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Marine Hemi?

Discussion in 'The Hokey Ass Message Board' started by MeanMike, Oct 29, 2008.

  1. MeanMike
    Joined: Mar 10, 2006
    Posts: 56


    I just picked up a 354 marine hemi. It looks to be in decent condition. Is this possible to convert to a street motor? I'm told some marine engines spin backwards. Anybody have any experience or info on this subject? Any help is much appreciated.
  2. Shaggy
    Joined: Mar 6, 2003
    Posts: 5,208

    from Sultan, WA

    Some have adjustable rockers-good for a solid lifters look for valvecover dimples between the plug holes, also find out if it ran a radiator or was fresh or salt water. They can be very good motors to build Garlits did it in the 50's
  3. 41hemi
    Joined: Jul 2, 2007
    Posts: 955


    Yes they are excellent for conversion to street duty! They did make left and right hand rotation engines however this was done with the cam. You want to change the cam anyway. You will also need to have the crank welded up where the timing gear goes as the marine version is not "stepped" for the automotive gear. What year engine is it? It should have a plate riveted on the block by the distributor end of the block where an auto transmission bolts up.
  4. plym_46
    Joined: Sep 8, 2005
    Posts: 4,018

    from central NY

    Usually the rule of thumb was whether it was a single engine application or a twin engine setup. Usually with the twins, the reversed rotation on one to counter torque induced steerage, by twisting the props in opposite directions they canceled each other. Assuming each engine was powering its own prop. where they were married together with a gear box they had the same rotation.

    The other quick check where is the starter??

    Starter motors, when mounted forward of the flywheel, will turn clockwise (R.H.) to start a standard rotation (L.H.) counter-clockwise motor. Starters mounted aft of the flywheel will turn counter-clockwise (L.H.) to start the same engine. Everything is just the opposite when speaking of a reverse rotation (R.H.) clockwise engine.

    CaddyRat likes this.

  5. scootermcrad
    Joined: Sep 20, 2005
    Posts: 12,372


    The marine heads sometimes had a strange steam cavity in the middle. It would have taller ports in that location. You will want to make sure whatever manifold you run covers that port up completely.

    Marine, truck and industrial hemis can all be converted for street use, despite what some may tell you. You just have to do a little more to them to make it happen. Most Hemis are unusable for street conversion. As already mentioned, you will need a different cam, timing assembly and crank work. You may be better off finding another crank. Most 354 cranks will work for the application and 331 cranks will drop in but the oil passages are a different size. Also, you may want to see what pistons you have in the holes. Will probably be to your benefit to swap those out as well. You can retain the rods though.

    Congratulations and welcome to your new addiction. Make sure you throw some pictures up for us to check out your score.

    One more thing... there should be some indication in the casting to tell you if it's CW rotation or CCW rotation. It may also have a geared timing train.

    More info on Hemis in the HEMI Tech index. Click on the banner in my sig. line and get ready to read what all the HAMBers have put together for your Hemi learning pleasure...
  6. HemiRambler
    Joined: Aug 26, 2005
    Posts: 4,204


    As I understand the "reverse rotation" marine Hemi cranks also had the KNURLS facing the OPPOSITE direction as you would want in a "normal" rotation engine.

    The other issue they can have is severe rusting in the water passages.
  7. Does it have ally exhaust headers?
  8. Shaggy
    Joined: Mar 6, 2003
    Posts: 5,208

    from Sultan, WA

    Dont forget the oil pump on reverse rotation!!
  9. 73RR
    Joined: Jan 29, 2007
    Posts: 6,550


    Hey scooter, what are ya smokin these days??:D:D:eek:

    Don't ya just love when the brain and the fingers get disconnected??

    The tall centre port is a water passage, also on truck heads, not usually on industrial jobs, used to keep the carb temp even. Picture those farm trucks working a wheat field for 12-14 hours straight.
    If the marine engine was in salt water, it might be junk. All that I have seen were badly corroded. If this engine has the 2-1bbl intake, look at the bottom of the manifold for evidence of cracking or perforations.
  10. Until you open it up you have no idea what it may be.

    You are going to end up replacing half the stuff on it when you rebuild it.
  11. MeanMike
    Joined: Mar 10, 2006
    Posts: 56


    Thanks guys. I pulled off the bell housing to bolt ti to an engine stand. I'll check what side the starter is on tomorrow. It had exhaust manifolds on it, not headers. I'll open her up this weekend and have a peek. Hopefully she won't be too bad. I'll post some pics too! I'm hoping this motor is rebuildable. Thanks again for the info. The hemi index on here is awesome!
  12. Not true.

