6/1 Metro First Run -- Waterpump Problems

[vtmetro]

Hello all,

I just ran my new Metro 6/1 yesterday and had a great time seeing it spring to life.

Unfortunately, after about 5 minutes of running, I thought I heard some "off" sounds -- a little more clackety-screechy than the first minute -- but I wasn't sure. I stopped it -- had planned to anyway at this point to change break-in oil. I drained it and cleaned out the sump. Then after checking things over to see if I could find any source of the noises by slowly rotating by hand -- nothing.

There was no casting sand in the bottom of the engine, when I first examined it, and none after the 5 minute run either. The magnet I put in looked good. Nothing I could see was causing any problems.

The water pump was leaking out of the pulley end, I figured it must be a stiff seal or packing of some kind. The engine had sat for a year in the crate and the pressure of the fan belt may have deformed the seal in one position. I hoped running might help the seal.

I started the engine again to see if the sound was still there, but I couldn't hear it. I applied some pressure to the flywheel rim with a 2 by 4 to help load the engine to set the rings. After 10 minutes more, I thought the internal mechanical noise was maybe more noticeable. Then all of a sudden it stopped and the engine suddenly ran extremely quietly and smoothly compared to how it had been before. But then I started to see smoke coming out of the lower back side of the engine. So I looked at where it seemed to be coming from. What could that be? No exhaust down there -- it couldn't be -- an exhaust leak would be up at the head. Then I saw it. The fan belt was smoking, and the water pump pulley was stopped. Must be seized.

I stopped the engine. Took off the pump. Opened it up. It had ball bearings at the pulley end of the shaft. And no bearings at all at the other end. The ball bearing had a broken inner shell -- bits of metal and ball bearings loose. It was very cruddy and rusty, with very little grease in it. What grease there was looked like something wiped off of the garage floor.

The more I looked at this pump the less I understood. How could it possibly work without a bearing at the rotor end? How could it seal at the ball bearing end without a seal there? I did find what looked like a seal at the rotor end, but the metal part of it didn't fit the shaft.

I'm completely stumped by this pump. How could it possibly work? How could the water not have flowed through the ball bearing and out that end plate (in fact it did!).

It makes no sense to me unless there's a missing bearing and seals.

Can someone else here explain?

I can post a photo of the pump parts later tonight when I figure out how to do that on this forum.

Also, I'm thinking of going to just a non-pumped thermo-siphoning system.

I almost made up a new cover plate for the pump location on the block, with a pipe nipple. But ran out of oxy-acet.

I notice that the piping on the pump system is 1" dia.

Is that what is found on the thermo-siphoning versions of these engines?

I thought I read 1-1/2" somewhere else.

I hope not, because I just bought 13 feet of 1" radiator/heater hose for the pump system. Also I'd have to make a new fitting for the head as well.

[ronmar]

Well that is the best thing about a thermosiphon, no pump to quit unexpectedly...    The fittings on my 6/1 are 1", and my thermosiphon system uses 1" hose and pipe.  Your noises were probably the pump self destructing.  I notice with mine it runs a little noisier after it gets up to full temp, the oil thins out and everything loosens up a bit.  Even with a thermostat, because of the slow RPM and small fuel consumption,  these things take quite a while to get good and warm.  10 minutes with a 2X4 isn't really going to do much for seating the rings.  It needs some sustained(hours?) load at full op temp(around 195F) to do that.  They are a hoot to get running, but don't wait too long to get the genny on it.  That is the best way to get a sustained load onto the engine...

[vtmetro]

Thanks Ronmar. That's good news about the 1" dia thermosiphon.

I'd planned on breaking in under load for a lot longer (I do have a ST-5 belted to the engine), but the pump self-destruct put an end to it sooner than planned. I didn't want to run electrical loads until I knew more about out of the box RPM, etc.) I think the 2x4 against fulcrum and flywheel was doing a good job of loading the engine. I was able to drop the RPM, and I probably could have stalled it with more pressure. That's a brake on the flywheel with a 10' lever. I checked the revs with an optical tach I had already. Put a piece of reflective tape on the flywheel rim. As set up it ran 677 RPM. I dropped that with the governor adjustment to 650.

