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How to Break in GM 3.1 Crate motor


Bake82

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Hey guys,

 

I picked up a cheap 3.1 crate motor this weekend. Brand new still in GM crate and wrapping. I will be using it for my turbo cutlass swap and will need to break it in obviously. Anybody have any tips for me on how to do this? I'm thinking no/little boost for the first couple hundred miles, but also thinking that I should just break it in how I'm going to be running it in the future.

 

Anyways any help is appreciated! Thanks!!

 

 

Kyle

 

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I'm pretty sure those engines have all been broken in and seated. Everytime there was a replacement installed at the dealership I worked at there was absolutely no break in process. Obviously you want to give it a chance to fully heat up and expand, make sure that the w/p is functioning and everything. Other than that I wouldn't be too concerned.

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Id just drive it normally ( not beating the piss out of it ) for the first oil change. and dont use synthetic oil either until after the 1st oil change.

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I've heard pouring sand down the intake helps break in the cylinder walls.

 

I've read in some manuals that there are break-in periods, but that's also for people who know nothing about cars. I would imagine you could call a GM dealer if you wanted any kind of authoritative answer.

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The single most thing you don't want to do with a new motor is extended drive time at the same RPM/SPEED. Vary your speed every 10-15 minutes on the highway. other tan that cahane the oil first 500 miles, and take it easy for first 1k.

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Many of the "tips" in this thread are old ideas of what you have to do, other than not to drive it at one RPM for extended periods of time for the first 500 miles (totally agree as well as the GM manuals state this). I would start off with synthetic: LS2's, BMW's, Porsche,do and they can't be wrong (many other high end performance cars). I would use NO BOOST until the rings seat in the honed cylinder walls, other than that i would just take your time getting to the point to use boost, hell if it is brand new you might as well take out the pistons and rods and get Eagle and Diamond (eagle rods,Diamond pistons) while it is still not in the car. All of that is up to you of where you want this project to go. later Jay

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hell if it is brand new you might as well take out the pistons and rods and get Eagle and Diamond (eagle rods,Diamond pistons) while it is still not in the car.

 

i agree. upgrade to forged internals and stronger rod bolts (arp for example) while the engine is out of the car.

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The single most thing you don't want to do with a new motor is extended drive time at the same RPM/SPEED. Vary your speed every 10-15 minutes on the highway. other tan that cahane the oil first 500 miles, and take it easy for first 1k.

 

Exactly. This is what my mechanic told me after he installed my Jasper reman 2.8L in my 88 International Series.

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Don't drive at any one speed for the first 500 miles.

 

Don't redline it. Other than that have fun!

 

^That's what every new GM engine says in the manual.

 

Just take her easy. Then open her up. I would definitely upgrade internals, and heads (P+P).

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thanks guys for all the tips. I've known about the not driving it at steady RPM's for the first 500 or so miles. Just wasn't sure of anything else.

 

 

As far as upgrading internals etc.....I am not in the market to do that at the moment. I will run with the crate motor until I have the money, time and desire to build a 3400/3500 turbo motor in the future. for now I'm looking at just using the 3.1 and getting the most out of it reliably with the T25 turbo I have.

 

Nigel. If you hear anything different let me know man! THANKS!!

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Somebody said use synthetic oil to break it in. I wouldn't chance that with a flat tappet cam. Use regular motor oil or better yet something like Shell's Rotella T that's got the additives zinc and phosphorus and so on.

 

This is from the TGP board. The same subject just came up.

 

 

Well first off you don't need to make a tool to pre oil it before starting. As I remember it's a 7mm socket on a long extension, just chuck it in a drill motor. Can't remember the direction but you will find out. After you put the top end on just spin the pump up until you have oil pressure on your gauge for a few seconds.

 

I would seriously recommend adding the GM start up lube or start up lube from crane or comp cams to save your cam especially if you have any trouble starting it. Upon initial start up pull the fuel pump fuse and crank until you have oil pressure for a few seconds. Like 20 to 30 seconds to get the lube mixed in with the oil. Then fire it. You don't have to run it at 2k to oil everything as there is no splash from the crank to help oil the cam. A high idle is sufficient. Just keep the oil pressure up.

 

These motors are famous for wiping cams out. If you have the time put an oiler on #10 lobe.

 

Good luck, hope it runs like a stripped ass rabbit.

 

Jud

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The one other item I would suggest doing is getting coolant into the block. Either remove the thermostat and try to directly pour some coolant into a by-pass hose if this engine has one. I have had engines in the past that were almost damaged at the initial start because of no coolant. Don't wait on the thermostat to open for circulation, it might be too late. Good luck.

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I checked at work Kyle, and they said just to take it a little easy. But you can drive it "normally" for the first little bit. You should have no issues.

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I have a few questions about the break in on my rebuilt motor..

 

1) turbo - should I leave the EBC plugged in, or just plug the wastegate into the compressor housing to keep the boost down?

 

2) old gas - the 93 that's been sitting in the tank is a year and a half old. winter blend. even with that dry gas stuff, will this harm the break-in in any way?

 

humm. I think that was it.

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if you stabilized the fuel it shouldn't be a big problem, but if you are going to do it you might as well do it right so if something goes wrong you won't have to blame yourself. it doesn't take very long to remove and install the tank. maybe 2 hrs. might as well empty it and start fresh.

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the reason you would/should drop the tank is to remove the gel that is in there when the fuel sits for a period of time, thus preventing it from entering your fuel lines at all, thereby preventing any issues. If the gas isn't 2 years old I wouldn't worry about it, just run it out of the tank and put some new stuff in. I removed mine but the gas was 4 years old.

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