    Oil pumps (as well as distributors) are the exact same for the left-hand as the right-hand 331 and 354 Chrysler Marine engines.
  13. If you want to see if it is a left hand or right hand Chrysler Marine engine, take a look at the helix in the center of the flywheel. It will become very obvious which direction the engine ran. Starter placement will not indicate anything as the starter is in the same location on right as well as left hand engines.

    The typical automotive engine is a right hand rotating engine. If you look at the flywheel end and have your right hand's thumb pointing in the direction of powerflow, your right fingers will point in the direction of rotation. A left hand engine will require using your left hand's thumb to have the fingers pointing in the correct direction...

    Keep in mind that most of the Chrysler Marine engines were installed in the boats "backwards" in that the flywheel end of the crankshaft was towards the bow (front) of the boat! The exception is the V-drive installations (engine over propshaft). The transmission was connected to the crankshaft at the timing gears end of the engine. While this is at the "back" of the engine in a typical marine installation, it would be the "front" of the engine if it were in a car... thus the confusion.

    Solid lifters and the corresponding (and very sought after, i.e. expensive) adjustable rocker arms are standard equipment on these marine engines. Factory adjustable rockers require the use of the bumpy valve covers - and they should say "CHRYSLER MARINE" on them.

    As stated previously, Chrysler Marine engines will have a stainless data plate attached to the block near the distributor. Stamped into it is the model, you are looking for a code of M45, M45S, M45S-3, M45SP, or M45SP-3 to identify the engine's displacement and power rating.

    Also stated earlier but worth empahasizing is to check the condition of the cooling jackets if the engine were raw water cooled and used in salt water. Typically, the zinc anodes were not replaced as they should be and the salt water has taken its toll corroding the cooling passages.
    Last edited: Oct 29, 2008
  14. tiredoldman
    Joined: Oct 8, 2006
    Posts: 5


    Also everything on the motor was gear driven. Water pump, generator and camshaft. If you are not going to reuse these parts please contact me. I have a boat with a factory 331 hemi in it and spare parts are always welcome.
  15. Ramblur
    Joined: Jun 15, 2005
    Posts: 2,101


    Saw one last weekend in its "natural" habitat...

  16. fab32
    Joined: May 14, 2002
    Posts: 13,985

    Member Emeritus

    I can't imagine what the ChrisCraft must be worth. I'm thinking it looks better now than when it was new. Here is one application where "over restored" is OK in my book. I'd almost hate to put it in the water, but couldn't resist seeing how the hemi would pull it across the water. Too cool for words.

  17. That boat is awesome. It must look like a shark on the water with that fin and probably moves like one too with the Hemi.
  18. dreggie61
    Joined: Dec 13, 2008
    Posts: 1


    If the street application for the marine hemi turns into a bridge too far, I am looking for a marine hemi for marine use. Maybe I could buy it from you. (570) 604-6271

  19. mickeyc
    Joined: Jul 8, 2008
    Posts: 1,209


    Hello Mike, MickeyC here, I too recently picked up a marine hemi. Actualy I bought the whole boat, for the motor. Some motors were convereted car pieces and are easily converted back. These were used in my area a lot in shrimp boats before diesels became popular. Mine is a 331 2x4 carb set up
    and is a Chrysler Marine factory setup. The motor features chrome valve covers and adjutable lifters and drives off of the font of the motor with all acessories being gear driven the spec. plate says 250 hp. Get yourself a copy of the Hemi book by I think Ron Ceridondo? I find it helpful.
  20. hemicoupe32
    Joined: Nov 23, 2007
    Posts: 315


    There is nothing wrong with useing a mariene engine. Just check the water jackets and see how bad the rust is. Many of these were freash water cooled and very useable. Might be cheaper to find another crank as the stock marine crank will need to be modified to use in a street motor. If your gonna do a rtebuild anyway then it doesn't matter about the timing set up as you will be changeing it .Put new pistons and cam with new lifters. I prefer adjustable push rods for a hydrylic motor. I had Daytona Auto Design refurbish my rocker assemblies. Excellent job. Bob Walker at Hot Heads can give you all the info and parts required to bring it back to life. Just remember it ain't no small block chevy. You are not going to build a good old hemi on the cheap. Not one that will last.

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