Puppeteer

Author Topic: Big end wear or damage  (Read 3853 times)

Yellownev

  • Newbie
  • *
  • Posts: 17
    • View Profile
Big end wear or damage
« on: November 27, 2021, 08:52:40 PM »
Please excuse my terminology and somewhat blunt approach to asking for help but here goes.

I've a 16/2 in my canal boat that was marinised for the boat and it had run very sweet for the last 10 years ( about 2000 hours on it) Recently cruising along the canal I noted smoke coming from the crankcase breather and a distinct 'knock' - never heard before. On advice from the people who put the engine in the boat i got access to the engine via the crankcase 'door' and under one cylinder these were pieces of metal, small  - on showing this to the installer they suggested it was the big end shell bearing.

On that side I can introduce same 'knock' by grabbing the bottom of the conrod and feeling some movement which i assume means the big end 'shell bearing' has failed. i suspect the smoke was the bearing heating up during its failure. I may be to blame for this as I had not completely filled the engine to the top mark on the dipstck   -I assume therefore the bearing has run dry and hot hence the smoke and bearing failure ?

The same engineer suggested unbolting the conrod and checking for wear/damage with a view to replacing the bearing. Now I have seen there are different thicknesses of replacement bearings shells to ( I assume) account for wear such as I may have. He suggested this should be an easy thing to do and check... he's experienced I am not

My questions to the enlightened is ..... is is a relatively simple thing to unbolt the conrod via the open side of the crankcase. Then is it a matter of checking the surface as well as measurements of the shaft the conrod bearing clamps to. If there is not real wear replace the shell bearing with like for like .... if there is wear replacing the shell bearing with one to compensate for the wear?

Obviously if the crankshaft surface is damaged too badly i expect that it is the crankshaft out to have it build up and turned back to spec?

Sorry if my questions are basic and contain incorrect assumptions and or terminology. I'm struggling to get anyone to take the work on and I may have to get my own spanners out .... hence the questions ?

Any observations/experience or feedback gratefully received

Nev



Powdermonkey

  • Newbie
  • *
  • Posts: 41
    • View Profile
Re: Big end wear or damage
« Reply #1 on: November 30, 2021, 12:17:46 AM »
Hello Nev,

Simple, yes.  Easy?  Meh.  Not easy.  But not hard either.  Firstly, my engines have had a bit of a "spacer" located between the connecting rod and the cap.  This spacer (or series of spacers) sets the clearance between the "big end" and the shaft. 

I did the math with the engine disassembled.  IF I recall correctly, you're wanting 0.0015" inch of clearance for every inch of diameter of your shaft.  My 30/2 was set up with ~ 0.004" of clearance on both connecting rods.

Now, the next part:  Being that your engine is still together, you're going to want a different way to measure your clearance.  You need to go to a "good" auto parts store and get yourself a hold of some "Plasti-gauge".  You're looking for some that's accurate in the 0.002"-0.010" range.  Follow the directions, and check out your current clearance.  Adjust as necessary.  PM me if you need more assistance.

Yellownev

  • Newbie
  • *
  • Posts: 17
    • View Profile
Re: Big end wear or damage
« Reply #2 on: December 02, 2021, 08:39:36 PM »
Hi, Thanks for taking the time to respond to my question - I've sent a PM

Regards

Nev

38ac

  • Hero Member
  • *****
  • Posts: 2152
    • View Profile
Re: Big end wear or damage
« Reply #3 on: December 02, 2021, 10:55:36 PM »
Adding to the other reply if you did indeed melt the bearing it is imperative that you clean the crankcase. Personally I would also pull the oil pump and check it for debris  and flush the lines. The Lister technical data specs the  clearances with new parts at .0025"- .003" with allowable wear .003". So, clearance could be as large as .006" and be within the spec to run it,  however I would never let one out of the shop with that much clearance.
Collector and horder of about anything diesel

listard-jp2

  • Hero Member
  • *****
  • Posts: 657
    • View Profile
Re: Big end wear or damage
« Reply #4 on: December 03, 2021, 11:43:55 AM »

OP, is that a genuine Lister CS 16/2 engine you have in your canal boat?

