Author Topic: Loose Rocker Shaft---  (Read 7884 times)

hotater

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Loose Rocker Shaft---
« on: July 18, 2006, 03:31:41 PM »
 As you all know by now my FuKing engine is an educational experience....it's a lot like owning a mule.

The latest drama was caused at assembly in India.    I caught it once and thought it was corrected.  It wasn't, it was only delayed.

The block that holds the rocker arm shaft steady was bored a tad oversize and the pinch slot, on my engine, was too narrow.  That meant the shaft had movement when the engine was running.  Not MUCH movement, but I could feel it by bridging  a finger between the head bolt and the end of the rocker shaft.  After about 500 hours it had loosened to the point I had to re-cut the pinch slot to give it more 'holding power'.  The problem is that the top of the block is tapered to the rear which puts an uneven strain on the holddown nut....the whole part was miss-made, miss-fitted, and not up to the job, but it took a while to figure that out.

In the past month my engine has gradually 'de-tuned' it'self to the point of having to tweak the governor to maintain 60Hz.  This is a SURE sign the engine is losing power.  Pay attention to it.
  The exhaust side rocker was beginning to show some dirty lube and was 7 to 10 degrees warmer than the intake and the exhaust side shaft end was beginning to really wiggle.  I took it apart Sunday afternoon.

Post mortem shows the original loosness of the attaching block allowed the block to wallow out a little and the shaft to loose it's parrallel sides by a small amount of wear.  After 6,000 hours the shaft and the hole were no longer tight enough to maintain rigidity.

I'm machining a new block on a 'platform' that extends from side to side and is held down by all three headbolts and supports the new rocker shaft in the center and both ends.  It's WAY more than is needed, but it's fun to put together things (of COURSE I don't have a piece of steel big enough...it all has to be fabricated and fitted and line bored) that LOOK good, anyhow.  It'll look like a gyroscope guidance system on a dirty John Deere, but that's half the fun.

The entire saga with a bunch of pictures will be on George's site as soon as I can get it together.

In the mean time---  Check the wiggle between the outer head bolts and the end of the rocker shaft.  If there's ANY movement there, you WILL have problems with it in the future.  Be advised.    ;)

7200 hrs on 6-1/5Kw, FuKing Listeroid,
Currently running PS-Kit 6-1/5Kw...and some MPs and Chanfas and diesel snowplows and trucks and stuff.

fattywagonman

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Re: Loose Rocker Shaft---
« Reply #1 on: July 18, 2006, 04:39:49 PM »
Loctite makes a good product for an easy fix if you catch it early...
http://www.midwayautosupply.com/detailedproductdescription.asp?19911

GuyFawkes

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Re: Loose Rocker Shaft---
« Reply #2 on: July 18, 2006, 05:08:45 PM »
Loctite makes a good product for an easy fix if you catch it early...
http://www.midwayautosupply.com/detailedproductdescription.asp?19911

from that URL

"The proper way to install bearings and races."

no, the proper way is to make sure bloody things are in tolerance and fit.

there is the proper way, and there is every other way.

loctite and all the other "stick shit" and plastic metals do more harm than good, bodged up crappy half assed jobs that are ten times as expensive to fix properly afterwards...

back in the day when I was earning a living as a marine engineer, I used to celebrate the fact that most boats had onboard engineers who were bloody useless, because if they were any good I'd have been out of a job, but the ones with cupboards full of stick shit and plastic metal products were my favourites, because they turned every single minor job into a major money earner, and as an aside made me look really good because you'd end up replacing so much buggered up kit that instead of a small running repair that didn't make a whole heap of difference, you'd replace whole assemblies or subassemblies, which looked nice and shiny new and also usually noticeably improved the performance of whatever the thing was.

using stick shit products on a lister style engine is like using "no more nails" to make an axe handle out of toothpicks

don't get me wrong, ___SOME___ of these products, when USED APPROPRIATELY are marvellous, we have a silicone product here called "Sticks like shit", all the tradesmen buy it because the name says what it does, it does stick like shit, what it gets used for is in new build houses, all the wall units are stuck onto the plasterboard with two small tacks to hold it while it dries, fast, cheap, dirty and crap.

we did the plumbing for the 2" fire main on this boat

(and castlemaine's tub too)

it had previously been done in malta during an earlier refit, leaked everywhere for days, so when we did it everyone is standing around waiting for leaks....

we used the old adjustable pipe die that dad nicked off the yanks army when it came over for the landings in ww2, and red lead and oakum, skipper had to put his hands on the pipe to feel the cold and thrumming because he didn't believe there was any water in it, never mind pressurised, literally not a drop leaked.

red lead and oakum was possibly slighly more messy on the hands when using it, but cleaned off REAL easy when done, it was DIRT cheap, less than 1% of the cost of stick shit crap, it allowed you to disassemble in years if needed, and allowed you to assemble as slowly as you liked to get your angles and lengths right (anoyone who has done piping will know what I mean) and most importantly of all it actually did the job 100% where none of the stick shit products could come close

gasket paper+ grease, maybe the odd bit of shim steel, that is all anyone needs to build a lister style engine....

