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  1. #1
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    Default Re-Engine considerations.

    I'm on the committee that maintains our YC's power boats. Most are 4stroke Honda RIBS and Whalers, but two are inboards. One a 23 MAKO CC, the other a 24 Privateer. The Mako is heading for new engine time (existing one is in it's second boat!) as its over 24 seasons old (FWC). Now that MERC is rolling it's own scratch engines, I'm looking for feedback on the current "production" "V" engines. The "stock" MAKO CC engine is a 350 CID 260 ish HP engine. These days, as I understand, MERC's current 260HP is a 5.0L V6. I have concerns about a 5.0L (or a 4.5L??) in the MAKO.
    Capt Bob
    1969 23ft ChrisCraft Lancer
    Merc 5.7L 260HP/ Volvo 280
    1972 22ft Bristol
    Honda 7.5HP 4 stroke Long shaft

  2. #2
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    DC Burbs/Maryland Eastern Shore
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    Default Re: Re-Engine considerations.

    I’d be putting in an exact replacement of what comes out. 24 years of service is quite a good selling point in my book.
    Practicing the ancient art of ren-ching

  3. #3
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    Chaumont Bay, N.y., USA
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    5,195

    Default Re: Re-Engine considerations.

    Mako is heading for new engine time (existing one is in it's second boat!) as its over 24 seasons old (FWC).
    Ayuh,... The current motor is a 350, 4bbl( '93 could be a quadra-jet, or the weber/ carter afb),.... Merc,..?? What drive,..??

    Are ya lookin' for a full blown bobtail complete drop in crate motor,..??
    Or,...
    A fresh long block with the accessories from the original,..??

    What's the Budget,..?? labor rate,..??

    Electronic motors(efi, mpi) will need much more installation time,.... wirin' changes, 'n all,... maybe not,...

    No doubt the simplest, probably the smartest answer is as noted,.... Drop in a new 350 4bbl carbed motor, 'n shoot for another 24 years,....
    Any Grease is Better,... Than No grease at All....

  4. #4
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    Default Re: Re-Engine considerations.

    Didn't we have this conversation?

    5.0 Mercruiser is NLA.
    Chris
    Dockside Marine Services
    Jersey Shore.
    Mercruiser/Mercury Certified
    Let the insanity begin.

  5. #5
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    Default Re: Re-Engine considerations.

    Chris, yes we did have this conversation, however, I'm dealing with folks who think that because they have a room full of sailing trophies, that they know all about power boats. ( Sailing is hard, powerboat is easy, therefore we know more) For example, I spent an inordinate amount of time convincing them it was not a good idea to take a middle aged Suzuki 4 stroke 40 hp "salvaged" from a RIB that was beyond economical repair and install it on a late 70s 13 ft whaler.... that said, there is supposed a "good deal available on a "leftover" 5.0".... hence my query. The bean counters don't understand the difference between a 5.7L marine engine and a 4.5L at roughly the same HP other than the latter is "cheaper". Given the current plans are for a total engine replacement in 3 to 5 seasons ( absenting elbow failure), I'm trying to get some info on any issues with the current Mercruiser built (not marinized) product line. In looking more carefully at specs, I'm a bit put off by the WOT operating ranges and quoted HP of the new engines, i.e. over 5000 rpm. I think if I do the math and derate the engines to a mid/upper 4000 rpm range, I'm pretty sure the HP will be in the 260-275 HP region. Both anticipated re-engine projects are on straight inboard boats. Just trying to get equivalent performance from the boats. Mission profile is that they are used, in one case twice on Sundays all (NJ) summer and the other is used 3 to 4 times a week all summer for patrol and race management duties. Currently looking at the the 6.2L ECT @300 HP, but am turned off my the Smartcraft instrument system. This will cause a major issue on the classic circa 70s boats.
    Last edited by sandkicker; 11-07-2017 at 01:12 PM.
    Capt Bob
    1969 23ft ChrisCraft Lancer
    Merc 5.7L 260HP/ Volvo 280
    1972 22ft Bristol
    Honda 7.5HP 4 stroke Long shaft

  6. #6
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    Default Re: Re-Engine considerations.

    if they are working and the plan is a total replacement in a few seasons, why the bandaid??? either change them or dont.

    Since they are both worthy of the 'vintage' consideration, the 'new' EPA rules are something to consider as well....once you 'upgrade' I don't think you can go backwards....

    The 'factory reman' option may be worth considering....for the engines - the existing gears should be overhauled for a few hundred each.....

    The analog gauges can be maintained by adding the appropriate sensors (& wiring) though the tach may take a bit more effort.

    Finally, the rated RPM has been increasing for a while - it surely doesn't mean you need to operate it there....

