Engine break-in procedure

[lcw1980]

Hi what kind of break in procedures you guys use for rebuilt motors? Asking cuz I had mined rebored to 83.5mm with wiseco pistons. Thanks

[sydwayz]

use valvoline racing oil or amsoil or any other kind of oil with zinc in it for proper break in and after start up and every things fine rev to 2000 rpms for 20 mins and after 500 miles drain the oil and replace it with whatever u like at least thats what i did

[r34 gtr]

Backed mine down the driveway and onto the street, then I revved it up, dumped the clutch and proceeded to rag it through several gears. Shortly after it died and I had to get it to run properly again. The break-in process was complete though, I seated the HELL out of those rings. I rule.

[kapower06]

Amen r34GTR, I let my $9000 built motor warm up, then drove it like I normally would, HARD!!!! I have 250miles on it now and my SDS shows 19.9 in mg for vacuum, and thats at 900 rpm with 280* 8.8mm lift cams.

My take is break it in how your going to run it.

IF ITS BUILT RIGHT, THEN YOU WONT HAVE A PROBLEM, all I can say is to warm it up before you start the break in.

[articzap]

Only exception to break it in hard is if you got new cams. Usually those need to idle at 1500 RPM for 30 minutes to break in. Other wise drive the piss out of it.

[progman]

A good engine tuner can break the rings in on a dyno in about 4 hours. The only down side to not breaking your rings in good is that you can glaze your cylinder walls. If you don't care if you get 2-3% blow by as opposed to 4-8% then don't worry about it to much just take it easy for awhile.

"The initial bed-in of rings is achieved by giving the car a full throttle burst for a few seconds, followed by snapping the throttle shut and coasting for a few more seconds. This should be repeated at least 12-15 times with the engine at normal operating temperature. Accelerate the vehicle in top gear from the slowest speed it will pull in that gear.

By giving the engine full power, the high gas pressures force the rings out against the bore wall. Snapping the throttle shut causes a vacuum in the cylinder, which draws up the extra oil. This, and a low engine speed, minimizes the risk of glazing the allows the ring face and cylinder wall to cool.

After the rings are initially bedded-in, the engine can be operated at up to 80% of its rev/power potential, but constantly vary the speed. If this is not done, the rings may still glaze. After about half an hour of this on the dyno or the race circuit, the rings can be considered as being run-in. A road engine with chrome rings should be run in for around 200 miles, preferably in one session. Again, constantly vary the engine speed and include heavy acceleration for short bursts as for initial bedding-in. Avoid constant high speed until the engine has done 500-700 miles.

Standard break-in procedure on an engine dyno:

rpm engine load (torque lb/ft) Time (mins)3500 40 104000 50 304500 70 305000 85 305500 100 30

Note: This is the procedure used for engines of 1600-2000cc. Other engine require a different run-in load according to their displacement and torque output."

-A, Graham Bell

[lcw1980]

Seems everyone here likes hard driving break-ins. Would a mountain pass be a good place to break in?

[MeanGreenS13]

i got my car runing and 10 minutes later i was out on I95 doing 140+ mph haha havent had a problem as far as engine integrity goes. I DONT LET MY ENGINES REST LET IT BE KNOWN haha

[sjbsuperman1425]

from what my "instructor" told me in my college class, he "said" that after rebuilding an engine, the rings and what not will seat within the first few minutes? i'd like to know what Dee has to say about this lol.

<-- i like the little guy lol

[boost_boy]

from what my "instructor" told me in my college class, he "said" that after rebuilding an engine, the rings and what not will seat within the first few minutes? i'd like to know what Dee has to say about this lol.

<-- i like the little guy lol

Honestly, I crank the engine, check for leaks, pull onto street, and go boosting in 1st gear only; never taking the car out of 1st gear. I do this for a couple of bursts, return to my garage and check compression and plugs. When the compression checks out okay and the plugs are bit dirty, but not oily, then I know I'm on the right track. Drain the oil (10w-40) after the first 50 miles and drive the car as you would normally. Keep in mind that new rings love it when you engine break. Next oil change is at 500 miles (same oil as before) and remember, new rings love engine breaking . And lastly, your engine should be healthy on compression and there is no need to keep checking it, so change your oil at 1000 miles with the oil of your choice and enjoy your new motor. I have a freshly built 4G63 in my Hyundai Elantra that has only 23 miles on it and she has 160psi all the way across the board. That's how I do it, but others may vary.

