Part Two: The Intake Port

[Dolmar Junkie]

Refilling the spray rig.....

Opened the wrong valve on mine in a brief moment of non attentive attention,after thoroughly filling my mouth and eyes,had a very interesting chat with poison control. They convinced me that I wasn't going to die .

 

[Fruecrue]

Well...??...???.....???
Did you survive?

 

[Dolmar Junkie]

Yes....and yes. Yes, that too.

AKA mixed grass.... are you doing square bales or round? I want to build a bale accumulator and grapple , I am 2 old to sling bales....

 

[spencerpaving]

Correct me if I'm wrong....piston port engines have a better efficiency at higher rpms due to resanot efficiency? But have spit back at lower rpms...where reed valves work good without spit back and provide good sealing until say 11500-12000 or until reed flutter happens or don't matter at that rpm due to incoming air inertia? ??

 

[Dolmar Junkie]

Well...??...???.....???
Did you survive?

Living breathing w/minimal drain bamage ..
3min post spray, you could not have convinced me of it...

 

[Hedgerow]

Correct me if I'm wrong....piston port engines have a better efficiency at higher rpms due to resanot efficiency? But have spit back at lower rpms...where reed valves work good without spit back and provide good sealing until say 11500-12000 or until reed flutter happens or don't matter at that rpm due to incoming air inertia? ??

I was under this impression too. But there are different materials to make reed valves out of to mitigate this no?

 

[Mastermind]

AKA mixed grass.... are you doing square bales or round? I want to build a bale accumulator and grapple , I am 2 old to sling bales....

Square in this field. Round in some.

 

[Mastermind]

Refilling again.

 

[XP_Slinger]

Correct me if I'm wrong....piston port engines have a better efficiency at higher rpms due to resanot efficiency? But have spit back at lower rpms...where reed valves work good without spit back and provide good sealing until say 11500-12000 or until reed flutter happens or don't matter at that rpm due to incoming air inertia? ??

Good question. I would think reeds have limitations on their ability to close and seal much like a valve springs limits. If you want higher rpm an upgrade may be needed?

 

[RIDE-RED 350r]

Carbon fiber is a popular material used to make high performance reeds where old school stock units were commonly made of steel. I'm sure reed petal thickness plays a factor too but I have never seen any thickness options from the leading manufacturers like V-Force, FMF, Boyesen, ESR, etc. They all have their own methods and designs with the petals as well as the cages themselves

 

[Al Smith]

I'm not so certain reed valves have an RPM limitations .Case in point being Mac Kart engines .
Years ago on AS Art Martin mentioned a very little bit about his 90 Stihl that evidently was legionary on the west coast .It used the piston ported part for induction but transfered through reed valves in the transfers .It ran at around 9,000 RPM no tuned pipe .Might sound slow but consider it was running a big sprocket with 1/2" chain .R's aren't every thing .

 

[p61 western]

The Pioneer p62 was 11,500 bone stock. I'm curious to know if the reeds do have a rpm limit.

 

[XP_Slinger]

Now that we've covered Reed race engines; what are we to do with work saw intake ports? Squaring was very popular not that long ago. What changed?

 

[TreeLife]

I would leave it cylindrical, finished rough. I might even be tempted to stipple the intake tract to promote turbulence and fuel suspension.

 

[Al Smith]

Stipples were one theory.Weather it worked or not might be a subject of debate .I cut the stipples out of the intake on an 038 Av Stihl along with a few other modifications and it turned out very well .
Now it's been said which I tend to agree with that a mirror finish is not what you want .Something like a craytex finish is better .

The theory behind that is because the intake is going from a greater pressure,atmosphere to a lesser pressure,crankcase that this creates a cooling effect .This in turn would have a tendency to cause the fuel /air mixture to condensate on the walls of a mirror smooth intake track as opposed to a vapor like mixture .
For those who do not know the subject 038 av is an interesting bit of engineering .Besides the stippled intake it had an off set combustion chamber and a hemi domed piston .

 

[Four Paws]

Refilling again.

What'syour application rate? Any Dicamba or surfactants added in?

 

[Four Paws]

Squaring was very popular not that long ago. What changed?

It was never hip to be square...

 

[drf256]

I just did some measureing, grinding and finishing on a 262 intake.

The intake flange entrance was 360mm2 and the opening in the plating was 380mm2. Both approximate.

I lowered the floor 1.4mm and went from 138 to 152 duration. I matched the factory port exactly on the bottom, same corners. I gained more than enough area. I used to widen this port. I don't see the point anymore.

 

[Deets066]

I still like em a bit square, I usually go as wide as the skirt allows on the intake too

 

[Deets066]

I just did some measureing, grinding and finishing on a 262 intake.

The intake flange entrance was 360mm2 and the opening in the plating was 380mm2. Both approximate.

I lowered the floor 1.4mm and went from 138 to 152 duration. I matched the factory port exactly on the bottom, same corners. I gained more than enough area. I used to widen this port. I don't see the point anymore.

Pics