Last night I noticed a distinct lifting motion of one of my rockers during operation. After closer examination I also noticed lots of cast iron dust. I pulled the assembly today and there is about 80 thou wear on the pivot shaft and maybe 1/16" wear on the hole in the rocker itself. There is similar wear on the pivot shaft on the side that was still working ok.
Since water had made it up the head stud holes and was steaming off, I suspect that lubrication was lost and failure ensued.
I have not used grease for the rockers since day 1 and basically dribble oil all over (including the top hole) every time I lube the valve guides.
Questions:
Has anyone experienced failures of the rockers ?
What lubrication method did you use ?
How did you fix your issues ?
What I am thinking of doing is boring out the rockers themselves to get a true hole and inserting a bronze sintered bushing. I was also going to replace the pivot shaft with a solid shaft with springs on the end just like the original units.
Thoughts ?
Sounds like a good plan to me. I think grease would be a better lube than oil in this instance, as it's got to stay in place. Oil, unless you're constantly dripping it on, will run out quite quickly.
I must say, you're having sweet FA luck with this engine :( Is there any part of it you haven't had to re-build?
BTW: The original CS's have hollow shafts with a grease cap; when the grease cap is given a tweak (once every 24h if I remember rightly), a bit of grease is squeezed out of holes around the pivots.
I have not experienced this situation. I just use the same oil as used for the valve guides. You may want to consider switching to the "Gaskets-to-Go"
gaskets in lieu of using standard copper gaskets to eliminate any cooling water from coming thru the head stud holes:
http://www.gasketstogo.com/Listeroid.htm
My rockers came with bronze bushings like these:
http://www.generatorsales.com/order/Rocker_Arms.asp?page=Rocker_Arms
Bob B.
I think that there would be meat enough to bore out for a thin bronze bushing but it will not be an easy job to get the alignment correct. Even the originals (listeroid) often need some fudging of holes in rocker shaft stand and shimming the rockers in and out to have them half azz line up centred over the valve stems. It will take some creative jigging to machine. Ideally the shaft should be fairly hard if you want to gain much over the original setup.
I think it will be much cheaper to buy an new assembly. There may be a closer source in Alberta but John F could likely fix you up fairly quick, being as you are the same side of the border.
Quote from: Jens on November 23, 2010, 11:41:18 AM
I had a look-see at jigging for boring. I think that alignment should be relatively easy if one was to assume the parts are not precision parts. In other words if one assumes that 'close' is good enough. I agree that ideally one should use a surface hardened, ground pivot shaft for best wear resistance.
Well you can certainly assume that there was no precision in their original conception! Some have pretty ugly misalignments that you could improve upon or conceivably make worse; that part is up to you, and your tolerance for "good enough", lol :) How are you going to do the boring?
Yep, Jens - I also suffered the rocker arm wear....
I used (and still use) grease but, like you, found that more grease came out of the brass grease cup fitting than was being pumped into the rocker Shaft.
In my case, the rocker arm wear was completely through the bronze bush and into the cast arm itself; it was on the exhaust valve. There was absolutely zero marking to the rocker shaft.
I replaced the complete rocker assembly and fitted a hydraulic grease nipple in place of the brass screw cup. I now only apply grease when the engine is running and hot - in the belief that more grease is likely to find its way to the rockers rather than just oozing out of the biggest gap.
HTH
Regards,
Ian
I don't have any appreciable wear on mine, but not all that many hours either. Oil holes on top of the rockers and grease cup are counter productive IMO. I also think the grease takes the path of least resistance and exits too easilly instead of being forced where it belongs. Rubber seals alongside teh rockers might improve this I have an idea to use come small copper capillary tubing to take a little off the oil pump and send it up to drip into the rocker holes. This would require drilling a drain passage in the head and the addition of a siphon tube to pull the oil level in the cups down to the proper point once oil starts to build up. This however would give a source of oil to feed the end bearing of the camshaft in past the IP cam lobe...