God knows how many old engines are still going around on gaskets I've cut out of cornflake packet or cigarette carton or pirelli calendar, if the faces are good that;s all it needs, if the faces aren't good then dress the bloody things up until they are.

In Hotaters case (no pix so guessing) braze em up and line bore and bush and job's a good un

rocker shafts always have vertical loads, they wear at the top and bottom, if you select the right materials even as it wear in to the bushing it will keep the full bearing surface area, so all you need to watch is losing the lube out the bottom gap, if you wanna high tech it here is a good place to fit needle rollers, HD used them on heads yonks ago and they are still better than anything the jap bikes had.
--
Original Lister CS 6/1 Start-o-matic 2.5 Kw (radiator conversion)
3Kw 130 VDC Dynamo to be added. (compressor + hyd pump)
Original Lister D, megasquirt multifuel project, compressor and truck alternator.
Current status - project / standby, Fuel, good old pump diesel.

hotater

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Re: Loose Rocker Shaft---
« Reply #3 on: July 18, 2006, 05:38:48 PM »
Guy---

As a maintenance machinist that repaired and rebuilt mining hydraulics I can say with certainty that the 'stick shit' is a money maker to the one that has to repair it.  What's little understood is that the expense incurred to repair it for good is MINOR compared to the expense of not having use of the part.
  To follow your logic we'd all be whip-wrapping wiring with linen thread and varnishing it instead of using zip ties....or duct tape, depending on what's on hand

Point of information re: rocker shaft.   The shaft and the block are the only parts worn.   The rocker bushings are still a slurp fit on a 5/8" endmill shank with no side play.  I intended to install roller bearings but it's a LONG way to town and back and the bronze bushings are still 'new' after 6,000 hours.  Why bother.
7200 hrs on 6-1/5Kw, FuKing Listeroid,
Currently running PS-Kit 6-1/5Kw...and some MPs and Chanfas and diesel snowplows and trucks and stuff.

kyradawg

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Re: Loose Rocker Shaft---
« Reply #4 on: July 18, 2006, 08:04:58 PM »


Peace&Love :D, Darren
« Last Edit: August 03, 2006, 02:56:31 AM by kyradawg »

cujet

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Re: Loose Rocker Shaft---
« Reply #5 on: July 18, 2006, 08:47:32 PM »
I love threads like this!

Doing it right in my book is getting rid of all such crap. Pipe threads are a no-no, as is Locktite, silicone, buna-n o-rings and the like. Teflon tape belongs in the PVC pipe department, useless for anything that matters.

I just removed a $350,000.00 rudder actuator from our Gulfstream G550. Now, that is a nice piece of eqpt, done right. I love to look at it! It is probably the nicest machined part I have seen in many years.

Hotater, I thought I remember you had some other problems recently. Would you be willing to post a running tab of the problems you have had since you blueprinted your engine and got it ready for real work. I truly believe this would be helpful for those of us who have just put together blueprinted Listeroids. We would know what to expect.

Also, I suggest you consider some method of preventing a valve to piston crash during a gear failure with your planned setup. Maybe some form of load relief bungee on the pushrods?

Chris
« Last Edit: July 18, 2006, 08:51:17 PM by cujet »
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GuyFawkes

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Re: Loose Rocker Shaft---
« Reply #6 on: July 18, 2006, 08:55:49 PM »
well, not really.

paper gaskets (if not already impregnated) were greased, that took care of that and any excess grease went away HARMLESSLY in the lube system.

stick shit is used from new assembly in lots of places now because it is faster and cheaper, all done by robot...

stick shit has LOTS of problems, #1 is it is not a solid and not not have a form, so you need different grades for different joints and indeed for different joint assembly processes, a joint that gets assembled and torqued quickly needs a different grade than one that is torqued slowly.

making paper gaskets used to be expensive, making the guillotine patterns cost time and money, lots, nowdays you can laser cut them, but it is still quicker and cheaper to manufacture using stick shit.

if you get really high tech you don't need anything, you can finish mating surfaces to such precision that they don't need any gasket, with some materials you don't even need any fasteners, the surfaces will bond to each other by themselves.

