Logo
Click for Chrysler parts and manuals!
Results 1 to 15 of 15
  1. #1

    Default 318 engine plumbing

    New to the forum and very new boat owner. Way over my head already! I bought a 1980 Trojan 32 as a project. The engines were no good so I pulled them and bought short blocks. I have them all re-assembled and ready to go back in the boat, except I can't seem to find a diagram showing how all the water (cooling) hoses go back on. Its a raw water system and I have replaced the strainers and sea cocks. Any and all advice would be greatly appreciated.

  2. #2
    Join Date
    Mar 2009
    Location
    Portland, Oregon,
    Posts
    11,394

    Default Re: 318 engine plumbing

    Which style Chrysler exhaust manifolds you will be using?
    A few good photos would be helpful.
    Rick ... aka Ricardo..... AQ series Volvo Penta repair
    Portland, Oregon
    28' SDN F/B w/ twin Volvo Penta 5.7L DP drives

    "Intellectual growth should commence at birth and cease only at death." Albert Einstein

    Please... no PMs! Post your questions on the forum.

  3. #3
    Join Date
    May 2010
    Location
    DC Burbs/Maryland Eastern Shore
    Posts
    1,647

    Default Re: 318 engine plumbing

    Generally speaking the flow of seawater is from bottom to top. Up and out.
    Raw water cooled system:
    Seawater to raw water pump. Raw water pump to thermostat housing intake. Thermostat housing to circulating pump (usually a large u shaped hose) circulating pump directly to block. Swish swish swish around inside engine. Back to thermostat housing. Thermostat housing to exhaust manifolds. Over the side.
    Fresh water (closed) cooling system:
    Seawater to heat exchanger raw water IN. Seawater from heat exchanger OUT to Exhaust Manifolds and over the side.
    Coolant in heat exchanger to Circulating pump (big hose on bottom). Circulating pump directly to engine block. Swish swish swish around inside block to Thermostat housing. Thermostat housing to heat exchanger coolant IN (big hose).
    If there are coolers for oil, transmission fluid, fuel, etc. These go in the raw water circuit regardless of whether the system is closed or raw water. Generally they come before the raw water goes to the thermostat housing (raw) or heat exchanger (closed).
    Dig around on line you'll probably find the diagram you seek.
    Practicing the ancient art of ren-ching

  4. #4
    Join Date
    Mar 2009
    Location
    Portland, Oregon,
    Posts
    11,394

    Default Re: 318 engine plumbing

    IMO, Chrysler Marine designed their R W cooling system quite differently from the others (back then) and from what you will see today.

    Just a suggestion....... you may want to update the way in which the seawater path is plumbed.

    For one thing..... I would rid myself of any belt driven seawater pump.
    Some of the Chrysler guys here have gone with the Johnson crankshaft pump. An adapter is required, and you can find what the guys did in this forum section.

    Secondly.... even while the array of T-stat housings look different, most will direct the seawater in a similar fashion.

    As obatsea says above..... "Seawater to raw water pump. Raw water pump to thermostat housing intake. Thermostat housing to circulating pump (usually a large u shaped hose) circulating pump directly to block. Swish swish swish around inside engine. Back to thermostat housing. Thermostat housing to exhaust manifolds. Over the side."

    What some may not understand, is the bi-pass side of the system.
    While the full supply of seawater is going to the T-stat housing, only a portion of it goes through the engine on as "As Needed/As Required" basis. The actual thermostat dictates engine seawater demands.
    Depending on engine demands (heat dissipation to seawater), most seawater is going on to the exhaust system.

    Again..... just a suggestion:

    Click image for larger version. 

Name:	Chrysler Raw Water cooling system suggestion.jpg 
Views:	47 
Size:	24.0 KB 
ID:	20369
    Rick ... aka Ricardo..... AQ series Volvo Penta repair
    Portland, Oregon
    28' SDN F/B w/ twin Volvo Penta 5.7L DP drives

    "Intellectual growth should commence at birth and cease only at death." Albert Einstein

    Please... no PMs! Post your questions on the forum.

  5. #5

    Default Re: 318 engine plumbing

    Quote Originally Posted by RicardoMarine View Post
    For one thing..... I would rid myself of any belt driven seawater pump.
    Some of the Chrysler guys here have gone with the Johnson crankshaft pump. An adapter is required, and you can find what the guys did in this forum section.
    If crankshaft is so good, why doesn't Mercruiser build them that way?

  6. #6
    Join Date
    Mar 2009
    Location
    Portland, Oregon,
    Posts
    11,394

    Default Re: 318 engine plumbing

    Quote Originally Posted by TPGG View Post
    If crankshaft is so good, why doesn't Mercruiser build them that way?
    The F5B-9 and F6B-9 sell for under $200, and they last a long long time.
    The Merc OEM pump is proprietary, and sells for hundreds more..... some are near $700 each.

    Merc is one of the few who is not yet on board with the crankshaft style seawater pump!

    Crankshaft pump:
    ..... no side bearing load from belt tension.
    ..... no belt tension to concern ourselves with.
    ..... easy impeller access for winter removal during lay-up.
    ..... uses impeller cam in lieu of eccentrically positioned impeller.
    Rick ... aka Ricardo..... AQ series Volvo Penta repair
    Portland, Oregon
    28' SDN F/B w/ twin Volvo Penta 5.7L DP drives

    "Intellectual growth should commence at birth and cease only at death." Albert Einstein

    Please... no PMs! Post your questions on the forum.

