View Full Version : Help with oil viscosity???


Bad News22
07-04-2012, 07:19 PM
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.

tom falco
07-04-2012, 07:23 PM
15w40

Gray86hatch
07-05-2012, 06:45 AM
Alum or iron

96 Comp T/A
07-05-2012, 07:17 AM
15w40

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.

My6speedZ
07-05-2012, 07:17 AM
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.

Bad News22
07-05-2012, 08:00 PM
Alum or iron

Aluminum

Bad News22
07-05-2012, 08:01 PM
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.

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....

Gray86hatch
07-05-2012, 08:13 PM
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

My6speedZ
07-06-2012, 02:54 AM
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....

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.

Blk98Vert
07-06-2012, 03:44 AM
The boosted guys seem to love 5W-40. Its what I use and I have no complaints

tom falco
07-06-2012, 05:52 AM
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.

Dyno Junkie
07-06-2012, 06:12 AM
In both our current LS3 and our previous 605 horsepower 15.5psi 6 cylinder engined car I run Castrol Edge 10w-60.:nod:

Gray86hatch
07-06-2012, 07:36 AM
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

Bad News22
07-07-2012, 07:39 PM
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.

djfury05
07-07-2012, 08:14 PM
So now that you've decided on the weight, which oil you going with?

Gray86hatch
07-07-2012, 08:24 PM
I have a case of gibbs ls30 I am going to put in the car next week
syn 5-30 with zddp

Tim

tom falco
07-07-2012, 08:36 PM
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!!

Gray86hatch
07-07-2012, 08:46 PM
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

tom falco
07-07-2012, 09:02 PM
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.

tom falco
07-07-2012, 09:09 PM
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.

Bad News22
07-07-2012, 09:41 PM
So now that you've decided on the weight, which oil you going with?

Mobile 1

westtexasbuff
07-08-2012, 12:55 AM
http://fc03.deviantart.net/fs48/f/2009/210/5/a/face_palm_by_Draculasaurus.gif

Man... so much misinformation in here. The oil you use is going to be based on your bearing clearances. And based on what you've stated, I'd recommend Valvoline 20w50. We use it on all the 1000+ hp builds here. The looser your clearances, the thicker the oil you need to run. Saying ALL turbo LS guys run 10w30 is nonsense :eyes:

Bad News22
07-09-2012, 08:03 PM
http://fc03.deviantart.net/fs48/f/2009/210/5/a/face_palm_by_Draculasaurus.gif

Man... so much misinformation in here. The oil you use is going to be based on your bearing clearances. And based on what you've stated, I'd recommend Valvoline 20w50. We use it on all the 1000+ hp builds here. The looser your clearances, the thicker the oil you need to run. Saying ALL turbo LS guys run 10w30 is nonsense :eyes:

I agree that the top number should be based on your bearing clearances and what delivers optimal oil pressure but why wouldn’t you want to run the lowest possible bottom number available e.g. 0W?

tom falco
07-09-2012, 08:37 PM
I cant believe this discussion. As an engine builder for more years than i would like to admit i have only used a hand full of different oils

Bearing clearances will determine oil bleed down if set correctly and within street limits not an all out race motor clearances are pretty standard. That is the way we build engines for the street. Certain engines have built in issues that effect oil choices. Example 2.3 ford engines will strip out the dizzy gears because of pump loads. So we build these engines on he high side of clearances and we use a 10W30 exclusively. On chevy motors we normally use 15W40. All engines have a relief valve to control pressure from cold to hot. Set properly it should compensate for variances in clearances. If an engine needs heavy oils to compensate for excessive clearance the bottom end is not built correctly. If the clearances are to tight and light weight oils have to be run that is an issue as well. Controlling oil pressure with oil viscosity is not the way it is dun. Oil viscosity is controlled by the environment. If you live in a cold climate you need different oils. If you live in Florida basically viscosity are a non issue to some extent. Basically mult weight oils with to much spread are not as good as close numbers. Wh have had many MOBIL reps in the shop and they inform us on performance applications to stay within a 3-3 1/2 step number for oils. Oils with spreads like 10-60 are way out of line. They contain to much VI improves and not enough oil. Think of it as a rubber band. It can only be stretched out so many times. Now i know some will come back saying that is why you change oil . TRUE but we had a condition many years ago when VI improvers in certain oils failed and the oil turned to muck. The oil was so thick engines were wiped out in relatively low mileage. Also we have found that those o-20 and so on and so forth dont work worthh a hoot in engines that rev high and have multipple valves like HONDA NISSAN TOYOTA. Those engines use oil at an alarming rate with the ZERO base oils. We never use anything lower than a 10W30. Just what we found to be true. Good luck on your oil choices.

tom falco
07-09-2012, 08:49 PM
I agree that the top number should be based on your bearing clearances and what delivers optimal oil pressure but why wouldn’t you want to run the lowest possible bottom number available e.g. 0W?

