McCulloch Chain Saws

[clint53]

No need to yell about it Clint.
Yes the pin can be pressed out.

Thanks very much.
That wrist pin assembly was new to me.

 

[PogoInTheWoods]

I'm gonna use the LRB piston with Caber rings since the LRB rings are tapered just like Caber rings.

This is a Mac illustration and perhaps a possible point of interest using the tapered Caber rings if the ends need squared for your particular application.
(The dots indicated on the Mac rings below are simply dimples in the rings for easier clarification of the taper orientation.)

​

 

[Xpropane]

I'm gonna use the LRB piston with Caber rings since the LRB rings are tapered just like Caber rings. I know there is 3 different transfer types.
Numbers I finished with .050 squish intake duration- 124degrees exhaust duration-159degrees blowdown-22degrees

Im wondering how many of these Mac saws have you ported?

 

[Maintenance supervisor]

Speaking of mac projects. I have been working on one for quite some time now. Id like to tell you all about. It is really exciting for me anyway. This will be a long post and likely warrant some questions. So several months ago i was discussing at work to a new aquaintence about my chainsaws. The guy is a picker and loves engines. He is a motorcyclist, dirt bike, mini bike rider rebuilder but most importantly at work a turbine mechanic/machinist and his true passion is machinist work. If its broke ill just make the part he says. Good ol boy type personality. So, i was discussing some issues with macs and my favorite 82cc saws. Of which are the total lack of cylinders for scored ones and the cost of replating one. So...if you see where this is going?!!!! He says to me. I want to help you. I said go for it. So i gave him 2 junk cylinders to do whatever he wanted. He went to his shop and began measuring and thinking. Well, after further discussions and some literature i loaned him he had a plan of attack. I visited his shop and we worked out a plan. The first cylinder was completely destroyed for this project. Sacrificed for the sake of repairs. Then i had to fund the build which i agreed to up front. So together we had a fix. A cast iron sleeve for the 82cc saws!!!! It took a lot of trial and due to his personality, little error but a sleeve was made. Next it was put into a hogged out cylinder of a sp80. Then i went to pick it up and it was up to me for testing. Hell yes i say!!! So, i built a 82cc mac saw of parts i had. Most importantly the engine. The rest looked like a used saw. So i got this cylinder on an oil tank, new seals, new intake boot. Nova chip for ignition and to mention a 92519 B piston. Very important that i used a B from the start. Since the A and C pistons are not available. Also since ive succesfully used a LRB 92519 and they are available. Anyway, i spent several hours getting my parts together and 2 evenings putting together the puzzle. Saturday morning was go time! Crossing my fingers and fresh fuel mix.....i started to pull it over slowly just to listen and feel...all seemed good. Then i yanked it like a stolen saw. Great compression and then it popped!!! I thought...its gonna light off. Low and behold the darn thing lit off!!!!! Not only that, it sat and idled with very minor carb adjustments. I could not distinguish it from any other saw to be honest. I reved it easy and let it idle awhile, while i called my new best friend to let him listen. Next was to shut it off and restart. No issue at all. Then to get it hot. Off to the woodpile and it idled all the 200 yards to get there walking with no issue. Then e few small cuts. Seems great. Then bigger cuts..running strong. Next was a horrible noise and sluggishness. Shut her down!!!!! Tear it apart and find the sound....the sleeve moved. Darn it. My buddy says bring it to me. With a bit of fixing he hands it to me a few days later. Mind you very little damage to anything. Slight mark on the piston. Not major, ... so back together it goes. Same scenario, starts and idles great. He assured me that sleeve aint moving this time! so i said im running it. Off to the pile. After a full tank of fuel and seriously hard running , it worked with zero issues!! Fellas, i have a sp80 cylinder with a B piston in it , inside of a cast iron lined cylinder, that runs like a scalded dog!!! This cylinder was total garbage to start. Deep scores and lots of chrome damage. It is now brand new. It runs cuts very strong and is a new engine! I cannot type my excitement enough. This guy made a cast iron liner and put it in a 82cc sp/pm cylinder successfully. He asked me to tear it back down so he could take measurements after i ran it again so he has my cylinder. Ill get it back tomorrow hopefully. Hear his assesment and rebuild it. I have a few pictures and a short video of this project to share. I did ask if hed be willing to help others out and he said yes. Now, i am in no way selling this or marketing this project. I asked for help he tried it and prevailed. So i am simply telling you all with complete and utter excitement that it can be done and was done and i tested it. A cast iron lined super pro 80 saw exists. The transfer cut out he did and mapped is actually for the sp81 and pm850. He has 3 cylinders of mine to sleeve next. A sp81, and 2 pm850 cylinders. It was great to be involved and watch this happen. I truly hope he can help others with their 82cc saw cylinders.

