Looking to re-power my 342. Who and what would you go with?

WildboatingWildboating Posts: 752Member ✭✭✭
As the title says, I am thinking it is time to repower my 350 Mag Mpi engines that currently have 500 hours on them. This was not on my todo list but Last year i had to rebuild the heads due to tuliped valves at the tune of nearly 7k and now i find myself with problems again.
 As many of you have, i have been counting down the days to launch the boat which came for me yesterday. Unfortunately for me, within 10 minutes on the water i knew something wasn't right.   We put new props over the winter because the boat wouldn't turn over 4000 rpm previously.  We went from 24p 3 blade to 20p 4 blade at the suggestion of hill marine after walking through the characteristics of my motors and our end goal results.  After a nice warm up cruise i started to throttle up and found the boat would list to the port side heavily. I worked with the trim tabs to level the boat out and cruised up to 4500 rpm at which point i noticed the starboard motor peg the oil pressure.  I promptly returned to idle and lifted the hatch to a knock sound in the motor on the starboard side.  I shut it down and limped to my dock on one engine.  My mechanic came down and fired the motor which knocked for a few seconds then cleared up at idle.  If you rev the engine up to about 1600 rpm the bottom of the motor starts to chatter horribly which left him and another mechanic with the same consensus that I had spun a rod bearing.  I am being told that i will cost about 3k or more to tear the motor down, replace or repair to get us back up which now puts me at 10k in motor repairs and still left with 500 hour motors and who knows how long the other will last.  

So back to my original statement, I'm thinking it makes better sense to replace my 350 mag mpi motors with new 6.2 stroker long block motors which will give a nice 140 total horsepower boost and a nice amount of torque.  If you were in these shoes would you keep repairing or just replace and be down with it?  I should be able to sell my one good engine off and the other for repair and get a few grand out of them which will help bring the cost down.   Im thinking i can do the complete swap and repower from the 350's to 6.2 for about 10g after selling my engines off.   Would you do the same, any companies you suggest for picking up the 6.2 long blocks?
2003 Rinker 342 Fiesta Vee, 350 Mag MPI, Bravo 3 2.20:1 w/ 22p 4 x4 props

Comments

  • shawnmjrshawnmjr Detroit MIPosts: 744Member ✭✭✭
    I think this is a topic for @Michael T
  • raybo3raybo3 Revere MAPosts: 3,361Moderator mod
    I am sure Alwaggs will chime in here. Did you not like the performance of your 350? You looking for more speed? If you like the way the boat performed why not just replace the bad engine and help keep the cost down?
    2002 342 Fiesta Vee PC Point Of Pines YC Revere MA. popyc.org
  • WildboatingWildboating Posts: 752Member ✭✭✭
    I am open to all suggestions here, however i bought the boat a year ago.  Last year the boat would not go over 4000 rpm and if there were 6 or more people it would not plane at all.  I was told you need new props, that i was over propped.  So over the winter i investigated and bought new props and went to test yesterday and the new rpm and bite seems to have been a culprit in destroying a rod bearing.  I don't know if i would have been happy with 350's as i have been burdened with problems from day one of the boat arriving.  I pm'd AL yesterday however i have not heard back yet, we all know that man is busy.

    2003 Rinker 342 Fiesta Vee, 350 Mag MPI, Bravo 3 2.20:1 w/ 22p 4 x4 props

  • Black_DiamondBlack_Diamond Holland, MichiganPosts: 4,018Member ✭✭✭✭✭
    I can't see how changing the props caused a bearing to spin. 

    The 350 MAG MPI when propped correctly should be fine. That is my set up. 

    2003 342FV "Black Diamond", 350 MAG MPI, 20P 4x4 Props, PC BYC, Holland, MI
  • WildboatingWildboating Posts: 752Member ✭✭✭
    Would over revving cause a bearing to spin?  What about when i seen the oil pressure peg to 80psi

    2003 Rinker 342 Fiesta Vee, 350 Mag MPI, Bravo 3 2.20:1 w/ 22p 4 x4 props

  • WildboatingWildboating Posts: 752Member ✭✭✭
    BD what props are you running?

