Where are the oil experts?

joenintiesc

joenintiesc

Registered User
I need some help figuring out which is the right oil to use.

1994 SC, recently rebuilt motor with all the go fast goodies
Driven mostly in Spring/Summer/Fall, less than 3000 miles/year
Full Synthetic

Last oil change I used RP 5W30 and Motorcraft filter.

Ford specifies 5W20 according to this:
https://www.ilma.org/resources/ford_motorcraft_oilquickreference.pdf

Seems like I read a lot of feedback here that 10W30 would be best? For my situation above?

Brand? I've used Royal Purple in the past, but I'm considering Amsoil, or maybe Lucas, or maybe just Penzoil Ultra/Platinum?
 
maybe bob is the oil guy forum

meaning, i dont generally see people posting oil analysis reports here, and that they would probably know more about that.

From my other car, mazdaspeed 3, the general concensus was that pennzoil platinum was an exceptionally good oil, but the main problem with that platform was direct injection and fuel dilution, not so much an issue here, but it did hold up very well on the posted documents. another oil everyone raved about was rotella t-6, once again, very good oil with good wear properties under pretty harsh conditions(ahole tuners)
 
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Thanks for the replies! I checked the link to the Bob forum, but he was asking about a 100K mile engine, whereas my is new rebuilt.

Originally 5W30 was the recommended oil, but according to that link I posted Ford has since updated it in 2005 to 5W20. But then I've read here that 5W20 is too whimpy, lol.

Climate in NJ is cool to very hot humid in the seasons I mentioned.

Before I posted I searched through a bunch of posts regarding oil weights and pretty much every weight oil in existence seems to be used by someone, lol! :eek:
 
joenintiesc said:
Originally 5W30 was the recommended oil, but according to that link I posted Ford has since updated it in 2005 to 5W20.
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I don't see the SC broken out, or did all 3.8s have roller tappets? You can try 20, but if it causes lifter noise on startup, you may want to bump to 30.
 
5w30 is what you want to run. 5w20 is thinner, and is being specified by manufacturers to help boost fuel economy numbers, but it will not provide enough protection given the stresses that our engines experience. 10w30 is the same thickness as 5w30 when hot, but is thicker when cold, which is not what you want. As for what brand, that really comes down to personal preference. If you are happy with royal purple, go ahead and continue with that. I personally use valvoline synthetic. Given the low mileage you put in the car, and that you don't drive it in the winter months, there really isn't any need to run synthetic oil (not that it will harm anything). The main advantage to synthetic oil over conventional has to do with maintaining viscosity as it breaks down. Only putting 3k miles a year on the car, the oil will never get to the point of breaking down, so I would run a good quality conventional oil and change it twice a year, once in March and once in September.
 
joenintiesc said:
Thanks for the replies! I checked the link to the Bob forum, but he was asking about a 100K mile engine, whereas my is new rebuilt.

Originally 5W30 was the recommended oil, but according to that link I posted Ford has since updated it in 2005 to 5W20. But then I've read here that 5W20 is too whimpy, lol.

Climate in NJ is cool to very hot humid in the seasons I mentioned.

Before I posted I searched through a bunch of posts regarding oil weights and pretty much every weight oil in existence seems to be used by someone, lol! :eek:
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5w20.is energy conserving for fuel economy 5w30 truly isn't a big difference

5w is when cold and signifies better flow.at start up when the engine is cold which there both 5w so no difference there

30w signifies the weight the oil becomes at operating temperature and is thicker at that time so slight differences but not significant

the internal temperature the stock engine obtains isn't significant vs our engines modified unless your comparing extreme modifications

most run cooler thermostats bigger intercoolers lower fan turn on temperatures ect all of which offsets the internal temperature stock vs modified

I run Amsoil signature series which is one of and/of the best out there

go on Amsoil. Com as well as independent testing to see!

It won't hurt to run 5w30 its a slightly wider range of coverage and overall is prob best choice
 
George95PearlSC said:
It won't hurt to run 5w30 its a slightly wider range of coverage and overall is prob best choice
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Lol, you were the one who told me last year about Ford changing the spec to 5W20 and that was the recommended weight, right after I did my first oil change using RP 5W30! :D :confused:

How do you like the Amsoil after using it for awhile now?
 
joenintiesc said:
Lol, you were the one who told me last year about Ford changing the spec to 5W20 and that was the recommended weight, right after I did my first oil change using RP 5W30! :D :confused:

How do you like the Amsoil after using it for awhile now?
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Yes you're correct and remember, i like it. I think I had mentioned that I felt the SC was more responsive. No issues its quite and purrs no upper end noise no lower end noise very happy.

