Cummins Piston-to-Bore Clearance

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Looking for information on the Piston-to-Bore clearance of the 5.9L
Cummins.  This is information that should be in the shop manual (if I
had access to one).  Need to know the clearance spec. and if there is
more than one piston grade.  Thx.

If available I'd also like to know the bore and piston diameter
tolerances.


Re: Cummins Piston-to-Bore Clearance


From my '99 factory service manual...
Cylinder Bore Diamater (Max)..........102.116mm (4.0203 in.)
Cylinder Bore our of round (Max) .....0.038mm (0.0015 in.)

Piston Skirt Diameter .........................101.864-101.896mm
(4.0104-4.0117 in.)

Sorry, I couldn't find anything on Piston-to-Bore clearance.

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Re: Cummins Piston-to-Bore Clearance



Ed H. wrote:
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Thanks for info !


Re: Cummins Piston-to-Bore Clearance


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That's because they hid it  :)  (bore diameter-piston diameter/2=p-to-b
clearance)



Re: Cummins Piston-to-Bore Clearance



Tom Lawrence wrote:
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You could calculate the piston-to-bore clearance if the service manual
has the bore size with tolerance (instead of the Max Dia.).  Using the
numbers above give an answer that I know isn't correct (.252mm max
p-to-b).

As comparison, the current 6.4L ITEC Powerstroke runs 0.0441-0.0909mm
piston-to-bore clearance.


Re: Cummins Piston-to-Bore Clearance


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You forgot to divide by two.  That would then be 0.126mm max clearance.



Re: Cummins Piston-to-Bore Clearance



Tom Lawrence wrote:
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Typically, p-to-b clearance is described as the diametric clearance.
For clarification, the Powerstroke clearance specs that I mentioned
above are the diametric clearance.


Re: Cummins Piston-to-Bore Clearance


I thing you are forgetting a few .00


Re: Cummins Piston-to-Bore Clearance



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The nominal bore/stroke dimensions for the 5.9L are 102mm X 120mm (4.01574"
X 4.7244").

Subtracting the piston diameter(s) from the nominal bore size gives a piston
clearance tolerance of  .104mm-.136mm



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