Vibration wasn't too bad. Subframe is on rairoad ties in wetted mixed size sand, per utterpower mention. It was amazing how quietly the engine ran after the water pump seized! Most of the mechanical noise was coming from that bad bearing.

I'm still curious about that single bearing at one end. Is that normal? I'll post pictures later.

[vtmetro]

Here's a picture of the bad ball bearing. The inner shell has broken apart, and the grease looks like it's 10 years old on this new (2009) Metro water pump. Actually the pump looked bad externally to begin with, like an afterthought. It wasn't painted green like the rest of the engine, and looked somewhat rusty. (Probably from its first run at the factory, when water leaked through it, and nobody bothered to replace it.) That's a piece of bearing race on the lower left. This is looking at the pulley end.



Notice there is no bearing at the impeller end. Just a seal that is loose on the shaft. It doesn't fit either the narrow portion of the shaft or the wider portion. Hard to understand how it could seal anything.



And here's a picture of all of the parts. There is also a grease cup on the housing that seems to have no purpose. The housing was not filled with grease (and a grease cup would be a poor way to do that anyway) and there is no bearing anywhere near it to be lubricated.





Does anyone know how this pump is supposed to work, or whether there should be a second bearing at the impeller end? I have no parts list for the pump, and no exploded view in the Metro manual.

The impeller is somewhat cone shaped on the end, and the housing end plate fits this roughly. But it's hard to believe that would work as a bearing.

Very confusing.

[ronmar]

That first pic with the broken bearing is of the pully side of the housing?  What is that thing on the shaft right next to the back side of the impellar?  It looks like it might have supposed to have been a bearing of some sort.  It looks lke there is supposed to be some type of O-ring on the back of the impellar plate.  Is this correct?  I don't think any part of the impellar would be used as a bearing sutface.  Because of the nature of a centrifugal pump, the center of the impellar must be clear to allow fluid to enter the pump at the center of the impellar disc. 

I don't think I have heard anything positive about one of these pumps, or of anyone getting any long term service out of them...     

[vtmetro]

That first pic with the broken bearing is of the pully side of the housing?  What is that thing on the shaft right next to the back side of the impellar?  It looks like it might have supposed to have been a bearing of some sort.  It looks lke there is supposed to be some type of O-ring on the back of the impellar plate.  Is this correct?  I don't think any part of the impellar would be used as a bearing sutface.  Because of the nature of a centrifugal pump, the center of the impellar must be clear to allow fluid to enter the pump at the center of the impellar disc. 

I don't think I have heard anything positive about one of these pumps, or of anyone getting any long term service out of them...     

Thanks ronmar. To answer your questions:

1.) Yes, the first pic is the pulley side of the water pump
.
2.) The thing on the shaft next to the impeller is the seal. It is a rubber dome on one side and a sheet metal disk on the other side. The rubber side is shaped like a dome with a hole in it. The hole side bears against the back of the impeller normally. The back of the impeller has a ring of plastic bearing material inset into it (what you thought were O-rings) that bears against the rubber cup. At least that's what it appears like to me.

There is no bearing at all at this impeller end of the shaft. I believe there should be one and it was left out by the assembler. But that's just my guess.

I am curious, because I have the means to rebuild the pump (mill, lathe, etc) if I just understood how it is supposed to be. I hope someone here is familiar with water pumps and how they should be inside, or has actually opened one of these particular ones up.

I realize that the originals weren't very good or long lived, but there's no reason why I can't rebuild it so it works well and lasts long, given proper machining, good bearings, and seals. Mine must be unusually bad. It lasted 5 minutes with a (probably) missing bearing . I imagine others at least have all their bearings!

The big problem I'd like to solve is just finding out if there is a missing bearing, or not. Maybe someone has a picture of one, or manual page, or just the commercial experience of rebuilding water pumps and can help with information on how this one should be.

[bschwartz]

Or, I could ship you the one I got with my engine that I never ended up using........

[NoSpark]

Welcome to the forum. I think the water pumps are just a gimmick. I live within four hours hours from two Listeroid dealers and that water pump almost got me to buy the Metro. Glad I went with the Anand and learned to thermo-syphon from the beginning. I saw a listeroid twin on youtube with what looked like a Chevy small block water pump mounted to a steel plate with hose nipples welded or threaded to the other side of the plate. I would do something like that instead of trying to repair or reengineer the Metro pump if I wanted a belt driven water pump, imagine how long an automotive pump would last on a slow speed engine, more than 5 minutes I can bet.