Or is something more like this (and of Indian origin)?

https://www.stationaryengineparts.com/Publicity.html

Yellownev

  • Newbie
  • *
  • Posts: 17
    • View Profile
Re: Big end wear or damage
« Reply #5 on: December 03, 2021, 03:39:13 PM »
Adding to the other reply if you did indeed melt the bearing it is imperative that you clean the crankcase. Personally I would also pull the oil pump and check it for debris  and flush the lines. The Lister technical data specs the  clearances with new parts at .0025"- .003" with allowable wear .003". So, clearance could be as large as .006" and be within the spec to run it,  however I would never let one out of the shop with that much clearance.

Many thanks for the extra I formation and adviceÖ. All very useful. Thank you for taking the time to post.

Yellownev

  • Newbie
  • *
  • Posts: 17
    • View Profile
Re: Big end wear or damage
« Reply #6 on: December 03, 2021, 03:41:45 PM »

OP, is that a genuine Lister CS 16/2 engine you have in your canal boat?

Or is something more like this (and of Indian origin)?

https://www.stationaryengineparts.com/Publicity.html

Ö.. it is that actual engine ( and boat) in the link. I purchased Tonys boat back in 2012. The engine has run very sweetly with many positive comments until this recent episode.. many thanks for the link as Iíve not read that before.

listard-jp2

  • Hero Member
  • *****
  • Posts: 657
    • View Profile
Re: Big end wear or damage
« Reply #7 on: December 03, 2021, 05:53:15 PM »
The same engineer suggested unbolting the conrod and checking for wear/damage with a view to replacing the bearing. Now I have seen there are different thicknesses of replacement bearings shells to ( I assume) account for wear such as I may have. He suggested this should be an easy thing to do and check... he's experienced I am not

As your engine is relatively new, the big end journals should still be on standard size, and if your lucky and caught it soon enough. You may be able to get away with just replacing the big end shell bearings (after polishing the big end journals).

However the condition of the big end journals is going to determine if this is a viable solution. If they are scored you may end up needing a crank grind on the big end journals.

Finally I would suggest replacing the big end shell bearings on the other cylinder whilst your in there.


My questions to the enlightened is ..... is is a relatively simple thing to unbolt the conrod via the open side of the crankcase.


Yes, I have done this myself on numerous occasions, however as your engine is installed in a narrow boat, you will not find it particularly easy.

Then is it a matter of checking the surface as well as measurements of the shaft the conrod bearing clamps to. If there is not real wear replace the shell bearing with like for like ....


Yes and Yes, Standard journal size would be 2.4975/2.498" if we were dealing with a genuine Lister CS engine, but more importantly is ovality of the journal. More that 0.002" out of round and your into regrind territory.


If there is wear replacing the shell bearing with one to compensate for the wear?

Yes, upto 0.0060" undersize. However, be sure to specify a Lead / Indium bearing for the top half bearing shell, because if you fit a white metal version you will knock out he big end in no time.


Obviously if the crankshaft surface is damaged too badly i expect that it is the crankshaft out to have it build up and turned back to spec?


It will be ground to the undersize (in 0.010" increments) at which the journal cleans up at.

Why not take it back to Redshaw's for some corrective surgery (that is if your not to far away)


Yellownev

  • Newbie
  • *
  • Posts: 17
    • View Profile
Re: Big end wear or damage
« Reply #8 on: December 04, 2021, 10:25:18 PM »
Many thanks Listard for your very helpful and detailed reply picking up the issues I asked question on. I will read through a few times to ensure I understand them fully. The last question on taking Percy back to Paul & Tony Redshaw its location sadly too far away, worst case could be the engine going leaving the boat behind !

I'll update but it may be a while  !

cujet

  • Hero Member
  • *****
  • Posts: 929
  • Lister power rules!
    • View Profile
    • www.cujet.com
Re: Big end wear or damage
« Reply #9 on: January 18, 2022, 03:34:43 AM »
Any updates?

