Broken piston after 343k kms(rebuild help)

Hi,
well this is very bad news for me .. last friday I was coming home when I went WOT in 4th gear to 4200rpm , was doing nice steady 1.7bars , shifted to 5th gear ,again no spike and 1.7 bars and ate 3800rpm it died!
Boost just went to 0 and power was gone.. no strange sound and I couldnt see any smoke because it was at night.
Since I was going nearly at 200kmh I did not stop and since I didnt see any smoke I though it was a safe mode due to something wrong.. probably a hose popped out... but I had to brake to get out of the high way and RPMs when down to 2200rpm.. I tried to accelerate and it started shaking every where... now I had light but still no smoke... but also no power and a strange feeling of only 3 cylinders pushing ... stopped the car 1km ahead since it was where I had space , popped the hod and it was oil all over the place... engine was running , obviously strange but no strange sound besides the miss on one cylinder.

So I stopped the engine and called the tow.

The car is at my mecanic and today the head came off and he found a broken piston! Apparently half of the piston is gone!

I was away for the weekend so I did not see it yet, but hes words where something like "half of a piston is gone! 3 pistons are ok , 2 of them look great... 1 of the sleeves has a mark and the one that broke is obviously marked"

So , I now need help for the rebuild and to know what happend to this failure.
The head and valves seem to be all ok , the noozles had 40k km and are PP502... car was runing at 180bhp for 35k kms.
Car runned 260k kms full stock , always using 5w40 Mobil 1 or BP Visco 7000Sport. Started tuning at 264k kms engine was never opened.

Can a piston brake for having too much use? Was it too much boost? Too much fuel?

Tomorrow I will go there and take some pics and post them here.

Hope you can help me on the rebuild , I want it back with 180bhp for daily drive... and at least for more 300k kms without failure

Regards

Got an EGT probe? Diesels are VERY sensitive to piston temps. A simple clogged oil spray nozzle can easily cause this to happen.

Aluminum does NOT have high heat strength. Oil is about 100 C, aluminum bulk temps over 250 C will cause about 75% of the strength to be lost. If the pressure is high enough, they will fail. A leaking injector can also cause this.

Keith_J said:

Got an EGT probe? Diesels are VERY sensitive to piston temps. A simple clogged oil spray nozzle can easily cause this to happen.

Aluminum does NOT have high heat strength. Oil is about 100 C, aluminium bulk temps over 250 C will cause about 75% of the strength to be lost. If the pressure is high enough, they will fail. A leaking injector can also cause this.

Click to expand...

Well I just had installed for the last 5k kms and oil cooler with a thermostatic plate, when this happened I had done 50kms (was nearly home ,I work 65kms from home) and oil was always at 80ºC. Is this too low? Probably to much pressure?

About EGTs , Im running a 1749vb with a big FMIC I dont get more then 45ºC of intakes and my car does not smoke much
Could it be done by privious setups?

The thing is that the car allready had all types of use... including 3 track days with 30mins pushing all the gears to 4500rpm... oil runing at 105-115ºC... dont think is that much but it probably helped.

I have a set of 4 spare injectors from a transporter... I used them in the past and where great , probably a rebuild part too.

Regards

I was running a few more horses than you Artur but the same thing happened to me in that the No3 piston had a crack right across the crown and a hole in the side of it at the second ring if my memory serves me.http://pics.tdiclub.com/showphoto.php?photo=46018&cat=500&ppuser=14463
http://pics.tdiclub.com/showphoto.php?photo=46022&cat=500&ppuser=14463
http://pics.tdiclub.com/showphoto.php?photo=46020&cat=500&ppuser=14463
http://pics.tdiclub.com/showphoto.php?photo=46243&cat=500&ppuser=14463
And obviously was the reason for the rebuild.....i guess that your piston may have a piece that has fallon off somewhere but if its a large enough piece it may have scored the bore pretty badly.

I havent seen it yet so I can not compare.
But what was your COD? (can we say this? lol)

About the rebuild please help me out , here are the thing I want to do:

New valves , all the head will be new.
New stronger/stiffer valve springs.
Better cam (what do you suggest?)
Head porting?
Better pistons?
New oil pump
Injector swap to the old transporter ones(will keep the PP502 it they are ok)
New rod bearings

Help me out , I want to keep the VB running with 1.65-1.7bars no more... I really like this turbo for daily drive but I want the max power I can get with this setup.

Regards,

Quote....
New valves , all the head will be new.........Ok/good
New stronger/stiffer valve springs..............older 1z has double valve springs or use Rosten stiffer spring by 30% plus better retainers too
Better cam (what do you suggest?)...........Use dbilas 260 sports cam around 300 euros
Head porting?...........ok/good
Better pistons?........2.0L PD pistons after re-bore
New oil pump...........ok/good
Injector swap to the old transporter ones(will keep the PP502 it they are ok)
New rod bearings.........there are a few around now you cold ask Rosten/stingrayRT

P.S if you want to go more or less all out you could follow P's rebuild http://forums.tdiclub.com/showthread.php?t=219187&highlight=better+pistons

Thanks for the help.
The 2.0PD pistons will fit my engine? Will it fit stock rods or only new rods?