  7. #7
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    Default Re: Re-Engine considerations.

    Quote Originally Posted by makomark View Post
    if they are working and the plan is a total replacement in a few seasons, why the bandaid??? either change them or dont.

    Since they are both worthy of the 'vintage' consideration, the 'new' EPA rules are something to consider as well....once you 'upgrade' I don't think you can go backwards....

    The 'factory reman' option may be worth considering....for the engines - the existing gears should be overhauled for a few hundred each.....

    The analog gauges can be maintained by adding the appropriate sensors (& wiring) though the tach may take a bit more effort.

    Finally, the rated RPM has been increasing for a while - it surely doesn't mean you need to operate it there....
    No... I wasn't clear. Total replacement in 3 to 5 years assuming the elbows last that long. Elbows fail, new engine.

    Doing some math. The 80% WOT RPM cruise on the new 6.2L is up to 4640 rpm!!! I think all MERC cares is the "advertized" HP and if the engine outlasts its warranty period. Per my calculations, derating the engine to a 4800 MAX WOT, gives you a 249 HP rating and a 3840 RPM 80% cruise. Engine of course should be propped to the 5800 RPM max range...
    Capt Bob
    1969 23ft ChrisCraft Lancer
    Merc 5.7L 260HP/ Volvo 280
    1972 22ft Bristol
    Honda 7.5HP 4 stroke Long shaft

  8. #8
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    Default Re: Re-Engine considerations.

    operation to satisfy the warranty period has been paramount in the industry for decades....nothing has changed with the current generation of offerings in this regard....

  9. #9
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    Default Re: Re-Engine considerations.

    Back in the early 80s I re-engined my first 23ft Lancer with a 240HP FWC /LM318 (Chrysler). I chose this engine because it was the engine of choice for the small commercial guys here on the Jersey shore... Those guys whose livelihood and safety depended on their engines. When i bought my second Lancer (12 years ago) I wanted to re-engine it and was disappointed to find out that MOPAR no longer made marine engines. Crusader was out of my budget so I bought my current 5.7L MIE. During the first year of ownership I discovered that I had what is called in the automotive industry a "Holiday Friday" example. VEry recently I discovered that the valves on this engine were never properly adjusted from the factory. And here I am again, I am looking for a commercial quality build engine for the club who expects decades of trouble free use out of its boats. To quote the head of our sailing program... "These boats are our classrooms." Every summer we have 80 to 100 kids 8 to 18 in the program.
    Capt Bob
    1969 23ft ChrisCraft Lancer
    Merc 5.7L 260HP/ Volvo 280
    1972 22ft Bristol
    Honda 7.5HP 4 stroke Long shaft

  10. #10
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    Default Re: Re-Engine considerations.

    Surely you had a class on stochastic processes.....so, if you build enough of anything, something will go wrong...

    If you want minimal opportunity, then find an excellent local shop with a stellar reputation and have them do a custom build and install and get the full warranty package....and be done with it.....just remind the board that premium products come with premium price tags....

  11. #11
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    Default Re: Re-Engine considerations.

    Quote Originally Posted by makomark View Post
    Surely you had a class on stochastic processes.....so, if you build enough of anything, something will go wrong...

    If you want minimal opportunity, then find an excellent local shop with a stellar reputation and have them do a custom build and install and get the full warranty package....and be done with it.....just remind the board that premium products come with premium price tags....
    Re: Stochastic processes class... worse than that, I had a self managed "Co-op" education program thru engineering school and spent a couple of years in reliability engineering for a company that made navigation and guidance systems for the military.
    I was not surprised, just annoyed, by the number of things that were quite avoidably done wrong on my engine between the factory and the mechanic that did the swap.
    Was just beginning to think about a custom build as I was typing my previous post and now that you mention it, it is starting to sound like it may be worth it. We will be needing to re-engine two boats with the same basic engine. Now all I need to do is find "that shop" :-). Not a whole lot of choices here in Ocean County.... then again, one of the local small shops I know about, builds race boat engines and has a day job of maintaining one of the "official fleets" here. A good place to start.
    Capt Bob
    1969 23ft ChrisCraft Lancer
    Merc 5.7L 260HP/ Volvo 280
    1972 22ft Bristol
    Honda 7.5HP 4 stroke Long shaft

  12. #12
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    Default Re: Re-Engine considerations.

