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bbc crank mounted pump?

With the GM crankshaft pulley with the raised dowel sections......, the Johnson F6B-9 or Sherwood P-105 are large volume candidates for you.
 
I posted these images earlier in another thread. Maybe they will help you.

Look at your main crankshaft pulley....... there should be two raised areas that serve as pump alignment dowels.
The balancer offers three bolt holes for pulley attachment.
The pump can mount in any of the three orienations, however, only one orientation aligns the pump with the dowels.
 

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Retiredroadracer said:
marine power shows a bracket. Is this nescessary, or will it work just as well without it?
Click to expand...
The bracket is a anti-torque arm, or anti-rotational arm, intended to prevent the pump body from turning against impeller resistance.... or worst case, bearing seizure.
As someone posting on this forum, and installing these for customers, I have to suggest using the arm.

As per real world experience, I'd say that the arm is not completely necessary.
The impeller resistance is not all that great.
If an impeller or seized bearing was to generate enough force to spin the pump body, I think that we'd have more serious issues.

I've been running these pumps on twin engines without the arms for years. My supply hose arrangement is such that the hose provides the anti-torque...... and I've had no issues to date.
I do have the arms, and will likely install them some day.

If asking whether or not to install it..... I'd say yes! Cheap insurance! :D


Edit:

The other beauty of the crankshaft pump, is the ease of impeller maintenance.
Four screws with the Johnson, and you're right there with impeller access.

Also, this pump allows us to easily remove the impeller for winter lay up. You'd be surprised at how much this will extend the life of an impeller when it's been removed for the lay up duration.


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Last edited:
Ricardo,
Back in 2013 you added to an article on crank mounted raw water pumps.
I have a 1996 Crusader 454 XL and std raw water pump is a nightmare to access to change impeller.
I want to change to crank mounted pump
I have ordered Johnson F6B-9 pump but am not sure that the pulley on the crank has those raised dowels that you say to use to align the pump.
Do you know the part number for the pulley that has the raised dowels? I would like to order just in case I have a different pulley.
FYI- Previous owner installed a new long block prior to my buying boat (1996 Pursuit 2600 center console). I have just about replaced all the 'accessories' that were attached to long block, alternator, risers, starter motor etc but want to replace the raw water pump

Regards,
Summitradon
 
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