Piston Inspection/Assembly/help

[rancher41]

Hello to all. I disassembled my Yanmar 2310 today to replace rings. The rings were bad in two of the pistons. I ridge reamed etc. and am going to be ordering parts. This is my first time at this and I would like some advice from those who have done this.

First, the sleeves look ok although I had to ream the ridges. How do I check ring gap to make sure I do not need to go ahead and replace the sleeves?

Second, two of the piston have some skoring on the sides. Do I need to replace the pistons?

Third, I am taking the head to the machine shop, what should I have them do to it?

Fourth, When I pulled the head the thid piston was at the top of its stroke, should I reassemble it this way.


fith , what is the procedure for checking the valves (after top dead center)?


Tourques:

Pistonrods?
Head bolts and sequence?
oil pan?
valve cover?

I know this is alot of questions but I sure need it to go back togheter ok and need the tractor on a daily basis.

Thanks .

Jim

 

[kenmac]

the 1 st place to start would be to purchase a parts manual & or a service manual . Service manual should give you all your specs.

 

[rancher41]

Yeah I plan on ordering the manual with the parts. What about the slight scoring on the pistons?, I can upload a pic. Also is the ridge I reamed off of the top of the cylinder wall to be expected?

Jim

 

[kenmac]

If you are talking about the piston skirts. I would say use them.If the piston is running up & down in a sleeve The cylinder shouldn't have a ridge.I haven't had a diesel engine apart but, I have had many gasoiline engines apart with a ridge but , the gasoline engine piston don't run in a sleeve which would cause a ridge

 

[MJPetersen]

Jim,

I would be interested to know how the rings were bad in the two cylinders. Were they broken? were they just worn? Was the spring tension taken out by overheating? What was "bad" about them?

There are a lot of factors in your questions. The scuffed piston skirts are usable, but the ring end gap, ring land wear, and cylinder taper are important points to consider.

End gap is checked with a new ring placed in the cylinder at the top of the stroke. You can square the ring in the cylinder by pushing it down with the top of an inverted piston with no rings on it. With few exceptions the end gap will not be a problem when installing new rings in an old cylinder.

Ring land wear is checked with a feeler gage with a ring installed in a clean ring groove.

The cylinder taper can be checked by using the same method as end gap, but checking at the top of the stroke and at the bottom and comparing the difference.

There are specs for all of these things. If any is out of the specified range then you need to re-sleeve the engine. Normally it is a package deal, which includes the sleeves, pistons, and rings.

Usually if the engine has sufficient wear that a significant ridge formed in the cylinder then it is better to re-sleeve the engine. In a non-sleeved engine they would bore it out and put in over-sized pistons. This is not to say that it will not work to simply hone the cylinder and put new rings on the piston. But the life of the engine will be MUCH longer with new sleeves.

Just my opinion.

Mike

 

[rancher41]

Mike,

It appears the top ring in the #1 got hot and lost its spring, also it is missing part of it broken. #2 cylinder has broken ring as well.
The scoring is on the skirt of two of the pistons.
So if the cylinders have ridges I should probably replace sleeves? How do I get them out?
The hour meter on the tractor reads 1680hrs
I will take in to consideration your advise.

Jim

 

[svcguy]

You should consider Yanmars recommendations for overhaul / rebuild. Overhaul is rings and bearings, rebuild is cylinders, pistons, rings and bearings. There is nothing wrong with taper or a ridge in a cylinder as long as it doesn't exceed the max allowable by the manufacturer. Once it exceeds the max allowable specs, you are marginalizing the unit by not following the manufactures recommendations to rebuild. To change out cylinders and pistons when not needed is a personal choice, much based on personality (and available funds). The real question is what is the relationship to your tractor? Many owners today don't use tractors the way we have in the past, the relationship has changed. Owners like to rebuild them, paint them, compare them with other owners and have them to new specs. (This isn't a slight towards anyone out there, it's just our changing society). The question you need to ask yourself honestly is do you have the tractor simply as a tool for specific work; or do you want more out of it. I treat my equipment really well, but I work it hard and I mean really hard. I blow out universals, have to replace tires, tie rods, clutch plates and am welding things back together constantly. I don't paint my equipment because I don't care about paint, but I am constantly overhauling equipment because of use. I really admire people who take the time to paint a tractor, I just can't be bothered. The long and short of it is, if you simply overhaul the engine just to haunt yourself that you didn't rebuild it, you better go all the way while you have it on the bench. Think of it this way, many people replace the rear tires when they begin to show age cracks. Others replace them when the side walls tear open. If you're the type of owner who doesn't want to see any cracks on tires or scratches on a fender, I would completely rebuild because you will be happy you did.

 

[MJPetersen]

So if the cylinders have ridges I should probably replace sleeves? How do I get them out?

Jim, The best way to go about this is to check the measurements that you make on the engine with what is specified by Yanmar. There will be a tolerance range +- and if the part fits in the range then reuse it, if it does not, then replace it.

How to pull the cylinders? I do not know what the proper method is. When I did it I made a puller with a piece of all thread, a few pieces of flat stock, and some nuts.

But the critical thing now is to determine what needs to be replaced and what can stay--or as srvc guy said, how well do you want to build this thing.

Mike

 

[rancher41]

Hey Guys,

Got the sleeves out via welding. Burnt through sleeve a littl. Will hone out. Is this ok???

Machinist said check rod bearings for copper color. Sure enough.

He said this could indicate crank journal excessive wear. What do you think?

A little bit discouraged today. Sleeves out, hope the pits in cylinder will not be a problem after honing. Sure wasn't planning on pulling crank.

Opinions please.

Thanks,

Jim

 

[rancher41]

Here is a picture of where I burnt through the sleeve. It looks worse in this picture. I only did it on the first sleeve. On the remaining two I tacked a pipe cap into the sleeve and they drove right out.

Regarding the crank journals any suggestions on what to look for. The machinist said to mike for specs. I thought I was on a role until the sleeve mishap and now the possibilty of having a crank with worn journals.

I can upload pics of the rod bearings with minimal copper coloring if it would help.

Really need to get the tractor back together but as previously mentioned, a little discouraged.

This board has gotton me pretty far along so far.

Jim