How to break in remanufactured engine?

[askoop]

Getting a remanufactured engine put in my Grand cherokee. Inline 6, 4.0L.

-What is the best way to break in the "new" engine?
-I have a stash of havoline synthetic 10w30, can I use this right away or should I go with dino for a while?
-I was thinking of changing oil after a day of running around after getting it back, then after 500 miles, then after another 1,000, then on to regular intervals. sound good, bad, overkill?

Thanks

 

[Gary Allan]

Use a dino. I used Havoline for my 3.0 Mitsubishi.

I, IIRC, changed it out @ 600 ..and then at around 1000 miles (1600).

Being unsure of the remanufacturing process, I did a long cycle of accel - decel events in 2nd gear for an hour or so over a few days. Nothing at WOT ..just a healthy throttle to about 60-65 mph (80+ can be achieved in 2nd gear) and coasting down to about 35-40 and repeating. Probably a waste ..but it can't hurt anything.

The only reason I say dino is due to the frequency that you're going to change it out ..or may change it out. Don't waste the money for no gain. When you're done playing around ..then do a 5k UOA on your synthetic of choice.

Naturally (cough-cough) I'd never want to influence your decision on what synthetic to choose

 

[unDummy]

Whats the builder say?

Heres what I would do.
Install engine, prime the oiling, and do an intial run-in like breaking-in an old school non-roller cam. ALL cam companies have really good(typically similar) variable RPM run-in. This will also help seat the valves and rings.
Use a known stout oil. HDEO's are easy choice. Optional additives recommended.
After 1st shut down, immediately change the oil/filter. Allow engine to completely cool down. Reprime the oil system and treat it like a brand new car for 500 miles. After 500 miles, change the oil to the Havoline.

There is no reason to waste the Havoline synth on the intial 20 minute 1400-3100 rpm run in, and the 500 mile rinse.

 

[Steve S]

What does the remanufacture recommend. If their engines are good enough to use wouldn't their advice be good enough as well?

 

[Thatwouldbegreat]

I agree with the other posts.

Old School-

-Prime the oiling system, run conventional multi grade oil per engine's oil spec.

-Warm up, vary RPMs,gradually increase load and RPM's;

-Listen for noises, check for leaks, watch guages, evaluate engine build and install.

-I like to drain the oil at 50 miles and 500 miles. Also check if there are retorqueing requirement.

-During the first 50 miles run partial throttle/ partial vacuum building to full throttle / full vacuum cycles in 3rd gear when engine is fulling warmed up ...to seat or 'work' the rings. Engine must be under some load, but not lugging or going above 2/3 max RPM.

-continue increasing RPM and pushing the engine over the first 1000 miles, but letting engine run and rev freely.

-After 1000 miles change oil and start 3000 mile interval with conventional oil.

-4000 miles switch to synthetic oil and determine best 'longer' interval

 

[HawkeyeScott]

Different tangent: How long did the old motor hold up before you needed a rebuild? WHat year of Jeep?

 

[askoop]

I am waiting to hear back from the engine company, so I will also take into consideration their advice, and probably use it, they did build the thing.

Engine had 130K on it. Bearing in lower end went bad and some possible cam shaft stuff too. I've always taken great care of it since I had it, my only thought on how this happened was that the original owner didnt keep up on the maintance as much as he/she should have.

Thanks for the suggestions.

 

[HawkeyeScott]

I see. That's too bad. But kudos to you for going the rebuilt route. I think too many people waste money on new or newer cars when they're faced with a major repair like yours. I had a GC tranny rebuilt a few years ago. Cost me $960 on a car that was paid for. Made sense to me.

Good luck Adam.

 

[askoop]

Engine company recommends...
-300 miles, then first oil change
-let warm up before driving (which mechanic will do)
-do not redline in these 300 miles, take it kinda easy, but normal driving without redline is recommended
-use manufacturers oil spec/grade
-no synthetic for first few changes.

I think What I will do is...
- change at 300 miles with dino 10w30
- change at 2,000 miles with dino 10w30
- change at 5,000 miles to my havoline synthetic 10w30 stash and go to a 5K/6month OCI

Will use NAPA gold/wix filters

What is a good, quality dino 10w30 you would recommend for the first 5K?