection in the from of ZDDP that is needed? Good question. Most high mileage oils are SJ or SL rated and have higher levels of ZDDP but still only about 1000 PPM at most (Mobil 1 10W40 High Mileage oil claims to have 1000 PPM). Joe Gibbs and Roush Racing each carry a line of oils that are supposed to have a high dose of ZDDP but on their website I can not find the PPM amount. There are ZDDP additives you can purchase but you need to be careful if you decide to go that route. Too much ZDDP reacts with other components in oil’s formulation and causes corrosion – the last thing you need. So if you decide to use an additive make sure you know the ZDDP level in the oil being used (generally hard to find out unless you do a virgin oil analysis) so that you will only mix enough ZDDP to reach about 1500PPM. Another option is to use a Heavy Duty Engine Oil, I.E., diesel engine oil that is also rated SJ or SL for passenger car use like Rotella T.
If your older engine has not been rebuilt recently and modern gaskets and seals installed then oils like Mobil 1 High Mileage, Joe Gibbs, and Roush may leak for they are synthetic formulas. Therefore, the standard 15W40 conventional Rotella T could be a better choice for older original engines or older rebuilds.
Maintaining an older or vintage car is becoming more and more challenging. First one had to have the heads and valves re-worked so as to allow them to survive using gas without lead. Then one had to worry about compression and the lower octane ratings. More recently one had to worry about gas mixed with ethanol that tends to eat away at the older fuel systems and gaskets in carburetors. And now, oil you depend on as the life blood for your engine is lacking a key ingredient needed to provide proper lubrication for an older car with a flat tappet valve train.
__________________
Good info here :up:
Since some members here are selling older vehicles and some are buying them I thought I would put this out for the benefit of those who may not be aware that that today’s oils may not be the best thing for yesterday’s cars. When the Thunderbird was re-introduced the North American standard for passenger car motor oil was SL GF-3. In 2004 the standard became SM GF-4 and later this year the standard will be SN GF-5 with Honda, Toyota, Nissan, and GM having their own individual standards. When a new standard comes out it is supposed to be backwards compatible with the previous standard and that is true to a point but are today’s oils backwards compatible to cars made in say the 50’s or 60’s? Not really.
To meet ever increasing emissions standards the levels of Zinc dialkyldithiophosphates (ZDDP) decreased in the SL standard and fell off a cliff in the SM standard for passenger car motor oil. Modern engines with overhead cams or engines with roller lifters and rockers arguably do not need a healthy dose of ZDDP. However, older flat tappet engines do. Modern oils do not have a ZDDP replacement in their formulation that provides the lubrication necessary in a flat tappet engine.
Older flat tappet engines need about 1300 to 1500 parts per million (PPM) of ZDDP to keep the cam and lifters from self destructing. This is especially true in higher compression “muscle” car engines of the 60’s and early 70’s but applies to engines made before that as well as up to the point where manufactures converted flat tappet configurations to roller.
So, what oil do you place in your classic treasure to give it the protection in the from of ZDDP that is needed? Good question. Most high mileage oils are SJ or SL rated and have higher levels of ZDDP but still only about 1000 PPM at most (Mobil 1 10W40 High Mileage oil claims to have 1000 PPM). Joe Gibbs and Roush Racing each carry a line of oils that are supposed to have a high dose of ZDDP but on their website I can not find the PPM amount. There are ZDDP additives you can purchase but you need to be careful if you decide to go that route. Too much ZDDP reacts with other components in oil’s formulation and causes corrosion – the last thing you need. So if you decide to use an additive make sure you know the ZDDP level in the oil being used (generally hard to find out unless you do a virgin oil analysis) so that you will only mix enough ZDDP to reach about 1500PPM. Another option is to use a Heavy Duty Engine Oil, I.E., diesel engine oil that is also rated SJ or SL for passenger car use like Rotella T.
If your older engine has not been rebuilt recently and modern gaskets and seals installed then oils like Mobil 1 High Mileage, Joe Gibbs, and Roush may leak for they are synthetic formulas. Therefore, the standard 15W40 conventional Rotella T could be a better choice for older original engines or older rebuilds.
Maintaining an older or vintage car is becoming more and more challenging. First one had to have the heads and valves re-worked so as to allow them to survive using gas without lead. Then one had to worry about compression and the lower octane ratings. More recently one had to worry about gas mixed with ethanol that tends to eat away at the older fuel systems and gaskets in carburetors. And now, oil you depend on as the life blood for your engine is lacking a key ingredient needed to provide proper lubrication for an older car with a flat tappet valve train.
__________________