  7. #7
    Join Date
    Mar 2009
    Location
    Portland, Oregon,
    Posts
    11,394

    Default Re: 318 engine plumbing

    The F5B-9 and F6B-9 are also reverse rotation capable, by simply reversing the inlet and outlet hoses.
    These pumps can also be orientated to have the inlet/outlet ports on the Stbd or Port side.
    Rick ... aka Ricardo..... AQ series Volvo Penta repair
    Portland, Oregon
    28' SDN F/B w/ twin Volvo Penta 5.7L DP drives

    "Intellectual growth should commence at birth and cease only at death." Albert Einstein

    Please... no PMs! Post your questions on the forum.

  8. #8
    Join Date
    Jun 2008
    Location
    Island Heights, NJ,
    Posts
    3,144

    Default Re: 318 engine plumbing

    Quote Originally Posted by TPGG View Post
    If crankshaft is so good, why doesn't Mercruiser build them that way?
    From time to time, I've thought ( cynically??) that Mercury works as follows....1) Get through warranty without failures, then 2) keep the "Certified Mechanics" gainfully employed and the OEM parts division busy.
    Capt Bob
    1969 23ft ChrisCraft Lancer
    Merc 5.7L 260HP/ Volvo 280

  9. #9
    Join Date
    Mar 2009
    Location
    Portland, Oregon,
    Posts
    11,394

    Default Re: 318 engine plumbing

    Very true, Bob!
    Rick ... aka Ricardo..... AQ series Volvo Penta repair
    Portland, Oregon
    28' SDN F/B w/ twin Volvo Penta 5.7L DP drives

    "Intellectual growth should commence at birth and cease only at death." Albert Einstein

    Please... no PMs! Post your questions on the forum.

  10. #10
    Join Date
    Dec 2014
    Location
    Ontario Canada
    Posts
    84

    Default Re: 318 engine plumbing

    Our 1972 318 is plumbed this way. Hopefully the repower goes well.
    Click image for larger version. 

Name:	Closed loop system.jpg 
Views:	25 
Size:	27.1 KB 
ID:	20794
    If your system does not have a heat exchanger it may be plumbed this way.
    Click image for larger version. 

Name:	Open cooling loop.jpg 
Views:	21 
Size:	22.3 KB 
ID:	20795
    Last edited by Toonl; 06-23-2019 at 10:12 PM.

  11. #11
    Join Date
    Mar 2007
    Location
    West Hartford, CT,
    Posts
    72

    Default Re: 318 engine plumbing

    When you plumb up the manifolds, make sure that they fill with water starting at the lowest point, and that water exits at the highest point. This ensures that your manifold will be filled fully with water and without any air pockets. Air pockets will cause extreme "hot spots" on the manifold, and bad things will happen.

    When you finally fire up the rig and take her for a run, check the temperature of manifolds. They should be "hot to touch", but not "hot to burn" (as in-the skin on your hand). Paint may discolor, but should not burn.

    If you smell or see slight smoking, investigate. Feel parts of manifolds, risers, hoses. There may be a section at riser joints that do not see water and get hot hot, but everywhere else should be "hot to touch".

    Good luck. ,Noel.

  12. #12
    Join Date
    Jun 2008
    Location
    Island Heights, NJ,
    Posts
    3,144

    Default Re: 318 engine plumbing

    Some mopar manifolds have an internal tube that routs the water from the front of the manifold to the back.
    Capt Bob
    1969 23ft ChrisCraft Lancer
    Merc 5.7L 260HP/ Volvo 280

  13. #13
    Join Date
    Mar 2009
    Location
    Portland, Oregon,
    Posts
    11,394

    Default Re: 318 engine plumbing

    The OP has posted once only, and that was on 5-20.
    I think that we've lost him!
    Rick ... aka Ricardo..... AQ series Volvo Penta repair
    Portland, Oregon
    28' SDN F/B w/ twin Volvo Penta 5.7L DP drives

    "Intellectual growth should commence at birth and cease only at death." Albert Einstein

    Please... no PMs! Post your questions on the forum.

  14. #14

    Default Re: 318 engine plumbing

    Actually it was 5-19

  15. #15
    Join Date
    Mar 2009
    Location
    Portland, Oregon,
    Posts
    11,394

    Default Re: 318 engine plumbing

    Quote Originally Posted by mcomm View Post
    Actually it was 5-19
    Strange......... I'm seeing 05-20-2019, 02:00 AM.

    None-the-less, I think that he must have gotten his answers elsewhere or he had someone do the work for him.
    Rick ... aka Ricardo..... AQ series Volvo Penta repair
    Portland, Oregon
    28' SDN F/B w/ twin Volvo Penta 5.7L DP drives

    "Intellectual growth should commence at birth and cease only at death." Albert Einstein

    Please... no PMs! Post your questions on the forum.

Similar Threads

  1. Plumbing Help Please!
    By ScottP797 in forum OMC Sterndrive and Inboard Forum
    Replies: 5
    Last Post: 03-16-2016, 09:16 AM
  2. Plumbing a header tank to engine, for a water heater
    By slickmick9514 in forum Boat Plumbing Systems
    Replies: 2
    Last Post: 08-15-2013, 04:04 AM
  3. lm 318 plumbing issues...
    By politicallycorrectcraft in forum Chrysler Inboard and Sterndrive Forum
    Replies: 14
    Last Post: 03-10-2012, 06:35 PM
  4. 318 plumbing
    By skip saunders in forum Chrysler Inboard and Sterndrive Forum
    Replies: 1
    Last Post: 05-10-2010, 03:20 PM
  5. manifold plumbing
    By yellowsubmarine in forum Volvo Penta Gas Engine Forum
    Replies: 14
    Last Post: 05-09-2010, 08:41 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •