rebuild engine oil change

[Moondocker]

Hi all,
Just wondering what the rule of thumb is regarding how long (how many hours) should a new rebuild run before the first oil change? I have about 5 hours on a new KLC with Brad-Penn 30w break-in oil and will change it to 30 w running oil. Just not sure at what point to do that.
Thoughts?

[mfine]

What did the builder recommend?

[Moondocker]

The builder said "4 or 5 hours". The rep from Brad Penn said that recommended change for an automobile engine is 150 miles. Not sure how to quantify that for a boat engine that works much harder than an auto. I'm just going to run it a few more hours then change it.

[jim g]

A Chris Craft service bulletin from the sixty's said that a 100 hours on a marine engine equaled 10,000 miles on a car engine.

[joanroy]

I've heard opinions from a couple of sources that a marine gas 350 with good maintenance and conservative use should last about 1000 hours. I'm hopeful that's true. My engines have about 650 hours and I really don't want to change them out any time soon.

[tkhersom]

First I guess I would do whatever my builder recommended. Oil is cheap compared to critical parts of an engine.

Joanroy: That is interesting. The 350 in my Formula just rolled 1100 hours. One of the guys I work with said it should go about 4K hours with good maintenance and maybe a new distributor. (he does tend to be a bit optimistic, maybe I will ask another.)

[joanroy]

Moondocker, sorry I got off track and I agree with Troy. Go with the engine builders recommendations.

Just wondering if there is an expected gas marine engine life in hours. Not just for the newer motors, but also for professionally rebuilt antique motors? Would be good to know the expected remaining useful engine life if your shopping for a used boat.

[Greg Wallace]

Traditionally typical OEM recommend first service including oil change at 20 hours

[Moondocker]

Thanks for all of the input. I put 3 hours on it this weekend and changed it out at almost 8 hours. Good to go.

[DennyDowning]

Well, I've read this thread a few times now.
I would not be shy about changing the oil several times during a break in period.
20 hours... Heck, change it at 10 and then change it again at another 10.
And then change it again.
Take a look at the oil color on the stick; how does it look?
If it is black then change it out.
I am not an expert by any stretch but I know that good oil is key to an engines life.
And most of the manufacturing debris and break in metal shaving happens early on.
One writer said it best when he stated that "oil is cheap".
Your engine will love you.

Denny