Puppeteer

Author Topic: cracked piston  (Read 1563 times)

vegoil

  • Jr. Member
  • **
  • Posts: 70
    • View Profile
cracked piston
« on: March 30, 2020, 03:31:26 PM »
I have been having bad luck!
renewed the cylinder and piston Because the old piston gudgon pin broke and went threw the side of the cylinder.
I have set the bump to 0.095thu thinking there was to much firing compression. also checked the injection timing to what i thought was 20 Deg zig zag mark using the spill method using a short tube so I could see when the fuel stopped flowing. It turns out that there are two marks on the flywheel one mark 20 Deg but mostly been ground away, and the second mark 26 Deg that was the one I had been using!! Because I am running on WVO it was set even a Little further advanced.

I wonder If this is the cause of my second Piston only lasting for a week! before it cracked blowing out oil and fumes threw the breather.

Any Ideas Please

listeroil

  • Full Member
  • ***
  • Posts: 208
    • View Profile
Re: cracked piston
« Reply #1 on: March 30, 2020, 10:16:16 PM »
Pistons got to be the problem. The barrel looks like an Indian one I bet the piston is as well.  Get the seller to replace it.

saba

  • Full Member
  • ***
  • Posts: 119
    • View Profile
Re: cracked piston
« Reply #2 on: March 31, 2020, 12:37:28 AM »
I think you need to send some pictures of the piston.
I used a few parts from india the barrels/liners were garbage with cast pockets in the liner surface, and leaking water threw the block. Pistons looked fairly ok.

Did some pretty stupid things but nothing ever broke big time.

Greetings Bernhard

snowman18

  • Full Member
  • ***
  • Posts: 216
    • View Profile
Re: cracked piston
« Reply #3 on: March 31, 2020, 06:50:22 AM »
Would be interesting to have a sample of that cracked piston shot with an XRF to see what the composition of the metal alloy is.

As in China may back yard foundry's cast parts from a common mold, so there's absolutely no quality control.

This video shows people in China working their backyard foundry's just look at the type of scrap metals being brought in by the peasants.

The video below the first one  shows a backyard foundry in India.

https://youtu.be/60_Q-kAZbXA

https://youtu.be/VpZwFu91Nq8?t=3

mikenash

  • Hero Member
  • *****
  • Posts: 818
    • View Profile
Re: cracked piston
« Reply #4 on: March 31, 2020, 08:27:47 AM »
In automotive diesels I think cracked pistons tend to be from trauma?

For example, our Fonterra fleet experimented with LPG-fuelled diesel engines years ago - they went like the clappers but cracked pistons were the result

I wonder if having the injection timing substantially wrong could add "load" or "shock" to combustion forces?

Better-educated brains than mine will know

vegoil

  • Jr. Member
  • **
  • Posts: 70
    • View Profile
Re: cracked piston
« Reply #5 on: April 05, 2020, 04:44:32 PM »
would you recommend setting the bump to what it is in the Lister hand book 0.075" to 0.080" rather than lowing the compression to 0.095" and the timing 18 Deg 2 Deg retarded.

as I mentioned before the timing marks on the flywheel may have been wrongly marked in the factory Back in 1959 as the zig zag is 26 Deg the 20 Deg has been ground away. I am now going to use a digital inclinometer as in the last post's photos.

There has always been a knocking sound. I had a visit from a garage mechanic he had a listen to the original Lister CS 8/1 engine he told me that that old type of engine all sound like that. I am thinking that he needs his hearing tested!

I am waiting on a replacement piston from the company I bought it from, as they are going to replace it free of charge.
« Last Edit: April 05, 2020, 05:44:20 PM by vegoil »

vegoil

  • Jr. Member
  • **
  • Posts: 70
    • View Profile
Re: cracked piston
« Reply #6 on: April 07, 2020, 05:22:31 PM »
this is a photo of the piston. I have found out that the top ring that came with the piston was wrong it was chrome.
that may explains why there was blow by heating the side of the piston, then crack.

answers Please.

sirpedrosa

  • Hero Member
  • *****
  • Posts: 613
  • 21NOV2019 - Finally I hear that sound... again
    • View Profile
Re: cracked piston
« Reply #7 on: April 07, 2020, 07:06:27 PM »
Hi Veg

this is a 8/1, wright?

Is the cylinder bore chrome? if so, it cant have a chrome ring because is to hard!

In my point of view this piston was hited by start spray. Its splited at middle line of wrist pine (small end).

Does it have more symptoms?

that knocking sound seems to be early injection point.