Found the video.  

http://www.youtube.com/watch?v=DevNCcNmYew

[Amarbir[India]]

Welcome to the forum. I think the water pumps are just a gimmick. I live within four hours hours from two Listeroid dealers and that water pump almost got me to buy the Metro. Glad I went with the Anand and learned to thermo-syphon from the beginning. I saw a listeroid twin on youtube with what looked like a Chevy small block water pump mounted to a steel plate with hose nipples welded or threaded to the other side of the plate. I would do something like that instead of trying to repair or reengineer the Metro pump if I wanted a belt driven water pump, imagine how long an automotive pump would last on a slow speed engine, more than 5 minutes I can bet.

Found the video.  

http://www.youtube.com/watch?v=DevNCcNmYew

Hello Nospark Sir ,
 In India Where i Live Some Of these Belt Driven Pumps Are running For Ages .Whats a Good system To Make a Better Water Cooling Solution for The Slow Speed Engines thats Your Favourite As i Would Like To Mod My when i start working On My Yellerator Lister Generator Project

[NoSpark]

In India Where i Live Some Of these Belt Driven Pumps Are running For Ages .Whats a Good system To Make a Better Water Cooling Solution for The Slow Speed Engines thats Your Favourite As i Would Like To Mod My when i start working On My Yellerator Lister Generator Project

I'm sure there are some well made water pumps but this has got to be the tenth Metro pump I've heard of failing within 15 min, looking at vtmetro's pics you know its got to be some kind of a joke.



Thermosyphon would be the easiest and there is nothing mechanical to break.

[vtmetro]

Thank you kindly bschwartz, I certainly would like to open up, and/or try another one and compare them if you don't need it. Would you PM me with cost/shipping?

Hello, NoSpark, thank you for the hydrosiphon suggestion, I already set up a temporary one and ran the engine a couple of hours total with a generator load. But I still want to understand and repair the pump I got. The reason: this is a hobby as well as a power source, and It bugs me not to understand why something doesn't work, and not to be able to fix it.

To me, that water pump is something that somebody designed and built. And with the intention that it work. I believe that. Now maybe an assembler screwed up or the materials and finish were a problem, but that is true to some extent of the entire engine. I knew that it would be a mechanical project from the start. I knew to check for casting sand, and all of the other warnings on the otherpower site. Yet I went ahead anyway, bought the engine, and took it on as a project. Not unlike restoring an old auto, or an old airplane.

So, I want to understand that water pump, what was wrong with it, and what I can do to make it work, if I can. Even though I can hydrosiphon a cooling system. I even have a couple spare electrical circulators kicking around here. But I want that water pump to work, or know the reason why not. Silly, perhaps, but a lot more interesting to me than watching television, which people around me seem to find more exciting than I do. You actually probably know what I mean I bet Maybe I'll figure out why the other ten failed. If I get bschwartz's pump, first thing I'll do is take it apart, before running it. To see what is what. I'll post photos.

Amarbir, hello, and welcome. I bet some pumps do work for a long time. Hard to believe that somebody would go to all the trouble of making castings, fitting seals and ball bearings, casting and finishing impellers, installing circlips, lubrication fittings, bleeder screws, etc. if all they intended was to make a pump that lasted 15 minutes. The customer repercussions in India for a 100% failure rate within 15 minutes of first running probably wouldn't be any less vocal than here or anywhere else in the world.

Why it failed is a mystery to be solved. And interesting, mechanically, too. Just the sort of thing that powers forums.

