does anyone know the compression ranges?

Forum for Infiniti M37, M56 M35h Hybrid and Q70 owners.
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reggiebrown40
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2011 Infiniti M56x - Dead

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Need to know the acceptable cylinder compression (psi) ranges for an M56. Thanks in advance.


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VStar650CL
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For an '11 it's 242 psi standard, 206 minimum, 14 maximum difference between high and low (measurements at 200 cranking RPM). You can find compression specs for any particular model on the first page of "Service Data and Specifications" at the bottom of the "Engine Mechanical" section of the FSM. For the '11 VK56 M it's EM-300 here:
https://www.nicoclub.com/service-manual ... 1%2FEM.pdf

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reggiebrown40
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VStar650CL wrote:
Sun Oct 02, 2022 5:43 am
For an '11 it's 242 psi standard, 206 minimum, 14 maximum difference between high and low (measurements at 200 cranking RPM). You can find compression specs for any particular model on the first page of "Service Data and Specifications" at the bottom of the "Engine Mechanical" section of the FSM. For the '11 VK56 M it's EM-300 here:
https://www.nicoclub.com/service-manual ... 1%2FEM.pdf
Thanks!

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reggiebrown40
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Can you run a compression test with no manifold? What about a crack in the block? What would the result be? Building a case against a repair shop.

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VStar650CL
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reggiebrown40 wrote:
Fri Nov 11, 2022 12:34 pm
Can you run a compression test with no manifold?
Yes.
reggiebrown40 wrote:
Fri Nov 11, 2022 12:34 pm
What about a crack in the block? What would the result be?
Depending where the crack is, it may or may not effect compression. Most cracks which affect compression are in a cylinder head and not the block.

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reggiebrown40
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2011 Infiniti M56x - Dead

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VStar650CL wrote:
Fri Nov 11, 2022 1:05 pm
reggiebrown40 wrote:
Fri Nov 11, 2022 12:34 pm
Can you run a compression test with no manifold?
Yes.
reggiebrown40 wrote:
Fri Nov 11, 2022 12:34 pm
What about a crack in the block? What would the result be?
Depending where the crack is, it may or may not effect compression. Most cracks which affect compression are in a cylinder head and not the block.
Image

Like this? Hard to see from the screen shot, but this is the left side of the engine block before spark plug #1.
Attachments
crack.jpg

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VStar650CL
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I don't know Infiniti like I know Nissan, but that looks to be the rear timing cover and not the block.

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reggiebrown40
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Thanks. Appreciate the help.


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