I use oil to lube my rockers, but not motor oil. I use 90 weight gear oil in my oil can for all the external lube. A little more sticky and stays in place a bit better than motor oil does at op temp. But I also make frequent rounds and oil the moving bits every couple hours in operation. Another thing I have been looking at is I have not had the valve cover inplace for a little while. I find the sight of a working valve train captivating:) This kind of defeats the oil mist process, as any mist from the warm oil in the valvespring cups drifts away...
How many hours are these rocker failures happening at? I have about 1250 hours so far on my 6/1. I haven't even considered checking for excess play..... maybe it is something I should investigate.
I use a rocker cover..... it's called the workshop roof ;D
Cannot remember exactly how many hours when I noticed the rocker arm issue. I probably noticed it about 1000 hours but I am sure it was a gradually operating process.
The exhaust rocker is the furthest away from the grease cup on my single. Considered putting a second grease cup on the other end of the shaft (closer to the exhaust rocker) but later decided to work on a single hydraulic grease nipple instead.
Probably another 2000 - 2500 hours since then with no OBVIOUS rocker issues.
HTH
Regards,
Ian
I like the idea of modifying to put a grease nipple at the end of the rocker shaft.
Then just keep a mini-grease gun hanging on the wall beside the machine.
Packing that grease cup and having 25% of the grease squeeze out in the wrong places is not optimal.
veggie
After a bit of grease comes out of the hole on top of the intake rocker, I put my thumb on it and turn the pot until some comes out of the exhaust rocker too. I think I'm going to try and reverse the shaft so the holes point down and see how that works. I think there are notches in both sides of the rocker cover.
Recently I'd just been using regular oil for the rocker assembly (because it was on hand). Previously was using chain saw bar oil because it was thicker. Great idea about a grease fitting! Why not just drill out the grease cup and fit the grease zirc there?
The grease cup uses a 1/8BSP thread - the same as many grease nipples. No need to drill out anything - just take the grease cup and fitting off.
The shaft is keyed to locate around the stud but it is also left and right mirror imaged - so if you currently have holes in the TOP of the shaft - it is incorrectly assembled. Take the fittings off the shaft and turn it through 180 degrees so the notch is still in the right place but the holes (in the shaft) are at the bottom. Then reassemble.
Shaft holes pointing upwards (IMO) are about as much use as a chocolate teapot and WILL lead to rocker arm wear due to insufficient greasing of the arm bush.
HTH
Regards,
Ian
Jens, I plan to do what Ian said.
Keep the oil to it often. Is there being any washdown of the valve stems? Maybe you need to put some steam cylinder oil in the coolant too!
Well people have been saying for a long time that they are running their cars on water! maybe thumper has pulled it off.
In this case I am sure you are better off with the non oil holed valve guides. Hope the stopleak does the trick but the steam coming in spurts makes me worry that it is compression forces driving the water. In that case it would not even have to be bypassing the gasket anywhere to get into the stud bores.
So before my big end bearing failure, I would notice a little water around the rocker arms and valve guides but I could never find where it was coming from. And there was a little "chocolate milk" mixed in the coolant when I drained it. The coolant overflow tank always had water.
So hearing your leak description makes me think these are prone to headgasket leak. Maybe check the head bolts torque often?
you definitely don't want antifreeze to come into contact with brg shells, it has a tendency to cause them to flake out
and go away quick.
as for sealing the studs, get a stick of that ace hardware pipe dope, we talk about here frequently
it can be used on wet threads no problem, seals excellent and is good for water, antifreeze, oil, gasoline, diesel, nat gas, propane, hyd
etc. actually i have never seen it not work with anything i come across.
if i had a listeroid the head studs would certainly be installed with that dope as a sealant, as would any other leak prone stud or bolt.
quick and easy to use, and cheap as dirt
fwiw
bob g
Good tip. Thanks. It didn't have anything to do with my big end failure I think b/c no water in crankcase. Easy fix,
thanks.
some brg babbit composition takes a ridiculously small amount of antifreeze to attack and delaminate the layers
leading to early failure.
detroit diesel had some issues with that happening, it took very little antifreeze for the brgs to start to flake
and come apart. certainly far less than it took to make things milky.
just fwiw, something to protect against on your way back together
bob g
"............ the aftermarket head gasket is the way to go but it involves setting the piston clearance ........."
