340 HP engine break in

[lincdarrow]

Do you guys know what is recommended for engine break in. The motor has 1.2 hours showing on it. I know for outboards it is a bit of a vary rpm deal.

Anybody have some background on it?

[chpthril]

Drive it like you stole it Ricky Bobby



J/K, Drive it like normal and have the first service done at 20 Hrs.

[dingleberry]

I have been told during the first 20 hrs - don't run it at wide open throttle, vary the rpm's every couple of minutes, best possible break-in is to spend the days wakeboarding (lots of rpm variation). Then 20 hr service.

[lincdarrow]

I LOVE RICKY BOBBY

thanks guys

[chpthril]

I have been told during the first 20 hrs - don't run it at wide open throttle, vary the rpm's every couple of minutes, best possible break-in is to spend the days wakeboarding (lots of rpm variation). Then 20 hr service.

All these engine are bench/dyno tested before shipping, they are either put together right or wrong and no matter how you drive them will make a difference. Drag racers rebuild the engine between every run, right? Ever seen them go down the track on a test run varying the RPM's, nope, they drop the hammer and go.

During the course of a normal day on the lake, the RPM's will be fluctuating with out you trying to do it per a "break-in" procedure.

*EDIT* I forgot to add, during the dealer's initial seatrial, the engines WOT RPM's are supposed to be noted, so it's allready been there!

[dogbert]

Sounds like cars these days. When did you ever hear the dealer tell you about driving a new car a certain way until it's broken in?

[dingleberry]

OK - my ignorance is showing

I'm not a mechanic, but I play one on TV

[chpthril]

OK - my ignorance is showing

I'm not a mechanic, but I play one on TV

I stayed at a Holiday Inn Last night


























J/K, 17 yrs automotive technician and Instructor.

[balair]

All these engine are bench/dyno tested before shipping, they are either put together right or wrong and no matter how you drive them will make a difference. Drag racers rebuild the engine between every run, right? Ever seen them go down the track on a test run varying the RPM's, nope, they drop the hammer and go.

During the course of a normal day on the lake, the RPM's will be fluctuating with out you trying to do it per a "break-in" procedure.

*EDIT* I forgot to add, during the dealer's initial seatrial, the engines WOT RPM's are supposed to be noted, so it's allready been there!

Take it from a drag racer/engine builder, apples and oranges my friend. NHRA top fuel guys do rebuild their engines every turn, not pro stock. Once they are done they run the engine for about 10 minutes, fluctuating the RPMs to break in the cam and rings. First you must understand what the point of a break-in period is, to eliminate premature wear. Top fuel cars race 1000 feet plus burn out, not really any worry about wear. NASCAR and Prostock...you bet your a$$ they break their engines in.

As for a car or boat engine, these things are meant to last hundreds of hours and need to be broken in. When breaking in an engine, the moving parts seat themselves in the correct positions and form microscopic groves. If one were to just drive it balls to the walls at first, these groves will be much larger and parts will wear out much faster.
As for why engines seem to break in faster than they used to....manufacturing has come a long way and parts are made with much higher precision and therefore need less time to seat.

for the first 20 hours avoid anything higher than 75% throttle and vary the RPM, but do not idle your engine for 20 hours because that will do nothing.

[chpthril]

Join Date: Apr 2006
Location: gastonia, NC
Boat: 2006 22ve
Age: 39
Posts: 8,669

Join Date: Feb 2005
Location: Okoboji IA
Boat: 2008 RZ4 Yellow/Black
Age: 22
Posts: 1,304

I got underwear older then you

There's not a lot of difference between race engines and street engines...in either materials or assembly, I've built both, some of which are still out there bust'n molecules.

Bearings - nothing to seat, it's all about correct clearance and lubrication
Roller lifters - almost 0 friction, nothing to seat
Roller rockers - almost 0 friction, nothing to seat
Rings - if installed correctly and the cylinder are honed correctly, they will look the same @ hour 1 as they do @ hour 1K
Valve seat - a three-angle valve cut will flatten out in about 30 mins of fire-up and create a perfect seal.
Cam lobe - Break-in was a myth. The problem was lobes get lubed by oil splash from the crank at high RMP. If the engine was not run at off idle speeds upon initial run, the lobes got starved of lubrication and would gualde the lobes and/or lifters.

