Changing Piston rings

HomervilleBill · Apr 5, 2010

In the quest to solve some issues with my Ford 860, I decided while I am at it, I would take the head off have the valves changed. I have now decided I might at well change the rings and bearing. I was going to use a cylinder hone, then replace the pistons. The bores look, and feel fine, is is necessary to have them rebored? Your advice is helpful. Thanks.

Bob · Apr 5, 2010

"The bores look, and feel fine"

Checking with a bore gauge for wear and taper is a bit more accurate!

Also, check out the information linked below about fitting rings and ring groove wear.
Reeds Tips

BCnT · Apr 5, 2010

if theres no ridge towards top of liners,you should be good to go with just honing...use cast iron rings tho [hastings] chrome rings dont seat too good unless its a fresh bore.
check ring groove gap to see if your pistons are worn before removing old rings.

JDemaris · Apr 5, 2010

The ring side-clearance is critical. Get a new ring, stick it into the old piston, and measure with a feeler gauge.

You can repair worn pistons with Hastings ring-shims, but probably not worth the bother with a Ford tractor, since new pistons are cheap.

Bspauld · Apr 5, 2010

I would think the piston to cylinder clearence is important to

El Toro · Apr 5, 2010

You should have those cylinders measured for wear. Hal

JDemaris · Apr 5, 2010

Many things are important. But, with a used gas engine, ring grooves in the pistons are often the first thing to get worn, and often the most common to be overlooked. In a diesel, even worse - unless they are Plasma-Keystone rings. Cylinder taper is also important, since it causes excess ring movement in those piston grooves. Scores in the cylinder walls are also a problem. As to clearance? Yes, but I'd stick it at the bottom of my list. Much of that depends on if you've got aluminum cam-ground pistons, or older split-skirt pistons.

Years back we used to "rebuild" old pistons, #1 by knurling the skirts to make them fit tighter, and #2 by recutting the grooves and adding repair shims. I still do it on engines I can't find new parts for - OR if the new parts are super expensive.

Walterdavies · Apr 5, 2010

If you don't have any lip at the top of the cylinders then they are most likely in good enough shape to just hone and put in new rings. Wear on cylinders starts at the bottom and pushes out at the top. Any lip that can be felt with the finger nails means a bore job.
Walt

showcrop · Apr 5, 2010

You need to check the liners top to bottom, As they will get tapered. I had one where the rings could ride up and down 1/16 in the grooves.

Bspauld · Apr 5, 2010

the first thing I do is mike the bore and the pistons,if the clearence is going to be ok I hone it to straighten the bore out,but thats just me to,

Anonymous-0 · Apr 5, 2010

doing an inframe honing job is a great way to destroy bearings, very hard to get all of the grit out

Leroy · Apr 5, 2010

First of all that engine is NOT desgned to be bored as it uses sleves and if the bore gets bad you pull the old sleeve out and install a new one. The new sleve is cheaper than a bore job and with bore you would have to get oversize pistons and they are not made for that tractor. If in any dought just buy a sleve, piston and ring kit. Wonder why all other posters did not comment that you DO NOT bore one of those engines.

Changing Piston rings

HomervilleBill

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Bob

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BCnT

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JDemaris

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Bspauld

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El Toro

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JDemaris

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Walterdavies

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showcrop

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Bspauld

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Anonymous-0

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Leroy

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