View Full Version : Rebuilt Engine Break In

09-27-2011, 06:29 PM
So after two years I'm hoping to start my car up this weekend.

Engine was rebuilt; cylinders honed, valve job, new bearings/seals/rings, etc.

This is something I've been kinda nervous about for a long time. I want to do it properly and get the best possible compression out of my efforts.

I know I will have to pull the EFI fuse and crank it over several times in order to prime the oil system. I also understand its not ideal to allow the engine to idle for long periods of time after the initial start up.

My plan is to basically follow the instructions on this website; http://www.mototuneusa.com/break_in_secrets.htm and keep the rings under load so they seat properly.

Is there anything else I should do? Anything I've left out?

Will I have to set the ignition timing?

I've heard of people wiring the wastegate open in order to stay out of boost for the first while, is this necessary?

Would any of you be willing to write up some quick step by step instructions on how you would go about breaking in an engine?

I'm hoping to turn the key on Saturday, any advice would be appreciated. :)

09-27-2011, 07:07 PM
Will I have to set the ignition timing?
Did you mark the position of the distributor when you removed it? If so and you aligned it back to those marks it will be fine for initial break-in, but I'd still double check it after. If not then yes, you will.

To be clear, we're talking about a ST185, correct?

09-27-2011, 07:22 PM
You pretty much got it. As for the wastegate thing. you cant keep it open unless you disconnect the actuator rod from it.

Prime the system, start it, let it run for long enough to come up to operating temp, check for leaks in coolant, oil, etc. If it passes, shut it off, drain the oil. (you should be using dino oil at this point). New oil and filter. Start it up, take it for a drive, take it easy on it, put a few miles on it, bring it back, check everything again. No leaks, no overheating, etc.

If it passes, then take it out and keep it under load and vacuum. Thats what seals your rings. Find a place where you can do some third and 4th gear pulls. Im all about breaking an engine in hard and fast, cause the longer you take, the more wear you put on the engine IMO. When youre doing your pulls, its just as important to decel with it in gear and let the engine pull vacuum on the rings, so do a pull toward the top, let off, then do another one. Start in third, pull toward the top, let off, shift to 4th. Pull toward the top, let off. Same thing in 5th. Take it home, check for leaks, etc. Change oil and filter again.

Then just put 500-1000 miles on it regular driving. After that, youre good to switch to synthetic (and you should).

If you want to see what good this is doing, perform a compression test before starting the engine first time. Record numbers. Then perform a compression test after doing what I said, and record numbers. Your compression WILL be higher. Ive done this breakin process on several engines Ive rebuilt. Never had an issue with one of them.

Hope this helps.

09-28-2011, 02:18 AM
I agree with what Luni said aside from the recommendation for the first oil change. I see no good reason to do one after the very first warm up, there is nothing hard in the oil until after that first 20 miles or so of break in. I do my changes at 20, 100, 500 and synthetic at 1000. The hard pulls are all about rings and thats where the crosshatching is doing its job. After 100 miles or so the remainder of the break in is for rotating assemblies and not quite as critical. Avoid idling as often as possible. Better to be under power and building oil pressure and flowing water than sitting there running low RPM. Avoid redline as well obviously.

09-28-2011, 02:50 AM
You will find as many ways of breaking in an engine as there are people rebuilding them. When I was building customer's engines, (and getting paid for the break-in), I would follow TRD's Formula Atlantic break in procedures (5 oil filter changes within 2 hours, with various types of runs in-between) But after that two hours, the engine is good to go for a full race. For a street vehicle, I would do the following.

Prime it and fill with a thick dyno oil 20w-50 or the like.
Start it, and "MAKE" it idle (typically it will be a slightly fast idle on a new engine) let it idle for 15 minutes while you are checking for leaks, topping off the coolant, and setting timing.

Shut it off and drain the oil while it's hot, let the engine cool, change the filter, and fill it back up. with a 10w-40 (dyno oil)

Then do a 20-30 min drive varying speeds, and get some hard accels/decels in. Change the oil and filter, and fill back up with what weight you normally run (dyno oil)

Over the next 500 miles, drive it in variing conditions., I don't baby it, but I don't beat the crap out of it either. change the oil and filter, and run synthetic.

I have seen engines with poor break-ins just start pissing oil all over the dyno (out of the PCV tube), then pulled the engine apart, and the rings were trashed and there is still cross hatching on the cylinder walls.

In fact, Total-Seal sells a dry break in "lubricant" that fills the voids in the cross hatching so that the cylinder walls and rings can wear in with each other.

09-28-2011, 03:57 AM
There's a lot of metal particles and assembly lube in the first oil after startup that's why I do that. If you read my way it's pretty close to the way Temperacer posted. I'm happy with that.

09-29-2011, 04:47 PM
How long will I have to crank it to fully prime the oil system?

Any advice on breaking in my new clutch? Its just a stage 1 Exedy.

