Oil - Shelby GT

Re: Oil

Aloha Geteup,

Tell us what year and make your ride is ...

then I'm sure one of us can talk shop with you

Kenn

 

Re: Oil

I have a blown 2006 GT, same motor as your Shelby GT, and I use 5W20 Royal Purple. I switched to synthetic at my second oil change and never went back. Stick with the 5W20 because these motors have variable valve timing that is control by oil pressure.

 

I'd go with whatever weight your owners manual

recommends, full synthetic. Mobile 1 is pretty hard to beat, although Amsoil tests out as good if not better in most areas when compared to Mobile 1. Castrol Syntec is very good also. The only thing with Mobile 1 is that they have been making synthetic oil longer than about any one else, so they probably have the best additives/formulations down fairly well.

Some folks like to break a new or rebuilt engine in with conventional dyno oil, as there is a school of thought that the rings/bearings etc. may not break in and seat as well with synthetic. I think the synthetics of today have dealt with that, as many car manufacturers now use and recommend Mobile 1 synthetic in their new cars, (especially those with turbo's or S/C's). The only problem with using Mobile 1 in the 2007/2008 GT500 for example, is that Mobile 1 is not available the 5/50 weight full synthetic that is recommended for the 07/08 GT500. So I guess it depends upon what weight is recommended for your car, what is available, and what brand you prefer.

FWIW I use Mobile 1 or Castrol full synthetic's, at the recommended weights, in all my vehicles. Mobile 1 has some interesting variations available as well, such as Extended Performance, High Mileage, Truck & SUV etc.

Good luck.

Doc

 

Re: Oil

I have received a couple PM's on this, to clarify my statement, I have a blown 2006 GT means I have a 2006 Mustang GT with a blower on it. Not that it has a blown motor. Sorry if I made some think that Royal Purple blew my motor.

 

Re: Oil

I use either Amsoil or Mobil1 in all my vehicles. Amsoil in the motors I change myself and Mobil1 in the motors that get changed at the jiffy lube. I have yet to change oil on my Shelby but suspect I will do it myself and use Amsoil.

 

Amsoil

The choice you will have to make is whether or not you want to stay with the 5/50 weight the factory recommends, assuming you have a GT500, as 5/50 full synthetic is recommended for the GT500. Not sure about the Shelby GT, but it may be 5/30, as it is not S/C. I don't see 5/50 weight offered on the Amsoil site.

Doc

 

Imho

7000 miles between oil changes is a ton of miles, especially for a 130K + engine, whether you use synthetic oil or not. Good thing you use synthetic oil or you good chance you might be rebuilding the engine.

True, many manufacturers say you can go up to 7500 miles depending upon how you use your vehicle, light vs. heavy service etc., but I never, ever go past 5000 miles, even with synthetic. By the time the oil change mileage hits 3000 miles the oil starts to get mighty black/watery, even though it may still have some viscosity left when using synthetic. It's a good idea to change the oil and filter between 3000 and 5000 miles. The way I look at it is oil is cheap, engines are expensive.

I have had many, many cars over the years, and none of them, including my race cars, have used oil.

Doc

 

Re: Amsoil

The book and the oil filler cap on my Shelby GT says to use 5w-20. Amsoil has 5w-20 and 0w-20 oil, no 5w-50.

As far as knowing when an oil is used up I don't think anyone can make that determination by looking at the dipstick. Oil analysis is inexpensive and the only way to determine the condition of the oil. I have done oil analysis and discovered that oil lasts far longer;30,000miles Dodge pickup w/360ci engine; than the 3000 miles that people have been led to believe is required. I have been using the longest drain interval;7500miles; recommend by the owers manual for years and have not had problems.

I had a Toyota pickup w/ a v6 that would use oil when worked hard, the dipstick would show down 1/2 quart, and I would refill and it would go down 1/2 quart. If I left it 1/2 quart down it would not use any more oil. So I stopped topping off the oil at 1/2 quart low and would only top off when it reached a full quart down which never happened.

 

Oil

Thanks for your input.

No doubt the oils, especially the synthetics of today are darn good oil.

Oil analysis not only tells you the condition of your oil, but also the condition of your engine. Not a bad thing to do, especially for high performance, racing applications. However, just because the oil may still have some lubricating qualities left after X amount of miles, does not mean that once contaminated with carbon, metal, even chemical particulate, it will not hasten internal engine wear. Only clean oil provides that cushion/security. Most successful well seasoned racers can tell a lot about the condition of their engines oil just by feeling it between their fingers, smelling, even tasting it, but analysis is superior, of course. I wouldn't recommend drinking it to test it though. J/K :+)

There are so many factors that enter into the oil change interval. Primarily a persons driving habits, engine modifications, how hard the engine is used, whether towing, around town driving, proper warm up/maintenance etc.

Personally, I get a little uncomfortable when my engine oil is black as the ace of spades and as thin as water/gasoline, which it often is at between 3000/5000 miles. However, w/my drag car, a 1971 Olds Cutlass 442 Super Gas 468 C/I car , after one or two races, (which may be 3 time trials, and up to 5 or 6 1/4 mile passes depending upon how far I am able to progress - all WOT, and also warm ups, and idling in the staging lanes/burnouts et al), the Mobile 1 synthetic will be just as I described above. Does the oil still have some viscosity? Likely. Do I want to risk having to spend another pile of $$$ + a ton of work rebuilding my engine after it puts a connecting rod out the side of the engine block or spins a bearing, whatever, rather than invest $25/$30 changing the oil and filter? Hardly.

As I said, I change oil real regularily/frequently, and have never, not even once had an oil burner, or catastrophic engine failure in any of the 30+ cars I have owned in my lifetime. All have had good/above average oil pressure. I differ from you in that I fill my engine oil to or slightly above the full mark, where it stays. I like having lots of oil circulating around inside my engines.

It pretty much comes down to personal choice, kind of like brands of oil. I worked with a lady one time, who, by the time she changed the oil in her car it was so thick with carbon and sludge it almost wouldn't drain out. Needless to say that car's engine was not long for this world. But then she just changed cars. I tend to hold on to my cars, as most are collectors.

Best to go with whatever works for you.

Good luck.

Doc