I feel if would be fine for mine with it being stock I suggested 5w30 for you because you seem more comfortable but don't feel its necessary.

Those other viscosity work depending on what climate your in.in the northeast us 5w30 is common

those other viscosity are heavy and unless your heavily moded out and racing it's very unnessary

the most i will run is 5W30 in my opinion
 
joenintiesc said:
Why do some of the guys here with well know SC's run 15W50 and 20W50?
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In most of those cases, it is just not knowing any better. In a race only environment (like road race or circle track, not 1/4 mile) a thicker oil might be used because of higher operating oil temperatures. If the engine oil will be at a higher temperature, that makes it thinner, so in order to keep it at the proper thickness at operating temperature, you need a heavier oil for the higher operating temperature. In most of those situations though, the engine oil is pre-heated before actually running the engine and definitely before driving the car. The main reason you don't want to do this is because when cold, even a 0 weight oil is thicker than ideal, and will cause engine wear. The thicker oils will only exacerbate this problem, and if you don't need the heavier oil for protection when hot, then you are only causing extra wear when cold for no gain. What thickness oil your engine requires is based on your bearing clearances and engine oil temperature when warm. Ford specified a 30 weight oil for that, so unless you are running higher temps or larger bearing clearances, you don't want anything heavier than that. Running a 20 weight oil may not provide enough protection. As for the first number, that is the viscosity when cold, and you want it as low as possible to prevent engine wear on startup, since even a 0 weight oil is too thick when cold. If you can get 0w30, go for it, but that is not readily available. 10w30 will behave exactly the same as 5w30 at operating temperature, but will be even thicker at cold temps, which means more unnecessary engine wear on startup. Basically 10w30 was one of the first multi-viscosity oils, so people default to it, but 5w30 is always a better choice. 5w20 and 5w30 will behave exactly the same at startup, but the 5w20 will be thinner when at operating temperature, so if you are going to drive your car hard, I don't reccomend it. If you are going to go with a 20 weight oil though, you would be better off with a 0w20 since it will be the same thickness at temp, but thinner when cold.
 
I'd ran 5W20 in my Mustang for a little while, with no adverse effects, but went back to the stock 5W30. Like MadMikey says, 5W20 is often just to appease the CAFE suits, but it's really hard to quantify the longer term effects of running a thinner oil, in terms of wear and tear. Performance gains are really negligible (it's nothing that can be felt).

In both of my cars, I run Mobil 1 full synthetic 5W30, and it's done great, and I haven't been easy on the cars. In the past, i've used Castrol Syntec, Castrol Edge and those had done great, as well. I use a K&N oil filter on both of my cars, and it has done well, too. It has an anti-drainback valve in it so that the engine isn't starved of oil on startup.
 
MadMikeyL said:
In most of those cases, it is just not knowing any better. In a race only environment (like road race or circle track, not 1/4 mile) a thicker oil might be used because of higher operating oil temperatures. If the engine oil will be at a higher temperature, that makes it thinner, so in order to keep it at the proper thickness at operating temperature, you need a heavier oil for the higher operating temperature. In most of those situations though, the engine oil is pre-heated before actually running the engine and definitely before driving the car. The main reason you don't want to do this is because when cold, even a 0 weight oil is thicker than ideal, and will cause engine wear. The thicker oils will only exacerbate this problem, and if you don't need the heavier oil for protection when hot, then you are only causing extra wear when cold for no gain. What thickness oil your engine requires is based on your bearing clearances and engine oil temperature when warm. Ford specified a 30 weight oil for that, so unless you are running higher temps or larger bearing clearances, you don't want anything heavier than that. Running a 20 weight oil may not provide enough protection. As for the first number, that is the viscosity when cold, and you want it as low as possible to prevent engine wear on startup, since even a 0 weight oil is too thick when cold. If you can get 0w30, go for it, but that is not readily available. 10w30 will behave exactly the same as 5w30 at operating temperature, but will be even thicker at cold temps, which means more unnecessary engine wear on startup. Basically 10w30 was one of the first multi-viscosity oils, so people default to it, but 5w30 is always a better choice. 5w20 and 5w30 will behave exactly the same at startup, but the 5w20 will be thinner when at operating temperature, so if you are going to drive your car hard, I don't reccomend it. If you are going to go with a 20 weight oil though, you would be better off with a 0w20 since it will be the same thickness at temp, but thinner when cold.
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Thanks Mike, that is a very thorough explanation! The guy I bought the car from told me the following when I had asked him some questions about the oil and engine rebuild in general:

With regards to the motor oil. I broke it in on motorcraft synthetiic blend 10w-30. The rings were seated in via the acceleration and deacceleration method. You run it up from 40 to 60 MPH, then let off the accelerator and back down to 40MPH and then repeat the procedure about 6-7 times in a 10-15 mile drive.

