Rebuilt engine break-in period?

[SinisterSHO]

Maybe that would explain why most of the gen 1s I have driven/ridden in have been freaks. Everyone was out beating on thier brand new fancy Taurus back in 89-91.

 

[yamahaSHO]

What I did with my motor is start it up and check for leaks. After everything checked out, I turned it off to button up a few other pieces. When I started it a little later, I let it warm up and I did some runs with about 3-4 PSI. About 10 minutes into it, my idler pulley let go and I had to cut the SC belt off.

On the way back home, I hammered all the way home while allowing the motor to see high vacuum and RPM under engine decel. I ran and am still running just Castrol GTX 10W-13. I'm at about 2,000 miles on my motor and still have (although I've changed it 3 times) GTX. I did my first oil change immediately after my 20-minute break-in.

Around 4k - 5k miles, I'll switch to some synthetic. Per one of Gary's posts... I think I may go with Shell Rotella 5w-40.

The idea behind driving it hard is to use the combustion process to push the rings out against the cylinder walls. Same goes for high vacuum on decel.

 

[AREA 91]

I had 286 miles on my engine, then we went to the track for some 1/4 mile runs on a 75 SHOt of N2O!!! Yeah baby 13.91 @106. Now that's cylinder pressure on piston rings.

 

[Cross Eyed Joe]

Hmm...I always thought the break-in process for an engine was kind of like the break-in process of a clutch, you wanna go easy on it for about 500 miles, different RPMs, no hard driving. I guess I'll have to look into that more. Interesting...

So, should I wait to put in my new clutch until the motor is broke in?

 

[yamahaSHO]

Once the clutch is engaged, you can get on the gas all you want. It would be foolish to install the motor without the new clutch just to take it back apart to install later.

 

[AREA 91]

Once the clutch is engaged, you can get on the gas all you want. It would be foolish to install the motor without the new clutch just to take it back apart to install later.

X2

 

[Kilty423]

so wait..i just got my bearings replaced...whats the proper break in period for that? i was told 500 miles with keeping rpm's below 5k?

 

[Bringetto]

yeah on rod bearings you dont want to spin them too fast. thats part of why they are saying dont go full throttle for the first 25 mins

 

[SHOspazz92]

Shit, Even with a clutch I only went maybe 60 Miles before beating the ever living shit out of it, granted the first 60 miles was los angeles stop and go traffic... after that it was to 7600 rpm and beyond....


-sam

 

[yamahaSHO]

yeah on rod bearings you dont want to spin them too fast. thats part of why they are saying dont go full throttle for the first 25 mins

So in a new engine they should be beat on but just replacing the bearings, you should be easy?

As far as that goes, you'll have to use personal judgement. With a new engine, you'll have new rod bearings... so what is the differenct between beating on them to seat the rings, or when all you have replaced on the rod bearings.

 

[revhardSHO]

I think with an old engine / new bearings you want to be nice to the motor for the first couple hundred miles. This is because the crank problably has a slight wear pattern that you want to match with the new bearings that have no wear pattern. I just give them a little time to get acquainted with each other!

 

[Ishodu]

Just keep in mind that rod and main bearings are normally non contact bearings, they ride on a film of oil maintained by the oil pressure not the bearing itself.

 

[yamahaSHO]

Ideally, that's what they do, however, on WOT and lugging, they definitely make contact.

 

[Lance Cheney]

My 3.0L build to a 3.2L with wisco 10.5 pistons is almost complete. What is the recomended break-in period and method? Also, I have 80mm MAF, #36 injectors, and Tweecer. Should I break-in the engine with stock MAF, injectors, and stock ECU? I'm concerened about tuning the engine before it is broken in.

It'd be good if you're confident in your tuning ability or have a template program from someone with a fairly similar setup. Otherwise I would recommend putting in a stock MAF (clean it first) and stock injectors. You'll want to be able to get out there and hammer on it without fear of running the car way out of tune at WOT.

That said, I put in 30lb injectors, stage II cams, a self-modified Ted B LPM program, and an 80mm MAF for my first 3.2L buildup, so I'm not a very good role model -- although I had already dialed in the MAF previously on stock injectors so it wasn't really that far off and I'd consider myself a decent tuner, though having a Tweecer at the time sure would have been a big bonus.

-Lance