RE: McCulloch 32cc prop
 

is it just a little bump or full port height? The 32cc has a little bump, when I was porting mine I reduced it's size but left it there

RE: McCulloch 32cc prop
 

Careful. Lots of times engines with bridged exhaust ports don't have pinned piston rings. If you take the bridge out, the edge of a ring can get caught in the port. Frank Bowman can make a special ring for use with a pinned piston, and you can pin the piston yourself or have him do it for a nominal fee.

Other than that, it is not a good idea to thin the bridge. It then becomes thermally instable and can swell inward and score or seize the piston.

AV8TOR

RE: McCulloch 32cc prop
 

I don't know at this point, if the ring is pinned or not, but yes the pin would be necessary if removing the port bridge.
I have read that a port width of less that 50% to 60% of the bore is generaly not a problem as far as ring bulge. Does the Ryobi and Homie 25 have the cyl stability problem with the port bridge removed? I've heard it is done regularly on those engines to increas performance.

RE: McCulloch 32cc prop
 

I have done it numerous times on Homelite 25cc engines with no ill effects. I have one consistently running well over 9000 rpms.

AV8TOR

RE: McCulloch 32cc prop
 

So for a Mac 32cc a 16x8 groupner super is not enough prop?
This will be used in a large scale Airboat!

Cheers,
Chad.

RE: McCulloch 32cc prop
 

I have two of these and I use a 18 X 8 on them

RE: McCulloch 32cc prop
 

I've always liked the APC 18X6W they have proved to give the Max RPM's in both the Ryobi and Mc's

RE: McCulloch 32cc prop
 

that's what I'm running, it works good

RE: McCulloch 32cc prop
 

I don't think I've flown since february, stupid rain. I want to take out my planes! but I NEED a bigger memory card for my transmitter before I finish any more planes, I'm out of room. I'm stuck at work right now (8pm, been here since 7:45am) so I'm bored... I've got a bunch of planes to maiden and screw with but time and other projects keep getting in the way, and lack of funds...

My mac 32 has been breaking in slowly, I've put a little over a gallon of fuel through it maybe 2 gallons and it's running strong with that 18-6W prop, it sure pulls that ultra stick around nicely