Plumbing help needed for LS Motor install

  • 6 Replies
  • 566 Views

1BGBDWF

  • Join Date: Jun 2018
  • Location: Temecula
  • *
  • Newbie
  • *
  • Posts: 8
  • Karma: +0/-0
  • Registered User
    • View Profile
  • Liked:
  • Likes Given: 0
« on: April 29, 2019, 12:20:44 PM »
I'm in the process of converting a 1977 Howard 18ft from a BBC to a 6.0 LS motor with a berkley jet. I will be using PCM exhaust manifolds and risers and going thru the transom. I am a little confussed on running the water (plumbing) lines. Does anyone have a diagram, pictures or name of anyone that could help sort it out?
  • Boat #1: 86 19' Advantage
  • Boat #2: MB B52 Team edition


TrollerDave

  • Join Date: Feb 2008
  • Location: Chino,CA
  • *
  • Hero Member
  • *****
  • Posts: 1,071
  • Karma: +29/-0
    • View Profile
  • Liked:
  • Likes Given: 37
« Reply #1 on: April 29, 2019, 09:56:22 PM »
I canít figure out how to link a thread in this app, but if you search the thread 1970 Weiman by steves86ta, he has a lot of info of putting a LS in a jet boat. Maybe send him a pm and pick his brain. Once he got it dialed in, I think he was pretty happy with it.


Sent from my iPhone using SoCal Jet Boats

TrollerDave

  • Join Date: Feb 2008
  • Location: Chino,CA
  • *
  • Hero Member
  • *****
  • Posts: 1,071
  • Karma: +29/-0
    • View Profile
  • Liked:
  • Likes Given: 37
« Reply #2 on: April 29, 2019, 10:01:14 PM »
The 1970 Weiman thread is in the project section.


Sent from my iPhone using SoCal Jet Boats

Flusher

  • Join Date: Sep 2011
  • Location: Colton, CA
  • *
  • Macho Member
  • ******
  • Posts: 2,077
  • Karma: +74/-0
  • The Machinist
    • View Profile
  • Liked:
  • Likes Given: 26
« Reply #3 on: May 02, 2019, 05:54:53 AM »
Steve had headers, which I believe are currently up for sale.  Headers vs. wet manifolds makes plumbing different.

Do you already have the PCM manifolds and risers?


STEAM LINES

The steam lines need their own separate line directly overboard to minimize backpressure.  This is to prevent steam pockets from forming in the block and heads.  If you tee the steam lines into another line, flow could stall, forming localized hot spots.  The engine will be installed angling up towards the front, I would connect the steam lines to the line overboard at the front of the engine, to take advantage of gravity bleeding air out of the system.


BLOCK HOLES

The front engine plates of the LS rail kits we make are tapped with pipe thread for water in and out of the block.  There are several options for connecting your cooling lines to the block.  Whichever method you choose, the routing will be the same.  The lower rectangular shaped holes, on the timing cover surface of the block, are water in to the engine.  The upper round holes are water out of the engine.


PLUMBING THE SYSTEM

There are two ways to plumb your manifolds - 1) Pre-heating the water to build temperature in the engine.  2) Conventional Engine => Exhaust => Overboard.

1) Plumbing for Pre-heating

First, you will need to block flow from the manifolds to the risers.  I understand that that there are plates available for just such an application.  If the flow between the manifold and riser is allowed to short circuit, water will bypass the engine entirely.

I could not find pictures of PCM LS manifolds, so I am not sure about the configuration of the connections on them.  Regardless, you will want to connect the lines in such a manner that flow is either back-to-front or top-to-bottom, to help facilitate bleeding air from the system.  Tee or wye the line from the jet pump into into the manifolds.  A hose size of 1/2" inside diameter or -8 should be more than adequate.

Connect lines from the out port of each manifold to the corresponding side of the block, into the lower rectangular shaped holes at the front of the block.

Connect lines from the upper round holes on the front of the engine to the risers.  I think 1/2" (-8) is adequate, but you could use 5/8" (-10) to reduce restriction.

2) Conventional Plumbing

In the conventional strategy, the water enters the engine first.  Tee or wye the line coming from the jet pump and connect to the lower rectangular shaped holes at the front of the engine block with 1/2" (-8) hose.

Make a connection between the upper round holes at the front of the block to the inlet ports on the manifolds with 1/2" (-8) hose.

Depending on the design of your manifolds and risers, flow could either be internal or via an external connection between the manifold and riser.  Make whatever connections are necessary.
"I want to roll with my brother Joe" - Joe Bateman - January 29, 1950 ~ November 27, 2013

TrollerDave

  • Join Date: Feb 2008
  • Location: Chino,CA
  • *
  • Hero Member
  • *****
  • Posts: 1,071
  • Karma: +29/-0
    • View Profile
  • Liked:
  • Likes Given: 37
« Reply #4 on: May 02, 2019, 02:50:27 PM »
I figured it would at least get him some info and on track. I remember Steve dealing with this steam lines.
You are a wealth of knowledge Joe.
Thank you for sharing it.
Do you know of a lot of LS conversions going into jet boats? How have they been holding up?


Sent from my iPhone using SoCal Jet Boats

1BGBDWF

  • Join Date: Jun 2018
  • Location: Temecula
  • *
  • Newbie
  • *
  • Posts: 8
  • Karma: +0/-0
  • Registered User
    • View Profile
  • Liked:
  • Likes Given: 0
« Reply #5 on: May 28, 2019, 09:18:19 PM »
Thanks, the replies have been very helpful.
  • Boat #1: 86 19' Advantage
  • Boat #2: MB B52 Team edition

steves86ta

  • Join Date: Mar 2013
  • Location: Beaumont
  • *
  • Macho Member
  • ******
  • Posts: 2,372
  • Karma: +40/-0
  • Registered User
    • View Profile
  • Liked:
  • Likes Given: 27
« Reply #6 on: June 07, 2019, 09:18:38 AM »
joe nailed it on the head...

I ran my cooling lines into the bottom of the water pump holes, then out the top holes and overboard.

I eventually got rid of my steam lines and never noticed a problem. My theory is that the water is moving so fast in/out of the block they dont matter.

I did run dry headers so I am of no help there
1980 Bahner 21' Mini Day
1968 Rogers project

 


Website Security Test
Powered by EzPortal

anything
Website Security Test