Ok not to start to much of a war or anything lol, but I am looking for opinions on the two sythetics listed above. Does either get the nod or are they equally good?

Decently built NA sbc if that factors into anyones choice between the two.

Once our circle track einges have been broke in properly we have our customers switch to the 20/50 AMSOIL and have been using it for years with zero problems and if I thought there was a better oil out there I would be using it.

When we tear down engines after 2 or 3 seasons of hard running they all look good.

The temp gauge will tell you if your using a good oil or not as our oil pemps are with in 30 degrees of our water temp on the wet sump engines wiht no oil cooler.

Just what we have seen over the last 25 years or so.

If I was using a roller cam, my fist choice would be Mobil 1 with Royal Purple my second choice.

If it was a flat-tappet cam, my choice would be Brad Penn racing oil, 10w-30, after break-in with Brad Penn break-in oil.

tom

Truth be known, there is so little protection difference offered by the major synthetic oils that is really academic to say one is better than the other. If you look at the charts that list the temperature break down there is only about 10 to 15 degrees difference between all the synthetics. The temp is so high that your gaskets will be gone long before the oil gives up. Mobil 1, Amsoil, and Royal Purple are all superior oils, you are splitting hairs trying to decide which is better.

Vince

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The Mobil 1 products have changed there formular do to the new oil ratings and there oil is not recomended for use with flat tappets and any oil that does not say racing on the bottle should not be used in racing engines as a shop we deal with found out the hard way and when he called Mobil 1 they told him of the change after he had tore 14 lobes off a flat tappet.

As a former sales rep for Amsoil (I was in it for the cheap oil ) I can tell you my opinion. Amsoil, Royal Purple, and Red Line are all top notch oils, but they aren't really any better than Mobil 1 in most practical purposes. The boutique synthetics like the first three use slightly higher quality stuff, but in actual engines and use you won't be able to tell a difference. Its like using expensive butter in your brownies... They'll taste the same, but your wallet will be lighter.

As a synthetic oil lover, I run regular plain oil in my cars. I change them more frequently than I need to, its just my style, so synthetics would offer me no advantage.

Don't confuse the brand names I've mentioned with any other synthetic oil. Cheaper synthetics like Castrol, Valvoline, and the others are only PARTLY synthetic. The legal classification for synthetic oil is an oil that meets X standards for purity, so legally they can brand their really clean oil as synthetic because it meets the standard, but it can still come from the ground, not a lab.

That's why I made a distinction in my post between the flat-tappet and roller cams. The principle advantage of a synthetic oil over a non-synthetic type is the high temperature protection it affords. I prefer Mobil 1 over Amsoil becuase I have found that my truck uses about 1 quart of Amsoil over 2500 miles while Mobil 1 shows little difference on the stick over the same change interval. BTW, Amsoil buys their base stock from Mobil 1. The difference is in the blending and additive package.

tom

To the "synthetic" purist, Castrol is the traitor in the mix, atleast according to the base stock that regular oil uses and synthetic base stock. Here is a really good, but somewhat old, article about how Castrol BS'd their way into calling a petro based oil "synthetic". Interesting read. Don't pay any attention to the oil ratings as they have all changed over the recent years due to the ZDDP regulations, but the origins of the names are interesting.

Clicky here for the article.

Mark

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If you go to the Amsoil website you can pick the type and weight of oil you like and find specific lab data for that oil. That's a feature that I really like and tells me they're selling their product above board so to speak. There seems to be a lot of smoke and mirrors when it comes to oil. One thing I look for is the HTHS rating of oil. The higher the number the better the oil will hold up under high temps and friction, thereby protecting cams and lifters better. Personally I use 15-50 Mobile 1 in a broken in flat tappet 383 SBC street/strip engine. It has an HTHS rating of 4.5 which is pretty high.

Wher did you fine that info that AMSOIL buys there base stock form Mobil 1 as AMSOIL has been th pioneer in synthetics.

A shop near me has done dyno testing for Mobil 1 even the racing oil that came in boxes that said formulated for Roush Racing and this shop has seen it all and they recomend the Brad Penn oil or the Amsoil in there engines as they have done far more research with Mobil 1 then any other shop and if it was any good I am sure they would be recomending in there engines.

PM me and I will give you there name and number unless you have all ready done the dyno testing on the oil yourself.

Plus since Mobil one has changed thee formular I know of a few other shops that build performance engines that have gone away from there oil, It maybe OK for the street engines but not for what we are doing as we only build a few street engines a year.

[QUOTE=CNC BLOCKS N/E]

PM me and I will give you there name and number unless you have all ready done the dyno testing on the oil yourself.

[QUOTE]

That crack just earned you 1st place on my list of people to ignore.

tom

[QUOTE=machine shop tom][QUOTE=CNC BLOCKS N/E]

PM me and I will give you there name and number unless you have all ready done the dyno testing on the oil yourself.



Thats just about what I expected for a come back LMAO

Carl

I agree with Vince here. You take a look at http://www.joegibbsracingoil.com/oiltech.php

"Busch Engine Test Graphs"

Mobil 1 placed second to only Joe Gibb's racing oils. Dyno's can be very deceiving. joe gibbs racing oil said the moibl 1 was the second best oil overall.

Amsoil is also a good one.

Brand x is better than brand y, brand z is better than brand G so on and so on. I repeat, when it comes to high grade synthetics you are splitting hairs. You can quote all the dyno tests you want. The synthetic oils offer a protection level far greater than conventional oils and they are so close to each other in protection it is pointless to say one is better than the other.

Vince

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Their

Their

Vince

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