[M61hops]

Hi vmetro, I'd like to throw in my .02 on your water pump!  I think that the ball bearing was intended to take 90% of the side thrust from the belt tension and the body of the pump is a sleeve bearing that the shaft rides in, thus the reason for the grease cup  !  If it had been properly greased and had a good quality ball bearing it should last a long time.  Because the ball bearing failed, the shaft has eaten into the housing that was supposed to provide some support as a sleeve bearing.  If you wanted a lathe project the housing could be bored out and a bronze sleeve pressed into it for a new bearing.  That is what I would likely do for fun  !                         Leland

[Horsepoor]

I have a Metro 6/1 and have been using a Grundfos home 110 V heating circulating pump with excellent results. These pumps are extremely reliable and cheap. I purchased two on Ebay for $145 total including shipping but the price seems to have gone up. Here is a link:
http://www.e-comfortusa.com/product_info.php?products_id=317

I also installed the three speed version on my GTC 20/2 with excellent results. Two of my friends (Cujet & Rocketboy) have them on their engines with no problems. I agree that there is a small change for failure, but that is why you should build some type of over temperature shut down system over the next couple of years before your pump hits its mean time before failure curve. I quickly checked Patriot Plumbing Supply on line but didnt the deal I got last year for like $68 per pump when I ordered a two pack.

[vtmetro]

Just want to thank bschwartz for the water pump -- it arrived yesterday. Really wonderful folks on this forum!

I didn't have a chance to take it completely apart. I took off the pulley, and the cover plate on that end, and the outlet plate on the other end. The pump is identical to mine on the exterior.

What I could see so far was a well packed (greased) ball bearing, unlike mine which had little grease, or, more accurately,  black sludge and bits of metal in mine.

I didn't remove the snap ring retainer in the casting -- on mine the bearing was not a slip fit in the casting, it would require pressing out, but it also had a retainer ring. Not sure why that is.

There is no retainer on the shaft at  the pulley end, so something internal is preventing removal of the impeller and shaft assembly. Unless the impeller can be removed from the shaft, the only way to remove the shaft is out the impeller end. But I'm not sure what is retaining the shaft inside. A careful pull by hand didn't work. Hesitant to try to press it out, yet.

Looking at the impeller, I can't tell if it is pressed onto the shaft or screwed on. The end of my impeller looks a little different than the new one. The new one might have a round nut on the end, mine looks pressed. Will take and post pix when I get a chance.

To answer questions:

@M61hops, yes I thought of that, too, but there's no evidence of a sleeve bearing in the casting in mine. The hole through the casting is much larger diameter than the thick shoulder on the shaft. There was never a sleeve bearing in my water pump. Maybe bschwartz's version will have one, and mine was left out. Also the thick portion of the shaft isn't machined, so doesn't look like it would run in a bearing (unless it was supposed to be machined!).

There was a sort of off-center hole in a "bulkhead" or wall in the casting at the impeller end. But hard to believe that part of the casting was intended as a bearing, or that it would have been worn so wide. The edges didn't look like there was recent wear -- it looked like sand cast finish. It was maybe 1/8" thick. Look at the third photo above, I think you can see the hole. Hard to imagine as a bearing.

On the shaft, I do see a machined area, about 1/2" long right about where you'd expect a second ball bearing at the impeller end. There's also a recess in the casting that looks like it would take the outer ring of a ball bearing there. But no groove for a retaining snap ring (as there is at the pulley end). The machined areas on the shaft at both ends look the same, so I'm leaning toward the idea that there should be ball bearings at both ends.

True, a sleeved bearing would make more sense considering the grease cup location, though -- right in the middle of the shaft housing. Hard to figure what that's for. It would take about 20-50 cups full to fill the casting space and reach either bearing! My housing was empty of grease.

If I can figure out how to take apart the new pump without wrecking it, I'm sure we'll have an answer. It feels good. With the ends off there's no side-play I can feel nor end play. Something is acting as a bearing at the impeller end for sure. (Maybe a bearing!) It does turn a little stiffly -- probably the seals when turned by hand without water in the pump

@bruce: yup. I already have some electrical circulators on-hand, but am interested in figuring this mechanical METRO pump out anyway. It's a challenge. Even if I do go eventually with an electrical or thermo-siphon system, we'll have the information about how these pumps work -- or if they don't -- why they don't, and what can be done about it.

Just curiosity.

 

[bschwartz]

Oops, as for the packing grease, I put that in.  I was going to use it, so I packed in the synthetic grease.
I didn't look inside, but I suspect it may have been as dry as yours.  Sorry I didn't mention it first.  Bet cleaning it out will be a messy job.

-Brett