Posted by Bob Grimstead on Saturday, December 12, 2009 @ 12:38 PM:
Hi Guys,
This is a quick topic which came up for us recently.
Matthew had just had his motor re-built with a new AS41 crankcase (Brazilian, I think) and got all the original serviceable components put into that.
When we went to start it, the oil pressure rocketed to the top of its gauge and then the needle bounced around all over the place.
Bobby Warren got us a 200 psi gauge, and the same thing happened. The gauge was wrecked, with stripped teeth on its cogs.
It turns out that later AS41 crankcases should have two of the original plain pressure relief pistons in the pressure relief and pressure modulating chambers, and not the one with the shoulder. I'm not sure why, it's just the way it is. John Maher of John Maher Racing put us right.
Once we did that, the engine runs fine, although now we've got to change the magneto oil seal, which was blown during this over-pressure.
Yours, Bob
[Edit by Bob Grimstead on Monday, December 14, 2009 @ 12:16 PM]
Posted by Bob Grimstead on Monday, December 14, 2009 @ 12:15 PM:
Hi Guys,
In other words, don't use this pressure regulating valve on the latest crakcases.
I don't know why, I'm just passing on the information.
Yours, Bob
[Edit by Bob Grimstead on Monday, December 14, 2009 @ 12:16 PM]
