Cylinder bores

Top End (cylinders and heads)
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StueyC
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Cylinder bores

#1

Post by StueyC » Fri May 21, 2010 1:41 am

I've removed my cylinders to replace the base gaskets. The motor has only done 5000 miles and the bores look good obviously. Should I de-glaze the bores before refitting them?

Thanks.
StueyC



Bosheff
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Re: Cylinder bores

#2

Post by Bosheff » Fri May 21, 2010 9:11 am

Yes, if ya want the rings to seat properly....bosheff

StueyC
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Re: Cylinder bores

#3

Post by StueyC » Fri May 21, 2010 9:35 am

Thanks Bosheff. I'll give them a light hone and practice my skills at getting the right cross hatch angle.

StueyC

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Re: Cylinder bores

#4

Post by Cotten » Fri May 21, 2010 1:42 pm

Modern rings do not seat!
If even the surface coating of a ring is worn off, they are considered "worn-out".

Call a Hasting tech line if you do not believe me.
(Phone (269) 945-2491,(800) 776-1088 or go to http://www.hastingsmfg.com/ and click on "live support".)

Modern bores are meant to be so smooth that a cotton ball drawn against them will not pull strands!
A common glaze-breaker is an antiquated implement of destruction. Hastings described a ball-hone similarly when I inquired.

What is critical is the "plateau finish" that consists of varied depths of cross-hatch that hold oil.
If the bore is still straight and round, no grooves of ring wear are detectable at the top or bottom of the stroke, and there is still obvious cross-hatch, then fresh rings can be applied.

If not, then a fresh plateau finish should be applied. A pro with proper equipment can achieve this with a minimum of enlargement of bore size.

....Cotten

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Re: Cylinder bores

#5

Post by steinauge » Fri May 21, 2010 3:17 pm

Cotten,at service school in 75,80 and 82 we were told to use 280-320 grit stones on our paralell hones to finish size freshly bored cylinders followed by a 240 grit ball hone .we were told this provided the correct surface for the current OEM rings which iirc were Hastings.Now I grew up on the old iron rings that required a (relatively) coarse surface to seat.I have seen stones for the Sunnen AN type hones to 500 grit.Do these produce the "plateau finish" you speak of or is there a different procedure? Thanks.

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Re: Cylinder bores

#6

Post by Dave_R » Fri May 21, 2010 4:18 pm

From Goodson's Website:


Back in the old days (maybe 20 years or more) cylinder honing was done almost exclusively with rigid hones and honing stones which led to some problems such as rough cylinder surfaces. It used to be that the rings scrubbed or shaved off the peaks of rough material left by the rigid stones over time. You may have heard of breaking-in a cylinder. That's what this is.

This process works but it has a couple of down sides. First, the rings and cylinders wear much faster and second, all the debris being shaved off of the cylinder surface ends up in your oil which can cause engine component wear.

Understanding the evolution of piston rings is important too. Early thought was wide rings with high tension. The wide rings were tough enough to handle the rough surfaces (to a point) but they also resulted in higher emissions. So as emission requirements evolved, piston rings did too. Today’s rings are narrower with low tension so they result in lower emissions and longer ring life. But they come from the factory pre-lapped so they can’t take the abrading that the older style rings could handle. So as the rings evolved, the honing processes had to as well.

The evolution of the rings gave birth to a finish that’s called a plateau finish. As the name implies, instead of the peaks and valleys created by the hard abrasive, a plateau is created by knocking down the peaks on the cylinder walls. This is where Flex-Hones® and Ultra Finish Hones come into the picture.

Achieving a plateaued cylinder bore is a multi-step process:

1) Hone to size with coarse grit stones – between 150 and 220 grit – using a portable hone or a honing cabinet with rigid stones and wipers.
2) Remove the peaks using a fine (280 or finer) grit flex-hone depending on the ring face material.
3) Remove the material that has become embedded in the crosshatch with an Ultra Finish Hone.

The ultra finish hone is made up of a monofilament nylon strand that is impregnated with fine abrasive material that breaks down as the strands brush across the bore surface.

According to one manufacturer, "These tools are specifically designed for mechanical finishing tasks such as: deburring, sharp edge removal, radiusing, edge contouring, de-fuzzing, surface refinement and conditioning, plateau finishing, blending imperfections, reduction of surface stresses and micro crack propagation, cleaning, polishing and surface wiping prior to inspection gauging." Whew, what a mouthful. Ultra Finish hones, aka plateau hones, soft hones, whisker hones or brush hones, will NOT enlarge or deglaze the bore under normal use, unlike Flex-Hones. They are basically deburring tools that remove the folded materials partially filling the crosshatch depth – or as I call them, “the uglies.”


I did this last year with Weisco pistons and rings and it has worked well for me.

For your application, I would just oil it up good and assemble it as it is, and run it.

StueyC
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Re: Cylinder bores

#7

Post by StueyC » Sat May 22, 2010 2:37 am

Thanks for the advise guys. There seems to be two opinions. I went and honed the cylinders last night prior to the "don't hone" responses being posted.

It's a bit hard to un-hone them so I'll see how things go when she is running again.

Thanks.
StueyC

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Re: Cylinder bores

#8

Post by Cotten » Sat May 22, 2010 3:01 am

StueyC!

At least work them over by hand with ScotchBrite, following the 60 degree cross-hatch.
Scrub mercilessly with hot soap and water before WD-40 and then before any oil.
Subjecting the raw cross-hatch to oil before cleansing will just set the grit and "uglies" into place even tighter.

This will get you as close to the last step of plateau honing as one can hope.

And Good Luck.

...Cotten
PS: Steinauge! 1980 seems like just yesterday to me too.

mtnmn 1830
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Re: Cylinder bores

#9

Post by mtnmn 1830 » Fri Jan 01, 2016 3:21 pm

If re-ring ball hone only, not a stone. If piston to wall clearances is too big re bore to next size.

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