So I was talking to Dave the other day, about Mobil1 switching from a GroupIV oil group to a cheaper, less synthetic GroupIII oil group.
Dave had mentioned someone told him the switch to GroupIII wasn't ideal for a flat tappet valve train like the XJ's have. So I decided to do some research, looking to change the type of oil I run. After reading a bunch of posts over on BITOG I ran into this. Strait from Mobil:
http://www.mobiloil.com/USA-English/MotorOil/Car_Care/AskMobil/Flat_Tappet_Engines.aspx
Also from my thirdgen board:
http://www.thirdgen.org/techboard/tech-general-engine/410992-whats-good-motor-oil.html
This is good news for me, as I'm running the Mobil1 High Milage 10W-40. So just food for thought. Unless anybody else has any better info?
Dave had mentioned someone told him the switch to GroupIII wasn't ideal for a flat tappet valve train like the XJ's have. So I decided to do some research, looking to change the type of oil I run. After reading a bunch of posts over on BITOG I ran into this. Strait from Mobil:
http://www.mobiloil.com/USA-English/MotorOil/Car_Care/AskMobil/Flat_Tappet_Engines.aspx
Question: Does Mobil 1 Contain the Additive for Flat Tappet Cams?I build a few engines a year as I do muscle car repairs and I have been having a lot of camshaft failures. I just read that it is because the oil no longer has the additive for flat tappet cams. Can I use Mobil 1 to break in fresh rebuilt engines of '60s and '70s tech? Is it too slippery for new ring break-in? Will it give protection on new cam and lifters?-- Frederick Neidlinger, Dover/Dover AFB, DE
Answer: For older, flat tappet engines where wear may be more of a concern, we offer a number of oil products which are higher in phosphorus than API SM/ILSAC GF-4 oils. These include Mobil 1 15W-50, Mobil 1 Extended Performance 15W-50 (1200 ppm phosphorus), Mobil 1 0W-40 (1,000 ppm) and Mobil 1 High Mileage 10W-30 and 10W-40 (1000 ppm). For all newer engines and flat tappet engines in normal service, API SM/ISLAC GF-4 oils are preferred for better fuel economy and for the protection of catalytic systems with lower phosphorous (800 ppm).
Also from my thirdgen board:
http://www.thirdgen.org/techboard/tech-general-engine/410992-whats-good-motor-oil.html
This is good news for me, as I'm running the Mobil1 High Milage 10W-40. So just food for thought. Unless anybody else has any better info?
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