Author Topic: New pistons Petter PJ2, block after short time engine running. Clearance?  (Read 2939 times)

ajaffa1

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Re: New pistons Petter PJ2, block after short time engine running. Clearance?
« Reply #60 on: October 28, 2018, 10:15:03 PM »
Hey Rob, pistons should be round and the sides should be parallel. The cylinder bores should also be round and the the same size all the way up the bore. The manual should tell you what the correct clearance between the piston and the cylinder should be. Some pistons have a mark on them indicating which way they are to be fitted, this is usually because the gudgeon pin (wrist pin) is slightly offset in the piston.

The wear on the piston in the photograph suggests that the piston is not round and that the clearance with the cylinder wall is too small. Alternatively the cylinder walls are not parallel. Take them back to the shop that did the work and shout at them until they put it right.

Bob

Rob PetterPJ2

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Re: New pistons Petter PJ2, block after short time engine running. Clearance?
« Reply #61 on: October 29, 2018, 11:52:50 AM »
Hey Rob, pistons should be round and the sides should be parallel. The cylinder bores should also be round and the the same size all the way up the bore. The manual should tell you what the correct clearance between the piston and the cylinder should be. Some pistons have a mark on them indicating which way they are to be fitted, this is usually because the gudgeon pin (wrist pin) is slightly offset in the piston.

The wear on the piston in the photograph suggests that the piston is not round and that the clearance with the cylinder wall is too small. Alternatively the cylinder walls are not parallel. Take them back to the shop that did the work and shout at them until they put it right.

Bob

Hi Bob
you might encounter a dispute with the other guys here about the possible oval and parallel shape of pistons in general. I've read there are even barrel shaped pistons, and the oval shape would be normal when the piston is cold. It would get round when heating up. It's all about fractions of mm. When I measure the old pistons, the difference in length and with of the oval would be no more than 0.05 mm (roughly 0.002"), as written earlier.
The Lister LD manual, of a 1 cylinder engine, does mention the  direction of the pistons and says it would show the right positioning by the word "Camshaftside" on it.
My old-, nor the new pistons mention any such thing and do not show a mark, or sign. It only shows a number.
When I look into the bottom side of one of the old pistons, I see a tiny desaxation. It could be as little as the thickness of a penny, or even half of that. It goes to the side of where also the number is written at the piston's top.
I understand the function the desaxation (now that I've read about it).
I may have put the new pistons in wrong, both of them with the number at the other side. But could that have resulted in seizing after two minutes running stationairy without load?

I'm waiting for the better manual to be dropped in my mailbox, that's being sent by Jim Perkins from the UK.
It's a pity he had to tell me its a manual of a slighty different model, still... hm. I'll know how 'slightly' when I have it in my hands and see the illustrations.

I wait for that, study the book, before I dare go back to the engine renovation garage to show them what happened. I bought the honing tool and oil, but if honing needs to be done, I may still have them do it.

And yes, I will consult an expert, Matt!

There's one more unusual thing, with this engine: one injector has 4 spraying holes, the other one only three. This was discovered when I had them tested. For the rest, they're identical.
« Last Edit: October 29, 2018, 01:16:47 PM by Rob PetterPJ2 »

glort

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Re: New pistons Petter PJ2, block after short time engine running. Clearance?
« Reply #62 on: October 29, 2018, 02:13:23 PM »
I'm not sure I have any helpful advise left.
Good Luck with it.
« Last Edit: October 29, 2018, 09:35:51 PM by glort »

sirpedrosa

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Re: New pistons Petter PJ2, block after short time engine running. Clearance?
« Reply #63 on: October 29, 2018, 04:31:42 PM »
Hey Rob

Cheer up!

Unmount everything until the last piece, rebore cylinder to next oversize (or get new standards), fit new pistons (send damaged ones to recycle to get some pennies to help buying new ones).

I'll get there, with more acurate patience, and more burned eyelashes.

Think of the new pistons as less of a headache pill you did not spend at the pharmacy.

Don't forget its your boat engine, it must be reliable.

Thumbs up!
BR
VP
Bernard 18A - 1968 (mama's water pump - year of my birth)
Petter PAZ1 - Jun 1967, 3HP, sn 416xxxx

Johndoh

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Re: New pistons Petter PJ2, block after short time engine running. Clearance?
« Reply #64 on: October 29, 2018, 05:41:19 PM »
Holding back again Glort! You should say what you think
It is better to light a candle than to curse the darkness

mikenash

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Re: New pistons Petter PJ2, block after short time engine running. Clearance?
« Reply #65 on: October 29, 2018, 05:47:58 PM »
Holding back again Glort! You should say what you think

Yes.  Man turns to the forum for some advice and support and gets this.  Dickhead

Rob PetterPJ2

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Re: New pistons Petter PJ2, block after short time engine running. Clearance?
« Reply #66 on: October 29, 2018, 06:11:33 PM »
Glort

I'm of the opinion that your reply is rude, indeed, as you suspected, but then, you didn't care.
Your remark about the level of embarrassment is way out of line. You fill in for others too quickly. I'm very embarrassed. Still, I want to be honest.

