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Thread: Crown M47S Head Gasket....

  1. #141
    Join Date
    Mar 2001
    Location
    FL
    Posts
    232

    Default Re: Crown M47S Head Gasket....

    Knurling the guides is an option. Not as long lasting as new guides but I doubt that's a problem with the low hrs boat engines get. It's done without removing guides and you won't open a larger can of worms.

  2. #142
    Join Date
    Sep 2011
    Location
    Eagle River, Wisconsin
    Posts
    65

    Default Re: Crown M47S Head Gasket....

    Hello All,

    Does anyone know what the torque value is for the Manifold???? The head shows 57 lbs but I can't find the Manifold torque in the Maintenance Manual...

    Thanks Much....

    Chrysler Marine Flathead 6 M47S Crown

    Mike
    Eagle River, Wisconsin

  3. #143
    Join Date
    Jun 2003
    Location
    Central Coast, Ca
    Posts
    21,594

    Default Re: Crown M47S Head Gasket....

    It generally considered safe to use a standard torque chart by bolt size and type. In automotive work it would be unusual to find a fastener with less strength than "grade 5". "Grade 8" is common for head bolts, main bearings, and reciprocating components.



  4. #144
    Join Date
    Jun 2017
    Location
    spicewood, texas, usa
    Posts
    276

    Default Re: Crown M47S Head Gasket....

    according to my 66-73 chiltons, the intake and exhaust are both 10 pds. this is for there 225 straight 6. i don't think it would be much diff for yours. i have built numerous engines by using only feel for the manifolds. they do not have to be super tight , just snug and then a good pull.

    jim

  5. #145
    Join Date
    Jul 2002
    Location
    Seattle, WA
    Posts
    8,966

    Default Re: Crown M47S Head Gasket....

    Please see my advice on the Torque value for Mainifold Flathead 6 M47S Crown Chrysler Marine Engine



    thread

  6. #146
    Join Date
    Jul 2000
    Location
    N.E. Connecticut.
    Posts
    6,131

    Default Re: Crown M47S Head Gasket....

    Madoc1’s post prompted me to check one of my period “Motors Manuals” for Head nut torque specs. It seems to agree with the 70 lbs/ft and not the 57 number.

  7. #147
    Join Date
    Jun 2003
    Location
    Central Coast, Ca
    Posts
    21,594

    Default Re: Crown M47S Head Gasket....

    (Note also the 1/2" studs...)

    IMG_4375.JPG

  8. #148
    Join Date
    Jul 2002
    Location
    Seattle, WA
    Posts
    8,966

    Default Re: Crown M47S Head Gasket....

    Ok, you guys, I have been watching this thread for some time. I made a comment when the original poster first surfaced, but it was disregarded. I will offer a suggestion again. I don't want to argue and will not. However, please note that this advice is informed by 35 years of boat restoration; most of that was on runabouts.

    I am baffled as to why the poster would start restoration work by working on the engine. Even more mysterious is his choice to work on the engine in the boat. Why? It takes a couple hours to remove a boat engine. Why not do it? Your back and knees will thank you.

    If I were doing this restoration this is how I would proceed. (And I have done a few of this model.)
    1. Remove engine. Store it in a corner of your shop. Until you have had a chance to think carefully about how to proceed with power.
    2. Remove cockpit sole and inspect very, very carefully the bottom of the boat.
    3. Centuries are notorious for having rotten bottoms. The reason for this is that they have batten seam bottom and the batten prevent water from limbering down. Water get hung up along each batten and this promotes rot. Also the transom on this boat is curved. The lower and upper transom frames are up of three pieces of white oak. Unfortunately, these were glued with plastic resin glue. There is a 100% failure rate with these laminations. At least I have never seen one which has not delaminated and rotted. Replacing the bottom is a huge job. I have not done this job in years but my guess is that it would be between 10 and 20k. Some come back with a so-called "Chris-Craft bottom." These are double planked with plywood on the inside and plank on the outside. This will eliminate the standing water/rot issue.
    4. Replace topside and deck planks as required.
    5. Fair, sand and varnish hull.
    6. Consider the engine. Crowns were good engines in their day. They were made from the mid 30s to the 60s. Thus, the engineering on these engines is going on a hundred years old! The engine was not running and you have no idea of its condition. Before proceeding it should be completely disassembled Magnafluxed to check for integrity by a knowledgeable machine shop. There is a very slight judging advantage for original engines in the ACBS judging criteria. However, most knowledgeable potential buyers are going to prefer a more modern engine. Yes, some vintage engines add value. A Crown does not. Also, if you stick with the Crown you will have to provide 12volt power if you want modern systems. (There is no penalty for using 12 volt systems.) You will be much, much happier with a reliable power plant. By the way, don't assume that automotive parts with work on marine engines. For example, marine engines have a different cooling path and the head gaskets are different.
    7. Join the ACBS and network with people that actually own these boats. You are not being well served with advice here.
    Again, I don't want to start an argument, but it is troubling to see you guys wandering in the wilderness with this project. Hope you can put some thought into further efforts. Thank you.




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