Learn me Engine Break-In

I'm just about done putting a 3.4 liter GM 60 degree V6 crate engine in my Trooper. It has an upgraded cam, a bigger throttle-body, and I'm adding a wideband O2 sensor and display so I'll know what my air/fuel ratios are like.

What's the best way to break it in? I've seen lots and lots of stuff, and here's what I've come up with:

1. Put conventional oil and Redline break-in additive in
2. Prime oil pump
3. Install distributor, fill all fluids
4. Start, immediately set timing and such
5. Check idle A/F ratio with wideband
6. Let idle for 20 minutes (because pushrods)
7. Drive for 20 minutes alternating between heavy throttle and no throttle.
8. Change oil, add more break-in additive
9. Drive like a grandma for 500 miles
10. Change oil
11. Drive for another 500 miles.
12. Switch to synthetic oil
13. Done!

Oh-how do I prime the oil cooler? Anything special-I think it has a thermostat.

Roller lifters? If so, I think you can avoid the long idle.

A/F will be rich when it's cold. Unless you have some reason to suspect it, I'd ignore that.

Once you've seated the rings (step 7, the critical one), you're pretty much finished.

Where did the crate come from?

Could be broken in already. Without even spinning.

I would ask via the name on the outside of the crate what to do- they built it.

Hopefully you put something in your oil pump so it will prime (some use super duper thick oil, others use grease, others use vaseline). The step 2 you mention above is usually the second time you've manually got oil pressure in a fresh engine build...first being while it's still on the stand to prime it and make sure everything is oiling as expected.

No need to prime the oil cooler; if it has a thermostat, the high pressure oil coming out of the pump will blast the air out if it in seconds once the thermostat opens. If it doesn't have a thermostat then it will purge the air out in step 2 above.

Bryce

Re Steps 9 and 11, I have heard that just cruising at a steady speed, such as Grandma heading to the mall, is bad for an engine on break-in, even though you would think it would enjoy the easy work. However, this may be covered by a thorough Step 7, as per Keith.

This is the same way I was taught back in my apprenticeship days, and what I currently do:

http://www.mototuneusa.com/break_in_secrets.htm

The engine has hydraulic lifters, Kieth. I'm worried about A/F ratios because I have a funny EMS system.

It's straight from GM Performance, I'll ask them.

I didn't put anything in the oil pump, just a pickup.

I'd heard that before. No steady cruising it is.

start it up, check for leaks... hold the revs between 2k and 3k for 10-15 minutes, watching the temps and looking for leaks and what not.. take it out for a drive.... rev it up in first gear and let it coast down a few times to set the rings... do this a few times... watch the temp and check for leaks..

change the oil, drive as normal...

novaderrik wrote: start it up, check for leaks... hold the revs between 2k and 3k for 10-15 minutes, watching the temps and looking for leaks and what not.. take it out for a drive.... rev it up in first gear and let it coast down a few times to set the rings... do this a few times... watch the temp and check for leaks.. change the oil, drive as normal...

^THIS is has been recommended to me by many of the engine builders I worked with (I used to teach 5 axis CNC cylinder head porting...).

The important thing is the rev up/coasting down cycle.

Tom Suddard wrote: I didn't put anything in the oil pump, just a pickup.

Your pump needs some way to pull a vacuum and suck the oil up into the pump. A new, dry pump usually doesn't have tight enough tolerances to pull a vacuum without some help. If you already installed the engine, on most engines you can pour/force oil into the port that is normally the feed for the oil filter (oil passage between the pump and filter). If you get a few ounces in there, you should have the pump wet enough to get the pump to prime.

If you have an oil pump drive tool, which it sounds like you do, you can try that first to see if you're getting oil pressure or not. If not, try getting oil into the pump this way I've described and try with the tool again. If that doesn't work then cuss some, pray to the car gods, and then try spinning the oil pump backwards and forcing oil into that passage at the same time. Then spin the oil pump properly and see if you get pressure. If that still doesn't work, cuss a lot and report back.

Bryce

Edit: You might also be able to use a vacuum pump to pull oil out the oil filter hole I mention above (around the dry pump guts)...never tried that method.

Hmm, okay. This engine came with the pan already attached (I had to change it because I put it in a Trooper, not an S10). So, it's entirely possible that it did actually come with something packed in there.

If not, I'll try pouring oil into it. If that doesn't work, I'll drag it to the challenge parking lot and let y'all figure it out.

WonkoTheSane wrote:

novaderrik wrote: start it up, check for leaks... hold the revs between 2k and 3k for 10-15 minutes, watching the temps and looking for leaks and what not.. take it out for a drive.... rev it up in first gear and let it coast down a few times to set the rings... do this a few times... watch the temp and check for leaks.. change the oil, drive as normal...

