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New style piston
http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?f=5&t=83021		 Page 1 of 1
Author:  spoon [ Tue Sep 08, 2015 6:26 am ]
Post subject:  New style piston
Coal Burner History

This is a 2005 Limited. I purchased it with 87,000 miles from a local owner. When I received it everything was bone stock. The factory recall detune had been done. The services were done at the recommended intervals and the oil was Mobile 1 0W-40 and I think Fram filters.
Shortly after I got it I installed a lift pump and a new fuel filter head. And an oil separator. I use Rotella T6 and Wix filters. Timing belt change time came around and I did that service along with the rockers and water pump and inline thermostat. I found one rocker broken when I removed the rocker cover, that was replaced, no other damage. This was at about 97,000. The intake in the rocker cover had about ¼ to ½ inch of crud plugging things up. Typical form what I have seen others post. At some point the fan clutch was replaced. I should note that I live at 7000 feet and the PO used the CRD for trips of 40 miles and more. So the engine got little start/stop time and a little workout with the up/down travel.
After another 12,000 or so the posts on head gaskets started to heat up and I thought I should look into that. So, the head came off (head bolt torque was recorded here) and gasket, studs, rockers, Week’s intake elbow and steel glow plugs were installed. So the EGR was completely removed and the plumbing changed accordingly. I put a little over 700 miles on it and on a trip it lost power and died. This was while going down the interstate at about 70.
The Carnage
The reader interest may have just picked up..
The intake hose had blown off at the intake elbow. No rockers were broken but an intake valve was imbedded in the piston. I think this is the valve that had the original broken rocker. But I’m not certain. It definitely is the same piston. In looking at the valve (the valve stem pulled up through the guide with no resistance so a clean brake at the head) there is pitting on the stem at the brake area. There are a lot of questions and speculation that can go on about what caused this but the bottom line is a new piston/liner and head are in order.
So, the request to forum folks is what else should I look at and what do I need to change a liner.
Some additional information, the head gasket looked good the studs seemed to have even torque when I broke them free and there is a water leak into the combustion chamber. That is most likely coming from the broken valve hole. The glow plug was not harmed but the injector tip is another story. I am trying to post photos from Image Shack on a Mac but until I figure that out imagine how much damage a 1/8 inch piece of carbon or ceramic will do, then insert a valve head. So I am waiting to see what the collective experts think, and how much I need to look at in the bottom end.
Author:  spoon [ Tue Sep 08, 2015 6:41 am ]
Post subject:  Re: New style piston
Lets see how this works.
http://imagizer.imageshack.us/v2/640x48 ... dsUzpz.jpg
http://imagizer.imageshack.us/v2/640x48 ... 3sThie.jpg
http://imagizer.imageshack.us/v2/640x48 ... WDUOG4.jpg
Author:  flash7210 [ Tue Sep 08, 2015 8:22 am ]
Post subject:  Re: New style piston
First,
You will have to pull the motor before you change out that one piston.
So, while you have it out, you can thoroughly inspect the bottom end.
I suspect that all your rod and main bearings will be just fine.

Second,
I agree that the piston and liner should be replaced as a set.
You will need a tool to pull the liner, a tool to set liner depth, and ring compressor for installing the new piston.
You should also hone the new liner and while the block is out, remove all the pistons and hone the other liners too.
Consult GDE for more specifics about tools, liner installation, honing, rod bolt torque, and if the rod bolts need to be replaced.

Third,
You can get new head from IDparts, but if you want to save some money you can get a used head from VMspecialists in England.


Thats all I can think of for now.
I'm sure others can add more suggestions.
Author:  Mountainman [ Tue Sep 08, 2015 10:51 am ]
Post subject:  Re: New style piston
hmm, maybe the broken rocker slightly damaged the valve and it took a while for it to snap off. That's kind of scary for many of us that have replaced broken rockers.

Sorry your engine went to hell after you put so much work into making it reliable :banghead:

I'm gearing up for a sleeve replacement myself.

