Pioneer 650 build

[poulson01]

I stripped down my Pioneer 650 today.
Since I chickened out on my 346xp(s'), I decided to see why the 650 was so gutless (for a 100+cc saw). It has very low compression. You don't even need a compression release. Good thing cuz there isn't one. The exhaust port is really three ports. It's nothing more then three 3/8" holes drilled side by side on the exhaust side of the jug. The muffler is AWESOME! It's cast aluminum and has these cool fins or wing things on the sides. Looks like the chrome on a 57 Chrysler 300. It's about the same size as the one on my Mini Mac though. The intake port is ok, I guess but I think I can get some real power out of this old thing.
It was pretty ballsy compared to the saws I was running at the time. My main saws were a 4600 Mac and an XL12, my brush saw was a Poulan Micro and my tree saw was an Eager Beaver.
I used to be afraid of my 650 because it has no chain brake but that doesn't bother me anymore.
Anyway, I saw a vid on Youtube of a Pioneer 600 at a county fair race. I think with some tuning, it could decimate all. The only thing is the crank. It has some weight things fastened to the counterweights. They look like they'd fly off and shell the case if revved too high. The piston doesn't look very strong either. The rod and crank are beautiful forgings though.

I'll take some pics tomorrow.

 

[poulson01]

Here's some pics.

 

[pioneerguy600]

Hi there; I have a bunch of the 600 series saws and have lately been thinking about modifying one but was not sure where to start. From what I have gathered over on the chainsaw forum of AS the first thing to do is open up the muffler but I think the 600`s really only have open expansion boxes already. I for one will follow your rebuild and modifying closely as I have a lifelong interest in these saws and I think they should make a lot of power if the intakes and exhaust were opened up and the compression upped.
I have just come in from the shop where I was working on one of my 610`s today ,just putting it together with all NOS piston,rings seals and gaskets. I kitted the carb and replaced pickup line, filters etc. It fired up and runs well with 147 lbs compression ,it should get higher as it breaks in.
I would like to shave the base of the cylinder next and bring the squish down to .017 -.020 to see if I can raise the comp. some more, then tackle the ports. What do you plan on doing to yours if you do not mind my asking?
Pioneerguy600

 

[poulson01]

This is a pic looking down the barrel. It shows the exhaust ports and transfer ports in relationship to the piston at BDC.
Kool...Huh!!

 

[poulson01]

finished the exhaust port today and cleaned up the transfer ports. I put the engine together without the base and head gaskets, checked, and decided to run just a head gasket. I figured I'd be grinding the exhaust port up a little bit anyway. I'll leave the intake alone since the actual port is in the engine case and it looks ok to me.

 

[poulson01]

One other thing I'm thinking about is the squish area. It's huge! I want to try the "Somender Singh grove" thing, maybe one or two. This is the only chainsaw engine combustion chamber I've seen that this would work.

 

[chainsman1]

i can be wrong but,the reason why the factory had make small holes instead of big ports,its because there is no ring locator pin on the piston. so the ring end gap is going free in any directions.

i hope you will not damage the engine with an big exhaust port

 

[poulson01]

i can be wrong but,the reason why the factory had make small holes instead of big ports,its because there is no ring locator pin on the piston. so the ring end gap is going free in any directions.

i hope you will not damage the engine with an big exhaust port

I'm still working on that. I was going to file the rings at the gap so that they angle down. Then peen some of the ring land so that the rings won't spin.

 

[epicklein22]

Interesting project you have there, keep us updated on the results. It should be fun to see what you can get out of the old beast.
:greenchainsaw:

 

[chainsman1]

I'm still working on that. I was going to file the rings at the gap so that they angle down. Then peen some of the ring land so that the rings won't spin.

good idea

 

[slabmaster]

Have you thought about putting a pin in the ring groove to keep the ring from spinning an catching a port? I peened groove might stop the ring from sealing and cause a compression leak.

 

[poulson01]

Have you thought about putting a pin in the ring groove to keep the ring from spinning an catching a port? I peened groove might stop the ring from sealing and cause a compression leak.

Like this?
Should be going back together soon.

 

[SilverBox]

Ever get this beast finished? I have a 650 that I'm about to start in on, but I doubt I'll tear it down, just want to try to get it running.

 

[poulson01]

No it isn't finished yet. Economy....boss went bankrupt....etc. I picked up a seasonal position with the village of Kyrias Joel to get me through the winter. I'm getting ready to go into hibernation for the cold weeks coming. I'll get to it then. I have been thinking about it for a couple of weeks. Soon, I'll be compelled to get back to finishing it. It should really rip!

I reconsidered the base gasket omission. I made one up a few weeks ago out of the thinnest stuff I could find. I have to measure everything again to make sure it's what I want. I have a little more porting to do on the case also.

 

[SilverBox]

Make any more progress? I replaced the fuel line from the glass bulb to the carb and from the bulb into the gas tank on my 650. I can get it to fire if I put gas into the intake of the carb and it pulls gas up into the glass bulb now from the tank. But it doesn't seem to want to run on its own. Oh well I guess I get to rebuild the carb . Unless anyone has any ideas.

 

[poulson01]

Woops! Haven't logged in in a while. I just had a bunch of work done on my house so I've been busy with that. There's only two things left to figure out. One is the ignition system. It was always flaky and finally quit. I haven't even looked at it yet so I don't know if the coil is any good or not. It was probably just crud on the points but...we'll see. The other thing is the pins I put in the piston ring groves/lands. I don't like them and I have to really think about what I'm going to do there. I just don't like the split pins and I need to come up with something better. Maybe a busted drill bit or something.

 

[spankrz]

be careful with the exhaust as wide as it is. on a partner p100, the exhaust port is wide like that but it has a stem in the middle because the rings can pop out so much without one. there is a name for this, something like a "bridged" port or something.... time to consult the handbook!

 

[SilverBox]

I rebuilt my carb and got er running. Sounds pretty good, put it on my mini mill today.

http://www.youtube.com/watch?v=U9ocfzG-nUQ

 

[Gregford]

Any further along on this mod?

I'm very interested in what you're doing with an older engine as I'm considering doing much the same to an old Canadien 271 and my Husky 380s.

I'm very interested in whether you gain a lot of rpms and power. Keep us posted!

 

[DroppedP51]

Update?

I as well have wanted to do this as well to a pioneer 600/650 just as a play thing