Engine Repower

CrewLounge

Time to repower the 6.2's in my 342.  Any recommendations on who to use, which rebuilder, Mercruiser Reman, etc?

Wildboating

Wow, Sorry off topic slightly but that is Great news Alswagg!!  4000?? On the original motors? 

Handymans342

Yes, I have 160000 on my 454 and dont burn a drop of oil.

LaRea

... but a typical recreational boat engine running 50 hours a year is not going to last 5000 hours.  Most people say it would be more realistic to expect 1500-2000 hours for a major rebuild.  Right?

Wildboating

That was my understanding too LaRea.

Wildboating

• AlSwagg,  Are you saying you think running synthetic oil has something to do with the longer life?

LaRea

I'd guess it's more about how you operate the boat.  To go 5000+ hours, I think you'd have to run the boat at least an hour a day, 250+ days a year, and stick to a commercial-grade maintenance schedule.  Recreational boaters generally don't do that.

Veering back on topic ... assuming CrewLounge's engines are toast, what's a good strategy for a rebuild?

Handymans342

Alswagg said:

40 hrs roughly equates to 3,000 miles in an auto.    4,000 hrs is around 300,000 miles.    I have 368,000 on our shop suburban original 454 Vortec.  

Oh man, that means I only have 44000 miles on my diesels! I can go another 25 years

JC290

Handymans342 said:

Alswagg said:

40 hrs roughly equates to 3,000 miles in an auto.    4,000 hrs is around 300,000 miles.    I have 368,000 on our shop suburban original 454 Vortec.  

Oh man, that means I only have 44000 miles on my diesels! I can go another 25 years

even longer for you can't add hours sitting in shrink wrap lol 

Handymans342

Just add another year  LOL

CrewLounge

Al, mine have 700 hours each and I'm getting oil on the top side of my throttle body. Some might suggest blow by. The start fine cold, but I have to crack the throttles on my 6.2's when they're warm. Suggestions?

CrewLounge

Ok, what about the oil leaks around the front and rear of the intake manifold?

CrewLounge

Yea, if I run on plane for an hour or so, I have oil in the bilge from the port engine only. Also, you mentioned cooler is better.  Should I remove the thermostats as well as use synthetic oil?

Handymans342

Al, so the 6.2s are having the same intake issues as the 454s? 

howardrams

Can't imagine rebuilding engines at 700 hours.  Oil leaking near the intake manifold could even just be from the rocker covers, front cover, as some have mentioned.

CrewLounge

Ok. Thanks Al. I'll clean it up and try that. Would you remove the Tstats or leave them in. They are 160's

CrewLounge

That's what I thought. Thanks !

YWAIT

What temp is the 496 supposed to run at? WOT for 5 miles   or just idling around.  Im getting a mess of oil in Bilge cant see where it is coming from.

MarkB

YWAIT is your motor running cold? Like 120F?  If so, it could be running rich, sending fuel into the oil. Oil could be filling up and spilling out.  Is it thinned out? If this is the case, stop immediately. Oil thinned out with fuel is not a good lubricant. I won't say too much more as Al is here to chime in.

CrewLounge

Al, I have switched to synthetic oil.  I still get some blue-ish smoke when I start up and when idling in after a run. Any ideas?

Michael T

CL - What synthetic brand and weight are you using? What is happening with your oil consumption according to your dipstick after a run or day on the water?

CrewLounge

Mercury 25-40. Not much difference on the stick

212rowboat

I'll take this opportunity to share a discovery I've made..... well.. I didn't discover it, it's been around a while, but it's something you fellas with crazy expensive engines ought to consider.

on my 6.4L powerstroke diesel I am silly maintenance minded.  I've never ran any more than 5k miles on it w/o a change of both filter and oil.... It holds 15quarts... I run high quality synthetic (Schaeffer's 9000 group four full synthetic cj4 in 5w-40)... 

I usually turn black around 1.5K miles.... Even though analysis perks out well, I still swap it at 5k miles regardless.  using a zddp based oil, when it goes bad, it goes bad quickly, as the compounds separate and fall off of hard parts.  

anyway, I introduced a bypass filtration system on that rig... it sips 10% of the flow and funnels it to a 2 micron absolute (@98% efficiency) filter, before reintroducing it to the engine.  The filter is marketed by Amsoil.  I run the 100 model. 

So... I JUST sent in a sample to Blackstone this morning of an oil with 9800 miles on it.  I would never have ran this long on ANY oil, but, the stuff is still pristine, with only the hint of black ash present.  I want to know how the detergents are holding up, which is the reason for the analysis.  

9800 miles.... absolutely crazy to me....

oil doesn't break down, it contaminates- and when the contaminants exceed the lubrication properties is when you should change it... this oil is still green (Schaeffer's has a green tint to it) more than black... The compounds in the oil intended to protect DO expire/break down, which is the only reason I sent in a sample.

A bypass oil system can easily be introduced to these engines- and it would be worth it.... Al, that engine you're swapping oil on every two weeks?  You could likely extend it to monthly or even every other month. 

I didn't take this venture lightly, I researched and researched, did a lot of sampling and determining there was no fuel dilution or excessive blow-by from combustion gasses indicating engine issues, or water infiltration due to not reaching temperatures capable of burning off moisture, ect.... I researched like my trucks engine depended on it, and it kinda does...  My only regret is that I waited until 90k miles to introduce it... 

fellas- consider the by-pass system... 

to put it into perspective, some over the road truck maintenance guys are reporting 400k on ONE oil change interval, using lab results to coach them every 25k miles, and swapping when the analysis indicates them to do so... this is up from around 40~50k miles usually... these guys make their living off of their trucks- keep that in mind, so they aren't going to do something risky... this saves them not only engines longevity, but a LOT of money swapping oil (those things hold like 14~15 gallons of the stuff), and not to mention, doing a good deed for the environment. 

CrewLounge

al, what do you think about Motor Honey or Smoke Stop oil treatment?