McCulloch 790 project...

[Eccentric]

I expect it is worth replacing the rings as long as you have it down that far, rings are not so expensive and can make a big difference in compression...if you want the saw to really pull hard in the cut.

Standard rings will be 58353 is the bore is 2.119.

Mark

I think you made a typo my friend. You've told me before that the bore for a 103cc Mac is 2.217" (while a 99cc Mac is 2.165"). The 80 and 87cc Macs are 2.125". The 58353 part number for the rings is dead on of course...

I measured the piston with my micrometer, and it came out to 2.2345" I kinda forgot how to read a micrometer... :bang: I may be wrong, so I will post a pic of the measurement after I eat some lunch. If I'm and this measurement is right, I assume that means the piston may be an overbore size.

Mark just made a typo I bet. Understandable, with all the world traveling he does for a paycheck.

I got a cheap but good set of snap gauges from Amazon.com for less than $20. Measure your bore and piston carefuly. You may have a saw that's already at an overbore (my guess being .020" based on your earlier piston measurement).

 

[promac850]

I think you made a typo my friend. You've told me before that the bore for a 103cc Mac is 2.217" (while a 99cc Mac is 2.165"). The 80 and 87cc Macs are 2.125". The 58353 part number for the rings is dead on of course...



Mark just made a typo I bet. Understandable, with all the world traveling he does for a paycheck.

I got a cheap but good set of snap gauges from Amazon.com for less than $20. Measure your bore and piston carefuly. You may have a saw that's already at an overbore (my guess being .020" based on your earlier piston measurement).

Will check all measurements again, and again, and again, until I am sure I've got it right. Gotta get some snap gauges and clean the cylinder before I can measure it. Meanwhile, I can check the piston over and over as much as I want.

 

[Roanoker494]

6 Piece Telescoping Gauge Set

Use coupon code 20TOOL for 20% off, brings the the cost down to $12 + $7 shipping.

 

[promac850]

6 Piece Telescoping Gauge Set

Use coupon code 20TOOL for 20% off, brings the the cost down to $12 + $7 shipping.

I will look into that. I also am going to check with my neighbor, he might have a set I could borrow. He used to build some awesome pulling tractors with Honda 750 engines.

Hopefully he'll have them... if not, I'll have to get them at HF or Amazon or the like.

Sorry to make you guys jump through hoops to find this info for me... I just want to make sure I get exactly what you have as you had good results... there are lots of different sets available from various places.

 

[dieselsmoke]

I think you made a typo my friend. You've told me before that the bore for a 103cc Mac is 2.217" (while a 99cc Mac is 2.165"). The 80 and 87cc Macs are 2.125". The 58353 part number for the rings is dead on of course...



Mark just made a typo I bet. Understandable, with all the world traveling he does for a paycheck.

I got a cheap but good set of snap gauges from Amazon.com for less than $20. Measure your bore and piston carefuly. You may have a saw that's already at an overbore (my guess being .020" based on your earlier piston measurement).

+1 on the .020 overbore. the piston looks good, I wonder why no or low compression???? :confused2:

 

[promac850]

+1 on the .020 overbore. the piston looks good, I wonder why no or low compression???? :confused2:

I think the rings... the bore looks excellent, and just appears to need a little cleaning. I did notice some streaks, but nothing like it would be if it was aluminum transfer. I just hope it doesn't need to be bored...

Checked the rod journal on the crank, and it is perfectly the same all over... something around .6215" forgot exactly what the number is.

 

[promac850]

I did the ring end gap trick to measure the cylinder... it's almost perfect. There is only a .001" difference from the bottom of the cylinder and the top, there is a .0005" difference in the middle from the top... I'd say I'm good to go on just putting new rings in.

The cylinder and other parts of the crankcase/stuffer plate, etc. are clean, well clean enough for me...

I still am not sure about painting the engine after I get it together, as my big compressor is not completely set up yet, and I have not made the soda blaster yet...

I'm pretty sure the stuffer plate will need that JB weld trick applied, as it seems to look a little leaky... I may be wrong though.

 

[heimannm]

...if the bore is 2.219/2.218, can't imagine where that came from...

The ring end gap trick only tells you if the bore is straight, not what the diameter is. You need to know both and make sure the piston is about 0.004" smaller than the bore.

Mark

 

[promac850]

...if the bore is 2.219/2.218, can't imagine where that came from...

The ring end gap trick only tells you if the bore is straight, not what the diameter is. You need to know both and make sure the piston is about 0.004" smaller than the bore.

Mark

I will be ordering some gauges now.

 

[slipknot]

Did ya get them t-gauges?

 

[promac850]

Did ya get them t-gauges?

They shipped yesterday, I think? Should be here soon, like tomorrow or Monday.

I am waiting on them gauges too... I wanna get this thing going!!!

Six cube club, I'm headed your way...

 

[leeha]

They shipped yesterday, I think? Should be here soon, like tomorrow or Monday.

I am waiting on them gauges too... I wanna get this thing going!!!

Six cube club, I'm headed your way...

In all my years, I have never needed a set of them gauges yet.
Get that thing together.



Lee

 

[promac850]

In all my years, I have never needed a set of them gauges yet.
Get that thing together.



Lee

But... but... Mark said to check the clearance of the piston...

And, um... I don't want to tempt Murphy with some classic beast like this... they ain't a dime a dozen anymore.

And gotta buy some rings too.

 

[nmurph]

But... but... Mark said to check the clearance of the piston...

And, um... I don't want to tempt Murphy with some classic beast like this... they ain't a dime a dozen anymore.