    Quote Originally Posted by sandkicker View Post
    Re: Stochastic processes class... worse than that, I had a self managed "Co-op" education program thru engineering school and spent a couple of years in reliability engineering for a company that made navigation and guidance systems for the military.
    I was not surprised, just annoyed, by the number of things that were quite avoidably done wrong on my engine between the factory and the mechanic that did the swap.
    Was just beginning to think about a custom build as I was typing my previous post and now that you mention it, it is starting to sound like it may be worth it. We will be needing to re-engine two boats with the same basic engine. Now all I need to do is find "that shop" :-). Not a whole lot of choices here in Ocean County.... then again, one of the local small shops I know about, builds race boat engines and has a day job of maintaining one of the "official fleets" here. A good place to start.
    You are putting too much thought into this......
    Chris
    Dockside Marine Services
    Jersey Shore.
    Mercruiser/Mercury Certified
    Let the insanity begin.

  13. #13
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    Default Re: Re-Engine considerations.

    Quote Originally Posted by Docksidemarineservices View Post
    You are putting too much thought into this......
    Boat out of water, rotator cuff issues so no surf fishing for bass.... bored :-)
    Capt Bob
    1969 23ft ChrisCraft Lancer
    Merc 5.7L 260HP/ Volvo 280
    1972 22ft Bristol
    Honda 7.5HP 4 stroke Long shaft

  14. #14
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    Default Re: Re-Engine considerations.

    Quote Originally Posted by sandkicker View Post
    Boat out of water, rotator cuff issues so no surf fishing for bass.... bored :-)
    Further the ratings of current MERC (and Volvo) engines.
    presumably, if you are purchasing "the whole package" it some how all works out BUT for an engine only replacement....

    Generally, for non race boats, "at the prop" MAX RPM is limited to 3000 RPM to avoid cavitation.... hence the popular 1.61 ish reductions. A 4800 RPM max WOT engine with a 1.61 reduction yields a just under 3000 RPM max prop speed. At 5800RPM ( the current popular MERC/Volvo max/rated RPM), the prop speed with a standard 1.61ish reduction jumps to just over 3600 RPM, a 20% "overspeed".
    Capt Bob
    1969 23ft ChrisCraft Lancer
    Merc 5.7L 260HP/ Volvo 280
    1972 22ft Bristol
    Honda 7.5HP 4 stroke Long shaft

  15. #15
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    Default Re: Re-Engine considerations.

    Good point, but if this is a 'cruiser application' it doesn't matter all that much.

    Jeff

  16. #16
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    Default Re: Re-Engine considerations.

    Yes, cruiser... I'm planning on stipulating a 4800 MAX RPM for the boat. Propped for 5800 but throttle stopped @ 4800.
    Capt Bob
    1969 23ft ChrisCraft Lancer
    Merc 5.7L 260HP/ Volvo 280
    1972 22ft Bristol
    Honda 7.5HP 4 stroke Long shaft

  17. #17
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    Default Re: Re-Engine considerations.

    At 5800RPM ( the current popular MERC/Volvo max/rated RPM),
    Ayuh,.... What motors have you found with a 5800 rpm redline,..??
    Any Grease is Better,... Than No grease at All....

  18. #18
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    Default Re: Re-Engine considerations.

    Wondering about that myself!

    Jeff

  19. #19
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    Default Re: Re-Engine considerations.

    Quote Originally Posted by bondo View Post
    Ayuh,.... What motors have you found with a 5800 rpm redline,..??
    The current Mercruisers "SBM??" (6.2) redlined at 5400 while the current small "V6 and V8" engines by Volvo (Merc based???) redlined at 5800.


    http://www.volvopenta.com/marineleis...ne.html#Select
    Last edited by sandkicker; 11-10-2017 at 03:07 PM.
    Capt Bob
    1969 23ft ChrisCraft Lancer
    Merc 5.7L 260HP/ Volvo 280
    1972 22ft Bristol
    Honda 7.5HP 4 stroke Long shaft

  20. #20
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    Default Re: Re-Engine considerations.

    Eeeeeeeeeeeeeeeeeehhhhh!

    Wonder how long the rings and valve springs will last at 5,800 rpm?

    Jeff

  21. #21
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    Default Re: Re-Engine considerations.

    Bob:

    its even worse than that, at least on the volvos - pg 2 on the link shows the 6.2's are now rated @ 6000 RPM.....but, they are EPA compliant....

  22. #22
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    Default Re: Re-Engine considerations.

    sigh.... its bad enough that you go to the supermarket and food packages have less in them and the cable companies (at least Comcast) now charge for viewing last seasons on demand shows and in a few cases current season shows that are more than a month or so old that you have already viewed, but now they are selling 200 HP engines as 250HP engines and specing them so they will barely live past warranty. I think in Volvo's case, they are specing the engines at the higher RPMs for the whole sterndrive package i.e. at the prop HP.
    Capt Bob
    1969 23ft ChrisCraft Lancer
    Merc 5.7L 260HP/ Volvo 280
    1972 22ft Bristol
    Honda 7.5HP 4 stroke Long shaft

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