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shannon sheets
Samba Member
Joined: March 14, 2006
Posts: 2
Location: royal,ar
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 Posted: Tue Mar 14, 2006 3:09 pm Post subject: roller cranks and roller rods |
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| Is there such a thing?If so will you please tell me about them?Advantages and disadvantages. |
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DaveM
Mad Samba Scientist
Joined: June 11, 2002
Posts: 3010
Location: Dry side of Oregon
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| Posted: Tue Mar 14, 2006 3:39 pm Post subject: |
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SPG made roller cranks and were available in the mid 60's through the 70's (my guess here). Not sure if they are still available for a VW. They got a bad rap due to their intolerance to hard starts. Their design is/was intended for smooth high rpm motors (think motor cycle motors that rev to 11k rpm). Early rollers were prone to twisting but later on, people started to pin and weld them. I've got a number of them and plan to use them in a 40 hp, 1500 and 2liter vintage motors.
You can read about them more on my web site by looking at some of the empi catalog listings I have:
http://www.amayesing.com/oldvwlit.htm
I've talked to several off road racers that love roller cranks, claiming they've run hours on a motor with no oil pressure.
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Sounding like a broken record as to why You should be measuring protein during harvest in order to better your agronomic practices. |
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Bugman Jeff
Samba Member
Joined: May 20, 2004
Posts: 636
Location: Evansville, WI
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| Posted: Tue Mar 14, 2006 4:05 pm Post subject: |
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| DaveM wrote: |
I've talked to several off road racers that love roller cranks, claiming they've run hours on a motor with no oil pressure. |
I'd believe it. Because it's a roller bearing, it doesnt need to be pressure oiled. Splash oiling will work ok for while, and if running offroad, i'd bet theres lots of oil splashing around in the crank case.
The only real downside is that they are very labor intensive to rebuild because the crank needs to be pressed apart to get the rods off.
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Restorer of Porsche Speedster 80486  |
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DaveM
Mad Samba Scientist
Joined: June 11, 2002
Posts: 3010
Location: Dry side of Oregon
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| Posted: Tue Mar 14, 2006 4:15 pm Post subject: |
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| Bugman Jeff wrote: |
| <snip>The only real downside is that they are very labor intensive to rebuild because the crank needs to be pressed apart to get the rods off. |
This is true. The only *good* roller is one that is NOS or near perfect. Those that you find for sale claiming needs work are not worth the effort.
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Sounding like a broken record as to why You should be measuring protein during harvest in order to better your agronomic practices. |
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vwpride58
Samba Member
Joined: November 29, 2004
Posts: 148
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| Posted: Tue Mar 14, 2006 4:39 pm Post subject: |
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| There is a reason that they are not made anymore. Cant run too high compression with them and rpms are limited do to them being pressed together. Although based on what DaveM has said welding them would fix the down sides, but I would stay with the tried and true. |
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