eyebrows

[Ronald van Essen]

To all tech guys

Just read that there are modified sleeves with eyebrows???-on 3.5 K&B

What are they, and what are they used for?

I know there are differences in the holes or ports in the sleeves of different manufacturers, but I guess this is a special mod to the engine.

Ronald.

 

[chunk t]

To all tech guysJust read that there are modified sleeves with eyebrows???-on 3.5 K&B

What are they, and what are they used for?

I know there are differences in the holes or ports in the sleeves of different manufacturers, but I guess this is a special mod to the engine.

Ronald.

99829[/snapback]

​

An "eyebrow" is a machined arch placed at the top of a port to alter the timing of the port. Eyebrows are used on exhaust ports. K&B's 8906 3.5cc outboard (this is the black carb water cooled o/b from the early to mid 1980's) featured the eyebrows on the exhaust port next to the bridge - the later 8907 (gold carb version) has the entired port opend to the same timing as the earlier 8906's eyebrow. In addition to simply adding eyebrows to a port, size and location will play a roll in how abruptly the exhaust gases are expelled and the flow patern.

Hope this helped

chunk t

 

[Propjockey]

I've got a pic of different styles, but can't upload it. PM your email to me and I'll send it to ya.