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Is the Pioneer P50 flywheel interchangeable with the P51 ???

Here's my post (from "Inexpensive 80-100cc Chsainsaw ..." thread. Folks suggested I post the question here):

Here’s a link to a P50 flywheel. I don’t know if it’s the same as on a P51, but maybe.
https://www.ebay.com/itm/PIONEER-P5...459632&hash=item261610e671:g:DosAAOSw6hZcfaiO

(My reply):

The plot thickens...

Thanks for the ebay link! The (stamped) ebay P50 flywheel number is indeed same as P51 IPL part number 474645, but it looks a bit different than mine.
I looked at P50 data sheet; looks like it used points type ignition?

So, I pulled my battered P51 flywheel, and its marked "FWM-1746" (and underneath looks different than the ebay flywheel as well)
Studied the "Pioneer Disassembly and Assembly Procedures Manual (Large Series)" and see that there were (apparently) three diff types of (pointless) ignition systems used on these saws. My (battered but working) coil is blue and marked "Prestolite" (if that matters)

So...I'm a bit unsure how to proceed...
 
Is the Pioneer P50 flywheel interchangeable with the P51 ???

Here's my post (from "Inexpensive 80-100cc Chsainsaw ..." thread. Folks suggested I post the question here):

Here’s a link to a P50 flywheel. I don’t know if it’s the same as on a P51, but maybe.
https://www.ebay.com/itm/PIONEER-P5...459632&hash=item261610e671:g:DosAAOSw6hZcfaiO

(My reply):

The plot thickens...

Thanks for the ebay link! The (stamped) ebay P50 flywheel number is indeed same as P51 IPL part number 474645, but it looks a bit different than mine.
I looked at P50 data sheet; looks like it used points type ignition?


So, I pulled my battered P51 flywheel, and its marked "FWM-1746" (and underneath looks different than the ebay flywheel as well)
Studied the "Pioneer Disassembly and Assembly Procedures Manual (Large Series)" and see that there were (apparently) three diff types of (pointless) ignition systems used on these saws. My (battered but working) coil is blue and marked "Prestolite" (if that matters)

So...I'm a bit unsure how to proceed...

Did your saw have spark before you pulled it apart? Those blue prestolite coils are known to fail. And yes there are a couple different ignitions on those saws. I've got one here that doesn't run at the moment that needs the ignition and carb swapped with a parts saw.
 
Is the Pioneer P50 flywheel interchangeable with the P51 ???

Here's my post (from "Inexpensive 80-100cc Chsainsaw ..." thread. Folks suggested I post the question here):

Here’s a link to a P50 flywheel. I don’t know if it’s the same as on a P51, but maybe.
https://www.ebay.com/itm/PIONEER-P5...459632&hash=item261610e671:g:DosAAOSw6hZcfaiO

(My reply):

The plot thickens...

Thanks for the ebay link! The (stamped) ebay P50 flywheel number is indeed same as P51 IPL part number 474645, but it looks a bit different than mine.
I looked at P50 data sheet; looks like it used points type ignition?

So, I pulled my battered P51 flywheel, and its marked "FWM-1746" (and underneath looks different than the ebay flywheel as well)
Studied the "Pioneer Disassembly and Assembly Procedures Manual (Large Series)" and see that there were (apparently) three diff types of (pointless) ignition systems used on these saws. My (battered but working) coil is blue and marked "Prestolite" (if that matters)

So...I'm a bit unsure how to proceed...
Did your saw have spark before you pulled it apart? Those blue prestolite coils are known to fail. And yes there are a couple different ignitions on those saws. I've got one here that doesn't run at the moment that needs the ignition and carb swapped with a parts saw.

Thanks ML12. Yeah; had spark, and ran briefly on starter fluid after I did initial clean up. The flywheel is missing 6 fins; looks like it tangled with a loose blower cover. I'd like to find a flywheel (and maybe blower cover), but want to make sure I look for the right one...
 
Pioneer P51: Open Pandora's Box?

OK, Pioneer Experts - Should I strip down and inspect my P51 project saw, or just fix the obvious problems (eg, carb, fuel lines, starter, etc) with external stuff and hope for the best?
- Is there a list of generic seal and bearing numbers somewhere? (I've searched...)
- Assume I'll have to make new gaskets from scratch?