^THIS is has been recommended to me by many of the engine builders I worked with (I used to teach 5 axis CNC cylinder head porting...). The important thing is the rev up/coasting down cycle.

It's not revs you're looking for, it's cylinder pressure. Heavy throttle, vaccum, heavy throttle, vaccum.

If it's an engine from a current production car, it'll be prepped exactly like they are for new cars.

What if it is a non street driven car?

Then you break it in on the dyno or in a parking lot or in the pits, I guess...

Tom Suddard wrote: The engine has hydraulic lifters, Kieth.

Yeah, but roller or flat? I don't think GM ever did one of these 2.8/3.1/3.4L with a flat lifter. At least if its a GM 3.4L crate, I have no idea why they would use flat lifters.

Flat lifters need the 20 minutes of fast idle because the cam is splash-lubed. Regular idle won't throw enough oil on the lobes for break in. Roller lifters need no break-in.

If its a flat cam, your procedure above is perfect. If its a roller cam, skip the 20 minute fast idle and just go with the rest.

Oh.. one more thing. If its a flat-tappet cam, change oil after the 20 minute fast idle, then at 100 miles, 500, and 1000. Then go on to your regular interval. If its a roller cam, do the same basic thing but skip the 500. You have no idea what kind of machining shavings are stuck in some nook just waiting to destroy something or clog a filter.

Personally, assuming roller lifters, I'd pull the plugs and fuel pump relay, crank till it builds oil pressure, start it and run it in like everybody said, lots of wot and high vacuum. You never want it to sit at any given RPM for the first few hours. No driving like a Grandma.

I was always told to drive it the way you want it to run.

You don't have long to actually get the rings and cylinder walls to break in. If you miss the window, you'll have glazing and such, and pretty much never successfully break them in.

What Keith said about cylinder pressure is very true and important.

I'll disagree about the worries about holding a particular rpm. That really is meaningless. The implication is to not simply hold a steady load.

Worries about bearings and bearing surfaces are pretty much vastly overblown. They are already well polished and well formed. You're really not breaking anything in here.

Camshaft is more an issue of lubrication. But with a roller lifter, it's a non-issue. High ramp angles and tappets, that's a different matter, especially with the newer oils. You don't have this issue. Not that this issue is a break-in issue anyhow.

You don't have long to actually get the rings and cylinder walls to break in. If you miss the window, you'll have glazing and such, and pretty much never successfully break them in.

What Keith said about cylinder pressure is very true and important.

I'll disagree about the worries about holding a particular rpm. That really is meaningless. The implication is to not simply hold a steady load.

Worries about bearings and bearing surfaces are pretty much vastly overblown. They are already well polished and well formed. You're really not breaking anything in here.

Camshaft is more an issue of lubrication. But with a roller lifter, it's a non-issue. High ramp angles and tappets, that's a different matter, especially with the newer oils. You don't have this issue. Not that this issue is a break-in issue anyhow.

After the idle period put a bunch of your friends in it and drive up the nearest big hill at 3/4 throttle. Go back down again with throttle closed and repeat about ten times. The weight will push the rings into the walls and the high vacuum on the way back down will do the same. I've done 17 motors like this. Of course, you live in FL so big hills are at a premium.

Jerry From LA wrote: After the idle period put a bunch of your friends in it and drive up the nearest big hill at 3/4 throttle. Go back down again with throttle closed and repeat about ten times. The weight will push the rings into the walls and the high vacuum on the way back down will do the same. I've done 17 motors like this. Of course, you live in FL so big hills are at a premium.

By the time he gets to a big hill, it'll be time for his 3k oil change!

curtis73 wrote:

Tom Suddard wrote: The engine has hydraulic lifters, Kieth.

Yeah, but roller or flat? I don't think GM ever did one of these 2.8/3.1/3.4L with a flat lifter. At least if its a GM 3.4L crate, I have no idea why they would use flat lifters. Flat lifters need the 20 minutes of fast idle because the cam is splash-lubed. Regular idle won't throw enough oil on the lobes for break in. Roller lifters need no break-in. If its a flat cam, your procedure above is perfect. If its a roller cam, skip the 20 minute fast idle and just go with the rest.

as far as i know, the truck 3.4 had a flat tappet cam.. but maybe not..it would be easy enough to pop a valve cover and take a look down into the valley to find out..

I just got in from the shop—its so, so close to running! :D

I'm 99% sure the lifters are flat, I did some research and checked the old motor and it confirmed this.

Am I going to miss my chance to break in the rings if I break in the cam?

I am using a break in (zinc) additive.

just do it... flat tappet cams have been around forever, GM installed millions of engines just like that one in factory built vehicles and i don't think too many of them had cam or ring break in problems..

20 minute high idle (1,500 - 2,000), then commence the break-in. Flat tappets or no, you'll be fine.