What weight oil should I run in my new forged 427 build? .0021 on the mains and .0025 on the rods. Should be around 1200hp with 20lbs. I was going to run 5w-30 but a local engine builder (nobody special, not even a LS guy) said that was way too thin so I thought I would ask here.

 

15w40

 

Alum or iron

 

x2, The 5 horsepower you would gain going with the thinner oil is insignificant @1200HP, compared to the protection you would get with a thicker oil.

 

Go to bob is the oil guy.com and read the oil 101. It will help you understand oil's alot better. It's alot for me to try and go into here. But short answer is from a quick search it seems alot of the turbo guys are running 10-w30.

Or call a sponsor that does alot of FI stuff and ask them what they recommend.

 

Aluminum

 

Funny you mention that. I actually spent awhile last night reading threw all of his stuff. What I took away from it is that I should be running 0W40 which I don't believe is right....

 

If you have a good pump. 15-40 is going to make a ton of pressure.

Mine makes 70-75 cold idle with 5-30 and 25 with 200 degrees of oil temp.

Dads stock 6.0 with a stock pump makes 80 WOT with 200 degrees with 15-40. Going to be switching it to 5-30 next oil change.

Tim

 

You basically should run the lowest weight oil that allows you to see proper pressure all the way to redline if I remember correctly. They have a forum area over there, try a search for boosted cars and see what the guys over there recommend.

There used to be a guy on here that was the resident oil expert but I don't think he comes around anymore.

 

The boosted guys seem to love 5W-40. Its what I use and I have no complaints

 

This is the oldest question in the world and the most confusing.

Basically light weight oils were developed for gas mileage and gas mileage ONLY!!! The EPA ratings on vehicle stickers are accomplished with extremely thin oils. These oils were never intended to be used on the street. But the EPA forced the issue by saying the mileage was NG because the oils were not available to the public. So they flooded the market with the stuff. Basically the multi grade oils run somewhere in between their ratings if i am correct. Example a 10-30 runs at app a 20. And so on. Rule of thumb is you should not increase an oils spread to lets say 10-50 ETC. Oils with high spreads are loaded with VI improver and less oil. Oil pressure is controlled by bleed down and clearances. The relief setup in an engine is designed to control the pressure at a steady rate to some degree. Thats why when you start a cold engine you dont blow the oil filter off. As an engine gets older you need a heavier oil. Most owners manuals recommend different oil for different climates and different engine service conditions. Sustained high speed heavy duty or extream conditions means different oils. Just a THOUGHT.

 

In both our current LS3 and our previous 605 horsepower 15.5psi 6 cylinder engined car I run Castrol Edge 10w-60.

 

On a 950hp sbf goes 9300 thru the traps with rp11lite we see oil pressure in the mid 40's.
The bearings outlast the trick rings and super lite crank. It is all about oil control.

I am a beloved in lighter oil but the volume needs to be correct for the usage.

Texas mile guys were killing parts until they got the volume issues figured out

Tim

 

Well after reading threw Bob is the oil guy's webpage a few more times I think I am going to run 0W40. The reason I stated earlier that I dont think I should run it is because an reputable LS engine builder said to run nothing less than a 10W-XX, however after reading threw the webpage it doesn't make since to run anything less that an 0W-XX. The room temperature thickness is as thin as can be to aid in initial startup and lubrication then pick whatever top oil weight number you need to achieve adequate WOT hot oil pressure.

 

So now that you've decided on the weight, which oil you going with?

 

I have a case of gibbs ls30 I am going to put in the car next week
syn 5-30 with zddp

Tim

 

5W30 ZDDP on a roller engine. What am i missing HERE??????????????