The MAIN function of a gasket is not to create a seal, that is secondary, the MAIN function of a gasket is to facilitate easy disassembly and repair, since we are moving to a world where "that is bust, fit a new (assembly)" gaskets are less use, you are going to throw that part away and replace it, so who gives a shit if you can disassemble it.

I will repeat, stick shit is crap, proper engineering uses gaskets, see primary function of a gasket above.

--
Original Lister CS 6/1 Start-o-matic 2.5 Kw (radiator conversion)
3Kw 130 VDC Dynamo to be added. (compressor + hyd pump)
Original Lister D, megasquirt multifuel project, compressor and truck alternator.
Current status - project / standby, Fuel, good old pump diesel.

hotater

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Re: Loose Rocker Shaft---
« Reply #7 on: July 18, 2006, 09:21:34 PM »
Cujet---

My engine works every day it ain't broke down and I cronicle each as they occur.  The problem this summer has been it seems everything is breaking down so 'planned' maintenance just don't happen.  It's repair 'something' everyday and hope the important stuff keeps working.

I just completed my valve train project and found the location of the rocker shaft is off  a BUNCH.  I must have mis-read something somewhere.  Back to work.  I'll change the design some too.   The anchor points to the outside head bolts is a bad idea as is the outboard supports of the rocker shaft.  I spent a LOT of time machining surfaces just to have a locator point for reaming three holes as separate parts to be assembled in alignment.....  but the location was WRONG....and that screwed up the new shaft I'd made....back to work.

AND....gimme a tube of RTV  every time I need a gasket....or one of those other stick shits.  I dis-like paper gaskets, especially on something that's constantly being worked on!
   EASY is better because EASY leaves time for taking it easy later......as long as 'easy' is the best it's going to get done at all.
7200 hrs on 6-1/5Kw, FuKing Listeroid,
Currently running PS-Kit 6-1/5Kw...and some MPs and Chanfas and diesel snowplows and trucks and stuff.

mobile_bob

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Re: Loose Rocker Shaft---
« Reply #8 on: July 18, 2006, 10:02:20 PM »
i am not a formally trained engineer, but i am a mechanic that has to work with and repair that which has been
engineered by others,

i would agree that silicone sealants are a product of automation, a time saver in manufacture. in the right applications
there is nothing quicker if not better.

for instance,
small block chevy's, we all remember the front and rear intake rubber seals, and how they sometimes would pooch out, then they went ot having little tits, to locate them and that was an improvment, when they went to silicone it was a perfect solution to a long standing problem.

large gear cases, 3rd members and the like, gskts worked fine, but silicone is faster and just as effective.

sealing stamped sheet metal covers was always a problem, and silicone fixed this problem quite nicely.

now the down sides

if the surfaces arent clean, free of oil they can and will leak.

if you put too much on and that which is squeezed outside also has an equal amount squeazed in, this plugs oil pumps, oil galleys, and crankshaft cross drillings, i have seen catastophic failures this way.

used in conjuction with gskts, make them very slick and then the force the gskt out of place, causing more problems.

loctite thread lockers,

they have their place where you cannot lock the bolt another way, such as tie wire, or lock washers, lock tabs etc. but..

i can't tell you how many broken bolts are nearly impossible to remove in place with red loctite in use.

brg mount, this stuff really has no place in my books, it is often used where an outer race (fixed) should be allowed to creep.
without this designed creep rapid wear and failure is the result.

teflon sealant/thread dope, like it or not it is a fact of life for most applications because the pipe fittings are of such poor quality typically.

i dont like thread tape, if done improperly pieces of the stuff seems to migrate into places where it sticks valves, needle seats, and the like. i quit using it unless i have no other choice to get something up and back online.

i would agree that most of this stuff would not be necessary at all if machining was done to a higher level, but sadly it is not for reasons of economy.

many years ago i used to build alot of 504 and 555 cummins engines, i got a new crank for one that was made in England, it was a thing of beauty, every surface was machined, i mean everything! all the journals of course, as well as the bob weights.
was it necessary to machine to such a high standard? no.. but that is the attention to detail that is lacking in most products today.

the 3126 cat engine has a problem with oil cooler leakage, they will all leak oil sooner than later, the housings are so lightly cast of aluminum and the cooler cores are stamped steel, these stamped cores are not even close to flat! they have upgraded gskts and gskt glue many times, same results.. it is poor attention to details and poor machining period.

a note on surface finish, head gskt problems are routed many times to the quality of not only being flat but at what RMS value the finish is, too course and they weep, too fine and they walk and work the gskt to death. i have refused machine shops that have given me a mirror finish on a head, as well as those that looked like they were ground down with 20 grit stone. you have to have it close to being right or you will always have problems.