If I have to change rods I was thinking of installing Rosten 2 piece forged from 40CrNiMo steel with PD150 pistons ...does this work on stock crankshaft?
Can I install PD150 pistons on stock rods and head... etc?

About the cam , dbilas 260 sports what will the gains be?

regards

I have just had one fit so if your going to all this trouble of doing a head job and slightly larger piston and probably a better inlet/exhaust manifold you should so a gain in power of around 10hp+ and less smoke output.

mojogoes said:

I have just had one fit so if your going to all this trouble of doing a head job and slightly larger piston and probably a better inlet/exhaust manifold you should so a gain in power of around 10hp+ and less smoke output.

Click to expand...

That would be nice.. actually the 180bhp where enough , I just need them to keep in one piece now

About the rods and pistons , Im already at page 6 of piranhas rebuild and I see he installed the 2.0PD pistons on Roten rods on stock crankshaft so my idea can work? I dont want to bore the engine to 2L.. some how I think it will become weaker ?
The PD150/160 pistons are also available in 1mm bigger size?I think that will be my limit... and probably run on stock rods.

But one thing is for sure , I can do all of this and if a injector gets stuck is will blow anyway wont it?

Regards

You cant use the stock rods with ARL pistons. And you need to get ARL oil spray nozzles aswell since the stock ones are pointed wrong with new pistons.

I would definantly reduce the boost. 1.7bar is insane from that tiny turbo.

hatemi said:

You cant use the stock rods with ARL pistons. And you need to get ARL oil spray nozzles aswell since the stock ones are pointed wrong with new pistons.

I would definantly reduce the boost. 1.7bar is insane from that tiny turbo.

Click to expand...

Thanks for the help. Any ideia of what pistons should I install besides the stock ones?

About the boost , for the turbo 1.7 is ok , still on its efficiency range... and it would still smoke a little with 1.5 ore 1.7bar.

Will try to see the engine today.

Regards

mojogoes said:

I have just had one fit so if your going to all this trouble of doing a head job and slightly larger piston and probably a better inlet/exhaust manifold you should so a gain in power of around 10hp+ and less smoke output.

Click to expand...

I just mailed dbilas to know what they have.

I heard that the 260 cam are too big of a change.. the idle will change and feel a lot different. Is this true?

Regards,

If the dBilas cam is anything like R-koneistus 260degree cam the idle will be just fine. The change is after all pretty mild.

ArturCosta said:

I just mailed dbilas to know what they have.

I heard that the 260 cam are too big of a change.. the idle will change and feel a lot different. Is this true?

Regards,

Click to expand...

Yes like Hatemi has said the idle should be just fine........i've heard from a UK member that infact the idle is nice and quieter than it was before the 260 cam was fit.........though i should know how good this cam is at first hand very shortly.

rosten has some forged rods for arl style piston with small journall crank.. IIRC

Yes go with the above piston and crank

We will let you know this week how the Dbilas cam idles....mine just came in.

mrchill said:

We will let you know this week how the Dbilas cam idles....mine just came in.

Click to expand...

That would be great! I really dont want to have it to idle at 1100rpm or something like that.


Well I just came from the mechanic and here is a pic of the 3rd piston (the one with the electric injector.




The other 3 pistons are ok , after a close inspection this has only 2 possibilities , injection fail (injector or pump) or "normal" piston end of strength. At the shop where it is the mechanic allready saw a lot of this engines stock with this problem so he sayd something like "343k kms and runing with 180bhp this wasnt that bad".

I will post some more pics latter and the list of things going in.
Still havent desided on the pistons , I will not change the rods as they are fine.

Be right back

Here are some more pics:

Piston nr 2




Piston nr 4



All 4 pistons




Sleeve from piston 2... the piston is ok but the sleeve has that mark



Do you see any bad marks? Attention they have water in this pics as the head had just been took off.

Regards

mark's aren't normal for a tdi.. usually even after 200k km you can still see the honing mark's in the bore.. seems like overheating/lack of lubrication or ring failure..

also very strange the marks are in that area, if there are marks I'd suspect them to be at the backside, which takes the highest load, or the pin retainer must have failed

Rub87 said:

mark's aren't normal for a tdi.. usually even after 200k km you can still see the honing mark's in the bore.. seems like overheating/lack of lubrication or ring failure..

also very strange the marks are in that area, if there are marks I'd suspect them to be at the backside, which takes the highest load, or the pin retainer must have failed

Click to expand...