Other than rocker to push rod loads and valve tips ZYNC is not that important on a roller cam. Some say the rocker and push rod tips need ZYNC. As an engine builder i find this not an issue. On flat tappet cams and who the hell uses those antiquated cams any more. You need ZYNC. And their is no guarantee zync will prevent premature lobe wear. If you are street legal with cats ZYNC is out of the question. I always include CATS in all my builds. I personally dont like the weather in KANSAS. I use a lot of motorcycle oils and normally run 15-40. In my 2.3 turbo engines i use 10-30 because of aux shaft and dizzy gear failures. Personally our mobil reps have been pushing 0-30 and 0-40. I dont like this oil one bit. I know how they work and i know what they do with cold starts. But the stuff just does not sit well with me. Theory is the faster the oil gets to the parts the better. I know all of this. But i have seen many an engine destroyed like the issue some time ago with sludged oil from a certain brand. Basically any good synthetic 10-30 is fine for the most part. But i always lean to the 14-40. Many engines today that we service with V TECH and multiple valves run through oil like crazy. Honda TOYOTA and Chrysler are examples of oil users as the manufacturers say. They claim oil usage in their engines is normal. On the NISSAN'S especially the V6 like in the G3.5 using a 4-20 is disasterous. I run 15 -40 in those and if you dont that engine is going to FAIL. They use oil like crazy. Just me could be wrong!!

 

It deff does not hurt. My pushrods and rockers have looked prefect since I started using the additive

I have heard that oil temps have dropped as much as 50 degrees with the gibbs over Mobil 1 same weight

Tim

 

I have heard that oil temps have dropped as much as 50 degrees with the gibbs over Mobil 1 same weight

Explain why this would be TRUE????

I have been building turbo 2.3 fords for many many years. And even when the oil had loads of ZYNC they still flattened out cams. I have changed more cams in the 2.3 ford than any other cam in my career. Second is the small block chevy. Even when the oils were loaded with ZYNC those cams went FLAT.

 

To make a 10w-40 oil, the manufacturer would start out with a 10 weight oil as the base stock. All by itself, this oil would thin out so much at normal operating temperatures that the oil film would be useless. So, they add these very special very long molecules, the VIIs. The VII molecules are as much as 1000 times as long as an oil molecule. The VII molecules curl up in a little ball at room temperature, but as the temperature gets higher they uncurl and stretch out, like a cat sleeping in the sunlight. The more stretched out the molecule is, the more it impedes the normal flow of the oil, thus raising the effective viscosity. Now, this sounds just a little too good to be true. Well, there are two catches: first, these molecules are not lubricants, so the more of them that you add the less oil you have sitting around lubricating things. Secondly, these VII molecules can be broken into pieces by various pressures and forces, like being squeezed through the transmission gears in a motorcycle or the hydraulic valves in a diesel engine. Every time a VII molecule gets broken, the oil loses some of its high temperature viscosity. Synthetic oils made from pure PAOs and/or Diesters typically have very few VIIs, so these oils are far less subject to viscosity breakdown due to shearing of the VII package. As a result, synthetics are far more stable in a motorcycle engine.

10w-30 oil increases its viscosity at high temperatures by a factor of three, which requires a significant amount of these VII molecules. 10w-40 oil increases its high temperature viscosity by a factor of four, which requires even more even longer molecules. 20w-50, which sounds a lot like 10w-40, only increases its high temperature viscosity by a factor of two and a half, so it requires fewer of these molecules than even 10w-30. 15w-40 also increases its high temperature viscosity by about two and a half, so this oil is also substantially more stable than 10w-40. Most passenger car oils today use inexpensive VII molecules that break apart relatively easily. Conversely, most diesel engine oil VIIs are chosen from more expensive chemicals that are more shear stable, since an oil change in a large diesel is expected to last for 15,000 to 150,000 miles.

One way to judge the VII content of your oil is to read the VI, the Viscosity Index, at the manufacturer's web page. The base oils all have similar VIs to start with, so generally speaking, the higher the VI in the blended oil, the more VIIs are present, and the less suitable the oil is for motorcycle usage. John Evans did just such a survey of Valvoline, Chevron, Exxon, Quaker State, Citgo, and Conoco oils. He found that the 5w-30 oils all had VI's in the range of 158-162; the 5w-20 oils had VIs of 148-154; the 10w-40 oils had VIs of 147 to 150; 10w-30 oils had VIs of 134 to 139; and 20w-50 oils had VIs of 120 to 125.