Does low ash = more engine wear?

Messages
451
Location
Bribie Island, Oz
Here's the story. My Ford 5.0L V8 has a duel fuel setup. It runs on petrol or LPG gas. I understand that LPG has higher combustion temperatures, and therefore a "low ash" oil is recommended. Now, the special LPG engine oil I am running at the moment has a SA of 1.3. Castrol GTX Gas has 1.0. There is a new BP Visco Gas oil that has a SA of only 0.5. So, at first glance, the BP oil would the the best for the engine. My question is "would this 0.5 oil have any effect on engine wear, assuming the ash content is derived from AW additives.?" [I dont know] Can someone please give an informed answer on this? Thanks Dave
 
Messages
6,388
Location
Washington St.
My understanding is that gas engine oils are for engines designed to run on natural gas or LPG, not for converted engines. The sulfated ash mainly comes from the metallic salts used for the detergents. Ken
 

DavoNF

Thread starter
Messages
451
Location
Bribie Island, Oz
Thanks Ken. In that case, if the ash is mostly detergents, and LPG is a very clean burning fuel, a low ash oil should give adequate protection. The car is my "weekend limo", does about 4,000 miles/year, and has oil changes every 6 months. Dave
 

TC

Messages
1,644
Location
California
I suspect that any "gasoline" oil will do just fine. From the Union 76 (part of Conoco-Phillips) motor oil spec sheet: "76 Super Motor Oil is recommended for 4-stroke cycle gasoline, LPG, or CNG engines only. It is not recommended for methanol-fueled vehicles." From the Citgo Supergard spec sheet: "...recommended for gasoline engines...Supergard motor oils are also recommended for use in gasoline engines which have been converted to operate on compressed natural gas (CNG), liquifed natural gas (LNG), and liquified petroleum gas (LPG - which includes propane and butane). Consult the vehicle owner's manual for proper engine lubricant selection." Most GASOLINE oils are low-ash, so you shouldn't have a problem anyway. Union 76, Valvoline, and Kendall all produce 0.8% ash per ASTM D874. With more calcium and/or magnesium detergents, DIESEL oils have higher ash, such as Shell Rotella (1.47%), Chevron Delo 400 (1.34%), and Pennzoil Long Life (1.45%). As Ken2 mentioned, ash relates mostly to detergents/dispersants, rather than AW additives such as zinc, moly and phosphorus. If you're running a "gasoline" oil, as opposed to a "diesel/multi-use" oil, ash should be of no concern to you, and none of this directly relates to engine wear. [ March 16, 2004, 08:04 PM: Message edited by: TC ]
 
Messages
11,005
Location
Canberra ACT Australia
The BP Visco Gas is very good on our Timken, a real surprise. Pennzoil Gas is as good if not better and Ron in Melbourne has standardised all his forklift clients on the Pennzoil but impressed by the BP. Commercial decision in the end. Previously used Fuchs.
 
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