Re: Calling Allen in NE or other engine expert

Posted by Allan in NE on September 24, 2004 at 05:51:36 from (148.78.243.24):

In Reply to: Calling Allen in NE or other engine expert posted by Glenn F. on September 23, 2004 at 19:09:05:

Hi Glenn, how goes it?

These other fellas have nailed it right on the head and let me say right up front that I've never been closer to a Case than about 10 feet; never been inside one, so don't know anything about your tractor. Hey! They are the orange ones, aren't they? :>)

But, iron is iron I guess and please be forewarned that you, nor anyone else here for that matter, are not going to like what I'm about to say and I’ve received a lot of static over the years, ‘cause I’m so darned bull-headed and picky about this subject. This just is one of my pet peeves, so give me the benefit of the doubt here and allow an old man a soapbox for a minute, okay? :>)

Let’s face it, the piston/cylinder is the most critical area of any engine; this is the very heartbeat of that engine.

If you stop and think about it, that whole machine (whether it is a tractor, a car, truck, power-plant or boat) is built around that piston/ring/cylinder-wall fit and it's compression seal against the head. This is the exact location where the power comes from and this is the area where oil consumption is controlled. If there is any oil-burning going on, it is going to happen here at the combustion area.

Over time, things tend to wear; the cylinder wears, the rings wear, but more importantly and what many builders never, ever think about, is that darned piston.

Forget the pin and the outside of the piston for a minute. What I worry about is the ring grooves, because under normal conditions those rings are continually moving in and out. In addition, they are forever changing direction & actually ‘slapping’ from land to land at every single stroke that piston assembly makes.

On top of the rings, you have hot combustion gases and their resultant pressures burning away anything and everything that is combustible it it’s path (trouble is, this includes the engine oil too).

Underneath and inside the rings, the engine oil is always trying to ‘push into’ and lube this area of normal engine wear. It is a constant and forever ongoing battle, one force pitted against the other force. This goes on continually anytime the engine is running and happens far worse when the engine is cold.

End result is that the ring is wearing not only at the cylinder wall, but it is also wearing against that piston groove and it is not wearing in a sharp, well defined, square-edged fashion either; it wears in a “rounded” fashion. Wear comes at the upper and lower edge of the piston groove and also at the deepest edge of the groove. Pistons wear, it is just that simple, even though this wear is oftentimes not all that evident.

So, what happens? A guy will put a new ring against that worn piston and/or cylinder wall and they just do not match. From all indications, they seem to fit, but they just do not!

They never will either, no matter what you do. You are “building in” an oil consumption & ill-fitting engine component problem, right off the bat, right out of the box. We’ve torn this engine down and went to all this work to, in turn, ‘build in’ a problem.

Additionally, manuals and a lot of the experts will tell you that maximum cylinder bore taper and cylinder wall wave should not exceed .012” to .015”. Boy! That’s a stretch! New engine manufacturers use a figure of .005” absolute maximum differential. Zero taper and wave is considered ideal.

What I’m trying to say, is that if I’m going to go to all the trouble involved in rebuilding an engine, the very ‘last thing’ I’m gonna do is put a new part in that engine to wear against an already worn out old part….It just simply doesn’t make any sense to my mind. I install the whole she-bang in as a new set: a new cylinder (sleeve or bore), new piston/pin assembly and new rings, all of which are compressing against a fresh, well-machined head.

What type of ring to use? Given an ideal fit, it doesn’t matter one fig and it is totally up to you and how you are planning to use the engine.

You have three choices: cast, chrome or a combination of the two, which is known as a “moly” ring. The chrome rings are the hardest of the bunch and resist wear more and usually last longer; cast rings are cheaper and softer, but just don’t have the long term, anti-wear staying power of chrome. Like the others have already stated, a cast ring will break in faster because it is softer.

Disclaimer: Can you get away with just ‘ringing’ an engine? Sure, absolutely. Happens every day. If the engine is just doing light duty work, it will probably last for many years this way.

The point I’m trying to make though, is that just because Bob the Beast Builder tears down an engine and throws in a set of rings, this certainly does not mean that he has a “new”, durable and long-lasting engine.

What he has really ended up with, is a very limited, ‘kind of a refreshed’ & “patched” engine with a few band-aids applied along with some leak stopping gaskets thrown in here and there. Further, the life expectancy of this motor will only be about 30% that of a new or a correctly rebuilt engine.

Sorry for the long rant Glenn, hope ya get ‘er going okay,

Allan

Follow Ups:

• Re: Calling Allen in NE or other engine expert Glenn F. 07:53:24 09/24/04 (0)
• Re: Calling Allen in NE or other engine expert JT 07:34:45 09/24/04 (6)
  • Re: Calling Allen in NE or other engine expert Allan in NE 08:34:04 09/24/04 (1)
    • Re: Calling Allen in NE or other engine expert JT 16:06:15 09/25/04 (0)
  • Re: Calling Allen in NE or other engine expert Glenn F 08:20:51 09/24/04 (3)
    • Re: Calling Allen in NE or other engine expert JT 12:39:26 09/24/04 (0)
    • Re: Calling Allen in NE or other engine expert Glenn F. 09:40:09 09/24/04 (0)
    • Re: Calling Allen in NE or other engine expert Allan in NE 09:06:26 09/24/04 (0)

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