To answer to your concern about the injectors.
This is how I got the engine. Understanding that three holes may deliver fuel different than four holes, I measured the delivered fuel of each, by letting turn on the start engine, and let the fuel be spit into two of those thin laboratory glasses, that make measuring liquids easier. I did that over and over again, and adjusted the delivery of the two fuel pumps according to it.

Pistons not reaching the same height.
This is how I got the engine. One of the pistons rods is a fraction shorter than the other, as I had guessed it was. It has nothing to do with the bearings. The rods aren't exactly equal. Noticing the difference, I took the shims, that were there when I got the engine, away, there, and put them under the other cylinder, to equal the bump clearances, and with the cylinder head gaskest, that I cut from material especially made for cylinder head gaskets, that I only do not remember the name of, because I bought it years ago, from a shop for Classics and old timers, after which they were exactly right, according dieselgmans notes.
I've been endlessly measuring the bump clearance in all kind of ways, to get to the 1 mm, and I was happy to see the engine fire at the first attempt, the two cylinders responding the same way, with equal force, and the cylinders warming up equally, as never happened before.

Suspecting the pistons to be slightly different
I had been measuring the pistons sitting in the cylinders and came to the conclusion they've not exactly the same diameter. I had measured them at different spots. My main conclusion was: they're different.
Well, THEY ARE. But why?
Now that I took the cylinders and pistons all off, again, and slide the pistons through the cylinders (WITHOUT THE RINGS), one immediately feels a difference. Piston 1 has to be pushed, doesn't like to go through, but will with a continuous push. Piston 2 slides through easily.
For Piston one, I can not imagine it expanding a bit through heat and then still going through. It seems to have its maximum width already.
Now I am aware there could be a reason for piston 1: it's damaged by the seizing. May be it got deformed, but....

But let me tell you:
BEFORE ANY TEST RUN a POSSIBLE PROBLEM WAS NOTICED by me, with THAT PISTON!
When I put the new pistons in the very first time, when I reassembled the pistons and cylinders I noticed getting piston 1 into the cylinder was more difficult than piston 2. And I told the engine revision garage right away. When turning the flywheel, piston 1 would lift the heavy cylinder up. Remember, they said it was "not unusual". They had said this happens sometimes when they assemble engines and they didn't think much of it. They had actually said sometimes force is needed to get a piston in, while another pitons easily slides in into the cylinder next to it. For me THEY were the specialists that I thought I had to trust, for them doing this work day in day out.
I think my suspicion was more right than their denial.

Blame?
I have already written about this, but when I called them about the problem of the broken piston, it was THEM, the specialists, telling me what they could do for me: bring the pistons, and the cylinders and we have a look.
I went there. They said: We'll measure the things, check things out, and you pay 40 euro for that and our advise.
When I came back after a few days they presented me with their idea: because of the scratches in the cylinder wall, we'll have to hone them. We'll search for new, slightly bigger pistons.
And when they found the piston supply shop, they let me know the price for the pistons, the shipping and the honing, and I said OK and then they went to do their specialists thing.
They didn't ask for measures. They gave me the impression they knew what to do and how to do it. Their workplace is a hall full of engines they are fixing (I hope). I earlier had good experience with them.
I don't know how they decided about the measures for the honing, how deep to go, how much the clearance should be. They seemed to know what they were doing!

Did they supply the rings? Yes, they came with the pistons they had ordered.
No, the ring gaps I did not put in the wrong positions. I could figure out all by myself, what was the logical thing to do, there.

If new honing clearly has to be done, then I'll be ready to pay for it again, when they think they have done it right the first time, even when it doesn't seem to have the right clearance.

Glort, thanks for your advises, so far.
You added a whole list of things to check. I have that list already. It's all in the Lister LD manual that I have mentioned a few times.
You forgot one thing: the fuel. That I should put diesel in.

BTW, the tank was loaded with red diesel, when I got the boat. I brought it away. I had to clean the tank anyway. And the fuel pipe. And the filters.

« Last Edit: October 30, 2018, 03:25:18 PM by Rob PetterPJ2 »

Johndoh

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Re: New pistons Petter PJ2, block after short time engine running. Clearance?
« Reply #67 on: October 29, 2018, 09:11:18 PM »
Is it possible that someone had replaced a barrel at some stage in the past? If you switch barrels do the pistons level correctly? Measure the conrods and barrels and see if theres a difference. Glort is a good bloke albeit with a low frustration tolerance.
It is better to light a candle than to curse the darkness

glort

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Re: New pistons Petter PJ2, block after short time engine running. Clearance?
« Reply #68 on: October 29, 2018, 09:39:47 PM »
Glort

I'm of the opinion that your reply is rude, indeed, as you suspected, but then, you didn't care.

I apologise.  I really did not mean to be rude and if I was I am sincerely sorry.