Why does the piston clearance need to be changed to use the aftermarket head gasket?
Your description sure makes me believe the head gasket is the culprit. I had a similar sounding leak up at the rockers, and the HG was at fault.
Jen if your coolant pump is electric you can put a capacitor on it and make a self holding circuit then very the size of the cap to get the hold time you need but you know this right? :) Tom T
If anyone is interested I flipped the rocker shaft around to point the grease holes down and added a zirk fitting. The rockers were fitted with brass bushings.
Jens,
How about a time delay relay on the circ-pump? Power the pump from the grid and the relay from the st head...that way you can choose how long the pump runs so your head doesn't boil. ;)
lloyd
Quote from: Jens on December 07, 2010, 08:31:45 PM
Quote from: Lloyd on December 07, 2010, 08:12:32 PM
How about a time delay relay on the circ-pump? Power the pump from the grid and the relay from the st head...that way you can choose how long the pump runs so your head doesn't boil. ;)
BTW Lloyd, I did not see a reply from you re my question to you on belts (industrial vs automotive)
I'll look for it again...I think one of the white papers I posted on the gates belt/drive engineering has the info...but I'll have to find it.
You can get a time delay relay for about $25.00, 1 min, 4 min up to 1 hour.
Lloyd
Jens,
Here's a starter by belt designation APPLICATIONS:
J's -Light weight,electric motors,Air
compressors,ice cream machines,
excercise equipment.
K's -Auto serpentine,available in all
lengths and custom cut-widths.
L's -Gas Compressors, Diesel Engines
Agriculture equip.
M's -Heavy equip.& compressors.
I'll look for the rest, I went through this when I was in search of a belt for my Perky/cat\Volvo. The industrial drive shops wouldn't even sell me a belt when, I told them my apllication...they said the shock load of the combustion cycle was to much for an industrial, and the I needed a K, L,or M series, as it turns out my dirve pulley is a K series...so that is what I went with...Was a big learning curve, and a lot of wasted time and worry.
Lloyd
Hi Jens,
Yes the L series is a "Heavy Industry" drive, not an industrial, The difference is in the cording used...so they are either shock tolerant (combustion stroke) or are designed for high HP elec/air/hydro drive...no combustion. There is also a clutchable drive belt.
Time delays are either activated on energize or de-energize...In your case the relay would be on de-energize, the coil would be energized by the thumper, and the the circ. by the grid (pass through). No logic required, it's all in the relay.
Lloyd
Quote from: Jens on December 07, 2010, 09:49:03 PM
Quote from: Lloyd on December 07, 2010, 08:35:48 PM
You can get a time delay relay for about $25.00, 1 min, 4 min up to 1 hour.
Don't you need some logic around the relay though ? I was under the impression that these relays time out after a given time past initial activation but what we have here is a situation where the relay must stay on for a undetermined duration and then, after the engine has shut off, start the timer.
Not only does there need to be some logic that does the delayed shut off (which I concede may be available off the shelf) but also the relay has to be activated when the engine starts up (this can not happen manually because I would forget it most of the time).
I guess I never completely wrapped my mind around the issues so something may indeed be available off the shelf but as I said, it seems to get complicated quickly.
Jens,
Look into 555 timer chips. These can be set up to do some amazing timing tasks.
I've built a bunch of simple timers using these cheap little chips. I may have a design laying about I can post here.
