Oil reccomendation for LS3 Stroker

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32
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Indiana
Ok, So i have a newly built LS3 Stroker. It is a 4inch stroke, with an ERL Sleeve system to put it out at 4.155 bore. Bearing clearances are roughly all .020 according the build sheet. Here is my issue, when it heats up and the oil gets hot (215+) the thing carries low oil pressure at idle. i have been using valvoline 20w-50 vr1 for break in. I would like to run a full synthetic that offerrs great protection. it is roller cammed but still would like some zinc to protect the thing. im wandering if i should do like a 15w-50 mobil 1? or something even more exotic and heavier to help the pressures like reline 10w-60?
 

rennocneb

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32
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Indiana
no i had it professionally built by ERL, and to put it bluntly they havent impressed on their knowledge thus far for oil. originally was told any 10w-30 or 10w-40 when i told them it wasnt carrying good hot idle pressure they said put in something thicker. Like i said not real impressed.
 

cp3

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2,645
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Kitchener, Ontario, Canada
Originally Posted By: rennocneb
no i had it professionally built by ERL, and to put it bluntly they havent impressed on their knowledge thus far for oil. originally was told any 10w-30 or 10w-40 when i told them it wasnt carrying good hot idle pressure they said put in something thicker. Like i said not real impressed.
Understandable for sure. Is this a street car or strip? What kind of use? High volume oil pump? Out of curiosity, what's it in? Any pics? I would concider M1 15w50, Rotella T6 (5w40) or possibly M1 0w40. All of wich have over 1000ppm of zinc shown in VOAs in that section.
 

rennocneb

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32
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Indiana
its in a pontiac g8 gt. i can get you all some pics it runs pretty stout after getting the tune close to right, thats another story, it has a melling 295 pump i beleive which is a high vol/pressure i think? its the pump they recommended, its a street car that gets ran hard.
 

rennocneb

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32
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Indiana
on the 20w-50 and hot oil like 235ish im seeing 16-24psi on the thin stuff more like 10. 2500 its carrying roughly 40psi, and 6000 cant say that ive had time to look lol.
 

rennocneb

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32
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Indiana
Ok I am at lunch and just beat on it a bit and watched the temp and pressure via HP Tuners. At an oil temp of 214 im only carrying 24psi at idle. I think thats probably just fine, but what happens when that temp goes to 235 in the summer, [censored] maybe 250. Im wandering is it the oil thinning out? or is the aluminum block growing that much as it heats up. at a cold idle the thing shocked me i havent checked it since the weather has cooled and im seeing 50psi at cold idle. even 35psi at 180 to 185 oil temp.
 

rennocneb

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Indiana
oh btw they did bring these cars back as a chevy just minus two doors and called a camaro SS lol. the camaro ss, cts-v, G8 GT/GXP are all the same car underneath.
 
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New England
Originally Posted By: rennocneb
oh btw they did bring these cars back as a chevy just minus two doors and called a camaro SS lol. the camaro ss, cts-v, G8 GT/GXP are all the same car underneath.
The CTS-V is not the same as the others. Hot idle pressure doesn't sound dangerous, nor does 40 psi at 2500 rpm, though not what I'd call great.
 

rennocneb

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Indiana
the cts-v and camaro, g8 share the same suspension parts and pieces the rears are a tick different, the trans is a 6l90 vs a 6l80 but they are for all intents and purposes the same car, most parts swap. Anyway, not here to debate that lol, just wandering about what oil to run in this baby, i think i may toss a good oil cooler on it over the winter. ive been looking at AMSOIL, Joe Gibbs oils, Royal Purple, Mobil 1, and Redline.
 

cp3

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Kitchener, Ontario, Canada
Originally Posted By: rennocneb
oh btw they did bring these cars back as a chevy just minus two doors and called a camaro SS lol. the camaro ss, cts-v, G8 GT/GXP are all the same car underneath.
Ya, current CTS is the Sigma II platform, Camaro/G8 is the Zeta platform. I'd take either! But I do like the 4 doors better. I wonder about the aluminum block. I recal someone mentioning on another forum that tolerances should be tightened up compared to iron but could be just forum fiction... At any rate your new numbers seem a little more bearable. I would do some searching and see what you can find on minimum pressure requirements from GM. The general standard I guess is about 10psi/1000rpm so in that light you aren't too bad.
 

rennocneb

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32
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Indiana
gm claims 8psi per 1000rpm for the z06 i know. Which means like 6psi at Idle id be scared to death to be honest with you. I guess im asking should i be seeing a big thin out in the oil from 180-215 temp? or is that the block expanding? if its the oil ill go get a good cooler. what oil would i be good at looking at the car has about 1500 miles on the engine with convential figure its about time to change it.
 
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Sunny Florida
below 6 psi the PCM will pull spark, so that's probably not a good rule! The 10 psi per 1000 rpm is so general it's simply not applicable to every engine. GM has invested a ton of research into these engines and they know what they're doing. It's not just pressure but volume as well. Accurate oil pressure readings are a must, do not trust the factory gauges. Also you need to know oil temp as well to relate to the pressures.
 

rennocneb

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Messages
32
Location
Indiana
im pulling the pressure and temp right from the PCM via HP Tuners. as i said im seeing a 24psi idle at 215 degree oil temp currently but thats running 20w-50 convential VR1. Wanting a rec for an oil that will be a bit better for my application but still carry enough hot oil pressure. Also trying to weight wether its the oil thinning due to heat, or if its the engine block opening up due to heat.
 
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8,051
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Michigan
Sounds to me like the engine assembler got the clearances too loose. Did they provide you with a record of bearing and journal measurements and final clearances? I can't stand the thought of trying to crutch the oil pressure with thick oil if the engine was built wrong in the first place. Here are the production specs for LS1 bearing clearances: Mains: .0007-.0021" Rods: .0006-.0025" The stock relief valve setting on the oil pump is 60psi @ 5000rpm. If the oil pressure is getting down below 15psi at idle after a hard pull, I would be worried. I have never seen the oil pressure at idle on my LS1 drop below 20psi on 5w30 oil, even after the hardest lapping session on a 100F+ day.
 
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