    2003 Rinker 342 Fiesta Vee, 350 Mag MPI, Bravo 3 2.20:1 w/ 22p 4 x4 props

  • zaverin1zaverin1 Saint Clair Shores,MIPosts: 803Member ✭✭✭
    I mean your hull is designed with limits like any other boat.
    more hp and $$$$ equal to maybe a few mph gain. Added stress to the boat and drives. Also would mean another set of props. Torque would help with hole shot and plane speed but that's about it.
    unless your rpm Gages are off there is a possibility you reeved to high but most boats will hit the rev limit and let you know.
    So I don't think that's it. I would stick either with reman power plants you have now or look up to see what your year offered for power. Also look what drive and gear came with bigger motors.

  • Liberty44140Liberty44140 Bay Village & Marblehead, OH.Posts: 1,346Member ✭✭✭✭
    Hey Wildboating. I ran from Rocky River to Marblehead last night on my 06 342 so I can give you my numbers. At 3900 RPM I cruised the 40 miles at 27-28 mph. I have twin 350 MPI's and the props are all 22P 3 blades on Bravo 3's. Tanks were half full and we were going in to a 5MPH Breeze. I do not yet know what WOT is, have not gone there. So you should be fine with the 350's. I looked at an 02' with 6.2's over the winter and man do they fill up the engine room, I dont know how you'd work on them. Good luck. 
    Wine-N-Down -- 2006 342 Express Cruiser

  • Cableguy GregCableguy Greg Pittsburgh, PAPosts: 3,000Member ✭✭✭✭✭
    The 6.2 is the same block as the 350, just stroked out. The 7.4, 496 or 502's are the big blocks, which will eat up the engine room. If it was me, I would go with the 6.2 or the 383 stroker. They are both small blocks, but with added power. 
    2008 280 Express Cruiser, 6.2MPI, B3, Pittsburgh, PA
    Go Steelers!!!
  • LaReaLaRea Alexandria VirginiaPosts: 2,079Member ✭✭✭✭✭
    I don't think bigger is better for your boat.

    My '03 with the 350/B3 package would cruise all day at 30-32 mph, and top out above 40.  I once got it on plane with 12 people aboard.  If your boat wasn't doing that, don't blame the engine size ... something was wrong with your engines, your props or both!
  • YoullbefineYoullbefine Quarterdeck Marina, Sturgeon Bay, WIPosts: 12Member ✭✭

    You could also look at remanufactured small blocks from Mercury as well.

  • Liberty44140Liberty44140 Bay Village & Marblehead, OH.Posts: 1,346Member ✭✭✭✭
    LaRea - What was your RPM at 30-32MPH? What pitch props?
    Wine-N-Down -- 2006 342 Express Cruiser

  • WildboatingWildboating Posts: 752Member ✭✭✭
    Thanks for everyones advice.  I heeded your recommendations and decided (thankfully) to keep cost down.  I ordered a new 350 mag mpi long block and am only going to repair the one now.  The cost for a new one was nearly the same as to repair my old one just much quicker.   All said and done, i just couldn't justify the massive cost to go to 6.2l at this time.  The stroker motors or the 6.2l just didnt offer enough gain to justify the cost.  I hope to be back up and running before next weekend.  I am also returning the 20p 4 x4 props for 22p 4 x 4 props.
    2003 Rinker 342 Fiesta Vee, 350 Mag MPI, Bravo 3 2.20:1 w/ 22p 4 x4 props

  • Handymans342Handymans342 Cape Coral, FLPosts: 5,374Member ✭✭✭✭✭
    Too bad you didn't have the money to switch to diesels. Then you would have a real man boat! LOL. Just sayin
  • zaverin1zaverin1 Saint Clair Shores,MIPosts: 803Member ✭✭✭
    What is up with this guy and diesels?
    u like to smell like diesel
  • Handymans342Handymans342 Cape Coral, FLPosts: 5,374Member ✭✭✭✭✭
    Yup
  • zaverin1zaverin1 Saint Clair Shores,MIPosts: 803Member ✭✭✭
    Lol
    it smells good
  • Handymans342Handymans342 Cape Coral, FLPosts: 5,374Member ✭✭✭✭✭
    Lol
  • Black_DiamondBlack_Diamond Holland, MichiganPosts: 4,018Member ✭✭✭✭✭
    I am running 22P Bravo-3. I used to have 24P and that was over propped, short on WOT rpm and was horrible, horrible to get on plane with 4 adults on board. Solved all my problems. 

