Fresh rebuild break-in

[thebigo]

What is the proper way to break-in a refreshed engine?

 

[thebigo]

I'm surprised no one responded.

 

[racing promotor]

We always just raced them

 

[Lkerley]

I let it idle for 20 min small revs off and on drain oil refill it and run with it.

 

[thebigo]

Thank fellas. I did a leak down and got 3%. So if I do either of the suggestions, it should (knock on wood) drop to about 1% after the break-in. Wish me luck.

 

[racing promotor]

Thank fellas. I did a leak down and got 3%. So if I do either of the suggestions, it should (knock on wood) drop to about 1% after the break-in. Wish me luck.

Good Luck !!

 

[OVALTECH1]

I run mine at 2,000 for 5 minutes with break in oil. Drain the break in oil while hot , refill with 4T and run for another couple minutes. Drain that while hot and refill with 14oz and go beat it on race day.

 

[OVALTECH1]

I have found that without a dyno to load it hard it takes a bit to seat those top rings up just idling it. After a race day it will seat up or it won’t either way it will still perform just fine at 3%

 

[knighty]

Assuming the bores been honed.......Run mineral based break-in oil for the first 2 hours running. Joe Gibbs BR30 is ideal. Or a cheap 30 weight mineral oil. Do not run synthetic oil.

Run the following intervals

30 mins change (No longer)
30mins change
1 hour change.

Just let it warm up for 5 minutes minimum, then hit it hard on the dyno or on the race track. You want the combustion pressure to push the rings up against the cylinder to abrade and bed them in properly. Don't nanny it drive it like you stole it.

Then after 2 hours go onto your synthetic oil. Once bedded in properly you should be seeing 1-2% blowby with 100psi feed pressure.

 

[Raging Bull Engines]

Properly prepared rings and bore seat in almost instantly.

 

[Bob Evans]

Properly prepared rings and bore seat in almost instantly.

That's been my experience. Most times I could feel them seat while rotating the flywheel before the head was installed.

 

[racinnut15xm]

Hammer on it on the dyno for a day

 

[bomber315]

Run the following intervals

30 mins change (No longer)
30mins change
1 hour change.

Just let it warm up for 5 minutes minimum, then hit it hard on the dyno or on the race track. You want the combustion pressure to push the rings up against the cylinder to abrade and bed them in properly. Don't nanny it drive it like you stole it.

Then after 2 hours go onto your synthetic oil. Once bedded in properly you should be seeing 1-2% blowby with 100psi feed pressure.

i surely hope your aren't letting it idle for 30, 30, 60... because if you are your rings are far beyond the point where you should hammer on it to break them in.

 

[flattop1]

i surely hope your aren't letting it idle for 30, 30, 60... because if you are your rings are far beyond the point where you should hammer on it to break them in.

They got a little differnt deal going on in the UK .
Rebuilt every third race or third year .
Its all the same for me start , stop , cool down , start rev rev .
If its not exploded its race time .

 

[knighty]

i surely hope your aren't letting it idle for 30, 30, 60... because if you are your rings are far beyond the point where you should hammer on it to break them in.

......no.....run it hard on a track or dyno fir those durations.

 

[bomber315]

......no.....run it hard on a track or dyno fir those durations.

Well good... Then I like that method then, you confused me for a minute there

 

[Petty Race Engines]

Put on on the kart and run the dog crap out of it !!

 

[alvin l nunley]

I'm sure a 4 cycle is different from a 2 cycle, but this is how I did it with my two-stroke.

With the engine on a dyno (not really necessary.) I would set the engine to idle at a decent RPM. Start it up, then wait. At some point, I sink when the rings seat, the RPM would take a jump. I assume this is when the ring seated. 3 full throttle pulls and it was broken in, ready to race.

In hindsight, I wish I had taken a compression check before and after this procedure. A good compression checker really comes in handy. Be aware; Pep Boys doesn't sell a good one. Plan on spending at least $100.

 

[Pete_Muller]

Here is my take on break-in: If the engine is built correctly, zero break-in is required.

If one thinks about it, what is "break in"? It might as well be called: "wear in" or even "wear away", right? If something requires "wear" (material removal) before it spins correctly, seals correctly, runs correctly, etc., why not figure out what those things are that need to be "worn", and machine/hone/lap/whatever them precisely so nothing has to be "worn away"?

Most of my experience in engine building is in 2-strokes, but once I measured every single part, and understood what was going on with ...
- shape of the piston
- straightness / squareness / roundness of EVERYTHING in the engine
- distorting the cylinder for honing EXACTLY as it's distorted when assembled on the engine
- lapping the ring precisely to the bore
- assembling the engine is a very repeatable sequence and method
- etc.

I never "wore in" an engine again. Start it and race.

So to rephrase my first sentence another way: If an engine requires break-in, something (or a number of things) were not done correctly in the build process.

There is absolutely no reason the same principles would not apply to a clone engine, or even a big-block Chevy.

flame away!

PM

 

[Kj26]

Man, I do it the easy way, pick it up from builder and go racing lol