Flow pattern

[rattler362]

I just replaced the oil tank vent on my 288 and noticed this pattern in the ext port take a look

 

[rattler362]

Sorry Men I was trying to post in the other board and got if a mod will please delete this and I will put it in the right place Thanks'

 

[cus_deluxe]

thats wild, never seen anything like that. was that a recently cleaned cylinder?

 

[Jon1212]

 

[rattler362]

I ported it has proubly 5 or 6 tanks thru it since I ported it

 

[cus_deluxe]

Im interested to hear what greater minds than mine have to say about what that means

 

[rattler362]

View attachment 429847

I really don't know Jonathon I hope someone can help I plan on running it just curious. I do apologize for posting this over here.

Mike

 

[mdavlee]

Is there a slight step in the port?

 

[BGE541]

HA just like a boat tail on a bullet... anything over 7* (graduation) and that (insert gas type here) isn't grabbing anymore.... My guess Mike?!

 

[mdavlee]

The flow would be fastest in the center from the highest point of the exhaust roof.

 

[rattler362]

Is there a slight step in the port?

Mike I went back and looked it was killing me no step that I can see or feel got me puzzled

 

[mdavlee]

Could just be the sides are the slowest flowing and is leaving some build up.

 

[rattler362]

I think you may be right

 

[mdavlee]

I'll try to take a look in the exhaust port of a couple saws and see if it's got a pattern like that before it completely soot up.

 

[rattler362]

I'll try to take a look in the exhaust port of a couple saws and see if it's got a pattern like that before it completely soot up.

Thank you Mike.

 

[pops21]

Looks like the it was opened up closest to the piston side and and not smoothed out till you get to the exhaust. Kinda like a river when you see the water swirling or calm on the back side of a bend or rock. Kinda like this ) ( vs \ /. This is allowing the soot to lay on the outer sides of the port instead of the middle where the velosity is higher.

 

[rattler362]

Looks like the it was opened up closest to the piston side and and not smoothed out till you get to the exhaust. Kinda like a river when you see the water swirling or calm on the back side of a bend or rock. Kinda like this ) ( vs \ /. This is allowing the soot to lay on the outer sides of the port instead of the middle where the velosity is higher.

Hey pops I widened the ext only smoothed and polished the roof and floor.

 

[pops21]

But did you widen it only closest to the piston? If so it would look like this ) (. or did you straighten it out after you widened it out so it would look like this \ / . I'm not saying what you did was bad or needs to be fixed. I'm just sayin from the looks of the soot the exhaust is deflecting off where you widened leaving the outer port with lower velocity.

 

[rattler362]

Pops I never took it like you were saying anything other than just trying to help figure this out I just said Hey cause it been a while since I saw you on here. I see what you are saying about the port I did widen the out side also .

 

[pops21]

Oh I know...... Its been a LONG time since I have been on here. I kinda got burnt out of saws and the forum drama. (even though I stayed out of it) .