If anything was done wrong during break-in, it was done before it left the factory, and would show up during Tige's 1 hour sea trial, or shortly after delivery, but again, it's all ready done.

[FIC]

I have underware older then both of your ages combined, there is more to breaking in an engine then just bearings , cams , and rings . I reccomend let the engine get to its normal operating temperature, before hammering the throttle, monitor all of your guages as you go through the warm up , and then you can drive it for normal watersports, all the time eyeing the guages that first hour. The reason you want to vary your speeds which is fairly normal in a boat as opposed to a car is you are all so allowing the computor to establish its fuel trim settings based on your local , which is based on allititude , barowmetric pressure which is crittical to clyinder burn . To lean or to rich can do just as much damage to a new engine.

[mneal]

Roller lifters? What factory marine engine has those? I mention that because the lifters and cam is probably the most important thing to get broken in, but I do agree that the 1st couple minutes is most important and since they are pre-run and somewhat broken in from factory. But I guarantee if you got an oil sample after say 20 hrs from delivery it is still polishing things as it runs the first couple hours. (mostly rings and steel from valve train, very little bearing material as those clearances are set by manufacturing tolerances). But to say they are 100% broken in is just not true. You are right there is almost no difference between "race" and production things aside from the tolerances and valve train stuff. But the duty cycle the lifestyle is way different.

OK, my 2cents on what to do, I would not drive it like I stole it quite yet, would not idle around either, just drive it like a normal boat, wake board, do whatever I would limit time @ WOT , vary the speeds, when the engine decelerates it causes a high vacuum and the negative pressure helps the rings faster, and perhaps most important change the oil...often. Oil is cheap. (make sure it does not have a break in oil of a specific viscosity that should be in there or even better change it with that proper oil until you reach the initial break in time period. )

Join Date: Apr 2006
Location: gastonia, NC
Boat: 2006 22ve
Age: 39
Posts: 8,669

Join Date: Feb 2005
Location: Okoboji IA
Boat: 2008 RZ4 Yellow/Black
Age: 22
Posts: 1,304

I got underwear older then you

There's not a lot of difference between race engines and street engines...in either materials or assembly, I've built both, some of which are still out there bust'n molecules.

Bearings - nothing to seat, it's all about correct clearance and lubrication
Roller lifters - almost 0 friction, nothing to seat
Roller rockers - almost 0 friction, nothing to seat
Rings - if installed correctly and the cylinder are honed correctly, they will look the same @ hour 1 as they do @ hour 1K
Valve seat - a three-angle valve cut will flatten out in about 30 mins of fire-up and create a perfect seal.
Cam lobe - Break-in was a myth. The problem was lobes get lubed by oil splash from the crank at high RMP. If the engine was not run at off idle speeds upon initial run, the lobes got starved of lubrication and would gualde the lobes and/or lifters.

If anything was done wrong during break-in, it was done before it left the factory, and would show up during Tige's 1 hour sea trial, or shortly after delivery, but again, it's all ready done.

[TeamAllen]

Roller lifters? What factory marine engine has those?

Don't they all? My 97 Merc. has them. I don't have roller rockers, but I do have roller lifters. I would think most have them. That is one way they are able to get the horsepower they do.

[live2dive]

This has turned into a pretty good "pissin" match and has been entertaining AND informative. Sounds like there is a fair amount of anecdotal information out there when it comes to this topic. In the medical field we find this a lot. It takes large well-designed studies to come up with information that stands the test of time. Even then, what we think we know often changes with yet a larger, better-designed study. It would be intersting to know if there is any good solid evidence out there for any of the various theories that have been discussed.

Oh, and in the case of a "pissin" match, it has been my experience treating patients that the older you get the less forcefull your stream......

[balair]

Maybe "seat" was the wrong word to use here. I'm meaning it in a different way. Agree with mneal on this one. The reason I say apples and oranges is because top fuel guys run their engines 1000 feet plus burnout, not a few hundred hours.