Good on you Vinny.

 

[heimannm]

Outstanding Vinny.

 

[big10pointer]

Wow Vinny That is awesome you really did save a saw from the scrap yard. It sounds really good also.
Xpropane This is the first 7-10a that I ported. Its not my first McCulloch or chainsaw, outboard, 4 wheeler, motorcyle and lots of Small and Big block Chevrolets. I love the large performance gain from porting it's very satisfying. Do you have any info on porting macs cause Im all ears the more we know the better our equipment will run.

 

[Jethro 2t sniffer]

View attachment 957679

Strange seeing snow on the ground in January

Well done Vinny. And your mate too. Give him a beer from us. Hope he's keen for pocket/mrs doesn't know about money

Wow Vinny That is awesome you really did save a saw from the scrap yard. It sounds really good also.
Xpropane This is the first 7-10a that I ported. Its not my first McCulloch or chainsaw, outboard, 4 wheeler, motorcyle and lots of Small and Big block Chevrolets. I love the large performance gain from porting it's very satisfying. Do you have any info on porting macs cause Im all ears the more we know the better our equipment will run.

Really curious how this will run. The wonderful thing about these Mac's over newer saws is their lovely low end power. Eg your in a log pile or some such and your tip is hiding in probably a not good situation and if it bites its guaranteed kick back. The Mac can cut nice and slow and safely and when it kicks it's a non event.

A new saw however can't pull the chain at slow speeds it stalls out over n over until you up reving it's head off to cut then whamo a huge kick.

Not to mention holding off a stall while accurately approaching the setup point of a hinge or other situation. It can easily be lost when porting these so it seems

 

[Mnmacguy]

Most parts are still available although real pistons are getting scarce, LRB offers a replacement. I'm going to put a saw together with one for a local tree service and put it to the test.

Mark

I'll be interested in your results. I have a Pro Mac 650 in need of a new piston. For the price of the LRB piston I am hesitant to buy it for their noted questionable quality and the one ring design.

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[Mnmacguy]

Before I go any further on this PM 6A.
Does anyone have a source for a piston?

I'm not positive but I think the Power Mac 6A uses piston 68098. There are a few on ebay.


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[Jeffrey F.]

Before I go any further on this PM 6A.
Does anyone have a source for a piston? I'm not finding much online.
Also, can that wrist pin be pressed out without destroying the bearings?

View attachment 957624

View attachment 957625

Believe it or not the jug is okay.
Clint

Let me check I think I have a used but good one. Mark Heimann probably has everything you need at the McCulloch chainsaw Museum 319-239-4813 or on here send him message.

 

[clint53]

Let me check I think I have a used but good one. Mark Heimann probably has everything you need at the McCulloch chainsaw Museum 319-239-4813 or on here send him message.

Thanks Jeffrey.
Mark has me covered already.

 

[clint53]

I'm not positive but I think the Power Mac 6A uses piston 68098. There are a few on ebay.


Sent from my moto g(7) optimo maxx(XT1955DL) using Tapatalk

Thanks. Mark has me covered.