R
Jens,
How long will thumper sit after it shuts down before the next restart???? If it's more then 4-5 hrs and the engine room is cold you may run into a problem where the block starts to sweat from the 24/7 circulation...I've seen this happen on marine engines that are hooked into the a hydronic loop that doesn't stop circulating the block coolant( if you have enough btus to waste and it can maintain the block temp above the condensation point it may not be an issue...but that big piece of iron is a large heat sink that will suck a lot of btu's).
If you use a time delay on de-energize power the coil of the relay from the gen output, then power the circ pump from the grid. When thumper shuts down the relay will start the count down for what ever time delay you choose to allow the grid to run the circ pump...so your head doesn't boil.
It's very simple with no reason to wrap/rap your head a round it.
Lloyd
Hi Jens,
NO...that's what the time delay function built into the relay is for...It holds the pass through power contact closed until the desired time passes, then it opens. It's a thermal switch that is built into the relay. iirc right Idec makes it in an 8 pin octagon with the base separate, the base has screw terminals, and the relay plugs into the base.
When my brother built his house, the hydronic installers wired up the 8 zone circ pumps to run continuous, and said it would be thousands of dollars to build a controller that didn't allow the pumps to run when there was no demand from the zone. I built a din-rail controller using the time-delays each tied to the t-stat for each zone. I think it cost about $300.00 in parts, I installed it 10 years ago and it has saved about $189.00 a year in less wasted energy, it extends the pump life by about 10 time a 24/7 life span...With labor I think he figgered it amortized in about 2.75 yeas and saved thousands over the life of the system.
Lloyd
Lloyd
Quote from: Lloyd on December 08, 2010, 08:53:32 PM
When my brother built his house, the hydronic installers wired up the 8 zone circ pumps to run continuous, and said it would be thousands of dollars to build a controller that didn't allow the pumps to run when there was no demand from the zone. I built a din-rail controller using the time-delays each tied to the t-stat for each zone. I think it cost about $300.00 in parts, I installed it 10 years ago and it has saved about $189.00 a year in less wasted energy, it extends the pump life by about 10 time a 24/7 life span...With labor I think he figgered it amortized in about 2.75 yeas and saved thousands over the life of the system.
Hi Lloyd,
Sounds like you have good knowledge about hydronic floor heating and associated control systems. I'm looking for a good hydronic design book or other source of design info. I have been patiently waiting for several months for the new revision of "Modern Hydronic Heating: For Residential and Light Commercial Buildings", by John Siegenthaler to be released (now scheduled for Jan 2011). I don't want to hijack this thread so maybe starting another thread would be best. Or perhaps even creating a hydronic section since storing heat in slab floor is another way to store/use thermal energy from a cogen application.
Thanks,
Bob B.
If I remember right you attach one wire from the cap to the line side of the coil and the other to ground after the power is dropped however long it takes the cap to drain off is how long the relay is held closed if you need more time a larger cap is used if less a smaller one. Its called a capacitor discharge timer. Its been a long time and that may not be quiet right.Tom T
Jen's & Tom,
They are not caps, but thermal switches...they are factory set and you buy the the relay with the time delay period you want. They aren't adjustable...they are pre-set by the factory.
They are used for everything from cool down boilers to pre-heaters in industry.
But I think they would be an ideal solution to your head boiling...no head wrap/rapping required.
Lloyd
Quote from: sailawayrb on December 08, 2010, 09:54:05 PM
Quote from: Lloyd on December 08, 2010, 08:53:32 PM
When my brother built his house, the hydronic installers wired up the 8 zone circ pumps to run continuous, and said it would be thousands of dollars to build a controller that didn't allow the pumps to run when there was no demand from the zone. I built a din-rail controller using the time-delays each tied to the t-stat for each zone. I think it cost about $300.00 in parts, I installed it 10 years ago and it has saved about $189.00 a year in less wasted energy, it extends the pump life by about 10 time a 24/7 life span...With labor I think he figgered it amortized in about 2.75 yeas and saved thousands over the life of the system.
