Fast Eddie
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- Joined
- Oct 4, 2013
- Messages
- 21,594
That’s not a breather you’re looking at on the rear of the timing case, that’s the oil return from the cylinder head. This has to be done on a Stage 3 Maney head cos he breaks into the stock oil return hole when he opens the inlets ports, so it has to be welded up. So, that’s also one potential head gasket oil leak cause removed!
It says ‘breather fitting’ in pen as that was simply my instructions to my machinist who had to drill and tap the hole for the fitting.
Engine breathing WAS gonna be taken care of by a cNw reed valve bolted to the back of the crank case ‘Combat style’ but this gave clearance issue between engine and box, so I’m using the Comnoz sump type that I used very successfully on the 850 motor.
My VERY limited understanding about this reed valve topic is thus:
No, you definitely do no want to keep the original breather position as well as one of the aforementioned, that would screw up the functionality.
The theory is to get the reed valve as close as possible to the source of the pressure, to avoid any ‘air cushion’ or delay in the pressure pulses acting on the reed valve. The theory behind blocking the timing cover etc is similar, the idea is to prevent an plenum chamber acting as a ‘cushion’. At revs the breathing happens as very short / sharp pulses, it’s not really ‘breathing’ as we might envisage. So, blocking the timing cover, siting the reed valve as close as possible to the crank case chamber, all helps to keep these ‘pulses’ clear and sharp.
As I said, that’s my very limited ‘lay persons’ understanding.
But what I do know with practical certainty, is that they work exceedingly well !
It says ‘breather fitting’ in pen as that was simply my instructions to my machinist who had to drill and tap the hole for the fitting.
Engine breathing WAS gonna be taken care of by a cNw reed valve bolted to the back of the crank case ‘Combat style’ but this gave clearance issue between engine and box, so I’m using the Comnoz sump type that I used very successfully on the 850 motor.
My VERY limited understanding about this reed valve topic is thus:
No, you definitely do no want to keep the original breather position as well as one of the aforementioned, that would screw up the functionality.
The theory is to get the reed valve as close as possible to the source of the pressure, to avoid any ‘air cushion’ or delay in the pressure pulses acting on the reed valve. The theory behind blocking the timing cover etc is similar, the idea is to prevent an plenum chamber acting as a ‘cushion’. At revs the breathing happens as very short / sharp pulses, it’s not really ‘breathing’ as we might envisage. So, blocking the timing cover, siting the reed valve as close as possible to the crank case chamber, all helps to keep these ‘pulses’ clear and sharp.
As I said, that’s my very limited ‘lay persons’ understanding.
But what I do know with practical certainty, is that they work exceedingly well !
