'89 Crossflow v6 150 break-in

[Zep25]

Finally time for to beak-in my self rebuilt '89 v6 150 crossflow. OEM service manual break-in instructions seem a bit aggressive, so I'm leaning towards something more like this...
Double oil 25:1 for first 40 gals
Warm up slowly at all stages
Vary rpms every 15 mins max at all stages

Hour 1 and 2- Idle in gear only (vary rpms, but keep <1500 with hot foot as carefully as possible)
Hours 3 through 5 - rpm 1500-3000, if I can get up on plane, stay as low on rpms as possible to stay on plane
Hours 6-10 - 3/4 throttle only
Hours 11-14 - WOT for only 2 mins at a time
Hour 15 on - catch fish

Does this seem reasonable?
Can I do the first 6-10 hours of the break-in all in one day?
Or is it more important/beneficial to have many warm up, run, stop and cool down "sessions" over multiple days?
Any thoughts are appreciated and thank you as always!

 

[Faztbullet]

What did you do to "rebuild " it?

 

[jimmbo]

There needs to be agressiveness to seat the rings. Acceleration by opening the throttles cause pressures to rise in combustion chamber and in turn press the rings harder against the cylinder walls, then constant speed and lower speeds reduce the pressure. Think of it like Rubbing Compound on Paint, then Polish. Repeated, many times over results in a smooth bore that seals well with low friction.

Since Wear(not the kind required for break in) is highest during warm up, it makes sense keep an engine at operating temp as much as possible. But since 10 hrs(typical break in period) makes for a long day, the first 3 hrs would be most critical.
The Manufacturers have put forth a Break in proceedure, if followed, that they feel gives the engine a reasonable chance to attain a long life.
Some will argue that just because only the rings were replaced a full break in isn't needed. I feel when any moving internal part(exception being a Ball or Roller Bearing on the ends of the crankshaft, or the bearing cages on rod bearings) of an engine is replaced, a full break in should be done.

 

[Zep25]

Rebuild included all 6 cylinders rebored and honed .003 over. New pistons, rings, gaskets, upper and lower crank bearings. Rebuilt carbs.

johnson service manual break-in...
hour 1- first 5-10 mins fast idle.
Next 50 mins planing boat but nothing over 3000 rpms. Change speed every 15 mins.
Hour 2 - plane boat then reduce to under 4000 rpm or 3-4 throttle. Maintain planing attitude. Vary speed as above.
Hours 3-10 - no continuous wot. Vary speed as above.

Would that be appropriate for this rebuild?

 

[jimmbo]

Yes, You can use Full Throttle to plane the boat and if it maintains plane at 3000 or so great, for the first hour. Second hour Full Throttle to plane and then run at 3500 - 4000 for the first 15 min then bump up the speed, with Full Throttle for a couple of minute, returning to 4000 for 10 or so, then run again around 4500 for a minute or two, then return to say 4200 for 5 - 10 then run at Wot, return to 4000. Eventually you can run at WOT for a few minutes then return to 4500 for 10 or so. The idea is never to stay at a particular RPM for any great length of time. As the time accumulates you can run WOT for longer and longer periods. By the time of 8 or 9 hr have passed you could be running WOT for 55 of the 60 minutes without concern

By the 3rd hour you will have a reasonably good idea was to whether or not you are propped correctly

 

[Faztbullet]

If you installed forged pistons stay under 3000 RPM for at least 3 heat cycles to temper them up.This adds a couple of hours to break-in. Also cooling system will need to be 100% .

 

[Zep25]

I used wsm pistons so I do believe those are forged.
What do you consider a “heat cycle”?
Warm-up, run for an hour, stop and cool down?

cooling system seems to be good on the muffs so far. Peeing good. Swapped out new impeller during rebuild. What should heads read on the surface with laser temp reader when hot?

 

[racerone]

So why do the new ----E-tech ----motors not require break in ??-----Brochure says----" run flat out right out of the box "----Anybody comment on that ?

 

[Faztbullet]

WSM are cast pistons.

So why do the new ----E-tech ----motors not require break in ??-----Brochure says----" run flat out right out of the box "----Anybody comment on that ? ​

Because since 2015 each engine is broken in at the factory in the test tanks with test wheels. Then the fuel /cooling system is flushed, inspected stamped,boxed and shipped. This is only the DI engines not the rebadged ones. They also reclaim the heated water in test tanks to heat the testing area and building hot water supply.

 

[racerone]

Statement was from a 2011 brochure.

 

[flyingscott]

Statement was from a 2011 brochure.

What I read in the brochure is that because of the "special" honing process no break in required. I also believe that was all the E-tecs not just the G2 motors.