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Thread: 45 ci omc boost port question

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    Default 45 ci omc boost port question

    The sleeve opening for the boost port is lower than the openings for the transfers. Is ther a reason for this? Can it be machined to match the height of the transfers which will make it match the block also. Thx. Jeff
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    Quote Originally Posted by AirRacer View Post
    The sleeve opening for the boost port is lower than the openings for the transfers. Is ther a reason for this? Can it be machined to match the height of the transfers which will make it match the block also. Thx. Jeff
    how do the ports in the piston line up?
    There is a simple mod and thats to make a late 45 piston cut look like the old 60hp one

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    Yes. I would recommend raising the boost port so it opens at the same time as the transfers or even a little sooner. Years ago one of the tricks to making a FA Konig go was to raise the boost port about .060" higher than the transfers. With the sleeves out, this is a real easy fix with a rotary file or even a regular hand file.

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    what about angle ?

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    Quote Originally Posted by Mike Schmidt View Post
    Yes. I would recommend raising the boost port so it opens at the same time as the transfers or even a little sooner. Years ago one of the tricks to making a FA Konig go was to raise the boost port about .060" higher than the transfers. With the sleeves out, this is a real easy fix with a rotary file or even a regular hand file.
    are you taking of ports above the piston or below?

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    Quote Originally Posted by quty06 View Post
    what about angle ?
    good question, thats very important.
    lots of dyno time and egt monitoring required there
    typically you lower the angle to shift the powerband up

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    I totally misunderstood the question. I would defiantly cut the sleeve back so all three of the transfer ducts are the same length. There is a design flaw in the 45 motors.
    Look through the 4 main transfer ducts. one is about 1/2 the size of the other 3. If the motor does not have to go through a tech inspection, that is where I would be working. You need a set of 6" long rotary files. You have to start with a 1/4" ball, then 5/16', then 3/8". Panful to do but well worth the results.

    Leave the angle of the boost port alone, just raise it .060" higher than the main transfers.

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    Thx for the interest guys. So my original question was about the area circled. Can i machine that area to match the entance area of the transfers? Is there a reason its shorter? This will be a drag engine so i cant kill the bottom end.
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    Im pretty sure that is what mike meant by making them all the same length.

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    Quote Originally Posted by AirRacer View Post
    Thx for the interest guys. So my original question was about the area circled. Can i machine that area to match the entance area of the transfers? Is there a reason its shorter? This will be a drag engine so i cant kill the bottom end.
    You need to check what the piston uncovers.
    So you need to crank in a block with piston and rod

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