Oil questions for a new 350 L31 Vortec- Break in and after oil choice

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The new crate motor I installed in my 1966 Chevy truck is an 350 L31 Vortec from GM Performance. Its still not put together fully so I still need to prime it.

Ive heard and read that break in isnt as crucial for this style of cam but I have been thinking to anyway. Question I have there is which oil to use and which weight? Ive looked at Driven and Amsoil so far and I really dont if there is truly that much of a difference.

What ever the break in oil I use I plan to run which rpm is the right one and for how long? 2000 at 10 min, or 20 min?

After that I would drain while hot since Ive heard to get the particulates out better and refill with which oil and at what weight? Its a cruising around town truck just to enjoy not a hot rod racer and its home is in Georgia if that helps to decide the weight.
 

OVERKILL

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If it has a roller cam, there isn't a camshaft break-in, so no need to do the RPM jig. Put it in, follow a driving break-in procedure, which GM should have provided you with telling you to change the oil after X number of hours or miles, and then do so.

This procedure seems reasonable, and, with a roller cam, as noted, you skip step 5:
 
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I disagree on there not being a break-in for a roller cam to an extent. There's still microasperities from the machining process that will get knocked off the lobe and lifters on that initial startup so having a good anti-wear (ZDDP) present to form a tribofilm as quick as possible will help keep that initial wear down.


I follow the same break-in procedure regardless of the cam. It's a process of varying rpm and load with heat cycles. I recommend Driven BR30 for the break-in. Fire it up, idle just long enough to check for leaks and ensure sufficient pressure, and then go to 2000 rpm for ~5 minutes. Shut it off, and let it cool all the way down. About 90% of the break-in is already done now (it's done in the first 30 seconds). The rest is about getting that other 10% to ensure a good seal with little to no leakdown and ensure good engine longevity. Crank it back up and go for a drive somewhere desolate. In 2nd gear, start at 2000 rpm and floor it to 4000-4500 rpm, then coast (in gear) back down to 2000 rpm and repeat. Do this 15-20 times. Now change the oil filter (not the oil), top it off, and go 100-250 miles in stop and go traffic (not just cruising down the freeway). Usually you'll in and out of it dialing in the tune anyway. Then change the break-in oil and put in your oil of choice. I like to short change that first one at ~1,500 miles, and then normal intervals from then onward.
 

OVERKILL

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I disagree on there not being a break-in for a roller cam to an extent. There's still microasperities from the machining process that will get knocked off the lobe and lifters on that initial startup so having a good anti-wear (ZDDP) present to form a tribofilm as quick as possible will help keep that initial wear down.


I follow the same break-in procedure regardless of the cam. It's a process of varying rpm and load with heat cycles. I recommend Driven BR30 for the break-in. Fire it up, idle just long enough to check for leaks and ensure sufficient pressure, and then go to 2000 rpm for ~5 minutes. Shut it off, and let it cool all the way down. About 90% of the break-in is already done now (it's done in the first 30 seconds). The rest is about getting that other 10% to ensure a good seal with little to no leakdown and ensure good engine longevity. Crank it back up and go for a drive somewhere desolate. In 2nd gear, start at 2000 rpm and floor it to 4000-4500 rpm, then coast (in gear) back down to 2000 rpm and repeat. Do this 15-20 times. Now change the oil filter (not the oil), top it off, and go 100-250 miles in stop and go traffic (not just cruising down the freeway). Usually you'll in and out of it dialing in the tune anyway. Then change the break-in oil and put in your oil of choice. I like to short change that first one at ~1,500 miles, and then normal intervals from then onward.

I've never bothered with a roller stick, just followed the engine break-in procedure as noted. Now, on FT rigs, like the Voodoo we put in my buddy's dad's S-truck, we followed the instructions to the letter as we didn't want to wipe out a lobe or lifter, but when we later did a roller setup it was just slap it in and go. I've never been advised by a cam grinder to follow a specific procedure for a roller stick either, including the custom one I had done for my 302. YMMV of course and it certainly isn't going to hurt anything following the procedure you described.

I'd likely describe it as there being little value in following a break-in process for the camshaft and lifters on a roller rig. The main purpose of the break-in is to, as you well-described, ensure good ring seal and engine longevity. On the other hand, with a flat-tappet setup, if you don't break it in properly, you'll be doing it again 😁

Now, all that said, you have vastly more experience in this department than I do, most of mine have been backyard/garage builds whereas I know you are involved in it professionally. I've typically just used an HDEO or M1 0w-40 as far as lube goes too with M1 0w-40 being my go-to for the Windsor rigs. The SBC's we just ran 15w-40 HDEO in them, including with the Voodoo.
 
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Should have a 191/196 (0.050) Hydraulic Roller in it. If so you don't need anything special. Put some regular old 10W-30 SuperTech or Havoline in it an run it 500 mi on the initial oil, change it and then another 2500-3000 mi and replace it. If it doesn't consume any oil in the last couple of 1,000 mi then put Mobil 1 10W-30 or whatever makes you happy in it (Can substitute 5W-30 or 0W-30 depending on climate).

GM used to include break-in instructions with crate engines did you not get them?
 

BlueOvalFitter

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The new crate motor I installed in my 1966 Chevy truck is an 350 L31 Vortec from GM Performance. Its still not put together fully so I still need to prime it.

