Author Topic: Connecting rod bolts on McCulloch 125 SP  (Read 2375 times)

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Offline Al Smith

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Re: Connecting rod bolts on McCulloch 125 SP
« Reply #20 on: May 05, 2014, 01:01:04 pm »
I little something to remember about salvaging a screwed up piston .Unless it's a huge void a low spot won't hurt you .A high spot will break the surface tension of the oil film and will ruin your day .

If somebody is going to try my half azzed fix don't even think about running 50 to 1 oil ratio .This is one area where you need the extra oil .

Offline sharkey

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Re: Connecting rod bolts on McCulloch 125 SP
« Reply #21 on: May 05, 2014, 06:40:38 pm »
Measure the old one and check the service limits.  Otherwise, think this one would work? http://www.ebay.com/itm/New-Genuine-McCulloch-Kart-Chainsaw-Piston-CP125-Std-Bore-/181380682436?pt=LH_DefaultDomain_0&hash=item2a3b2192c4 

Offline super44

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Re: Connecting rod bolts on McCulloch 125 SP
« Reply #22 on: May 05, 2014, 07:19:03 pm »
I saw that one but it's for the CP 125 and has the bearings in the piston and I think is a cast iron bore. Not sure if those rings are compatible with a crome bore. The one I am resurecting is a SP 125C. I read someplace that you can swap rods in some cases and get it to work.  I have a new set of rings coming in hopes that will be enough.


Offline Al Smith

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Re: Connecting rod bolts on McCulloch 125 SP
« Reply #23 on: May 09, 2014, 08:11:50 pm »
It's the same rings for both the SP 125 and Sp 125C .They are made of tool steel . Part number 85539.

Offline super44

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Re: Connecting rod bolts on McCulloch 125 SP
« Reply #24 on: May 29, 2014, 11:36:31 am »
well I think I got lucky on this one.  Found a NOS piton and rod assembly for $72.00 with shipping.  It was sold as a 101 cart piston with no PN.  Looked just like what I needed and it is.  I think that old beast will live on. ;D

Offline super44

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Re: Connecting rod bolts on McCulloch 125 SP
« Reply #25 on: December 28, 2014, 01:03:36 pm »
Finally time to put this one back together.  Two questions, torque on the connecting rod bolts and is it wise to add a little sealer to the intake plate?

Offline Al Smith

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Re: Connecting rod bolts on McCulloch 125 SP
« Reply #26 on: December 29, 2014, 10:37:26 pm »
According to the shop manual 105-110 inch pounds,oiled bolt .However according to SAE on grade 8 bolts 10-32 it's 62 inch pounds.They might be a higher grade than 8 though .

It's a hard bolt going into a sintered metal rod so the higher torque might apply .Trivia:the "**** rod " was developed by McCulloch motors and is standard practice today on most automotive engines .

If the gasket is a little stiff sealant is okay .If it's supple,in my opinion it doesn't need sealant .

Offline aclarke

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Re: Connecting rod bolts on McCulloch 125 SP
« Reply #27 on: December 29, 2014, 11:56:25 pm »
Interesting info on the "**** rod"  invention be from McCulloch!!

Offline Eccentric

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Re: Connecting rod bolts on McCulloch 125 SP
« Reply #28 on: December 30, 2014, 12:54:20 am »
The Homelite SXL-AO I tore down the other day has that **** rod setup.  Probably early 1970's production.  I'd mostly been seeing them in the large frame Macs (mid 1960's production) that I've had apart.

Offline 660magnum

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Re: Connecting rod bolts on McCulloch 125 SP
« Reply #29 on: December 30, 2014, 01:29:27 am »
I remember thinking in the early 60's how I thought that the Macs were the greatest chainsaws ever made. They may have very well been at the time?

Where I lived Homelite had the reputation of lasting longer because of the chrome bores.

I had more exposure to Lombards but thought of them as a cheaper alternative.
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