13b OMP valves difference??

[karl_tate]

well i was in need of some new ones and have bought some genuine mazda ones but the holes are different sizes.
 
just wondering why, should they be bigger like my old one\'s??
 

 
thanks
 
karl

[karl_tate]

bump :Thumbs-up

[andrewrx7]

The one on the right is an updated design introduced when Mazda updated the FD around the 1999 mark. Can\'t remember the exact details, but something to do with a slight reduction in the quantity of oil fed into the engine on the later FD\'s, and also a more precise feed to - the smaller hole helps with those changes.

[karl_tate]

thanks alot for that,

surely the more oil you are getting the better though??

its also alot harder to blow through the new one.

[m1tch]

I suppose its an Oil Metering Pump, rather than an Oil Pump, im guessing the updated design allowed more control?

[andrewrx7]

Here you go, from a  technical article published back in 1999:

Apex seal lubrication has become a critical issue. In a race engine, oil supply to the rotor housing by means of injection was precisely monitored and controlled, whereas in the production unit, a larger amount is supplied, just to be on the safe side. Some of the lubricant is fed into the trochoid chamber through a metering nozzle. The previous nozzle\'s oil passage was 2.0 mm (0.08 in.) in diameter. Negative pressure created in the rotor chamber would cause all the oil within the nozzle to be sucked out. When the engine accelerated rapidly, oil supply could not keep up with the speed. To prevent oil starvation, the previous system supplied a larger amount of oil to be on the safe side. In the new metering nozzle, the passage diameter has been reduced to 0.08 mm (0.003 in.), halving its volume of 0.0005 L (0.03 cu. in.). A new rubber seal is also inserted to fill a gap within the nozzle body where oil used to be sidetracked. Now, there is still some oil left within the nozzle after each suction, so that the lubrication system responds to the apex seal\'s requirement.

[karl_tate]

thanks alot for that bit of info


when it says a new rubber seal is inserted, is that inserted over the valve or inside where the valve screws in. wasnt very well explained unless im being stupid :Giggle

so it looks like i need this new seal as well.

[andrewrx7]

I think when it refers to the rubber seal, it appears to be in the context of within the actual valve itself : "to fill a gap within the nozzle body". I changed mine 2 months ago, and there is no rubber washer that you use outside of the valve. Brass washer,yes, but not rubber.

[karl_tate]

ah, that would make sense, told you it was me being stupid :2Rolleyes

if you dont mind me asking how much did you pay for them or were they not brand new??

cheers

karl

[andrewrx7]

Brand new, but I bought them about 18months ago! At the time about £60 for the pair - obviously cannot say what the prices are like today. I bought them through Clive, although I guess most parts suppliers on here can get them to.

[karl_tate]

ok cool, i bought mine direct from mazda and thought they were a bit steep at £63 but it seems the norm.
 
thanks for your help anyway.

[andrewrx7]

No probs. You replacing them during a re-build or with the engine in place in the car?

[karl_tate]

i have a rebuilt engine here and the new valves are ready to go in