I've be using Amsoil products for some time in my auto's, diesel pickup and motorcycle with good results. I was curious as to what Amsoil would suggest for a modern inboard. As I'm a prefered Amsoil customer (not a dealer), I have access to their technical support group. Following is an email I sent them where I copied some good points made by gman last August.
I have a 2005 Tige ski/wakeboard boat with a Marine Power 5.7L GM Vortex engine. The engine owners manual suggests not to use multi-viscosity motor oils (30W). Some forums I've read suggest that synthetics shouldn't be used if the engine will be idle for long periods (in my case - 8 months) as synthetics will leave bearing surfaces unprotected. Can you shed some insight on this? Following is a piece written by someone who made some interesting points:
"Most multi viscosity oil contain VI (viscosisty improvers) whcih are polymers. As the oil warms up the polymers tend to rearrange themselves into a chain. Under shear load and stress they can degrade and not return to the original state. In particular oils with the widest range such as 5W- 30 and 10W-40 require a lot of polymers which can sluge and burn and leave deposits. A wide range in viscosisty is more susseptible to breakdown due to the large content of polymers. A 20W-50 has a wide range but is not as prone to breaking down because it starts at a higher viscosity and therfore not as many polymers need to be added. Look for oils that can do the job with the least amount of polymers. I believe the mercruiser 25W-40 is a mixture of oils and does not contain polymers. Also straight weight oils do not have the VI and are less prone to changing under high heat and have the best lubrication, however, not as effective on start up."
This is Amsoil's response:
Thank you for contacting AMSOIL with your concerns.
In response to your inquiry, the article is false and has nothing to do with today’s modern synthetic formulations.
Our AMSOIL formulations are constructed of polarized molecules that actually have an affinity to metal. In othe words they are attracted to metal and the protective coating will not slide off during storage. Contrary to popular belief, it is not the oil itself that protects the metal from corrosion, it is corrosion inhibitors in the additive package. This is true whether the oil is synthetic or petroleum.
Quality synthetic formulations do not need to use viscosity improvers to achieve a wide viscosity range and will not shear back.
The best choice for this application is AMSOIL Formula Four Stroke Watercraft Oil 10W-40 (WCF). Like many of our products, it is a straight grade SAE 40 that has the cold temperature properties to qualify for a 10W making is an SAE 10W-40/SAE 40. It is loaded with zinc and phosphorus anti-wear additives and has a heavy treatment of anti-rust additives specifically targeted at marine engines. This is a super robust oil designed to handle the continuous beating marine engines deliver.
Click here for more info http://www.amsoil.com/StoreFront/wcf.aspx
This perhaps reads like a commercial but I'm inclined to use there multi-grade synthetic product. The link provides some additional application information and refers to Marine Power engines.
I have a 2005 Tige ski/wakeboard boat with a Marine Power 5.7L GM Vortex engine. The engine owners manual suggests not to use multi-viscosity motor oils (30W). Some forums I've read suggest that synthetics shouldn't be used if the engine will be idle for long periods (in my case - 8 months) as synthetics will leave bearing surfaces unprotected. Can you shed some insight on this? Following is a piece written by someone who made some interesting points:
"Most multi viscosity oil contain VI (viscosisty improvers) whcih are polymers. As the oil warms up the polymers tend to rearrange themselves into a chain. Under shear load and stress they can degrade and not return to the original state. In particular oils with the widest range such as 5W- 30 and 10W-40 require a lot of polymers which can sluge and burn and leave deposits. A wide range in viscosisty is more susseptible to breakdown due to the large content of polymers. A 20W-50 has a wide range but is not as prone to breaking down because it starts at a higher viscosity and therfore not as many polymers need to be added. Look for oils that can do the job with the least amount of polymers. I believe the mercruiser 25W-40 is a mixture of oils and does not contain polymers. Also straight weight oils do not have the VI and are less prone to changing under high heat and have the best lubrication, however, not as effective on start up."
This is Amsoil's response:
Thank you for contacting AMSOIL with your concerns.
In response to your inquiry, the article is false and has nothing to do with today’s modern synthetic formulations.
Our AMSOIL formulations are constructed of polarized molecules that actually have an affinity to metal. In othe words they are attracted to metal and the protective coating will not slide off during storage. Contrary to popular belief, it is not the oil itself that protects the metal from corrosion, it is corrosion inhibitors in the additive package. This is true whether the oil is synthetic or petroleum.
Quality synthetic formulations do not need to use viscosity improvers to achieve a wide viscosity range and will not shear back.
The best choice for this application is AMSOIL Formula Four Stroke Watercraft Oil 10W-40 (WCF). Like many of our products, it is a straight grade SAE 40 that has the cold temperature properties to qualify for a 10W making is an SAE 10W-40/SAE 40. It is loaded with zinc and phosphorus anti-wear additives and has a heavy treatment of anti-rust additives specifically targeted at marine engines. This is a super robust oil designed to handle the continuous beating marine engines deliver.
Click here for more info http://www.amsoil.com/StoreFront/wcf.aspx
This perhaps reads like a commercial but I'm inclined to use there multi-grade synthetic product. The link provides some additional application information and refers to Marine Power engines.
Comment