Because most oils are picked by the climate the engine works against. And it depends on the sustained speeds also. Another words i personally dont think one oil grade and viscosity can do this efficiently. My mobil REP informed me that choosing an oil with to thin and a broad VI number could be disastrous on a performance engine. basically ask any Toyota Honda or Nissan owner how much oil these engines BURN. IT'S A LOT!!!

tom falco
07-09-2012, 08:57 PM
SAE Viscosity Grade Motor Oil: 5W-30
Temperature Conditions: Below 0° F

SAE Viscosity Grade Motor Oil: 10W-30
Temperature Conditions: Above 0° F
Description: Most frequently recommended motor oil viscosity grade for most automobile engines, including high-performance multivalve engines and turbo-charged engines.

SAE Viscosity Grade Motor Oil: 10W-40
Temperature Conditions: Above 0° F
Description: The first multigrade introduced. A good choice for controlling engine wear and preventing oil breakdown from oxidation.

SAE Viscosity Grade Motor Oil: 20W-50
Temperature Conditions: Above 20° F
Description: Provides maximum protection for high-performance, high-RPM racing engines. Excellent choice for high temperature and heavy loads such as driving in the desert or towing a trailer at high speeds for long periods of time.

SAE Viscosity Grade Motor Oil: SAE 30 & SAE 40
Temperature Conditions: Above 40° F & Above 60° F
Description: For cars and light trucks, Not recommended when cold-temperature starting is required.

LS17000RPM
07-09-2012, 09:23 PM
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!!

I have used 5w-30 and 10w-30 on my g35 since brand new. The car now has 176,000 miles and I recently did a used oil analysis and the engine wear is the same as 100,000 miles ago. It will go another 100,000 miles easily.

Bad News22
07-09-2012, 10:10 PM
So based off of some of the above posts another question comes to mind. Why is it that "Bob is the oil guy" (a well recognized and respected oil expert) says that basically any weight oil even 0W is still too thick at ambient temp but yet some of the above posts say that even a 20W is fine? Seems to me that even in 70 degree weather 20W-XX would be pretty thick on start up.

tom falco
07-10-2012, 02:53 PM
I have used 5w-30 and 10w-30 on my g35 since brand new. The car now has 176,000 miles and I recently did a used oil analysis and the engine wear is the same as 100,000 miles ago. It will go another 100,000 miles easily.

I find this extremely fascinating as i make most of my money on foreign engines that cant make it past an advanced auto parts store without a transfusion. Especially the 35

Stumped1215
07-11-2012, 01:03 AM
I have used 5w-30 and 10w-30 on my g35 since brand new. The car now has 176,000 miles and I recently did a used oil analysis and the engine wear is the same as 100,000 miles ago. It will go another 100,000 miles easily.

I find this extremely fascinating as i make most of my money on foreign engines that cant make it past an advanced auto parts store without a transfusion. Especially the 35

I just wanted to tell you that I read all of your posts because I wanted to learn something, but its just f*ckin oil bro.:bang:

I Confederate I
07-11-2012, 03:18 AM
I've been having the same question myself. What oil weight is necessary for cammed engines? I run a...relatively large cam (.595I/.603E) not the biggest out there, but respectable. I also have LT headers, which tend to echo the valvetrain noise, making it louder. I occasionally have a tapping sound that comes from the engine. I have yet to be able to isolate the sound and determine its cause. It doesn't seem to be caused by going WOT but more by cruising on the highway. I run M1 5w-30 and have ever since I got the car. I spoke to a friend today that has been a mechanic for a million years and he told me that my oil wasn't right for my cam setup. He then recommended using a 20w-50...which I have a problem agreeing with. The ls1 manual clearly states not to use anything higher than Xw-30. I decided to run a quart of Lucas through the system to thicken the oil and see how it ran. So far, no tapping. Also, the valvetrain is quieter. Anybody ever have any problems with their stock oil pump not handling a Xw-40? Or 50?

crainholio
07-11-2012, 06:28 AM
Anybody ever have any problems with their stock oil pump not handling a Xw-40? Or 50?

At Bondurant racing school in 2004, they were running Mobil-1 15W-50 in their LS1 Vettes. I had the same question, seemed like very heavy oil to be running. Shop guy said they blew two engines shortly after fielding the cars, # rod bearing in both cases. GM sent an engineering team to inspect, came back with that oil recommendation. Two years later and not a single blown engine.

Clearly their environment and usage aren't what most of us throw at our engines, but it's a valid data point to consider.

I've run Mobil-1 15W-50 in my LS1 for road course days, including two road trips from NJ to TN...3 days of road course...then back to NJ. Blackstone oil analysis showed single-digit wear metals with none higher than previous reports using thinner oil during commuting and street use. Apart from a slightly sluggish throttle while the engine was cold, no negative impact I could find.