 

[vinnywv]

Sorry to not respond till now...had to get the little ones ready for night time. I used a standard piston from bob johnson. 2 thin rings. 92519

Thankyou everyone for the comments. Jethro yes he is willing to do this for anyone. I funded the jigs he built for the cylinders. Thats all on me. I wanted it done so the jigs are his now. Ill be going to his shop next weekend and actually doing an 850 and 81 cylinder myself. Ill be setting them up and hitting the go buttons on his machines. Im very excited for that. His shop is unreal with the tooling he has. I saw nearly everything in a machine shop but a planer table. And he is well versed on using the stuff he has. Good teacher too. Anyway. Im at work and gonna get in trouble if i dont get doing some stuff...lol

 

[Xpropane]

I do not have any experience with porting, I would like to try it but too scared to ruin a good cylinder! I have a pm 700 that I would like someone to port.

 

[serdie]

I do not have any experience with porting, I would like to try it but too scared to ruin a good cylinder! I have a pm 700 that I would like someone to port.

I bought my pro Mac 700 new in 88. It got disassembled and ported by my old buddy who used to race Mac karts. I run a 28” bar with full comp 3/8” chain and it will cut right through oak with no problem. I recently got to compare it with a stock 700 and was really suprised at the difference! Still use this saw today I’ve just taken very good care of it

 

[serdie]

I bought my pro Mac 700 new in 88. It got disassembled and ported by my old buddy who used to race Mac karts. I run a 28” bar with full comp 3/8” chain and it will cut right through oak with no problem. I recently got to compare it with a stock 700 and was really suprised at the difference! Still use this saw today I’ve just taken very good care of it

Send it to Bellhopper. Watch some of his videos. He does a great job with Macs

 

[rwoods]

@vinnywv, do you think your friend would be interested in duplicating a 101B liner but with a factory bore, assuming I can remove it?

All, anyone know how to remove the liner without damaging the cylinder on a 101B?

Ron

 

[Woodslasher]

Really curious how this will run. The wonderful thing about these Mac's over newer saws is their lovely low end power. Eg your in a log pile or some such and your tip is hiding in probably a not good situation and if it bites its guaranteed kick back. The Mac can cut nice and slow and safely and when it kicks it's a non event.

A new saw however can't pull the chain at slow speeds it stalls out over n over until you up reving it's head off to cut then whamo a huge kick.

Not to mention holding off a stall while accurately approaching the setup point of a hinge or other situation. It can easily be lost when porting these so it seems

I will agree that my 5-10 had a fairly low but unstoppable chain speed however, my 372 with the 75cc top end runs at a top rpm of 9600 in the cut, which felt similar to or even a bit slower than my SP81. On the whole, though, you are correct that newer saws and most ported saws are peakier.

 

[RolandM]

Speaking of mac projects. I have been working on one for quite some time now. Id like to tell you all about. It is really exciting for me anyway. This will be a long post and likely warrant some questions. So several months ago i was discussing at work to a new aquaintence about my chainsaws. The guy is a picker and loves engines. He is a motorcyclist, dirt bike, mini bike rider rebuilder but most importantly at work a turbine mechanic/machinist and his true passion is machinist work. If its broke ill just make the part he says. Good ol boy type personality.

Great job! Good to see everyone having fun. Some time back I put up my effort on the PM700 mild port job on these pages, and all is well with that saw.
My experience with iron bores is you need quite a bit more cylinder to piston clearance with iron sleeved engines compared to Ali bores, like several more thou. I did something similar on a Danarm 1-71 big bore project years back and I had to keep going back to the hone, as I was running tight and the piston would nip until I got it sufficient clearance!

Roland.

 

[Ranger-692]

Another question. I have a 7-10 style muffler on my 10 10/700 mystery machine that has both a baffle and a pretty restrictive spark arrestor. Do you guys remove these or maybe remove the baffle and leave the spark arrestor to run better/cooler? What’s the conventional wisdom here? Thanks!

Also any tips for removing the bolt that broke off in the nubbin on the cylinder that the top of the muffler anchors to through the baffle? Asking for a friend…