Could this have been during the 3rd piston brake?
I ran 2kms after it broke and dont forget I was doing 3800rpm and 1.7bars...the 2 other sleeves you can see the honing marks like tou say.

If that is lack of lubrification then it can be the time it was before I turned the engine off?

In the pic 1 of the piston 2 are that clean parts normal? I dont know if they where cleaned by the mechanic or are marks of overheating?

Regards

I would say that the marks were made from the particles from No3 piston that have broken off........did you have a feel of these mk's to find out how deep they are as they don't look to be too deep and should hone out ok.......your No3 piston look identical to mine with the crack in the crown plus hole in more or less the very same place........i believe that i ran my motor with this crack for some time before it finally and totally gave way , as i had lots of oil blowing by into my catch-can before it totally self destructed.

mojogoes said:

I would say that the marks were made from the particles from No3 piston that have broken off........did you have a feel of these mk's to find out how deep they are as they don't look to be too deep and should hone out ok.......your No3 piston look identical to mine with the crack in the crown plus hole in more or less the very same place........i believe that i ran my motor with this crack for some time before it finally and totally gave way , as i had lots of oil blowing by into my catch-can before it totally self destructed.

Click to expand...

My car started in 3 cylinders this day... it was the only thing I noticed different but it is possible that the crack was there for a long time.

About the marks on the sleeves , the 2nd sleeve you can feel any thing and in the 3rd one only 2 or 3 scratches can be felt.The other 2 look new Amazing how after 343k kms some parts of the engine look so nice... 5w40 really works great.

Mojo I have a question , what about some 81mm forged pistons to work on stock rods? Probably with PD150 combustion "hole"?

Regards

You can also use T4 transporter 151hp pistons or the forged piston from StingrayRT ...................so you must have been having plenty of oil/blow-by , do you use a catch-can or does your ccv breather go back into your intake or is it to open air.

Artur...........was it you that changed your cam for a different one or have i got the wrong person.

ArturCosta said:

My car started in 3 cylinders this day... it was the only thing I noticed different but it is possible that the crack was there for a long time.

About the marks on the sleeves , the 2nd sleeve you can feel any thing and in the 3rd one only 2 or 3 scratches can be felt.The other 2 look new Amazing how after 343k kms some parts of the engine look so nice... 5w40 really works great.

Mojo I have a question , what about some 81mm forged pistons to work on stock rods? Probably with PD150 combustion "hole"?

Regards

Click to expand...

Do you have a source for these forged slugs? If you do take the effort to get them made you can go for 82mm aswell, you can use the 2.0 PD headgasket

how do the rings of piston 2 look like?

mojogoes said:

You can also use T4 transporter 151hp pistons or the forged piston from StingrayRT ...................so you must have been having plenty of oil/blow-by , do you use a catch-can or does your ccv breather go back into your intake or is it to open air.

Click to expand...

CCV is stock , I just noticed some more oil going into the intake system on recent track days...but it could also be normal to the high RPM use on track.

No I never changed cams they are stock too.
I was reading that AFN cams are more aggressive than the latter models , something like 220degrees ate 1mm lift... so the 260 cam would not be that huge difference I thought..lift will go from 8,9 to 9,9 I guess.

About the forged pistons , how can I get a quote and specs for the stingrayRT ones?

Regards

Rub87 said:

Do you have a source for these forged slugs? If you do take the effort to get them made you can go for 82mm aswell, you can use the 2.0 PD headgasket

how do the rings of piston 2 look like?

Click to expand...

I will get quoting for the 82mm probably tomorrow .... but isnt 82mm too much to bore stock sleeves?

And sorry for these question , but what is the headgasket?

ArturCosta said:

I will get quoting for the 82mm probably tomorrow .... but isnt 82mm too much to bore stock sleeves?

And sorry for these question , but what is the headgasket?

Click to expand...

headgasket- junta da cabeca do motor

ArturCosta said:

CCV is stock , I just noticed some more oil going into the intake system on recent track days...but it could also be normal to the high RPM use on track.

No I never changed cams they are stock too.
I was reading that AFN cams are more aggressive than the latter models , something like 220degrees ate 1mm lift... so the 260 cam would not be that huge difference I thought..lift will go from 8,9 to 9,9 I guess.

About the forged pistons , how can I get a quote and specs for the stingrayRT ones?

Regards

Click to expand...

PM stingrayRT for a quote you can also buy the rods from him if you wanted/needed them or from Rosten you can clean all the intake system out of oil and it would be better if you ran a catch-can instead of it going back into the intake tract especially if you doing track days.......you can double vent it one pipe from the puk and the other from an adaptor thats incorperated into the oil filler cap P#-06A 103 465 (Breatherassy) Then both the pipe from the ccv puk and the one from the oil filler go into a catch-can.