Originally Posted By: Ecomike
I have a 1981-82 vintage Nissan SD-22 diesel engine, and I am having trouble finding any of the old spec oils anywhere. I do not want synthetic or semi-synthetic, and I want a pre SM/SN, CH-I (only), 15W40 or 20W50 dyno oil, with the old levels of ZDDP, etc. I might use a CJ-4/SL if I found it, and I would use a CH-I/SL if I found it.
I was able to stock up 2-3 years ago, but have not been able to find anything but CJ-4/SM for 9 months now. HELP! Please!
There is no ZDDP limit on SM or SN oils without Cx specification for grades 10W-40 or heavier. ZDDP limits only apply for ILSAC GF-x oils (energy- or resource-conserving) or newer-Cx-grade oils. Sx without ILSAC or without Cx has no ZDDP limit.
For CJ-4 oils the ZDDP limit is 1200 ppm phosphorus regardless of whether it's also SM, SL, etc.
CJ-4/SM oils in general should provide enough wear protection for flat-tappet engines. If you need ZDDP higher than 1200 ppm phosphorus, you need to find an SM-only or SN-only oil 10W-40 or thicker that has that much ZDDP (according to its datasheet or tech support). CI-4 oils also have more ZDDP but they are inferior overall to CJ-4. ZDDP alone doesn't translate into better wear protection. CJ-4 should provide more wear protection than CI-4, even for flat-tappet engines.
I personally would recommend Mobil Delvac 1300 Super 15w40 (phosphorus ~ 1000 ppm) for your application.
