Mcculloch collectors, 10-10s vs 555 vs 570. Differences? Reed valve vs piston port.

[lostone]

Maybe some of the collectors of Mcculloch saws can explain the differences between these saws to me.

The:
Pro Mac 10-10s (made 82-98) comes in at 57cc
Pro Mac 555 (made 77-78) comes in at 57cc
Pro Mac 570 (made in 77) comes in at 57cc's

About the only difference I can see is the 570 has the antivibe mount where the 10-10s and 555 don't. So what would be the difference between the 10-10s and the 555? besides.

Pro Mac 10-10s=Electronic ignition/piston ported
Pro Mac 555=Breaker/condensor/reed valve

Looking at the IPL I can also see that the Pro Mac 555/570's used reed valves that I don't see on the 10-10s on the exhaust.

What are the advantages/dis-advantages of reed valves other than breaking over piston port engines.

 

[lostone]

After doing some searching on engine designs I am finding that reed valve engines (if engineered correctly) can offer some power advantages over piston ported engines???? I'm not into porting engines so I will have to take the word of what I was able to find and read. There isn't much information on the Pro Mac 555/570 out there and I am unable to find any hp/kw ratings for them or the 10-10's for a comparison. As I understand it the piston ported engine allows for a small weight savings since you eliminated the need for the additional reed system and cost of manufacturing goes down as well.

 

[rwoods]

They are all piston port saws. Some older ones had a reed in the muffler. Some claim that the reed in the muffler can be tuned to produce more power. IDK. McCulloch claimed its newer non-reed muffler 82cc saws made more power than the old, but many here contest that. Ron

 

[rwoods]

BTW I have many miles on an 036 Pro - love that saw. Ron

 

[lostone]

BTW I have many miles on an 036 Pro - love that saw. Ron

I still haven't been able to get to use my 036 much. I probably have less than 2 hours of run time on mine. I know it's a crime the saw just loves to run. Had a 046 that someone had modded on and that thing was insane but had to let it go when I got hard up for some $$$, really miss that crazy thing.

Where I was reading on the reed vs piston port it was talking about how the piston port uses more of the cylinder wall vs reed therefore it effected the area for transfer ports. Again I am not a builder and not even to the point to know enough to be dangerous but just trying to understand a bit better on the principle behind different types of 2 cycle engines.

 

[rwoods]

There are folks here that can educate you on the differences. Unfortunately, I don't think anyone has any McCulloch factory horsepower numbers beyond a overseas brochure that list some pretty high numbers (McCulloch 800 in the same range as the much larger Stihl 660) - same time period that others were listing high numbers as well - Sach Dolmar 12hp 118cc, IIRC. Ron

 

[rwoods]

There are those here who can educate you on the differences of reed versus piston port though
not me. To my knowledge no one has any factory HP numbers for McCulloch other than a overseas sale brochure that lists the 82cc DE80 in the same power range as the much larger Stihl 660. Likely just sales inflations. IIRC around that same time Sachs Dolmar was listing their 118 cc saw at 12 HP. Ron

 

[lostone]

There are those here who can educate you on the differences of reed versus piston port though
not me. To my knowledge no one has any factory HP numbers for McCulloch other than a overseas sale brochure that lists the 82cc DE80 in the same power range as the much larger Stihl 660. Likely just sales inflations. IIRC around that same time Sachs Dolmar was listing their 118 cc saw at 12 HP. Ron

The numbers themselves where not important even if they overrated them. Seems a lot do it. The main thing i was looking for was seeing if they rated the reed engine as having more than the piston ported engine out of curiosity.

 

[heimannm]

All of the 10 Series are piston ported, in fact the block/piston/crankshaft dimensions are identical on all of the 57 cc models except for the impulse nipple on the 570.

The reed in the muffler was intended to reduce the sound levels and the "impression" of noise. The reeds in the mufflers don't seem to hold up all that well.

Performance wise the only differences would be overall condition, and perhaps one with a poor carburetor. All should have the larger SDC with the .750 venturi and .812 throttle bore. Some will be fully adjustable, some will have a fixed "H" jet but in my experience, the fixed "H" saw run pretty well at the altitudes I have run them (<1,000').

Mark

 

[lostone]

I am hoping mine will have the fully adjustable H jet. I will be anywhere from 4k to 10K on altitude.

After doing some more looking at it I found the one I bought is the 12-serial prefix so it actually has electronic ignition and U model so it won't have the reed exhaust. I know the part numbers are different on piston and cylinder over the 10-10s series that came along later but it seems as if the 555 was the predecessor to the 10-10s.