“ Live long and prosper” old Chinese proverb and some space guy with pointy ears!!!

will not happen at prolonged 7600 rpm runs!!!

 

i asked this becuase johnson lifters says 40 weight oil is too thick for the short travels to function

EDIT.....I MEANT TO SAY 50 WEIGHT OIL!!!!

 

I believe it. That's another reason thinner oils are used in modern engines, as thicker oils won't into the tighter spaces made by tighter tolerances.

 

And those same platforms are spinning bearings and toasting motors because they're trying to make 4/500+whp and run 0w20 oil. So stupid to run something that thin on a performance engine.

 

i needed to edit, i remember now i broke in motor on 20 w 50 which i was told was way too thick by jonhson, builder recommended this. and after calling them they said 10w 40 is the thickest that can be used and that is only when beating on it and when track temps raise the oil temp.

 

My comment was directed at using 40weight with the lifters mentioned. 0w-30 is at the other end of the spectrum. You don't use that in an engine of the caliber you speak of either.

 

Theres currently a battle on another platform about exactly that. The OEM recommends 0w20 even though it's a high performance turbo motor. People are tuning and pushing them and wondering why they're toasting bearings.

 

NHRA Pro Stoccks run 0w3 oil. Three, not thirty. This is coming from Poly, our resident oil expert, who works with all these guys. I get it that I’m not talking about an Oem with a warranty, but you’d think a Big Block making, i don’t know…1800hp?…would need more oil weight. Maybe poly will chime in here and clear the air.

 

im running driven gp1 15w40 with my lsx. Its a semi synthetic. which is better for lifters , bearings etc

 

If I remember correctly either Nascar or top fuel cars run much thicker oil like or 30 or 40 weight.

 

NASCAR might run fairly thick stuff, as they are running a LONG time and heat it enough to thin it down.
Top fuel/ProStock, or any pro-level drag racing, is totally the other side of the coin. They run at 1000% for seconds at a time and change the oil between runs, along with a bunch of engine parts where needed.
Two different worlds.

 

actually not really. This link shows top fuel dragsters run 70 weight oil.
https://www.enginelabs.com/tech-stor...osity%20values).

 

Good point. I actually think whatever they run only has a lifetime of a few minutes, startup to shut-down. I bet it's all over the map between different teams.

 

High Viscosity 60/70 is used/needed for Blown Nitro/Alcohol to fight Viscosity Loss due to
Extreme fuel dilution.

OP could use AMSOIL Signature Series 0W-40 which is specced for the GTR Twin Turbo,
Chrysler Demon/HellCat, and the C8 LT2, especially with Cats and or Frequent Driver.
Katech also limits Viscosity to 40 for lifter function.

For no Cats and intermittent use such as sitting during winter ~2-4 months.
The Z-Rod 10W-40 has more ZDDP but more importantly
Anti-Rust and corrosion inhibitors for prolonged non use.

Full Disclosure: AMSOIL User/Dealer since 1989.

 

Thicker oils also take longer to flow to the critical areas, when cold, and also run higher oil temps, when hot, everything being equal. A 15w-40 wouldn't flow as well cold as a 5w-40, or 0w-40. I think a lot of old school oil beliefs are still being applied to modern synthetics. Personally, I run 0w-40 oil, Mobil 1. Are there better oils? I'm sure there are, but not enough better to warrant opening my wallet for something I really don't need for my application/driving style. My builder actually told me NOT to run synthetics!!! How's that for a good example? I did use Dino oil for the first 1,000 miles, then switched to synthetic. Also, in my honest, personal opinion, whatever oil the Top Fuel, Pro Stockers, and NASCAR engines run is TOTALLY IRRELEVANT to my primarily street driven, sometimes at the dragstrip, built LS7 equipped car. My .02. Bob is the oil guy also has some excellent advice/results online.

 

I'm much less concerned with the first number than the 2nd number. People are swearing by 20 weight or thinner oils because the OEM says so. Then they add 100whp and 150wftlbs and wonder why they spun a bearing. We can certainly argue all day about the real world wear impact of cold starts when running a 0/5/10 weight, but the 2nd number when everything is hot is where you risk major engine damage by running too thin of an oil.

 

There's 3 primary factors that determine the necessary oil grade/viscosity...

