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Missing piston rings EH Wachs

Chris AW

Registered
I just took apart my EH Wachs vertical and found a couple of grooves with no rings. Is this intentional to carry oil? The engine generally lacks power and I’m wondering if I’m having blow by. What do you think?
C91452ED-7317-47F5-B695-9AD3C31F8662.jpeg
 

AndyG

Registered
Last Subscription Date
01/13/2014
should the center groove have 2 rings or one big one?
 

JBoogie

Registered
Age
38
Last Subscription Date
11/12/2013
should the center groove have 2 rings or one big one?
It really doesn't matter. Some places will only make them up to a certain width so your only option is to stack them. They may even seal better than one wide ring since you're making a longer path for the steam to sneak through. If the bore is bell mouthed or out of round new rings won't help much.
 

Chris AW

Registered
As it turns out, the ID of the cylinder is larger at the ends. The grooves at the ends of the piston travel into that larger ID. I tried it, and it runs horribly. So, I’ll just replace the two center rings and hope I get a little better sealing.
 

Odin

Subscriber
Last Subscription Date
07/13/2019
The stroke is long enough that the rings go off the ends of the bore and into the clearance volume at the ends? Seems an odd problem, makes me think either the piston is not correct for that cylinder or that the crankshaft has too long a stroke for that engine.

Only real fix I can think of that without making a whole new piston would be to put the existing piston in a lathe and make a new pair of ring grooves in it that are set in further so they don't travel past the bore they should be run in.
 

Pete Deets

Subscriber
Last Subscription Date
01/01/2020
Chris,
Is the larger diameter a step or is it just worn at the ends? Can you provide a picture of one end of the cylinder? Locomotive cylinders have a short counterbore at the ends and the pistons travel such that the edge of the rings just go past the larger edge. That way there is no ridge at the end of the travel from bore wear..............PD
 

Lester Bowman

Subscriber
Last Subscription Date
07/09/2019
Pete is Correct. A "counter Bore" is often applied on both ends of the bore allowing to ring to over run slightly thus avoid forming a ridge. Sounds like you have a tapering bore plus a counter bore. Run the rings as you suggested Chris. Might be all it takes. :)
 

JBoogie

Registered
Age
38
Last Subscription Date
11/12/2013
That piston must have been scavenged from something else. Sort of makes sense why the grooves are in the center. I would do some figuring and turn up a new one.
 

Chris AW

Registered
The stroke is long enough that the rings go off the ends of the bore and into the clearance volume at the ends? Seems an odd problem, makes me think either the piston is not correct for that cylinder or that the crankshaft has too long a stroke for that engine.

Only real fix I can think of that without making a whole new piston would be to put the existing piston in a lathe and make a new pair of ring grooves in it that are set in further so they don't travel past the bore they should be run in.
The stroke is long enough that the rings go off the ends of the bore and into the clearance volume at the ends? Seems an odd problem, makes me think either the piston is not correct for that cylinder or that the crankshaft has too long a stroke for that engine.

Only real fix I can think of that without making a whole new piston would be to put the existing piston in a lathe and make a new pair of ring grooves in it that are set in further so they don't travel past the bore they should be run in.
That was my plan. But taking measurements, even with wider rings wouldn’t take care of it. A friend recommended I could bore the cylinder to the larger OD. I’m just not sure if I’d be thinning the wall too much.

Chris
 

Chris AW

Registered
Chris,
Is the larger diameter a step or is it just worn at the ends? Can you provide a picture of one end of the cylinder? Locomotive cylinders have a short counterbore at the ends and the pistons travel such that the edge of the rings just go past the larger edge. That way there is no ridge at the end of the travel from bore wear..............PD
Yep. It’s a counterbore. It extends 1/2” from the end of the cylinder. Of course, the ports are located in that counterbore.
 

Pete Deets

Subscriber
Last Subscription Date
01/01/2020
Of course, the ports are located in that counterbore.
OK Chris,
That's what is supposed to happen. That way your rings can't lap over the port and give troubles.

As I type this a thought just struck me - On your new rings do the ends of the ring overlap or do they have an open butt gap like your old rings in the picture or did you get either a step or oblique cut ring end? If the ends don't overlap then the steam may be leaking through the endgap and out......PD
 

Pete Deets

Subscriber
Last Subscription Date
01/01/2020
And another question - how much taper does your cylinder have? All you'd need to do is make it round and square to the crank again. I hope your friend wasn't thinking of taking the counterbore out, that would be a mistake. Another purpose of the counterbore is to preserve an unworn reference surface to allow you to find the original center of the bore. For an engine to run best the center of the bore should line up with the center of the crank when the bore is fresh and the crank bearings are new. Boring out any more iron than it takes to make it round & square to the crank is wasted cylinder life.
 

Chris AW

Registered
OK Chris,
That's what is supposed to happen. That way your rings can't lap over the port and give troubles.

As I type this a thought just struck me - On your new rings do the ends of the ring overlap or do they have an open butt gap like your old rings in the picture or did you get either a step or oblique cut ring end? If the ends don't overlap then the steam may be leaking through the endgap and out......PD
Pete, The rings are square ended. However, there are two rings side by side in the center with any gap on opposite sides.
 

Chris AW

Registered
And another question - how much taper does your cylinder have? All you'd need to do is make it round and square to the crank again. I hope your friend wasn't thinking of taking the counterbore out, that would be a mistake. Another purpose of the counterbore is to preserve an unworn reference surface to allow you to find the original center of the bore. For an engine to run best the center of the bore should line up with the center of the crank when the bore is fresh and the crank bearings are new. Boring out any more iron than it takes to make it round & square to the crank is wasted cylinder life.
Pete, I’ll need to find a bore gauge to check the cylindricity. That’s a word I don’t use frequently.
Thanks, Chris
 

Pete Deets

Subscriber
Last Subscription Date
01/01/2020
Chris,
Is there a pin or some other way to keep the outer rings from lining up their gaps? Is it possible that may have happened? From your photo it also looks like the center ring groove allows for about twice as much ring as the outer grooves. It may also be a photo illusion. I can't give you a definitive answer but most all the rings I see that come out of steam engines are either step or oblique. ...........PD
 

Chris AW

Registered
Chris,
Is there a pin or some other way to keep the outer rings from lining up their gaps? Is it possible that may have happened? From your photo it also looks like the center ring groove allows for about twice as much ring as the outer grooves. It may also be a photo illusion. I can't give you a definitive answer but most all the rings I see that come out of steam engines are either step or oblique. ...........PD
Pete, Yes, the center groove is 3/16” wide and there are two 3/32” rings in there. There is no pin to prevent the ring gaps from aligning. I’m not sure that there is sufficient gap for a pin to fit in. I appreciate your advice.

Chris
 

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