Johndoh

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Re: New pistons Petter PJ2, block after short time engine running. Clearance?
« Reply #69 on: October 29, 2018, 09:43:02 PM »
Glort

I'm of the opinion that your reply is rude, indeed, as you suspected, but then, you didn't care.

I apologise.  I really did not mean to be rude and if I was I am sincerely sorry.

Dripping sarcasm and bitter irony I love it!
It is better to light a candle than to curse the darkness

glort

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Re: New pistons Petter PJ2, block after short time engine running. Clearance?
« Reply #70 on: October 29, 2018, 09:48:35 PM »
That's a bit rough.  I was not trying to be sarcastic at all. Just apologise for something I should not have said and my poor judgement in saying it.

Not trying to be an arsehole even if I come across as one.

Rob,
I apologise to you for my rudeness and misplaced Comments. I was out of line.  I am sorry for any insult caused and my lack of decorum. 
« Last Edit: October 29, 2018, 10:43:23 PM by glort »

glort

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Re: New pistons Petter PJ2, block after short time engine running. Clearance?
« Reply #71 on: October 29, 2018, 09:50:39 PM »

Yes.  Man turns to the forum for some advice and support and gets this.  Dickhead

Hey Mike,

I'll be in your part of the world in a fortnights time. 
Why don't we meet up and have a chat?  :laugh:

Rob PetterPJ2

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Re: New pistons Petter PJ2, block after short time engine running. Clearance?
« Reply #72 on: October 30, 2018, 11:00:36 AM »
Is it possible that someone had replaced a barrel at some stage in the past? If you switch barrels do the pistons level correctly? Measure the conrods and barrels and see if theres a difference.

Hi Johndoh
it has become a long thread with lots of text. It says somewhere I measured everything (barrels, pistons) and, together with there not being any freeplay in the piston rods' bearings, I was left with only one conclusion: the piston rods aren't equal, and that's why the pistons don't reach the same height in the barrels. They don't even LOOk equal. There's a slight difference in shape (a light curve in one), though they show the same code, "P57" and a "J" on them.
Now I'd be surprised if someone would say the light curve in that one rod (think of a saber) would have been caused by a mishap. Though, were it straight, it may just reach the same height as the other one... That's one for you, Glort, to add to the list ;-)!

So this engine has definitely been doctored on by a creative mechanic of the ship line it came from (in a life boat). As I wrote earlier one of the two bolts connecting oil banjos to the cylinder heads was wrong as well. A fraction too big and 6 mm shorter than the other one. Thereby damaging it's thread and by the latest re-assembly, causing oil to leak. Therefor I'm waiting for Jim Perkins delivery of an original bolt.
The old pistons weren't equal either. One was original Lister Petter, had this name engraved on it), while other one, the broken one, had only a number engraved.
I see no reason to believe that one of the cylinder barrels were ever replaced. They're identical.
« Last Edit: October 30, 2018, 01:40:14 PM by Rob PetterPJ2 »

Rob PetterPJ2

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Re: New pistons Petter PJ2, block after short time engine running. Clearance?
« Reply #73 on: October 30, 2018, 11:58:31 AM »
I sure understand your frustration, Glort, when you observe this guy, me, treating an old Petter as a learning object. I indeed thought that taking the thing apart and putting it back together in the reverse order would do the job. But what kept me busy was also: what was the cause, or were the causes, of the old piston to break? Why that one piston and not the other one? And that I had to check whatever could be checked, like
- equal fuel delivery
- fuel injection timing
- oil supply, oil leaks
- type of oil
- compression
- valves
- exhaust pipe
It was noticeable, due to the blue smoke, that there was a problem there, before this shit happened. A friend, very experienced in renovating classic cars and engines, helped me adjust the valves. I talked about the blue smoke to the owner of the oldest oil shop in town, having all the various oils for the old classic engines, and he suggested I should try thicker oil, for the engine having worn out. There was logic in it, so I did. Using the thicker oil may have been wrong, for being a possible cause for even quicker overheating.
While on a long boating trip, the engine had severely overheated, and seized, when the air cooling had been accidentally blocked and I had not seen it, steering at the front of the boat.
Since then, the engine kept heating up quicker, and the exhaust smoking more (and blue). I needed 9 hours of boating to get the boat home, which I did in steps, altered with cooling periods. And then one cylinder showed to be overheating extremely fast, making it clear there was a mayor problem in there. And then I found that one piston being broken.
And that's when I got my confrontation with the unexpected fine details of the Zen of Diesel Engine Assembly...
« Last Edit: October 30, 2018, 01:44:45 PM by Rob PetterPJ2 »

Johndoh

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Re: New pistons Petter PJ2, block after short time engine running. Clearance?
« Reply #74 on: October 30, 2018, 05:28:54 PM »
Was there any rust or water in the cylinder or sump? conrods arent easy to bend in service usually hydro-locking is the cause in my experience. You'll have to start at the beginning with 2 equal conrods and machined bores. 
It is better to light a candle than to curse the darkness