Break-in suggestions wanted
 

Just wanted to consult the collective brain trust.

I just rebuilt the bottom end of a 2.4 T motor. The top end had previously been done. I replaced the P+C's with a low mileage used set that spec'ed out as new so no need for new rings. The used ones measured as new.

So basically the only parts to "break in" are the main and rod bearings. I know that these parts don't really "break in" so...

Suggestions?

I would take the same precautions that you would if you had done the P+C's and rings. It's only a minor inconvenience for a short period of time. It's better to be safe than sorry...

used P+Cs, used rings, no break-in needed. new bearings also don't need to be broken in. drive it like you rented it.

Thanks John,

The voice of experience is reasurring and as always appreciated greatly.

With new rings isn't there a belief that you should break in with a spirited drive, vs the 20 minutes at 2k rpms?

How's driving it "...like you rented it" different from "...how you stole it?"

Would you still recommend a prompt initial oil change even with all used components?

When you're driving a stolen car you have to be careful not to go so fast that you attract the attention of cops that will check the rego and realise it's stolen. No such worries for a rented car ;)

The rings are used. So no break in was necessary. With no break in items a prompt oil change is not necessary.

The crank and rods actually ride on a film of oil so the bearings really don't break in. In fact when you put the motor together the crank should spin freely riding on the assembly lube.

I just wanted to confirm my thoughts because I'm an amateur. I just do this for fun.

I ran the motor for about an hour tonight and when I checked the oil it was spotless. It was almost impossible to read the oil level on the dipstick.

She purred like a kitten!

drive it like normal, no need for break in if you matched all of the old parts back up again.

Anytime you have an engine apart, you should do an early oil change. The reason, dirt. You will unavoidably get dirt in the engine when it is apart, especially the botom end. Although you do not have to worry about breaking in anything (if you didn't do rings or camshaft work) you still have to worry about assembly lube, and dirt. Use a cheep 30 weight oil. Go easy on the engine, except for ring break in proceedures which are full throttle, but short duration, things, and change the first oil and filter in about 500 miles. Again the main reason is DIRT and debre from the work. Many recommend this first change after the first 20 minutes of run in, again dirt, debre, and assembly lube is the main reason. No matter HOW clean you are, unless you are using a certified clean room, and do not use assembly lube (not recommended) you need to clean out the engine.