My limited experience with semi modern commercial saws over recent years is that the bottom end bits are generally OK unless there's something obviously amiss. Biggest exception is crank seals. I can't see any markings on the P51 seals, though the saw seems to pressure test OK. It hasn't been run in decades. Hate to pull it down and ruin NLA seals, if there's no source or substitute. Ditto the top end. No seize scoring visible through ex port and ~ 110psi with bad recoil starter, but worth opening up if no new parts available?

My hope is to use this as an occasional big brother saw to help out my little 026 Stihl. Plus, I'm kinda' beginning to like it's honest Canadian looks...
 
Check Rottman Sales for parts. They have a limited inventory of NOS Pioneer stuff along with most of the saw IPL's available for download. http://rottmansales.com/

Do a vacuum test as well as a pressure test on those seals. If they hold both, I'd leave well enough alone until service is actually needed unless you're hell bent on rebuilding the saw anyway. Nothing wrong with that, either. 507428746 should be your seals and are readily available, albeit at quite a premium depending on source. Rottman may be your best bet there price-wise if they have them.
 
Pioneer P51: Open Pandora's Box?

OK, Pioneer Experts - Should I strip down and inspect my P51 project saw, or just fix the obvious problems (eg, carb, fuel lines, starter, etc) with external stuff and hope for the best?
- Is there a list of generic seal and bearing numbers somewhere? (I've searched...)
- Assume I'll have to make new gaskets from scratch?

My limited experience with semi modern commercial saws over recent years is that the bottom end bits are generally OK unless there's something obviously amiss. Biggest exception is crank seals. I can't see any markings on the P51 seals, though the saw seems to pressure test OK. It hasn't been run in decades. Hate to pull it down and ruin NLA seals, if there's no source or substitute. Ditto the top end. No seize scoring visible through ex port and ~ 110psi with bad recoil starter, but worth opening up if no new parts available?

My hope is to use this as an occasional big brother saw to help out my little 026 Stihl. Plus, I'm kinda' beginning to like it's honest Canadian looks...

An exact match for the seals both sides are SKF CR 5606, National (Timken) 472705 Both double lip nitrile

It's a common seal 9/16 (0.5625") shaft diameter, 1" pocket bore, width is 1/4"

The seal is common to the P4X, P5X, P6X and the corresponding frame Poulans. They are also for the 1074.

I don't think the the Poulan 507428746 is available from Poulan anymore but there seems to be a bunch on ebay.
I would rather use new SKF or Timken seals.

That compression sounds a little low but maybe the cylinder is lacking some oil. I bought a nice P41 with compression of less than 90 psi but added some oil to the cylinder and it went way up. After running it some it settled at around 180psi.
 
Hey guys I need some help! I finally finished the ported pioneer 650! The problem is it won’t really idle or rev well! I tried to different carbs on it with really the exact same result. I have never ported a saw before so I am not sure about carb adjustments and if they need to change a lot. It was not a crazy port just cleaned it up and rounded corners off. Thanks for any help!
 
Check Rottman Sales for parts. They have a limited inventory of NOS Pioneer stuff along with most of the saw IPL's available for download. http://rottmansales.com/

Do a vacuum test as well as a pressure test on those seals. If they hold both, I'd leave well enough alone until service is actually needed unless you're hell bent on rebuilding the saw anyway. Nothing wrong with that, either. 507428746 should be your seals and are readily available, albeit at quite a premium depending on source. Rottman may be your best bet there price-wise if they have them.

Thanks, Pogo! I called Rottman and spoke with Kevin. Nice guy, and v knowledgeable! He answered my flywheel question straight off (no, the P50 wheel won't work). I'm going to pull the top end and inspect; measure ring gap, etc. I will vac test too (appreciate the suggestion)
 
An exact match for the seals both sides are SKF CR 5606, National (Timken) 472705 Both double lip nitrile

It's a common seal 9/16 (0.5625") shaft diameter, 1" pocket bore, width is 1/4"

The seal is common to the P4X, P5X, P6X and the corresponding frame Poulans. They are also for the 1074.

I don't think the the Poulan 507428746 is available from Poulan anymore but there seems to be a bunch on ebay.
I would rather use new SKF or Timken seals.

