Engine Chamber Volume at Barrington Diesel Club

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Sept 8th 2011,
What is the 3-53 Chamber Volume?

Steve,

I'm Jeff. I'm working at the Naval Post Graduate School in Monterey, California. I'm trying to find out a rather arcane specification for a Detroit diesel 3-53, 5033-6299. Specifically I'm interested in the clearance volume between the piston and cylinder head when the piston is at TDC. I'm having a difficult time finding this and am hoping you may have this information. I appreciate any help that you can provide, Thank you for your time.

Hi Jeff

Re: 53 Chamber Volume

Thanks for writing. I love these questions. The theory is basically very simple, which once gotten can be applied to all engines. You need engine bore, stroke, and piston ratio for the calculation.

Our website shows:

   53 bore = 3.875 inches
   stroke   = 4.5 inches
   ratio     = 21:1 (for naturally aspirated N engines)

We apply that information as follows:

Cylinder Volume = area*stroke
   = pi*r²*4.5 cu inches
   = 3.1416*(3.875/2)*(3.875/2)*4.5
   = 3.1416*1.9375*1.9375*4.5
   = 53.0696 cu inches (hence the term 53 series engine)

Now, for me, when I use words like simple, easy, I often make a mistake, which I did. I gave Jeff the wrong formula and I had to write to him again to correct it, but I'm not going to give the wrong data again on purpose, so I've had to alter the correspondence here accordingly. Mea culpa.

My 'Auto Math Handbook' defines Chamber Volume as follows:

  Chamber Volume =          Cylinder Volume
                                       Compression ratio - 1.0

Now for the 53 N engines:    = 53.0696
                                                            20

                                                    = 2.65348

For the record here are some of the other relevant formulas used in the 'Auto Math Handbook', I list them to avoid terminology variances and therefore confusion:

Compression ratio =   Cylinder + Chamber Volume
                                       Chamber Volume

Cylinder volume = pi/4 * bore² * stroke

Kind Regards

Hi Steve,

Thank you so much for your help. I greatly appreciate your passion and meticulousness. Regarding the clearance volume of the 3-53, does the curved surface of the piston affect the overall volume, or is that taken into consideration with the compression ratio? Does the 3-53's piston even have a curved surface? I realize some pistons have a curved/warped surface to better mix the fuel when in motion.

Regards,

Jeff

Hi Jeff,

Re: Help acknowledgment.

You're welcome, thanks for the acknowledging comments it always makes a difference to receive such.

Re: 53 Piston Dome

I attach a photo of a 53 piston and liner, and another photo taken from the 'Auto Math Handbook' with examples of different domes on pistons.

Yes the domes are always taken into consideration when defining the chamber volume, and there are various methods to measure its volume and to make adjustments to the compression ratio.

Racing enthusiasts are forever playing with compression ratios to get more power or torque. The 'Auto Math Handbook' I've mentioned has a good simple introduction to the subject, that book has been a treasure to me over the years. Published by HPBooks a division of Price Stern, Inc. Los Angeles, California, author John Lawlor 1991/2.

Kind Regards