synthetic oil
Race Director
Joined: Jul 2001
Posts: 15,892
Likes: 42
Le Mans Master
Joined: Oct 2007
Posts: 7,454
Likes: 977
From: RI, Now Franklin/Nashville TN
Depending on what you want to achieve... CJ-4 has a 1200 ppm phoshorus limit. CI-4+ has 1400 ppm. Thus a CJ-4 oil with phosphorus at 1199 ppm phosphorus will meet both CJ-4 and CI-4+ specifications. Not exactly what I'd want for my older equipment. There are still oils on the market that meet CI-4+ but not CJ-4 allowing them to carry more that 1200 ppm phosphorus. 
Racer
Joined: Nov 2009
Posts: 289
Likes: 0
From: Franksville Wisconsin
Exactly. I would not use synthetic oil in a older engine to the the detergents cleaning years of deposits and possibly plug the oil filter.
Racer
Joined: Aug 2005
Posts: 308
Likes: 0
From: Salem MA
having recently taken apart an original '69 427 that was switched to mobil 1 maybe 10-15 years ago, i assure you the sludge was not going anywhere without a putty knife and a pressure washer.
synthetic oil is just better oil, its not magic.
Instructor
Joined: Aug 2005
Posts: 138
Likes: 0
From: Virginia
I've got an '80 with the original engine and around 86,000 miles. I drive it a lot; about 66,000 miles in the last 7+ years. I have no scientific data and I'm not that smart. I've used Pennzoil 10W-40 for the 7+ years I've owned the car and she doesn't leak and runs great. To my knowledge, the pan has never been pulled. Maybe I'm lucky.
Travis
Travis
Racer
Joined: Nov 2009
Posts: 289
Likes: 0
From: Franksville Wisconsin
I know someone that switched to synthetic oil after 60,000 miles and at first 1500 miles oil pressure was reading low or fluctuating and he removed filter to find it plugged after changing filters often it eventally got better.I;ve been told don't use it in a engine with many miles on it. I used syntech in a turbo Mits eclipes and still changed my oil at 3000 miles.
Racer
Joined: Nov 2009
Posts: 289
Likes: 0
From: Franksville Wisconsin
Funny how many people think oil is magic. It all boils down to you need clean slippery s*#t
and change it from time to time. I use VR1 20/50 in my Vette and quite pleased with over 100,000 miles on it.
and change it from time to time. I use VR1 20/50 in my Vette and quite pleased with over 100,000 miles on it.
Premium Supporting Vendor
Joined: Aug 2001
Posts: 5,364
Likes: 38
From: King George VA
Understood! My understanding from this quote about diesel oils is that CJ-4 can have up to 1,200 ZDDP PPM based on what you are saying, but there is no requirement for the oil to have that amount of ZDDP. The CI-4+ rating means that it will have at least a minimum ZDDP of at least 1,200 PPM with an upper limit of 1,400 PPM based on how I read that quote. In order for the diesel oil to have the minimum amount of anti wear agents for flat tappet older engines, it must have a CI-4+ rating according to the quote, CJ-4 only is not adequate. The quote is from Mobil's website!
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AMSOIL Preferred Customer Program (Members buy at Wholesale - a savings of about 25%)
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Le Mans Master
Joined: Oct 2007
Posts: 7,454
Likes: 977
From: RI, Now Franklin/Nashville TN
My sentiments exactly! I would have no problem running Amsoil or Redline IF cost was comparable to the others. Since Mobil 1 15W-50 is a great deal at $22 for a flat tappet cammed engine, that is what I use since I want a group IV true synthetic, not a psuedo synthetic (Group III's-highly refined dino oil) offered by most of the major oil companies and legally allowed in the US to be called true synthetics, which they are not. I have used Mobil 1 in my C3 since 1986!
