6 replies to this topic

[NateDogg2909]

Hello all,

 

Ive got a 1990 998 which has no breather hole on the clutch housing as im starting to uprate most of the engine I thought more breathing would be better.

 

Is it feasible to cut out the casting and drill two holes, tap them and attach a standard breather?

 

If anyone has done it could I have a few pointers please.

 

Many thanks

[nicklouse]

sure best done when not assembled. 

 

but not needed as the standard system does ok for what is needed.

[Retroman]

It Is possible but it needs to have the casting type with a flange inside, its like a box with an open side.

 

The box flange is cast into the flywheel housing directly under the breather flange and it stops the drop gears throwing oil straight up into the breather canister.

 

I assume you are doing it with the engine out. The standard bolts for the canister are 5/16th UNC thread 3/4 long

[NateDogg2909]

It Is possible but it needs to have the casting type with a flange inside, its like a box with an open side.

 

The box flange is cast into the flywheel housing directly under the breather flange and it stops the drop gears throwing oil straight up into the breather canister.

 

I assume you are doing it with the engine out. The standard bolts for the canister are 5/16th UNC thread 3/4 long

 

Cheers Retroman

 

Yes its fully dismantled, im pretty sure the casting is correct, ill take a photo.

 

I was thinking of buying the 5/8 breather plate from DSN.

[carbon]

As Nick says, you really don't need an additional breather for the 998, as it has the tappet chest cover with breather (not an option with solid block 1275). Just make sure the wire mesh inside the can is not clogged up.

 

This standard breather set-up will work well for a 998, unless you're planning on going forced induction?

[NateDogg2909]

The spec is as follows

998+80

Port and polished head with 1098 intake and exhaust valves 1.3:1 rockers and 10.5:1 CR

Calver St road/race cam

[wile e coyote]

Agree  it's not stricty necessary  but .... if you want to - why not?  why not hit ebay / classifieds  for a used one? they're not exactly "consumables" - pop in a new idler bearing and you're good to go...