I think we need this stuff and more:
-torque wrench with degrees dial, or you can wing it, but precision would be nice on rod bolts...
-rear main seal, and about every other gasket under the hood...
-all new rod bolts
-I'm just doing a sleeve with pistons rings, seals, and shims for one cylinder only
-make sure the piston weights are stamped the same. VM specialists in UK told me they don't make our old ones anymore, but hopefully GDE or IDparts has what you need. I'm just replacing a sleeve that a stealership sanded the rim down...
Author:  Mike92104 [ Wed Sep 09, 2015 4:27 am ]
Post subject:  Re: New style piston
I know the piston is deformed because of the valve, and it's hard to tell from the picture, but it looks like there may have been some melting happening on the piston crown on the right side of the picture. The very edge of the piston looks a bit rounded over, and it shouldn't be. Is there any scoring on the sleeve on that side?

I melted a piston on mine because I ran it with a failed rocker, and it looked similar (without the valve of course) to that one. It took me a while to realize it.
Author:  Mountainman [ Wed Sep 09, 2015 11:35 am ]
Post subject:  Re: New style piston
-Spoon.
Looks like we don't need a full set of rods bolts. Word is that we can pull a piston and liner without pulling the crank. I'll let you know if I get in there before you do. Please report if you're able to validate this. :JEEPIN:
Author:  Mountainman [ Wed Sep 09, 2015 12:09 pm ]
Post subject:  Re: New style piston
-Spoon

For the better of the group, could you please take a measure for us when you pull that rod? I assume since it hammered a valve that you will replace it anyhow. If you could break loose those two rod bolts, oil them if dry, and torque them to factory specs, and then see how much torque it takes to make them just budge tighter (1 ft/lb at a time increasing), and then record the values. I'll do the same, and then we'll have 4 bits of data. If they all point just north of 65 ft/lbs, then I think we'll have a torque value to use, versus the degrees method. Maybe we should use new rod bolts for this. I think I'll try both, and that will give us 6. I'm not afraid of damaging a rod by over-torquing it a tiny bit, but if you are trashing it anyhow, you can try it fairly carefree.

Anyone know if we can torque these TTY bolts twice, or are they trash if we over-torque them slightly for just a few seconds? I think it should be safe cold/with no expansion involved...
Author:  Mike92104 [ Wed Sep 09, 2015 1:55 pm ]
Post subject:  Re: New style piston
TTY bolts are supposed to be replaced after use. Also the rods are balanced as a set, so you have to replace all 4 if you replace any.

Mike
Author:  Mountainman [ Wed Sep 09, 2015 4:36 pm ]
Post subject:  Re: New style piston
Mike92104 wrote:
TTY bolts are supposed to be replaced after use. Also the rods are balanced as a set, so you have to replace all 4 if you replace any.

Mike


I just wonder if torquing it cold for a few seconds stretches it enough to be "used".

That just sucks about the rod sets. Maybe Spoon will have some extras for testing then :frankie:
Author:  LMWatBullRun [ Wed Sep 09, 2015 5:21 pm ]
Post subject:  Re: New style piston
Mountainman wrote:
Mike92104 wrote:
TTY bolts are supposed to be replaced after use. Also the rods are balanced as a set, so you have to replace all 4 if you replace any.

Mike


I just wonder if torquing it cold for a few seconds stretches it enough to be "used".

<snip>


Yes. If in fact it is a true TTY bolt. Absent compelling evidence to the contrary, I would assume that it is in fact TTY if the SM says so.

(Head bolts we KNOW are NOT TTY, but these......?? )
Author:  senatorjohn [ Thu Sep 10, 2015 5:35 am ]
Post subject:  Re: New style piston
Why not balance the replacement rod to match the one removed. Not rocket science.
John
Author:  spoon [ Thu Sep 10, 2015 8:09 am ]
Post subject:  Re: New style piston
Sorry its taken a little long to reply. I think the rod should be replaced due to compression stress. The bolts I would think are one time use. I did not know the set was balanced given the low RPM of this engine. Are the rods and bolts available individually? I will be happy to do what ever measurements/tests we can come up with to help the cause.
On the offending valve, if that was the one with the broken rocker (and I suspect it was) sitting in one position - closed - for I don't know how long could have started corrosion. I will look at the guide and see what that tells me.
I don't think there is any piston melting. As you can see the head and piston top are beat to h;*ll. There is a deep score in the cylinder wall. It's interesting that the glow plug was not touched. The injector tip is another story, I think that is rebuildable. I need to look at the turbo to see if any extra part chunks made it that far. I'll keep this updated as I progress.