Ive heard and read that break in isnt as crucial for this style of cam but I have been thinking to anyway. Question I have there is which oil to use and which weight? Ive looked at Driven and Amsoil so far and I really dont if there is truly that much of a difference.

What ever the break in oil I use I plan to run which rpm is the right one and for how long? 2000 at 10 min, or 20 min?

After that I would drain while hot since Ive heard to get the particulates out better and refill with which oil and at what weight? Its a cruising around town truck just to enjoy not a hot rod racer and its home is in Georgia if that helps to decide the weight.
What does the spec sheet and/or warranty card read?
 

msg

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The only paperwork I received was a core return information and plastic bag to wrap it up in. The warranty from what I read going into this is void for me since Im not a certified dealer. Thats why I am trying to be extra careful getting this motor prepped up, hoping for the best. I have never worked on an engine replacement before so Im having to ask alot of questions as I go.
 
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If it's an L31 255 bhp net (not one of the Hot Rod Engines they sell based on it) it will have the mild hyd roller. You should be able to see the retaining spider for the Hyd Rollers in the valley. If you have the retainer clearance the Comp Cams XE268HR-10 with matching springs is a 66 bhp upgrade and makes more power from 3500 rpm up without hurting the bottom end. The time to do it is before putting it in the truck if it appeals. The L31 Cam likes a 2200 stall and the XE268 a 2800 stall if you are running an auto. We used to pull those out of the wrecking yard and do the cam swap and install for repowers.
 
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From

Your engine link shows you bought it from SUMMIT. When I used to race/build engines I bought A LOT of parts from SUMMIT. Why don't you call them and ask what they spec as to which oil to use?

191/196 (0.050) Hydraulic Roller.
Your good. Will be about 280 bhp net with a carb and headers.Maybe 15 bhp less with Center Dump Manifolds. Even with the stock cam that's stronger than anything they put in a truck in the 60's. Lots of people forget the LT1 350 went from 330 bhp to 255 bhp with just going from gross to net.

Don't forget you will need an electric pump and regulator. No way to drive the mechanical pump with that setup.
 
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msg

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Your engine link shows you bought it from SUMMIT. When I used to race/build engines I bought A LOT of parts from SUMMIT. Why don't you call them and ask what they spec as to which oil to use?

I did call Summit they forwarded me to GM Performance. I didnt get very much from them, other than its not needed to break in a roller cam and dont run synthetic until after 500 miles. I would ask, which oil and weight then should I use for this engine not being more than a weekend cruiser around town? He said there are numerous ones, but if it will be stored a good bit and not driven too much thats something to consider.
 
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msg

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191/196 (0.050) Hydraulic Roller.
Your good. Will be about 280 bhp net with a carb and headers.Maybe 15 bhp less with Center Dump Manifolds. Even with the stock cam that's stronger than anything they put in a truck in the 60's. Lots of people forget the LT1 350 went from 330 bhp to 255 bhp with just going from gross to net.

Don't forget you will need an electric pump and regulator. No way to drive the mechanical pump with that setup.

Thanks Gene, I did buy this electronic fuel pump,


still need to get it all put together. The cab is empty, still havent installed the gas tank in the cab, run new lines and sort out the fuel pump and so much more. Ive got a new wiring harness as well to put in. I was told to focus on getting as much of the engine put together before wiring and completing the body panel assembly in the front.

IMG_20200815_124937613.jpg


By the way, what is bhp? Base Horse Power?
 
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Brake Horsepower. Engine horsepower is measured on a dyno with a brake. Traditionally a water brake.

So bhp gross is 29.92 60F and 29.92 Barometric Pressure (Sea Level Standard) with no accessories on the engine.

BHP Net is 29.234 Barometric Pressure 77F and 0% Humidity with full exhaust as installed in the vehicle and full front dress as installed in the vehicle.

The major manufacturers have dyno chambers with controlled conditions but normally engine builders just record duno chamber conditions and use a mathematical formula to correct to the standard.
 
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This is from the GM Performance L96 6.0L Crate Engine in my Buddy's 1966. He uses Mobil 1 5W-30 for street use.

Use only engine oil that meets dexos1 specifications. For track events or competitive driving, use Mobil 1 15W-50 engine oil. Fill the engine with oil and follow the proper engine priming procedure. Also check and fill as required any other necessary fluids such as coolant, power steering fluid, etc.

Start the engine and listen for any unusual noises. If no unusual noises are noted, run the engine at approximately 1000 RPM until normal operating temperature is reached. The engine should be driven at varying loads and conditions for the first 30 miles or one hour without wide open throttle (WOT) or sustained high RPM accelerations. Run five or six medium throttle (50%) accelerations to about 4000 RPM and back to idle (0% throttle) in gear. Run two or three hard throttle (WOT 100%) accelerations to about 4000 RPM and back to idle (0% throttle) in gear.

Change the engine oil and filter. Inspect the oil and the oil filter for any foreign particles to ensure that the engine is functioning properly. Drive the next 500 miles (12 to 15 engine hours) under normal conditions. Do not run the engine at its maximum rated engine speed. Also, do not expose the engine to extended periods of high load. Change the oil and filter again, inspect the oil and oil filter for any foreign particles to ensure that the engine is functioning properly.
 

msg

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Thanks Gene, Ive planned on doing this break in before assembling too many things. Just enough to get it to a point where I can make sure the engine is working fine. Then I plan to assemble all of the body panels and finish it up. This break in will be done in the garage at my home.
 
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