Recent content by ringmaster

Resurrecting an old thread instead of starting a new one since much has been covered here already. My JLR 5.0 SC V8 (Range Rover) has increased output to600hp via software and a smaller supercharger pulley and it is often used to tow a 6000lb trailer. Oil change cost, marginal fuel...

I decide to veer slightly off course and went with Mobil 1 15W-50. I hope my 8.1L likes it.

Has any new info been uncovered on the C40 GT 0W-40 over the past few months? My Porsche calls for the original C40 0W-40 but I keep wondering if the GT oil has some added secret sauce that could be beneficial in the other high-revving N/A Porsche engines.

This Quicksilver? I haven’t heard of the brand before now. https://www.quicksilver-products.com/en/product/25w-40-synthetic-marine-engine-oil

The OM calls for SAE 40, CG-SJ4 oil and the sump capacity is 8qt w/filter. Oil cost isn't a consideration; this thing drinks close to 10gph of fuel while surfing which makes oil changes look cheap. I would like to run the oil for 30-40hrs over an eight week period.

I will look into the viability of doing a mid-season oil extraction / change while the boat is in the water. If this doesn't work out and I need to run ~30hrs without changing the oil, is there something better than the VR1 40wt?

Wish I knew. The water temp is rock solid at 160F but the boat doesn't have any oil temp gauge.

300hrs on the engine and in excellent condition. Runs perfectly. I have a thread here from last year asking which oil to use in this engine. The VR1 seemed like a good answer - maybe not? Unfortunately I didn't look at the dipstick before today. Amateur mistake! The owner's manual states...

2007 MasterCraft boat with GM Vortec Indmar 8.1L L18 running Valvoline VR1 Racing SAE 40 High Performance High Zinc oil. I paid a shop to do a seasonal oil change with the VR1 oil before putting the boat in the water this June. Yesterday, after ~20hrs of use, I pulled the dipstick to check the...

Thanks for keeping this thread alive. I like your suggestion of Rotella T6 15w40 and I can't imagine why the 8.1L wouldn't be very healthy and happy living with this oil. For the time being I did the winterization oil change with Valvoline VR1 Racing SAE 40 High Performance High Zinc Motor Oil...

My next oil change is coming up soon and still wondering if Amsoil AEQT 0W-20 synthetic with MB229.71 approval might be a good choice for my situation? My JLR 5.0 SC V8 has increased output (600hp) and is often used to tow a trailer. Oil change cost, marginal fuel efficiency gains and long OCIs...

@DuckRyder yes, as far as I know my marine 8.1 is mechanically the same as the 8.1L Vortec in GM trucks. I can understand Indmar wanting to avoid old 10W40 and 15w40 conventional oils with lots of viscosity improvers but surely we've moved past that with high-quality multi-grade synthetics...

Thanks for the replies. Can anyone think of a reason why conventional SAE 40 oil would be better than Rotella 15W40 synthetic for this application?

My wake surf boat has a 2007 GM Vortec Indmar 8.1L L18 (~300hrs on it) that was originally spec'd for 15W40 oil but Indmar later amended the spec to straight 40WT. I contacted Indmar asking which synthetic oil they recommend and their answer was "We don't recommend using synthetic oil in that...

Amsoil is mostly off my radar but in the search for an oil with the highest levels of engine wear protection this is an interesting question. Any thoughts on using EQT 0W-20 synthetic with MB229.71 approval in the JLR 5.0 V8?