also many years ago, i read a book by the mechanics, mechanic, namely smokey yunick.
he used a sealant on his head gskts made by a race part manufacture that escapes me now. he used it because
it sealed well, and could be removed with clean solvent allowing him to reuse the gskts over and over many times during dyno
testing.

i suppose there is a time and a place for everything, but use it properly and in moderation.

also getting to the route cause of the problem is the starting point, not just trying to get around it with some miracle sealant.

it all comes down to details, details , details, this is where blueprinting comes into play.

of course you have to start out with a soundly engineered product to start with.

bob g
otherpower.com, microcogen.info, practicalmachinist.com
(useful forums), utterpower.com for all sorts of diy info

cujet

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Re: Loose Rocker Shaft---
« Reply #9 on: July 18, 2006, 10:14:04 PM »
I knew Smokey Yunik well. I lived about 1/4 mile from his "Best damn garage in town" I remember him using a permatex red spray gasket spray on head gaskets. Kinda hokey, but it worked. And,,, those heads and gaskets were not easy to remove. They were near impossible to pry off!

Chris
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hotater

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Re: Loose Rocker Shaft---
« Reply #10 on: July 18, 2006, 10:19:57 PM »
Bob---
Gotta LOVE the voice of experience!!

The SAME goes for firearms and probably every other mechanical device that's REALLY understood.

I look at the older, forged and machined guns and marvel at the fixtures and special tooling it must have taken to make them,  THEN look at the stamped, formed, cast, and injected parts of the newest offerings and wonder WHY we make complicated machines to make CHEAP parts instead of making better parts on simpler machines!
7200 hrs on 6-1/5Kw, FuKing Listeroid,
Currently running PS-Kit 6-1/5Kw...and some MPs and Chanfas and diesel snowplows and trucks and stuff.

mobile_bob

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Re: Loose Rocker Shaft---
« Reply #11 on: July 18, 2006, 11:21:12 PM »
cujet you lucky bastad

i grew up reading , (or rather learned to read) popular mechanic's back when smokey had a section every month.

one of my biggest regrets is not being able (because of a miserable woman) to have met him in person before he died.

i have been racking my brain trying to remember what he used, i wanna say a product by milidon or something like that.
anyway the company that makes it developed it to seal copper gskts on nitro burners, cylinder pressures and stresses in those engines are far in excess of a diesel engine.

i remember he switched over to it in his later years and swore by it, it sealed very well and the parts would seperate without destruction of the gskt enabling him to reuse the same composite gskts over and over again, with only clean solvent to clean them.

i never had a use for it, but i remember what he wrote about it and logged it in the ole brain for future reference.

i still get mad thinking about the exwife and her being such a boat anchor.

bob g
otherpower.com, microcogen.info, practicalmachinist.com
(useful forums), utterpower.com for all sorts of diy info

twombo

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Re: Loose Rocker Shaft---
« Reply #12 on: July 19, 2006, 12:20:23 AM »
Cujet

Speaking of really impressive airplane parts.  The elevon mixer assy for the the SR-71 was a true work of art. Lovely titanium  forgings,  machined to an almost a mirror finish.  Several spring cartridges  (some sort of "artificial feel" devices I suppose) bellcranks and pushrod assemblies all combined in an amazingly compact  package, and the whole works had to work flawlessly at 4 and 5 hundred degrees. Met some of those old guys retrieving a broke bird at Key West after the turbine section of #2 engine took an ugly detour out the side of the engine nacelle.

It's amazing the the beautiful metal art we often never see because it is hidden away inside firearms and airplanes. If it doesn't work, somebodies butt is in a serious hurt!!

mike

snail

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Re: Loose Rocker Shaft---
« Reply #13 on: July 19, 2006, 12:32:46 AM »
couldn't resist this...

guy,
Quote
God knows how many old engines are still going around on gaskets I've cut out of cornflake packet or cigarette carton or pirelli calendar, if the faces are good that;s all it needs, if the faces aren't good then dress the bloody things up until they are.

never worried about the faces on a pirelli calendar before.Does lipstick make 'em seal better? ;D ;D

cheers,

Brian

t19

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Re: Loose Rocker Shaft---
« Reply #14 on: July 19, 2006, 02:22:56 AM »
couldn't resist this...

guy,
Quote
God knows how many old engines are still going around on gaskets I've cut out of cornflake packet or cigarette carton or pirelli calendar, if the faces are good that;s all it needs, if the faces aren't good then dress the bloody things up until they are.

never worried about the faces on a pirelli calendar before.Does lipstick make 'em seal better? ;D ;D

cheers,

Brian

9 out of 10 Walrus prefer a nice tight Seal :D
There is plenty of room for all of Gods creatures... right next to the mashed potatoes...