Dee

[float_6969]

This pretty much says it all;http://www.mototuneusa.com/break_in_secrets.htm

[dhen]

Bringing this thread back from the dead, but I wanted to see if anyone has anything new to add. I finally got my rebuilt engine into my car and I'm breaking it in.

My machine shop and a retired mechanic I know are adamant about going easy on the engine in the beginning, but people here are saying to thrash it. The machinist also said to use high-zinc non-synthetic oil in the beginning. I was thinking about using an oil for diesel engines, which is what some guys do with their 40-year old MG engines.

Any thoughts?

Thanks,

Darian

PS I read somewhere that 12 PSI of oil pressure at idle is normal for a warmed-up engine. Is this true?

[blownhemi]

My question is, do you guys do the hard break-in for both
- when the engine only got a hone and new rings
- when it was a complete rebuild with overbored cylinders?

[float_6969]

Hard break in regardless. The Diesel oil is great, and it's what I used myself. You definitely DON'T want to use a synthetic oil.

It also depends on what kind of rings you're using. If they're stock rings, the top ring is a Moly-faced ring, which breaks in VERY quickly from what I've found. The 2nd ring is a standard ductile Iron ring, and will take a little bit to break in, but nothing outrageous. The Oil rings are always chrome plated and they don't really "break in" like the 1st and 2nd do.

If you got your pistons from CP like I did, the 1st ring is chrome faced and they are VERY hard to break in, and take some SERIOUS beating on. The 2nd ring will be a moly faced ring and will break in pretty quickly, and the oil ring is standard.

I can tell you with my CP pistons, that I drove moderately till I got to about 2500rpms in 5th, and then floored it till redline, and then let it engine break back down to 2500. It burned oil like mad the first time and I thought, "this is a terrible idea", but I did it again, and the oil consumption dropped drastically. By the 3rd time you couldn't see it in the mirror, but my friend following me said there was still a little coming out of the exhaust. By the 5th run there was no oil burning at all.

When I did a compression test on the motor, all the cylinders were w/in 3psi of each other. I did a compression test the other day, and I've lost about 10psi since then (that was right at 6, very rough, years ago, LOL), and they're all still w/in 3psi of each other (I'm sitting at about 185psi now).

I've got another set of rings that are going to go in the motor, probably this winter, to bring it back up to where it was before. I'll break them in the exact same way I did the others, only I'll prob do it on the dyno instead of an old asphalt road near where I used to live, since going well over 100mph on the streets is never a good idea.

[blownhemi]

I've got another set of rings that are going to go in the motor, probably this winter, to bring it back up to where it was before. I'll break them in the exact same way I did the others, only I'll prob do it on the dyno instead of an old asphalt road near where I used to live, since going well over 100mph on the streets is never a good idea.

If you do pull it apart for re-ringing, do you plan on measuring the bores? If you do, please share the measurements! I'm really curious how much the CP pistons' slap wears the bores down in the long run (if any), and in what way.

[float_6969]

They only slap when cold. I don't run the motor past idle until they warm up, so I doubt there will be much wear. But when I take it apart, I'll check them, ofcourse.

[boost_boy]

I haven't experienced the piston slap expected from the CP pistons. I did experience some major valve train noise from the new sentra I had been working on, but the engine is out of my old one that was wrecked and has been sitting around since 2007. I did give it a new ported head with heavy duty valve springs, some better lifters (bad lifters are easily identified) and the same old HKS 264/272_8.5mm_ bump sticks as well as the same CP pistons and rings that had about 6500 miles on them. It made noises for a while and now when I crank it, it's just as quiet as my 240 with the CA in it.

[blownhemi]

Any one of you remember what your piston to wall clearance was with the CPs?