C-120 Auto #2

[lynnmor 6,796]

4 hours ago, Mr Magoo said:

I looked at those HF gauges. Do you all think they are accurate enough?

 

 

You use telescope gages with a micrometer.  As long as the gage is made well and moves freely without play, the accuracy come from the skill of the inspector.    Before measuring, apply a touch of oil on the contact ends.  Next, place the gage in the bore at a slight angle and snug the clamping screw so there is drag, but not too tight.  Now rock the gage over center and it will compress to the bore size, then remove it for measuring with a micrometer.  Do it multiple times to get repeatable readings.

[oliver2-44 8,861]

It’s interesting that all the carbon is around the valves and  only on a small side of the piston. I’ve been told thats caused by blow-by indicating the oil wiper ring is worn and/ or the bore is egg shaped

I 

[richmondred01 2,208]

I would look a bit deeper and check the valve guides. 

[Mr Magoo 226]

I am in the process of  gathering the tools I will need to explore this deeper. I am going to try and get good quality tools for the job. They may not be machine shop quality, but not bargain basement ones either. At least I will have what I need to work on my 856 too. I have a feeling it will need some motor work also. 

 

Thanks for the suggestions guys. I have felt since I got the 3 tractors that this one was parked many years ago because it had a problem. I think the previous owner liked the model and went out and found another C-120 auto to replace it instead of fixing it. 

 

 

[Mr Magoo 226]

I got some time to get the head and block cleaned up this weekend. After cleaning the carbon off of the top of the piston this is not exactly what I wanted to see. Another rebuild is not happening with this block. 

 

 

[Mr Magoo 226]

Well, looking at the specs I guess it can go over .020 over. That is of course dependent on how the cylinder measures.  

[richmondred01 2,208]

Your piston reflects that it is at .020 over however, the block is stamped.010 over.

It needs to to properly measured to be sure.

 

[richmondred01 2,208]

Your piston reflects that it is at .020 over however, the block is stamped.010 over.

It needs to to properly measured to be sure.

 

[Mr Magoo 226]

25 minutes ago, richmondred01 said:

Your piston reflects that it is at .020 over however, the block is stamped.010 over.

It needs to to properly measured to be sure.

 

I noticed that too. I figured it was stamped .010 on the first rebuild. 

[ebinmaine 63,214]

9 hours ago, Mr Magoo said:

Another rebuild is not happening

@richmondred01

Is sleeving these blocks an option?

Cost effective or no?

 

[richmondred01 2,208]

Yes they can be sleeved but it’s not cost effective. There are still plenty of good blocks around. 

[Tuneup 1,416]

You might be lucky as it appears that the piston is ground down at the exhaust valve point so is out of round at the top. Maybe the block is OK but a measure is required to be sure. The block is cast iron, after all.

[Mr Magoo 226]

Having someone else rebuild one is not cost effective either from the little bit of research I have done. I guess it depends on if you really just want to keep it forever. Paying someone to rebuild one or buying one rebuilt quickly exceeds the market value of the unit. 

[Mr Magoo 226]

2 minutes ago, Tuneup said:

You might be lucky as it appears that the piston is ground down at the exhaust valve point so is out of round at the top. Maybe the block is OK but a measure is required to be sure. The block is cast iron, after all.

Okay, here is a question I have. Can the bore be measured with the piston still in the cylinder or do you need to take it all apart? I realize that you could not measure the crank that way.

[Tuneup 1,416]

The experts would have to answer that but from a fellow layman, why not? Piston at BDC would allow a measure from the top of the bore to almost where the rings ride. Not the whole bore but, OK for me - again, just a shade tree guy. That piston looks like it's out of round on top. It can use a fresh one so that's an afternoon tear-down anyway.

[ebinmaine 63,214]

11 minutes ago, Mr Magoo said:

the market value of the unit.

Monetary market value. Maybe. That depends on your selling area.

 

But the value of having an older machine that's going to last much longer than the new replacement throw away garbage far exceeds the monetary value.

 

I would put $2,000 or even more into an old Wheelhorse all day everyday before I went out and spent twice that on a new mower.

 

[richmondred01 2,208]

Yes like Tuneup said it can be measured if the piston is at the bottom of the cylinder and .030 pistons are available if the .020 bore is out of spec.

[richmondred01 2,208]

21 minutes ago, ebinmaine said:

Monetary market value. Maybe. That depends on your selling area.

 

But the value of having an older machine that's going to last much longer than the new replacement throw away garbage far exceeds the monetary value.

 

I would put $2,000 or even more into an old Wheelhorse all day everyday before I went out and spent twice that on a new mower.

 

you should see if someone in your area sells rebuilt long blocks. This way you save buying the complete engine and you still get the satisfaction of using parts off your engine rather then trashing the whole tractor.

just make sure the wheel horse spec with the correct length and diameter crank.

[Mr Magoo 226]

15 minutes ago, richmondred01 said:

you should see if someone in your area sells rebuilt long blocks. This way you save buying the complete engine and you still get the satisfaction of using parts off your engine rather then trashing the whole tractor.

just make sure the wheel horse spec with the correct length and diameter crank.

The long blocks I have seen are in the $700-$800 range. 

[tom2p 2,393]

junk tractor with a good engine (long block) might be a good option 

 

[squonk 38,965]

6 minutes ago, Mr Magoo said:

The long blocks I have seen are in the $700-$800 range. 

You'll spend more than that rebuilding it correctly

[tunahead72 2,343]

11 hours ago, richmondred01 said:

... the block is stamped.010 over ...

 

11 hours ago, Mr Magoo said:

I noticed that too. I figured it was stamped .010 on the first rebuild. 

 

I don't have any experience rebuilding engines myself, but I have taken several Kohler heads off for inspection and cleaning.  I've never seen a marking like that on the block, is Mr Magoo correct that this engine was probably also rebuilt earlier at .010" over?

 

[richmondred01 2,208]

Most quality machine shops stamp the head and crank that have had work done.

If previous work had been done they XX out the old and restamp with the new. 
 

[Mr Magoo 226]

I cleaned up the head and will try and get it put on this weekend. I replaced all of the fuel lines, tank bushing, and shut off valve last weekend. The carb seems to be really clean and tight.

 

I want to try and at least get it running for a little while to assess the transmission. If I have a problem there it will probably not fix the motor.

 

 

[tunahead72 2,343]

Good luck, and keep us posted! 

 

What is that you used as the base for your sandpaper?