09-29-2011, 06:36 PM
There's a lot of metal particles and assembly lube in the first oil after startup that's why I do that. If you read my way it's pretty close to the way Temperacer posted. I'm happy with that.

There really isnt any metal after a few minutes idleing. The rings arent being put under load and if prelubed correctly there shouldnt be anything off the bearings. The prelube also disolves into the oil, and as you would imagine, its a LUBRICANT, so having it in your oil isnt exactly a problem. Additionally, a small amount of metal in your oil is actually helpful so long as its particle size is small, like the size that is getting through your filter. Its actually part of the process of creating wear patterns in your rotating assemblies.

Its a completely unnessessary step imho, and Im always on a tight budget with my builds. If throwing a $30 bill down the toilet isnt a problem for you then go right ahead.

How long will I have to crank it to fully prime the oil system?

Any advice on breaking in my new clutch? Its just a stage 1 Exedy.

hard to say, alot depends on if and how well you packed the pump. 10-15 seconds, if nothing, let your starter rest for 10-15, then go again. If you have no pressure after 3 attempts, there is a problem.

as for clutches, different manufacturers have different recommendations. I believe the general rule is just drive easy for 500 miles, and you will be doing that with the motor anyway.

09-29-2011, 11:06 PM
The original oil change is for particles from the bearings that I am worried about. It's the loose crap that can't be blown out, or hides in a voids when cleaning that I am worried about. Machining a block leaves alot of little shavings. bead blasting a head leaves a-lot of media (even if crushed walnuts). No matter how well you clean, no matter how well you blow passages out, there might be one or two grains of media or shaving sitting in a hidden recess that gets dislodged the first time oil under pressure is thrown though the system.

This is the reason for the first after idle oil change.

As for priming the system...


when you build your engine, pack the pump and the pickup with white lithium grease. This is so there is little cavatation during initial start up. As Facime said give it 10-15 seconds, then rest. Do this 2-3 times (or until your oil pressure light goes out. If you didn't pack your pump/pickup with white lithium, it will still prime, but it will take longer.

Oh... and whatever you do. If you didn't pack the pump/pickup with white lithium, don't bump the starter for 5 seconds and quit, 5 seconds and quit. You're not letting the pump draw for long enough, so the oil never reaches the pump and then drains back into the pan.

09-29-2011, 11:50 PM
Didn't pack the pump.. I mostly followed the bgb's instructions and it didn't mention anything like that.

So ill stick to 15 second intervals while priming. Would it be a good idea to hook up my battery charger to my little odessey battery while doing this? Just don't want to drain it with all the cranking..

I don't have an oil pressure gauge, am I able to use the idiot light?

09-30-2011, 01:37 AM
a strong battery should be fine, I would hook up the charger to the battery the day before to make sure the battery is in top shape.

09-30-2011, 02:39 AM
You are certainly in good hands with Austin's advice. Im not saying a little extra precaution is a bad thing, however the kinds of particles you are talking about are filtered out the first pass around the system. If you didnt pull the hex plugs in your crank, or use gun cleaning brushes in your block prep, then an oil/filter change after the first heat cycle isnt going to save you. I truely hear what you are saying, and I dont think I need to belabor the point, but honestly, until you start pushing particles though the system below about 20 microns (those which a filter isnt going to catch) you really arent in any danger of excessive wear in the first 20 miles of operation. Those kinds of particles, in materials capable of causing damage (tin, brass, steel, iron) simply arent produced with a 5 minute idle in the garage while you do your leak check.

Cheap insurance? I suppose so.
Pointless? imho, yes.

(p.s. love the new profile pic A.)

09-30-2011, 02:52 AM

09-30-2011, 04:01 AM
a strong battery should be fine, I would hook up the charger to the battery the day before to make sure the battery is in top shape.

I'm using an Odessey PC680.


PC 680 Specs:

680 cranking amps for 5 seconds
595 cranking amps for 10 seconds
525 cranking amps for 20 seconds
17 amp hours
Short circuit current over 1800A
25 minute reserve capacity with 25amp load
Female brass terminal w/M6 SS bolt
Length 7 1/16"
Width 3"
Height 6 9/16"
Weighs less than 15 lbs

It's a pretty small battery, I'm not sure if it will be strong enough to handle all the cranking.

09-30-2011, 04:06 AM
a battery charger will not keep up with the load of a cranking starter. Hell an Alternator won't keep up with the load of a cranking starter

10-01-2011, 05:09 AM
Keep jumper cables to a bigger battery.

10-01-2011, 05:46 AM
Tried turning it over tonight just to make sure the starter is working properly and sure enough it won't crank.. The starter either clicks once and makes a humming sound or repeatedly clicks.

I have a feeling the connections are fine and its the starter itself, something internal.

Also noticed a funny smell after the humming..

10-01-2011, 06:16 PM
I forgot to ground the transmission to the chassis.. Problem solved.

Should fire it up by the end of today hopefully.

Wish me luck!

10-01-2011, 07:02 PM