Hi Lloyd,
Sounds like you have good knowledge about hydronic floor heating and associated control systems. I'm looking for a good hydronic design book or other source of design info. I have been patiently waiting for several months for the new revision of "Modern Hydronic Heating: For Residential and Light Commercial Buildings", by John Siegenthaler to be released (now scheduled for Jan 2011). I don't want to hijack this thread so maybe starting another thread would be best. Or perhaps even creating a hydronic section since storing heat in slab floor is another way to store/use thermal energy from a cogen application.
Thanks,
Bob B.
Hi Bob....
I'm not an engineer. My formal edu. is in Fiance and Commercial Photography...2 careers, no mid life crisis... When I visited my brothers install and saw that the circs were running 24/7 I said that is a huge waste of energy...he contacted his contractor, and they said nothing on the shelf...but it could be custom ER'd for thousands....I said BS...it just as simple as having 8 gremlins standing by to through the switches...when the t-stat says no more heat for this zone.
So I did a little research based on some past experience with relays...and guess what...it was an easy solution..... I think the installers were so concerned with selling a system, and once it was installed they had little interest in making a more efficient product...bc they could earn no more.
Slabs are the original heat sink used in condensing boilers...since the 70's energy crisis...anything with a large mass, that is fairly dense will do it. Some mediums just work better. I began researching using salt back in the 70's, and it is a very fine medium, if you can contain the corrosive factor.
I was an early adopter in the 70's but like many, as the econ.... got better.... life's other choices got in the way...that's where I think big gov. should provide the leadership....but they too are lured by easy money.
O well I think community is where it's at now...like our little micro-cogen site, and like America was before the day of liberaly providing for our politicians theifdoms...I won't digress any further....really
lloyd
"I am remembering why I felt like a stationary engineer before ....."
Is that because you feel like you aren't getting anywhere ? ::)
A cheap fix might be the most inexpensive UPS Walmat or Office Depot sells, plug your circulating pump into the UPS which pulls power from the generator while running and will power the circulating pump for a few minutes after the generator shuts down or until you manually turn the pump off. Cheap, simple, off the shelf, perhaps $20.
I think I'd run the circulating pump off reliable AC and use a thermal switch on the head - above some temperature the pump runs; once it cools off the pump stops.
I also wonder if the reason you see leaking after it shuts off is that steam will go thru a smaller hole than water will. Not so much a pressure going up and pushing thru but steam (gas) goes thru a leak that water (liquid) won't.
Quote from: Lloyd on December 08, 2010, 11:00:36 PM
Hi Bob....
I'm not an engineer. My formal edu. is in Fiance and Commercial Photography...2 careers, no mid life crisis... When I visited my brothers install and saw that the circs were running 24/7 I said that is a huge waste of energy...he contacted his contractor, and they said nothing on the shelf...but it could be custom ER'd for thousands....I said BS...it just as simple as having 8 gremlins standing by to through the switches...when the t-stat says no more heat for this zone.
So I did a little research based on some past experience with relays...and guess what...it was an easy solution..... I think the installers were so concerned with selling a system, and once it was installed they had little interest in making a more efficient product...bc they could earn no more.
Slabs are the original heat sink used in condensing boilers...since the 70's energy crisis...anything with a large mass, that is fairly dense will do it. Some mediums just work better. I began researching using salt back in the 70's, and it is a very fine medium, if you can contain the corrosive factor.
I was an early adopter in the 70's but like many, as the econ.... got better.... life's other choices got in the way...that's where I think big gov. should provide the leadership....but they too are lured by easy money.
O well I think community is where it's at now...like our little micro-cogen site, and like America was before the day of liberaly providing for our politicians theifdoms...I won't digress any further....really
lloyd
Hi Lloyd,
Somehow I missed your response...
I now have "Modern Hydronic Heating: For Residential and Light Commercial Buildings", by John Siegenthaler. I also have his associated software applications as well. All truly great stuff if one wants to do hydronic...and I very much do...and passive solar too!
I won't digress further either...but I agree 100% with your digression :)
Bob B.