And gotta buy some rings too.

Why do I always get the blame when someone's foresight fails them?

 

[promac850]

Why do I always get the blame when someone's foresight fails them?

Whoa, not you Murph... I was talking about the evil third cousin's great grandfather's second brother on the fifth side of you...

In other words, no one related to you or the family... this Murphy is the bad one... not a good one like you...

Here's your cigar...

My foresight does not seem to fail me too often... which is good. At least I hope it don't fail me often...

Then again, I've tweaked Aaron's eccentric a few times. He didn't like it.

 

[Eccentric]

Whoa, not you Murph... I was talking about the evil third cousin's great grandfather's second brother on the fifth side of you...

In other words, no one related to you or the family... this Murphy is the bad one... not a good one like you...

Here's your cigar...

My foresight does not seem to fail me too often... which is good. At least I hope it don't fail me often...

Then again, I've tweaked Aaron's eccentric a few times. He didn't like it.

You're right. Neal's not the Murphy we need to watch out for. The "other" Murphy is a twisted SOB however. He's gotten me more than a few times...


You most certainly did not tweak my eccentric. You did spill my beer a few times.....dammit.

You're still on probation regardless. Just relax and keep thinking before hitting the "Submit Reply" button...

 

[Duke Thieroff]

You're right. Neal's not the Murphy we need to watch out for. The "other" Murphy is a twisted SOB however. He's gotten me more than a few times...


You most certainly did not tweak my eccentric. You did spill my beer a few times.....dammit.

You're still on probation regardless. Just relax and keep thinking before hitting the "Submit Reply" button...

Thinking may have got him in trouble in the first place, but such is life.

Sometimes people need to bump heads in order to find a way to get along.

Sometimes people may spill your beer, but as long as they offer to buy you another one the sin should be washed away. Unless they spill it everytime they sit next to you, then you gotta make some heads roll.

Aaron, I would never try to "tweak your eccentric." I don't know exactly what that means, but doesn't sound like anything I would want to do while dressed in my Sunday clothes.


Saying "you're on probation" sounds like it came out of RandyMac's quote book. Buddy, you're worse off than I thought.


Chris

 

[promac850]

Thinking may have got him in trouble in the first place, but such is life.

Sometimes people need to bump heads in order to find a way to get along.

Sometimes people may spill your beer, but as long as they offer to buy you another one the sin should be washed away. Unless they spill it everytime they sit next to you, then you gotta make some heads roll.

Aaron, I would never try to "tweak your eccentric." I don't know exactly what that means, but doesn't sound like anything I would want to do while dressed in my Sunday clothes.


Saying "you're on probation" sounds like it came out of RandyMac's quote book. Buddy, you're worse off than I thought.


Chris

Yep.

Yep.

Yep. I owe you some beers.

What was meant by that was pissing him off enough to permanently be hated by him.

Hmm... RandyMac seems to be the emperor king a la maximus around here... we must follow his orders.

Sorry if I spilled your beer again. I'll be sure to have a pack of PBR waiting for you if I ever turn 21.

As for my project six cuber, I am keeping an eye out for them gauges. I may clean some more parts up, if I can manage to open up a path to the parts washer.

Almost made another story on injured brooms, but deleted it. Spilling beer is alcohol abuse. I try not to cause it.

 

[ChainsawmanXX]

Get to work Kyle! lol

 

[Eccentric]

Thinking may have got him in trouble in the first place, but such is life.

Sometimes people need to bump heads in order to find a way to get along.

Sometimes people may spill your beer, but as long as they offer to buy you another one the sin should be washed away. Unless they spill it everytime they sit next to you, then you gotta make some heads roll.

Aaron, I would never try to "tweak your eccentric." I don't know exactly what that means, but doesn't sound like anything I would want to do while dressed in my Sunday clothes.


Saying "you're on probation" sounds like it came out of RandyMac's quote book. Buddy, you're worse off than I thought.


Chris

You don't know the half of it my friend.

Yep.

Yep.

Yep. I owe you some beers.

What was meant by that was pissing him off enough to permanently be hated by him.

Hmm... RandyMac seems to be the emperor king a la maximus around here... we must follow his orders.

Sorry if I spilled your beer again. I'll be sure to have a pack of PBR waiting for you if I ever turn 21.

As for my project six cuber, I am keeping an eye out for them gauges. I may clean some more parts up, if I can manage to open up a path to the parts washer.

Almost made another story on injured brooms, but deleted it. Spilling beer is alcohol abuse. I try not to cause it.

I don't hate you Kyle. Takes a lot more than the stupid moves you've made on AS for that to happen. You did piss me off a couple times, but that's not grounds for hate (that's more of a HS thing). You've spilled beer here a few times too many, and that's why you're on probation. Try not to step on your weenie so much.

Just don't try so hard to impress us. Take part in the tech talk when you know what you're talking about, and limit the 'banter' a bit until you get a firm handle on how men BS with each other. That takes time. I didn't have it down when I was 18. Since you're looking for work, have you tried starting out at a mower/saw shop? Get in on the ground floor.

I wasn't only joking when I said you need to sweep some shop floors, do oil changes, and make lunch/parts runs. Working with some extremely knowledgeable older guys in a shop sure helped me out. At the time, I probably knew more technical stuff than some of them, but in the areas of experience and temperment...........they were all miles ahead of me. Had to swallow my pride a few times. That's a valuable learning experience. Sometimes it's hard to shut up and listen when you're a young buck and your mind's going a mile a minute...