Wednesday, December 31, 2014

Measuring the Cylinder and parts value

I set the bore gauge to the cylinder reject size of 3.567 in.  The cylinder was unbelievable consistently 1.5 thou more than this.

As much as I would like to keep this engine I have no need for it and a plastic shroud, muffler, and dip stick will be way more then the $10 I have into it now.   The logical thing to do is to ebay the parts.

The question now is do I just part it out or have some fun making it run first.  Expectations is that parts are worth about the same either way.  It will be interesting to measure the difference between the virgin cylinder bore and the worn area.

There prices based on what similar parts sold for on ebay

  • 035 carb  $4.95 Economy Shipping
  • 025-$69.99 crank list for more $10.00 Standard Shipping
  • 012 stator
  • <20 head
  • 090 block $18.00 Economy Shipping
  • 025 piston and rod $5.95 Expedited Shipping
  • 075 flywheel  #698282 mod $12.95 Expedited Shipping
  • g50 oil pan $12.65 Expedited Shipping
  • 007 Push rods
  • 025 cam shaft and gov
  • 005 oil filler tube
  • 025 pulley $11 shipping
  • 010 head bolts $6 shipping
  • 010 other bolts $6 shipping
  • 020 carb linkage $6 shipping

They total to $348.

There may be parts I did not think of and ones that are in bad shape and cannot be sold.

Tuesday, December 30, 2014

Measuring the Cylinder

It is too cold so I brought the go-putz engine 28M707 and the 31P777 into the house.  Now that they have warmed up I am going to take another shot at measuring the cylinders.  In this post I will only be dealing with the 28M707.

Nominal bore is 3.440.  Used gauge block to verify and lock digital caliper at 3.440.  Setup bore dial indicator to zero at the caliper setting.  A real pain.  Then verified the virgin cylinder wall below the piston travel.   It may be faster to set the dial indicator on the virgin wall.  Not sure.

Checking the bottom of the bore verified the setting of zero as 3.44.  The wear along the axis of the crank travel is .012 over so we will need to bore this one to .020 over.

The bore below the piston is consistent as expected and will allow the hone to follow the center of the original bore.

Monday, December 29, 2014

Briggs 31P777-0237-G5

Bought a naked 31ci inch single cylinder BS engine today. 31P777-0237-G5.  I am seeing a lot of different HP figures for this engine so we will call it north of 15 and south of 20.   18 or 18.5 seems to be the the most common numbers.   Rumor has it that it has a cast iron bore.  18.5 is correct.

It is missing the starter and there is dirt in the filler tube which is missing the dip stick.  Need to figure out how to rinse the engine out.  I am not too worried with the pressure lube system. 

To the left is an image of a similar engine on ebay.

I should part it out but am tempted to get it running if possible.  One never knows why a 'found' engine is take out of service.

Starters from the old L-Head engines look like they might work.

The good news is that she is an oil burner and it has a cast iron sleeve!  It is too cold to inspect the bore.  The head gasket looked good.

Learned on the web that one can file the ends of of .010 rings and use them as .003 rings.  If it is out of round or tapered I will bore it out to .010 over and either get a rebuild kit or sell the block and bits on ebay.

Piston with rings is B&S 796173.  $87.52 with shipping from tewarehouse.

Service manual (missing images should be good one in repair books.
276781 Single Cylinder OHV .pdf