Keep giving news, and stay safe.
VP
« Last Edit: April 07, 2020, 07:58:10 PM by sirpedrosa »
By order of firing up:
Bernard 18A - 1968 (mama's water pump - year of my birth)
Petter PAZ1 - Jun 1967, 3HP, sn 416xxxx
Petter PAZ1 - Nov 1979, 3HP, sn 425xxxx
Lister 12/2 - 12651227, the pearl!

vegoil

  • Jr. Member
  • **
  • Posts: 70
    • View Profile
Re: cracked piston
« Reply #8 on: April 07, 2020, 08:20:42 PM »
Yes this is an old 8/1 The bore is India chrome it don't look it but apparently it is, I realise now that it was the wrong ring.
what do you mean by:{In my point of view this piston was hited by start spray}
« Last Edit: April 07, 2020, 09:44:57 PM by vegoil »

sirpedrosa

  • Hero Member
  • *****
  • Posts: 613
  • 21NOV2019 - Finally I hear that sound... again
    • View Profile
Re: cracked piston
« Reply #9 on: April 07, 2020, 09:45:42 PM »
Hi Veg

Start spray ignites very earlier, and so the piston is farway from TDC, therfore it will break the least strong piece, in this case alu piston.

Chrome bores CANT have chrome rings, its hard metal work in hard metal. Can you see result of this friction?

Chrome bores need soft rings...

Stay safe.
VP
« Last Edit: April 07, 2020, 09:50:04 PM by sirpedrosa »
By order of firing up:
Bernard 18A - 1968 (mama's water pump - year of my birth)
Petter PAZ1 - Jun 1967, 3HP, sn 416xxxx
Petter PAZ1 - Nov 1979, 3HP, sn 425xxxx
Lister 12/2 - 12651227, the pearl!

dieselspanner

  • Hero Member
  • *****
  • Posts: 655
    • View Profile
Re: cracked piston
« Reply #10 on: April 08, 2020, 07:03:41 AM »
Spot on Glort!

Every brickies labourer should be forced to read and understand the instructions for use of 'Angels Breath' before being allowed to start the mixer.

Mind you, there's a lot of farmers and small boat owners keeping diesel mechanics in business too....

Cheers
Stef
Tighten 'til it strips, weld nut to chassis, peen stud, adjust with angle grinder.

vegoil

  • Jr. Member
  • **
  • Posts: 70
    • View Profile
Re: cracked piston
« Reply #11 on: April 08, 2020, 08:39:50 AM »
I have never used easy start spray on this engine. it's a start o matic so starts and stops on It's own when it's working!

sirpedrosa

  • Hero Member
  • *****
  • Posts: 613
  • 21NOV2019 - Finally I hear that sound... again
    • View Profile
Re: cracked piston
« Reply #12 on: April 08, 2020, 11:55:04 AM »
Hi Veg

One thing for sure, this piston broke, and the next will brake also IF the other issus still not resolved. Take a close look at firing time.

Have you seen how I had done with my 12/2?

Stay safe
VP
By order of firing up:
Bernard 18A - 1968 (mama's water pump - year of my birth)
Petter PAZ1 - Jun 1967, 3HP, sn 416xxxx
Petter PAZ1 - Nov 1979, 3HP, sn 425xxxx
Lister 12/2 - 12651227, the pearl!

vegoil

  • Jr. Member
  • **
  • Posts: 70
    • View Profile
Re: cracked piston
« Reply #13 on: April 08, 2020, 12:11:23 PM »
I agree with you. would it be better to set the bump to 75thu and the injection to 18 Deg as not to have it advanced?

sirpedrosa

  • Hero Member
  • *****
  • Posts: 613
  • 21NOV2019 - Finally I hear that sound... again
    • View Profile
Re: cracked piston - Some manual readings will help
« Reply #14 on: April 08, 2020, 02:33:29 PM »
Hi Veg

The bump will give you the compression ratio - how do you want it? hard or smouth? See the book range spec! (if hard: low range, else top range)

Fire time: What states the book FOR diesel? ah, you want to run it veg? So what will be the rate of self combustion of veg related to diesel? (veg takes more time? therefore spill more far from TDC)

Read again (maybe twice) your other thread, here: https://listerengine.com/smf/index.php?topic=8993.msg104583#msg104583

Any doubt... strip it all down and rebuild it again.

But, stay safe... and inside.
VP
« Last Edit: April 08, 2020, 02:36:29 PM by sirpedrosa »
By order of firing up:
Bernard 18A - 1968 (mama's water pump - year of my birth)
Petter PAZ1 - Jun 1967, 3HP, sn 416xxxx
Petter PAZ1 - Nov 1979, 3HP, sn 425xxxx
Lister 12/2 - 12651227, the pearl!