Tearing further into the 107

[finsruskw]

Lay that head on a piece of glass and run some feeler gauges around the edge to see just how bad off it is in the low spot/s

[Ambush]

By the time you're done, you'll know your machines literally inside and out!

For the bore size, just a good caliper will tell you the size plenty close enough. Measuring the "ridge" at the top will be the size before any wear. If it seems right in the middle of a standard size, then quite possibly someone has honed it by hand. And if they did a poor job, then its likely tapered too. Regardless, if you have to buy a piston, you might as well get it bored. You can't fix a tapered bore with a flex hone and a proper hone will cost you more than the machine shop bore job, with no guarantee that you'll hone it correctly anyway.

I often see used sets of Mitutoyo 0" to 6" mics for sale on FB for $150, both inside and outside, and as long as the outside mics have the standards with them you can trust the measurements.

You can also buy a cheap set of telescoping "mics" and a good caliper to get you very close. Digital calipers are great to use, just remember that they don't like to be stored in cold shops in the winter as the batteries get sluggish.

Quite often doing it right the first time can save both time and money and you have the pleasure of using a good machine.

"Buy once, cry once".

[Cubcadet_107]

Originally Posted by finsruskw

Lay that head on a piece of glass and run some feeler gauges around the edge to see just how bad off it is in the low spot/s

Ya know, I shoulda done that! I already began the process of attempting to flatten the head again. I think it might be doable, but not too sure if there's gonna be much difference between the actual cylinder head above the piston, and the gasket mating surface. It looks like this head may have been sanded down a couple times before. I will take a feeler gauge and see what I get, I will say that you can definitely feel the warp as well as see it.

IMG_20210530_090823.jpg


I pulled the fan shroud off. Yeah, I think the seal might have gone bad ! I guess this is the result of blowing your seal and running the engine anyway.
IMG_20210530_090748.jpg

It took a decent bit of force but I got the flywheel pulled off. New gasket and seal kit will be on its way soon.
IMG_20210530_093526.jpg

Interesting little extra bit, I noticed that the piston has "std" stamped in the top of it two times. One is larger than the other, wonder how that happened?

[Cubcadet_107]

Originally Posted by Ambush

By the time you're done, you'll know your machines literally inside and out!

For the bore size, just a good caliper will tell you the size plenty close enough. Measuring the "ridge" at the top will be the size before any wear. If it seems right in the middle of a standard size, then quite possibly someone has honed it by hand. And if they did a poor job, then its likely tapered too. Regardless, if you have to buy a piston, you might as well get it bored. You can't fix a tapered bore with a flex hone and a proper hone will cost you more than the machine shop bore job, with no guarantee that you'll hone it correctly anyway.

I often see used sets of Mitutoyo 0" to 6" mics for sale on FB for $150, both inside and outside, and as long as the outside mics have the standards with them you can trust the measurements.

You can also buy a cheap set of telescoping "mics" and a good caliper to get you very close. Digital calipers are great to use, just remember that they don't like to be stored in cold shops in the winter as the batteries get sluggish.

Quite often doing it right the first time can save both time and money and you have the pleasure of using a good machine.

"Buy once, cry once".

I've been looking around for a good set of calipers or mics, although, the previous owner is my neighbor, and I've talked to him about it, and he knows the shop that "rebuilt" it 30 years ago. I'm considering taking it back to them and asking why the heck it looks like this after only ~30 hours of use!!

In all seriousness, the bore isn't tapered. There's slop on all 4 sides at the very top, at the very bottom, and in every place between. This engine is sleeved.... or, it was supposed to have been sleeved. It looks like it was but I can't tell for sure.

My plan is to take it to a shop and have them look everything over and measure everything. I'm not expecting the crank to need grinding, nor do I really expect the bore to be out-of-round by very much, because again, this engine has ~30 hours on it since it was last rebuilt! But hey, you never know. I can have them clean it up real well, and then I'll take it and rebuild it with a new piston, rings, and connecting rod. Probably replace the governor as well, because I know those will fail occasionally.

Hopefully during that process, the reason that moisture keeps building up in the crankcase will become apparent and can be fixed as well.

That's the plan at least! Before I do anything I need to get the 147's k321 off the workbench and back into the 147.

[jbrewer]

There's really only two places the water could get in that I can think of:




Condensation (I'm in NC and I don't see water getting in the crankcase of my machines. They're under cover but not environmentally controlled). Did I mention it's really humid here?





Water/Rain entering somewhere. If there's a big cyl/head gap and leaky rings, if this was power washed it'd get water in the crank.



If I were to bet, I'd guess door number two, but.....

[ironman]

Originally Posted by jbrewer

There's really only two places the water could get in that I can think of:




Condensation (I'm in NC and I don't see water getting in the crankcase of my machines. They're under cover but not environmentally controlled). Did I mention it's really humid here?





Water/Rain entering somewhere. If there's a big cyl/head gap and leaky rings, if this was power washed it'd get water in the crank.



If I were to bet, I'd guess door number two, but.....

You didn't mention about 40 days and 40 nights and the Noah forgot the Cubs.

[Cubcadet_107]

Ok, time for another update. I've been pretty busy lately getting ready for summer, having a bit of trouble finding time for my Cubs. Also been working on my 147 a lot lately, putting this one on the back burner.

However I got back to it yesterday, and the 107 is now engineless. The k241 is up on the work bench ready for a tear down. I've pulled the old seals out of the k301, turns out they're basically rock solid. No wonder they both leaked! Only thing I'm waiting on is the new gasket and seal kit so I can replace the seals and a few gaskets, and then the k301 is going into the 107. Pretty excited to get my favorite machine back up and running soon.

[jbrewer]

Originally Posted by Cubcadet_107

Ok, time for another update. I've been pretty busy lately getting ready for summer, having a bit of trouble finding time for my Cubs. Also been working on my 147 a lot lately, putting this one on the back burner.

Pretty excited to get my favorite machine back up and running soon.

Glad to see that your namesake is about to be back in service before long. Yeah, it's hard to get 50 years out of seals these days :-)


Please keep us posted as you work though this. Oh, and pictures!

[Cubcadet_107]

I'll make sure to get some pictures soon, probably a video of the engine running once everything is done too.

And, I almost forgot, I still need to figure out a way to get the old 90* exhaust elbow outta the k301 so I can mount up the vertical stack setup off the k241.

That's one of my favorite parts of the machine, and I sure ain't gonna go back to the stock setup!

[Cubcadet_107]

Well, I guess I'll update this again.

In just a couple hours, my "quick engine swap" turned into this:






I don't know how this engine ever ran in the first place!

Pulled the pan to replace the gasket, pan is aluminum. Engine has balance gears! Removed the balance gears, only to notice that the connecting rod isn't installed with the oil hole facing the camshaft! Fixed that, put the engine back together, stood it up on the bench and... "Clunk". The governor actuator arm fell off the governor shaft! so back apart again! All this, combined with 2 blown seals and a blown head gasket! How this thing ran is a mystery to me.

Fortunately I fixed the governor, and the engine is all back together on the bench again. At this point, I'm just waiting for the correct size seals to be shipped to the auto parts store and I can (finally) get this darn engine into the 107!