1. Operating oil temperature
2. Rod and main bearing clearance
3. The load on those bearings

Being that it's a supercharged engine and assuming it'll see street use, a 40 grade sounds reasonable. It all depends on your clearances though. I hate to say it but we can't trust the engine builder because there's a lot of them that blindly recommend "15W-40" or whatever grade for everything with no consideration as to what's actually ideal for that particular engine. There's a few good ones who do reach out for more information and consultation on oil choices, but the majority of them don't and push information that hasn't been relevant since 1975 or just false altogether.

Do you happen to have the clearances? Also, how is this engine going to be used?

Only a few dedicated race oils have no detergents in them. Usually they're the ones formulated specific to the racing application, in contract with the team, and not available to the open public. I've done quite a few of those oils.

Valvoline VR1 (conventional and synthetic), Mobil 1 Racing, Redline HP and Racing, Amsoil Dominator, etc... most all commercially available "racing" oils contain a standard DI additive package just with boosted levels of anti-wear, friction modifier, and extreme pressure additives. Valvoline VR1, for example, is 98% the same oil as standard off-the-shelf Valvoline with just 80% more ZDDP added.

Foaming is a major one, especially with high rpm engines. I've had fun with formulas that got down to <2 ml of foam under extreme agitation. By comparison, most gas oils are 10-20 ml and diesel oils as high as 50 ml.

They don't do that in fuel cars anymore. Pro Mods, TA, and pretty much anything running alcohol can (and do) still do that. In Pro Mods, it's not uncommon for the oil to be 5% water after 7-8 runs. They dump it, boil the water out, and pour it back in for another 7-8 runs. Those oils typically contain more detergent and dispersant than other oils to help keep the water in suspension.

I find it very odd that they were running VR1. That is not an appropriate TF/FC oil by any means. It's not shear stable enough and is too volatile.

I handle a lot of 0W-16, 0W-20, and 5W-20 oils for racing and performance engines and have seen no such increase in failures so long as the viscosity is fitting. Precise machining and consistent clearances mean tighter clearances can be used with greater load capacity on lower viscosity oils. That said, if we're talking OEM bottom end, I tend to prefer going up 1 grade from OEM any time an aftermarket power adder is used. It's just cheap insurance. A good synthetic 30 grade can take a lot of punishment.

The lifters and bearings doesn't know nor care what base oil is in them. They just care that it's there. GP-1 is a good oil for any engine with an aggressive flat tappet cam and/or sees long term storage, but it falls off quick above ~240*F.

NASCAR runs a 0W-16 with ~280*F sump temps and ~355*F bearing temps. That's for race day. They use a 0W-5 for qualifying.

Fuel cars run a straight 70 grade which is pummeled and diluted to about a 50 grade by the end of the 3.8 second hit.

Fuel cars dump the oil every pass, but Pro Stock, Pro Stock Motorcycle, and Pro Mods do not. They'll usually go 8-15 passes depending on a few factors.

Correct. I'm guessing your engine builder meant no synthetics for the break-in period?

Dedicated, application specific racing oils are quite different from their street oil counterparts. However, a few street oils are inspired by what's learned in the racing oils. If an oil change picks up 5+ hp, I pay attention to that and analyze it in extreme detail to determine the synergy at play. Sometimes that synergy can be transferred over to street oils to provide friction and power benefits without any change to service life.

Aside from engine break-in, there's no benefit to using a conventional over a synthetic oil. Conventional is less thermally stable (both hot and cold), doesn't tolerate water and fuel as well, is more volatile (greater evaporation at high temperature meaning more carbon deposits, varnish, sludge, and oil consumption), and is more shear and oxidation prone. The only benefit conventional has over synthetic is a higher pressure-viscosity coefficient that aids in boundary additive activation at low temperatures, hence the use of conventional oil for break-in. Even that's only true up to ~180*F.

 

I do NOT recommend API CK-4 HDEOs (diesel oils) for gas engines for a few reasons. While a couple contain more ZDDP (Rotella and Motorcraft), most of them don't and it's not relevant to a modern LS based engine anyway. They tend to be lacking in additives not relevant to diesel use such as friction modifiers, extreme pressure additives, and anti-foaming additives. Here's elemental analysis of Rotella T6 5W-40 HDEO compared to Mobil 1 FS 0W-40 PCMO. There's a reason they are rated differently for different environments. You'd be better off to use a Euro 40 grade oil like Mobil 1 FS 0W-40 or FS X2 5W-40, Valvoline Euro 5W-40, or really any oil that meets ACEA A3/B4 or Porsche A40.

 

Thanks "Poly", it's good of you to check in here occasionally to keep us all straight on engine lubrication.
ALWAYS an education...

 

Agree 100%. He’s the man.