spoon
Author:  Mountainman [ Thu Sep 10, 2015 11:36 am ]
Post subject:  Re: New style piston
Probably a lot less $$ to buy an injector of of ebay for just over 200 than get a rebuild. Even if you had to buy two...

I like what the Senators is saying, but can you find a shop that balances rods? The manual claims that only matched sets will be sold, I haven't looked.

$410 for a set of rods and bearings (I bet you'd be fine with new bearings without messing with the crank) and then just have to press the wrist pins out and in? Man, lose one cylinder and you're looking at over a grand in parts. I'd be looking for an engine with a good bottom end to rob a set of rods and a piston/sleeve set. Just when I thought I'd sell my spare engine, I better keep it around just in case I have similar trouble...

For testing, the new bolts are only $1.60. But, since the wise engineer chimed in, it sounds like the factory method is probably the best bet on these. Just make sure you read past where it says 40 degrees in the FSM, it's apparently 60 degrees after the initial torque.

Maybe someone on LOST has an old set of good used rods lying around for you?
Author:  flash7210 [ Thu Sep 10, 2015 12:58 pm ]
Post subject:  Re: New style piston
Looks like the wrist pins are full floating, so no need to press them in.
And looks like the rod bolts are actual bolts, so no need to press those in either and they are cheap enough to just order new ones.
Makes the job a lot easier.

I would carefully inspect the old rod upon removal. There is a good chance that it is still usable.
You may find that the wrist pin bent but the rod was ok.
If you have any doubts, before removing the pistons, use a dial indicator to measure piston height at TDC and compare that to all the other pistons at their highest points.
Author:  dh100m [ Thu Sep 10, 2015 1:22 pm ]
Post subject:  Re: New style piston
I had the same thing happen drop valve split liner bent rod #1 new liner used rod which was 20gm lighter than other 3 $20 scale from
wm and using old rod bolt cut down and screwed into rod ahead of bolt to bottom of thread lock tight red was within 2 grams of old rods. piston rings rod assembled for measuring all new bearings seals etc.
might be of some interest 6000 km so far
Author:  Mountainman [ Thu Sep 10, 2015 1:39 pm ]
Post subject:  Re: New style piston
dh100m wrote:
I had the same thing happen drop valve split liner bent rod #1 new liner used rod which was 20gm lighter than other 3 $20 scale from
wm and using old rod bolt cut down and screwed into rod ahead of bolt to bottom of thread lock tight red was within 2 grams of old rods. piston rings rod assembled for measuring all new bearings seals etc.
might be of some interest 6000 km so far


So you put a little piece of old rod bolt in the bolt hole and locktited it in place? I was wondering if a guy could sand a little off the 4 corners and get away with it, if it was heavier...

Lighter, now that's a lot more tricky, as you have all of the weight in one spot. But, do you have it on the crank end? That would be a lot more forgiving than out at the end of the pendulum.

Probably fine if you don't run it like a race engine I would imagine. I rarely take mine over 3k rpms... and never near red-line.
Author:  spoon [ Fri Sep 11, 2015 7:32 am ]
Post subject:  Re: New style piston
Some measurements are in order. At this point I don't know if the rod is bent but I want to replace it anyway. If anyone has a good spair I am interested.
Author:  lacabrera [ Fri Sep 11, 2015 7:44 am ]
Post subject:  Re: New style piston
I know VM sell them as a matching set but.
I wouldn't think a few grams would be a problem on a diesel engine that red lines @4000rpm? Barring in mind the carbon build up around the piston rings etc. that could add a weight difference.
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