API CH4 and API CH4 / SJ

API: CH-4 only meets the test requirements of CH-4. The latter one meets both and may also be used in a petrol engine which requires only SL.

When API rolled out its first classification it differentiated the Compression Engine (Commercial Diesel Compression Engine) from Spark Ignition and the nomenclature was as follows:

Down through ages the prefix was followed by an upgrade in alphabetical order starting with A.

1st API API classfication today
CA -->> CB --> ...--->CH4 for Diesel engines.
SA -->> SB --> ...--->SH for Petrol or Spark ignition.

Hussam Adeni

My question was,in what aspect the CH4 / SJ is more better than the CH4 oils.On what basis a diesel engine manufacture recommend the CH4/SJ oil over CH4 oil.There may be some additional bench tests and other oil performance test requirements.Which are those tests?

Thanks.

Menon

Are you trying to understand the difference between API CH4/ SJ AND API CH4 performance levels, it all depends on the additive manufacturer's claims.The additive manufacturer develops a package and tests the product to meet the required performance levels.Developing a package that could meet diesel and petrol engine requirements means more share......

Naturally there should be some advantages in the additive tech ?