Subject: Re: con rods
Author: David J. Otis
Date: Sep 15, 2004, 3:18 PM
Post ID: 1717535421
Greg Bender wrote:
| Your free subscription is supported by today's sponsor: ------------------------------------------------------------------- Sponsor a child today through Children International. Give a desperately poor child hope for a brighter future. For only $18 a month you can make a difference! http://click.topica.com/caacBBFb1dfltb2uzY8a/ChildrenInternational ------------------------------------------------------------------- Hey Skip, Your (and other's) comments on how Guzzi increased the stroke got me thinking. I understand that by increasing the journal height on the cranksaft, that you will naturally increase stroke. |
| However, it doesn't make sense to me that repositioning the wrist pin on the piston would would effect stroke at all. Regardless of the wrist pin location, the piston would still travel the same distance within the cylinder. |
cylinder with a 700/750 crank and you put it on an 850 crank (using the
same rod) that caused the piston to go down furthur, but also go up
further, what would happen? The piston would not stop at the top of the
cylinder, but would continue up the extra distance caused by the extra
crank stroke. The wrist pin was relocated to keep the piston from going
up past the top of the cylinder.
| Perhaps the wrist pin was relocated to accomodate the greater connecting rod angle that was imposed by the increased journal height? (So that the connecting rod would not come into contact with the side of the piston) Also, V700 pistons had 4 rings (one below the wrist pin), Ambo pistons had 4 rings (all above the wrist pin), and Eldo pistons had 3 rings (all above the wrist pin). Perhaps the wrist pin relocation was simply an artifact of the piston redesign? |
| Another thought: My Chilton manual states that the V700 and Ambo had 9:1 compression ratios, while the Eldo had 9.2:1 compression ratio (I don't know how accurate these numbers are). Could the wrist pin relocation increase the compression ratio? However, I would tend to think that other changes would have a greater impact on compression than this. |
pistons and the 850's were more flat top the heads stayed basically the
same, this counts for the different compression ratio.
| Finally, I took a few minutes to look up part numbers for the various connection rods and associated parts. In sum, all part numbers are identical for the V700 and Ambo, but the Eldo part numbers are different for all parts except the big end half bearings. Unfortunately, my parts books do not provide part numbers for the connecting rod itself (separate from the other parts). These differences in part numbers lead me to believe that although the connecting rods are interchangeable between the various models (as reported by others on this forum), that Guzzi may have beefed up or modified the associated parts for the 850. That being said, I do not have any of the parts in front of me to provide direct comparisons. SMALL END BUSHING Model Part Number V700 9111 2124 Ambo 9111 2124 Eldo 9111 2122 NUT FOR THE BIG END BOLT Model Part Number V700 9275 0082 Ambo 9275 0082 Eldo 9273 1090 LOCK PLATE FOR THE BIG END BOLT Model Part Number V700 1206 2300 Ambo 1206 2300 Eldo Not listed separately and not pictured in parts book BIG END BOLT Model Part Number V700 1206 2200 Ambo 1206 2200 Eldo 1406 2201 HALF BEARING FOR BIG END Model Part Number V700 1206 2000/01/02/03/04 Ambo 1206 2000/01/02/03/04 Eldo 1206 2000/01/02/03/04 CONNECTING ROD COMPELTE WITH BUSHING, BOLT, NUTS AND LOCK PLATES Model Part Number V700 1206 1500 Ambo 1206 1500 Eldo 1406 1501 This turned out to me more long-winded than I originally planned... Regards, Greg Bender 1971 Ambassador 2000 Quota http://www.thisoldtractor.com/gtbender Skip & Jane wrote:
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