View Full Version : OS 91 SZ-H Hyper \ ViperHead \ Magnum fuel
Hello guys,
i just got a OS 91 SZ-H PS Hyper, and planning to run a ViperHead right from the start.
Since im using Magnum 30% fuel, anyone have a good start setting for the head shims ?
thanks.
DavidH
05-31-2006, 08:57 AM
.024
David
David, are you flying that yourself ?
WillJames
05-31-2006, 09:14 AM
I flew the C-SPEC PS and C-SPEC Cline on Magnum and ran 24 like David is saying. You may get by with a little less on the SZ, not sure. The power was VERY GOOD with 24 thou and detonation was not an issue. You will definitely need more shims with the Magnum than people are running with CP and PM.
Greg Alderman will be at MHA this weekend and he is testing the SZ/VH and Magnum, he will know after he is done. He was running 24 thou but since he just switched from the MP2 to the newest Hatori for the SZ (SB-19?) he went back to the stock 8 to test. What muffler are you running? That makes a difference, the MP2 will need a little more thousandths than the Hatori from what I am seeing and hearing at the events.
Altimat
06-01-2006, 12:18 AM
Why does Magnum fuel require more head clearance?
our engines run hotter on Magnum fuel, im not sure why exactly, but its a fact.
DavidH
06-01-2006, 08:58 AM
Why does Magnum fuel require more head clearance?
Because in the Magnum 30% there is something added to the fuel mix that changes(raises) the flash point. Magnum 30% has a different flash point than other 30% fuels. So the compression has to be lower with Magnun 30% than it does with other 30%. Only way to lower the compression is to add more shims under the head.
If the engine is running hotter on Magnum 30%. I would think that the compression is to much . I would suggest adding some more shimming. Magnum has plenty of oil.
David