That compression sounds a little low but maybe the cylinder is lacking some oil. I bought a nice P41 with compression of less than 90 psi but added some oil to the cylinder and it went way up. After running it some it settled at around 180psi.

Gosh, Tim - that's perfect! Many thanks...really appreciate the seal numbers. Believe I'll open it up and replace 'em just based on age. I think I can fashion a case spreader/crank pusher like the one shown in the Pioneer assembly/disassembly instructions. Anything special about the crank bearings? How about the reed block - anything to watch for?

Not sure if my compression test was valid, as the starter cover and flywheel are damaged (I'm looking for replacements). The saw was locked up, but came free easily with a little penetrating oil. The piston looks semi OK thru the ex port, though I'm not sure about the cylinder - will disassemble and inspect (I have a 1970 Moto Guzzi 750 with chrome on aluminum cylinders that are peeling; I've seen same on old Porsche 911S barrels. Was this an issue with chrome on aluminum cylinder Pioneer saws?)

Wonderful to find such knowledgeable people as you and others!
 
Gosh, Tim - that's perfect! Many thanks...really appreciate the seal numbers. Believe I'll open it up and replace 'em just based on age. I think I can fashion a case spreader/crank pusher like the one shown in the Pioneer assembly/disassembly instructions. Anything special about the crank bearings? How about the reed block - anything to watch for?

Not sure if my compression test was valid, as the starter cover and flywheel are damaged (I'm looking for replacements). The saw was locked up, but came free easily with a little penetrating oil. The piston looks semi OK thru the ex port, though I'm not sure about the cylinder - will disassemble and inspect (I have a 1970 Moto Guzzi 750 with chrome on aluminum cylinders that are peeling; I've seen same on old Porsche 911S barrels. Was this an issue with chrome on aluminum cylinder Pioneer saws?)

Wonderful to find such knowledgeable people as you and others!

The Pioneer cylinders were pretty tough.

One thing to remember is the oil pump worm gear has to come off the crankshaft to replace the seal. It's an interference fit on the crank and it's not very strong. There is not a stop or anything to set the proper position. Use a reference point to measure where the worm gear needs to be returned to after you change the seal. Pioneer made a tool to do this. I have had luck using a couple of screw drivers to carefully pry the gear off the crankshaft. Do not pry in the gear body. Pry underneath the gear only as you can split it open. Tap it back on when you're done with a socket.

The inside of the worm gear looks like the outside making for some very thin spots.

The carb adapters are very fragile and lots of them were cracked by ham fisted repair guys. They are getting scarce.

Not sure about the bearings.
 
Gosh, Tim - that's perfect! Many thanks...really appreciate the seal numbers. Believe I'll open it up and replace 'em just based on age. I think I can fashion a case spreader/crank pusher like the one shown in the Pioneer assembly/disassembly instructions. Anything special about the crank bearings? How about the reed block - anything to watch for?

Not sure if my compression test was valid, as the starter cover and flywheel are damaged (I'm looking for replacements). The saw was locked up, but came free easily with a little penetrating oil. The piston looks semi OK thru the ex port, though I'm not sure about the cylinder - will disassemble and inspect (I have a 1970 Moto Guzzi 750 with chrome on aluminum cylinders that are peeling; I've seen same on old Porsche 911S barrels. Was this an issue with chrome on aluminum cylinder Pioneer saws?)

Wonderful to find such knowledgeable people as you and others!

The reed blocks are a pain. Most get cracks around the threaded inserts. I have bought some NOS ones still in the original package that had cracks. Most of the time the small cracks don't cause an air leak though.

I've had mixed results on the reed blocks sealing up. Its probably best to use some sealant between the case and reed gasket to help seal them up real nice. I've tried Hondabond and Permatex and both work well. The most recent build is sealed up with some Subaru goop that worked very well!

From my experience and that of others here with much more experience, the crank bearings and seals on the larger P series last a long time and dont fail very often. You might not need to mess with them if they aren't leaking.

About the only fragile parts on those saws are the reed blocks and ignitions. Other than that they're pretty solid and take a beating for many years.

If you're patient, many of the parts you might need will show up on Ebay.

Good luck with your rebuild project. You'll probably use the 026 less when you start running that saw.
 

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