Setting up a Nelson 40
05-10-2004, 07:01 PM
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Setting up a Nelson 40
Hello,
Can someone please tell me the correct set-up for a 2003 Nelson 40 Q-500 motor. It is an AAC. I want to know how many shims do i need under the liner and head. I have been told to set it up at 192 and .010 on the head. I checked and that works out to .008" under the liner and .003 under the head. Does that sound right?
Jerry
Can someone please tell me the correct set-up for a 2003 Nelson 40 Q-500 motor. It is an AAC. I want to know how many shims do i need under the liner and head. I have been told to set it up at 192 and .010 on the head. I checked and that works out to .008" under the liner and .003 under the head. Does that sound right?
Jerry
05-10-2004, 07:30 PM
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RE: Setting up a Nelson 40
The liner shim sounds close but the head shim.003 sounds a bit thin.
Unfortunately it is not easy to say that a specific shim will always be correct. The engine has to be measured. When I used to get my engines direct from the factory they were set as follows. Deck height (Top of liner to top of piston at TDC)0.190. Head clearance 0.013.
The easiest way to set the dimensions is to measure the distance from the top of the liner to the top of the piston at BOTTOM DEAD CENTRE. From this dimension subtract 0.706. This will give you the deck height. shim the liner accordingly. Once the deck height is established the head clearance can be set.
I am fully aware that some changes are made to the above figures. That is an individual choice.
Ed S
Unfortunately it is not easy to say that a specific shim will always be correct. The engine has to be measured. When I used to get my engines direct from the factory they were set as follows. Deck height (Top of liner to top of piston at TDC)0.190. Head clearance 0.013.
The easiest way to set the dimensions is to measure the distance from the top of the liner to the top of the piston at BOTTOM DEAD CENTRE. From this dimension subtract 0.706. This will give you the deck height. shim the liner accordingly. Once the deck height is established the head clearance can be set.
I am fully aware that some changes are made to the above figures. That is an individual choice.
Ed S
05-10-2004, 09:13 PM
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RE: Setting up a Nelson 40
Make sure you check it before running, especially if new. I had a couple new ones last year, that were both set quite a bit off from what I have been running (Roughly .191 and .011).
www.darrolcady.com sells a nice little micrometer with ring that makes it very easy to check your sleeve and deck height.
www.darrolcady.com sells a nice little micrometer with ring that makes it very easy to check your sleeve and deck height.
05-11-2004, 03:52 PM
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RE: Setting up a Nelson 40
Hi Guys,
Thank you very much. I measured it 3 times using the stroke and it comes out to a .008" shim under the liner. Now the head measures .185 does thet sound right? If it is then I did the math and 192-185 comes to .007 plus the .003 shim comes out to .010 head spacing. I want to make sure I have this right.
Jerry
Thank you very much. I measured it 3 times using the stroke and it comes out to a .008" shim under the liner. Now the head measures .185 does thet sound right? If it is then I did the math and 192-185 comes to .007 plus the .003 shim comes out to .010 head spacing. I want to make sure I have this right.
Jerry
05-11-2004, 05:49 PM
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RE: Setting up a Nelson 40
Jerry:
You got it right. Generally the Q500 engines use about 10 thou total head clearance while the Q40 engines use 15 or so. Within that range you can move the sleeve up or down. In theory if you move it down it moves the torque and HP peak down a little while moving it up raises the torque and HP peak RPM.
Barry
You got it right. Generally the Q500 engines use about 10 thou total head clearance while the Q40 engines use 15 or so. Within that range you can move the sleeve up or down. In theory if you move it down it moves the torque and HP peak down a little while moving it up raises the torque and HP peak RPM.
Barry