One thing I don't see mentioned is the connecting rod shims. To a small extent, removal of shims can "tighten" a new bearing a little, to fit a very slightly worn crankshaft a little better.

Put another way, simply assembling the connecting rod with new bearings and no shims under the rod cap could result in insufficient bearing to journal clearance.

This is one nice way these engines can be kept operational with minimal work.
People who count on their fingers should maintain a discreet silence

Yellownev

  • Newbie
  • *
  • Posts: 17
    • View Profile
Re: Big end wear or damage
« Reply #10 on: January 18, 2022, 08:32:08 AM »
Hi Cujet et al,

Nothing to report sadly as the cold weather and a few health issues have kept me away from the boat and the engine.

Thank you for the advice re the shims and the option of removal to possibly account for wear. I presume the Plastiguard tolerance check would be the guide to correct clearance along with a micrometer measurement. I have asked a boat engineer to come take a look but they are very busy as canal boats seem to have attracted a lot of purchase interest over the last couple of years as people stay local or realise their dreams sooner than planned.

If he does not show up soon it will be me and my spannerís ( wrenches) and your guidance. Itís a race of the engineer or the warmer weather !

Thanks for following up on my initial ask for guidance.

Take care

Nev

cujet

  • Hero Member
  • *****
  • Posts: 929
  • Lister power rules!
    • View Profile
    • www.cujet.com
Re: Big end wear or damage
« Reply #11 on: January 19, 2022, 02:45:13 PM »
I'll bet we can guide you through the job. Post some high resolution pictures of the bearing shells, the crank journal and the con-rod, with the shims currently installed. With proper supplies, it's an afternoon's job.

I may be possible that with appropriate care, cleaning and effort, the crank may clean up and be dimensionally OK, and the new rod bearing can be made to work properly. I have heard of this before, with excellent results. Although I've not had it happen to my engines.

I would also check the other rod bearing. If one let go, maybe the other is not far behind.

EDIT: It's not uncommon to occasionally replace rod bearings on some engines (think BMW six cylinders) and I'd consider it normal maintenance.
« Last Edit: January 19, 2022, 02:47:39 PM by cujet »
People who count on their fingers should maintain a discreet silence

Yellownev

  • Newbie
  • *
  • Posts: 17
    • View Profile
Re: Big end wear or damage
« Reply #12 on: February 13, 2022, 09:45:41 PM »
Hi all,

Not sorted yet as an engineer I contacted got in touch and is visiting a week on Tuesday to have a look ( and a feel) so for now Iíve deferred until an expert gets a look. I am looking to source gaskets for the crankcase door and the water elbows from the cylinders Ö Iíve dropped a message to Stationary engine parts in the hope they can sell me them or source them.

Sorry itís not a progressive update and thanks for  engagement so far.

Iíll update when the engineer has had a look !

Thanks again

Nev

cujet

  • Hero Member
  • *****
  • Posts: 929
  • Lister power rules!
    • View Profile
    • www.cujet.com
Re: Big end wear or damage
« Reply #13 on: February 16, 2022, 11:10:04 PM »
You may not have to pull the cylinder. I suggest cleaning up the journal and measuring first.
People who count on their fingers should maintain a discreet silence

Yellownev

  • Newbie
  • *
  • Posts: 17
    • View Profile
Re: Big end wear or damage
« Reply #14 on: February 22, 2022, 09:23:52 PM »
Well it looks like Iíll be having a go as the engineer put me off Ö..

Iíve a question before ĎI go iní what will be the nut size that Iíll need to removeÖ.. I ask as Iím unsure if the nuts are imperial or whitworthÖ. Iíve read around and my understanding  is whitworth were Ď imperialí in measurement but a spanner/socket  size up on imperial as the size is the bolt not the nut so 3/8 whitworth would need a 1/2 inch socket ? I do hope Iím not over thinking this ?

One other thought what is the torque setting if there is one for the cap nuts ?

I did say at the off Iím on a learning curve so please stick with me if you can !

Nev