Quick Question before I learn another hard lesson - Rebuilt 5.7

[M.A.CCruiser]

#1
Yesterday 09:16 AM by M.A.CCruiser
Very excited because I'll be getting my boat back from my mechanic this Friday after a new long-block install. (mercruiser 5.7 alpha 260hp). New manifolds and risers will be done already as riser failure is what caused the need for a new long block to begin with.

So here are my questions to make sure I cover my bases before I break it again: --


--1. What questions should I be sure to ask the mechanic before I put it on the water and accept delivery? I've been researching new long block installs and there is information about priming oil pumps, is it flat tappet or roller (probably should have already asked this, but didn't know there could be a difference on the same engine coming back) timing settings, carb tuning etc. So those questions I know to ask and say "Have you *insert question here*". What else should I ask?


--2. Check me on my Break-In knowledge - Good Lord there are so many different schools of thought on this- from "Just run it like normal, but vary the throttle and don't stay at WOT, just tap it there from time to time" to "Start it up and fast idle for 20 minutes before even putting it in gear, then vary throttle between 1500 - 2000 for the first hour..." Luckily getting it back Friday, and our Daughter is going out of town this weekend. So the lady and I are going to get out and waste fuel/break in the engine pretty much all weekend. With any luck will get in the 20 hrs and then have the marina give it a 20 hr service and be ready to go. If i understand my research - then if it is flat tappet I need to be gentle to break in the cams and do the fast idle/throttle vary, 1/3rd max for first 5 hrs, 3/4 max for next 5 with a few WOT hits. If it is roller then I should be a bit rougher on it to avoid cylinder glazing and properly get the rings seated.


Thought this thread could also be useful to anyone else getting back after a new install.


Thanks again everyone!

 

[Fishermark]

...I'll be getting my boat back from my mechanic this Friday after a new long-block install...

He will be the best source of information on the break in procedure. Different cams, piston rings, etc call for different break in procedures. He should know what he has installed and can help guide you. You've listed the common ones.

 

[H20Rat]

#
--2. Check me on my Break-In knowledge - Good Lord there are so many different schools of thought on this- from "Just run it like normal, but vary the throttle and don't stay at WOT, just tap it there from time to time" to "Start it up and fast idle for 20 minutes before even putting it in gear, then vary throttle between 1500 - 2000 for the first hour..."

I've seen that before, and that is the easiest way to create an engine that will burn oil, forever. The main purpose of break in is to seat the rings. The cylinders are honed to create a rough surface that will help wear down the rings for a perfect fit. To create enough pressure on the rings to do this, you need high cylinder pressures. Idling/fast idle without a load generates minimal ring pressure. All you are doing is polishing off the honing. For the most part, run it like you would normally, just avoid constant speeds and extended high throttle runs.

 

[M.A.CCruiser]

Ok - I have about 100nm round trip planned for Saturday - there are minimal slow-speed/no wake zones on the way. My plan is to get it up on plane (slowly) and then just keep bouncing the throttle. Normally cruise at about 3000-3200. Figure back and forth on the throttle between 2700-3600 won't be a problem keeping me on plane and also won't let it sit at one speed for a while.

What about oil additives? I've read about adding Lucas engine break-in additive

 

[Eric 3.7LX Alpha 1]

Hydraulic camshafts and lifters also need a special break in period. Roller cams and lifters do not.

I agree with Fishermark. Your mechanic will be able to guide you on a procedure.

 

[M.A.CCruiser]

Alright. Thank you!

It may just be my past experiences but I would love a few hints for questions to ask (#1 above)

This is my first I/O and I had engine failure due to riser failure 3 weeks after I took delivery (long story and lesson learned - yes I got a survey - but not an "engine survey").

So besides "what's the break in?" What would you ask?

 

[M.A.CCruiser]

due to unforeseen issues (long story - but lets just say i have more than just a new long-block now) i am actually just getting the boat back with it's new engine today. Confirmed it is a roller-cam engine - so then the only thing i'll be breaking in is the rings. Spoke to the mechanic and he confirmed:

keep it out of WOT for the first 10 hours - after the first 10 hrs some WOT is ok - but don't leave it pegged.
Don't just jam the throttle, work it up to speeds - especially while engine is not warmed to operating temps
vary cruising speeds - don't stay at one RPM too long
avoiding long idles if possible - try and keep 1500 as minimum RPMs if safe
check oil often
change oil at 20 hrs.

Looking forward to putting some hours on it!