    Al has noted on here before to run 22P with the 350 MAG MPI. 

    If you were only getting 4,000rpm WOT, that sounds like an engine issue. 1" of pitch = 200 rpm change, you would have to drop from a 24P to an 18P to get the rpm to ~5,200 WOT. No way, that is too small a pitch. 

    The 6.2l takes up more room as it is closed cooled too. Be big $ to swap with all the correct MPI stuff too. If your 342 is an '03 or earlier, no room for anything but the 350 or 6.2l anyways. 2004+ has a bigger engine room. 

    2003 342FV "Black Diamond", 350 MAG MPI, 20P 4x4 Props, PC BYC, Holland, MI
  • CrewLoungeCrewLounge Norris Lake, TNPosts: 92Member ✭✭
    Since you've already rebuilt the heads, I would go with 6.2 short blocks
  • AlswaggAlswagg Posts: 1,832Member ✭✭✭✭✭
    Remember you have a preprogrammed fuel table that is set to rpm and load.   The fuel table is set for a 350 mag not a 6.2.    You simply cannot increase cubic inch and expect more hp without changing the fuel table.  So, keep with the 5.7 350 ci.   Check your gearing should be 2.2-1.  Use 22 pitch props.  Rpm is limited by rev limiter at 5,250 rpm.   These motors need to achieve at least 5k rpm at wot or overheating of the valve train will develope.    
  • WildboatingWildboating Posts: 752Member ✭✭✭
    Al, any guess on what would cause spun rod bearing at 500 hours after repropping and hitting 4800 rpm?  Oil pressure shot up to 80, I shut it down lifted hatch heard a knock and shut it off.  It's not knocking now but rev up to 1700 and vibration chatter from bottom end starts. 
    2003 Rinker 342 Fiesta Vee, 350 Mag MPI, Bravo 3 2.20:1 w/ 22p 4 x4 props

  • zaverin1zaverin1 Saint Clair Shores,MIPosts: 803Member ✭✭✭
    It could be anything my man but common is oem defect ,
    over heat, or water intrusion. Engine Tare down will tell the story.

  • zaverin1zaverin1 Saint Clair Shores,MIPosts: 803Member ✭✭✭
    Not to mention oil delivery issue 
  • AlswaggAlswagg Posts: 1,832Member ✭✭✭✭✭
    Has the motor been torn down to verify rod bearing??  What weight oil?  Stuck bypass valve? The GM block runs continually well over 5k.  I would like to do an inspection.  
  • LaReaLaRea Alexandria VirginiaPosts: 2,079Member ✭✭✭✭✭
    @Liberty44140 - I think I was usually cruising around 3800 - 4000 RPM with 22P props.  That's where the boat seemed happiest ... around 30-32 mph.
  • WildboatingWildboating Posts: 752Member ✭✭✭
    We have not verified but my mechanic says he is positive.  I ordered a new long block which arrived today and we will yank the other out.  I am curious to tear it down and see what is actually going on.
    2003 Rinker 342 Fiesta Vee, 350 Mag MPI, Bravo 3 2.20:1 w/ 22p 4 x4 props

  • Black_DiamondBlack_Diamond Holland, MichiganPosts: 4,018Member ✭✭✭✭✭
    I'd sieze the opportunity to have Al look at it. He's not all that far from you really. 

    2003 342FV "Black Diamond", 350 MAG MPI, 20P 4x4 Props, PC BYC, Holland, MI
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