The $350 reedcase engine.

[szaki75]

For what purpose?

to avoid a narrowing squish opening and trap gas in the squishband. for me ideal would be a concentric squish cut with the piston dome, but to make the suitable tool looks to be a problem.
as for compression, we are on the same page

I've read you can make up the +1mm with a gasket ...not sure where you would find one without stacking them

it is one way to accommodate the +2mm stroker crank, but it changes the port timing (and duration) drastically. raising the cylinder by 1mm means 6-8deg change in the port durations.
a more elegant way is when you cut the 1mm out from the squishband. (it won’t disturb the timing since the relative position of the ports to the stroke won’t change)

 

[Seandonato73]

to avoid a narrowing squish opening and trap gas in the squishband. for me ideal would be a concentric squish cut with the piston dome, but to make the suitable tool looks to be a problem.
as for compression, we are on the same page

View attachment 68380

it is one way to accommodate the +2mm stroker crank, but it changes the port timing (and duration) drastically. raising the cylinder by 1mm means 6-8deg change in the port durations.
a more elegant way is when you cut the 1mm out from the squishband. (it won’t disturb the timing since the relative position of the ports to the stroke won’t change)

Hmm yes good point, tbh I've never thought about that, normally the squish band is so narrow it shouldnt matter, but if the chamber is relatively small I can see how it could cause a flame front issue.

 

[Troopermaniac]

Aight heres the new mandrel design.

 

[Troopermaniac]

Side ports are finished. Now waiting on an end mill cutter to do the 5th port. This is as precise as I can be with just my hands.

*edit* 5th port is done. What sucks is my bit chattered and hit the sidewall. Took 2 hours of buffing but I'm 100% sure it won't be an issue now. Pic makes it seem worse then it is you can't even feel it to the touch. Had to add more jb weld because I forgot that you need to mill outside the port wall.

Lastly I know this chainsaw dude in another forum he builds them for competitions and told me I should widen the bottom of the 5th port as it has netted him great results and then window it narrow to the bottom. "I said heck ill try it and if it doesn't work ill just buy a new head/ piston. Its not like these things are expensive.

It took quite a bit of work to be able to get the water to flow like this. Got the tip form a chainsaw forum https://photos.app.goo.gl/uq2y669rNnm29f6c9

 

[Seandonato73]

Side ports are finished. Now waiting on an end mill cutter to do the 5th port. This is as precise as I can be with just my hands.

*edit* 5th port is done. What sucks is my bit chattered and hit the sidewall. Took 2 hours of buffing but I'm 100% sure it won't be an issue now. Pic makes it seem worse then it is you can't even feel it to the touch. Had to add more jb weld because I forgot that you need to mill outside the port wall.

Lastly I know this chainsaw dude in another forum he builds them for competitions and told me I should widen the bottom of the 5th port as it has netted him great results and then window it narrow to the bottom. "I said heck ill try it and if it doesn't work ill just buy a new head/ piston. Its not like these things are expensive.

It took quite a bit of work to be able to get the water to flow like this. Got the tip form a chainsaw forum https://photos.app.goo.gl/uq2y669rNnm29f6c9

Wonder what class hes building for that would allow a reed engine, we don't really have the room for them when your doing a woods port, there have been guys that add boost ports beside the intake that has netted good results. Very interested in how it turns out, as well as seeing how the 11* chamfer works out in the squish band. Cheers

 

[Troopermaniac]

Wonder what class hes building for that would allow a reed engine, we don't really have the room for them when your doing a woods port, there have been guys that add boost ports beside the intake that has netted good results. Very interested in how it turns out, as well as seeing how the 11* chamfer works out in the squish band. Cheers

He has other tools and is in the rc hobby too. I got my mandrel idea from him. He is telling me that I should trim down the rear of the piston a small bit after measuring what degree it tops out at.

 

[Troopermaniac]

Ok whats the consensus on it as is https://photos.app.goo.gl/1xS3XexqQXiSKxja9

 

[buzzkill]

Ok whats the consensus on it as is https://photos.app.goo.gl/1xS3XexqQXiSKxja9

need to Dyno that thing ! sounds good seem FAT on the mixture , but for testing thats ok

 

[Seandonato73]

He has other tools and is in the rc hobby too. I got my mandrel idea from him. He is telling me that I should trim down the rear of the piston a small bit after measuring what degree it tops out at.

It has the same effect as raising the exhaust roof, more rpm, sacrifices torque

 

[Troopermaniac]

Banging my head agenst the table atm. Need to extract 3 screws and my old screw extraction kit is dulled out. Gotta wait a few days before I can take her fully apart now. My fault for using red locktite I wasn't thinking when I was putting it together.

 

[MonsterAir]

Well, that's a fook up! Your an animal!

 

[Troopermaniac]

Well, that's a fook up! Your an animal!

Thanks it must be cus I'm a fukin savage. Anyway something isn't right. I bought a 30mm stroker "from Kingmotor RC which is probably my fault for doing" and its the same size as my stock 32cc Rofun crank. "Waaat" now I'm confused. How long is the middle point of a 34cc crank supposed to be from piston pivot to crank pivot?

 

[szaki75]

con rod is the same lenght as i know. just the bigger end is 1mm outer in the 34cc crank

 

[Troopermaniac]

con rod is the same lenght as i know. just the bigger end is 1mm outer in the 34cc crank

Ah I thought the rod was longer. Well only way ill be able to tell is if I put together the engine and see the squish. I noticed the flywheel itself is smaller. Wonder if this would be a bad thing. I know shaved weight is good but never thought about this before.

 

[Seandonato73]

Just measure the pin from the crank centerline, the rod should be the same length, the crank controls the throw of the rod.

 

[Troopermaniac]

Just measure the pin from the crank centerline, the rod should be the same length, the crank controls the throw of the rod.

Don't have to anymore. After measuring squish with a dial meter I have determined that the KingMotors 34cc crank is a lie. Its actually .09 shorter! Looks like it might truly be a 30cc crank instead. So it looks like science prevails. Funny thing is the Rofun head gives a better squish band then the Rovan head "ports are in incorrect locations". "DARE I say Rofun is BETTER quality then Rovan!" I do. So looks like my whole porting job was for nothing and I gotta start over again with this head because that squish band is pretty much at my desired height after I do a gasket delete. "Gonna use HondaBond". W/e atleast I don't have that buff spot in the head anymore.

*Nutshell* If you didn't already get the gist if you decide to go cheap buy Rofun not Rovan and Kingmotors is unreliable with their specs.

 

[DougStar]

Funny thing is the Rofun head gives a better squish band then the Rovan head. "DARE I say Rofun is BETTER quality then Rovan!"

Wow so you can tell the difference between ??????? ???

 

[Troopermaniac]

Wow so you can tell the difference between ??????? ???

Funny thing is. I didn't expect much from Rovan and they still let me down.

 

[buzzkill]

Funny thing is. I didn't expect much from Rovan and they still let me down.

isnt Rovan and Rofun the same thing ??

 

[szaki75]

i had the impression they are the same...
rofun is the manufacturer and rovan the brand maybe?