1,000 miles later I draind the oil and used 10w-30 Mobil 1. I know many manufacturers use full synthetic from day one. I did a compression test at about 1,500 miles in as I always do on a fresh engine to check for cylinder balance and each cylinder came in at 148-150PSI on the nose with 3 full revolutions of the crankshaft. The engineis good to go. As a side note I file fit each piston ring. I used .006 thousands of an inch for every inch of cylinder bore on the top ring and .005 thousands of an inch for every inch of bore on the second ring. So I custom fit each ring to each cylinder for which it was installed. It's a tedious process using a file and fitting each one but this is why each cylinder is so well balanced with pressure. It's a supercharged application so I run the ring gap a little looser than on a naturally aspirated engine. The bore was set up about .0015 looser for each cylinder than the factory settings as again more
cylinder pressure means more heat so I like it a little looser. The block was zero decked meaning the pistons come up to exactly the top of the deck at TDC. The cylinder head to block surfaces are perfect. I do this to help eliminate head gasket issues and to keep the clamping force consistent across the surface. I used MLS gaskets and ARP cylinder head studs. Head gaskets should never be an issue for as long as you own it.
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I guess he used 10W30 for the reason you suggested? He lives in New England, so it seemed like 0W30 would have made more sense for a colder climate. I wasn't sure if I had been missing something on the 10W30 selection.

I'll stick with 5W30, but I'm going to skip the Amsoil for now since I hardly put enough miles on to justify synthetic, let alone a hard to get expensive syn. Will use RP or maybe Mobil 1 or Penzoil Plat/Ultra, which I use in my other vehicles.
 
1FSTBRD said:
I'd ran 5W20 in my Mustang for a little while, with no adverse effects, but went back to the stock 5W30. Like MadMikey says, 5W20 is often just to appease the CAFE suits, but it's really hard to quantify the longer term effects of running a thinner oil, in terms of wear and tear. Performance gains are really negligible (it's nothing that can be felt).

In both of my cars, I run Mobil 1 full synthetic 5W30, and it's done great, and I haven't been easy on the cars. In the past, i've used Castrol Syntec, Castrol Edge and those had done great, as well. I use a K&N oil filter on both of my cars, and it has done well, too. It has an anti-drainback valve in it so that the engine isn't starved of oil on startup.
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Thanks for the feedback. I've always been tempted to try one of those K&N filters. Probably a good idea for a car that can sit for days and weeks, even months at a time.
 
joenintiesc said:
I've always been tempted to try one of those K&N filters.
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The K&N (HP-2009) filter also has the bonus of a large hex nut built onto the end cap to help filter removal (no need for strap wrench). Comes in handy on our cars with the tight fit in that area, etc.
 
1FSTBRD said:
I'd ran 5W20 in my Mustang for a little while, with no adverse effects, but went back to the stock 5W30. Like MadMikey says, 5W20 is often just to appease the CAFE suits, but it's really hard to quantify the longer term effects of running a thinner oil, in terms of wear and tear. Performance gains are really negligible (it's nothing that can be felt).

In both of my cars, I run Mobil 1 full synthetic 5W30, and it's done great, and I haven't been easy on the cars. In the past, i've used Castrol Syntec, Castrol Edge and those had done great, as well. I use a K&N oil filter on both of my cars, and it has done well, too. It has an anti-drainback valve in it so that the engine isn't starved of oil on startup.
Click to expand...

Sounds like we are all on the same page and are basically in agreement, some had more detailed explinations! I like the 5w20, I don't run the car hard but agree 5w30 is the better choice overall especially with mods, and 0w20 even better vs 5w20 and 0w30 if existed even that much better!. But anything more is unnecessary.

I like the Amsoil especially because I don't drive much an feel its well worth it for the protection in regard to the shear fact the car sits, and it has protective properties for that fact alone.

Go on Amsoil.com Joey !
 
George95PearlSC said:
Sounds like we are all on the same page and are basically in agreement, some had more detailed explinations! I like the 5w20, I don't run the car hard but agree 5w30 is the better choice overall especially with mods, and 0w20 even better vs 5w20 and 0w30 if existed even that much better!. But anything more is unnecessary.

I like the Amsoil especially because I don't drive much an feel its well worth it for the protection in regard to the shear fact the car sits, and it has protective properties for that fact alone.

Go on Amsoil.com Joey !
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Actuall pardon me Amsoil has 0w20, 0w30, and 0w40 weight top end signature series oils >>> :D
 
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