Would you run these pistons?

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twentyeight

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I'm building a T4 (EuroVan) TDI conversion. The plan as of right now is an 11mm pump, VNT1749VB ARP head studs, and larger injectors (the motor has Sprint 520s in it right now, but I'll almost certainly go bigger).

The thing is it's a 1Z from a '96 Passat. My understanding is that the piston pins cannot safely support significantly increased power, and the higher rings have a habit of sticking. I've unfortunately experienced the latter in the middle of the desert.

I have a set of ALH (or AHU, I don't remember and I don't believe there's a difference) pistons, but one has a mark at the edge of the valve impression.
Can I safely file this down? I'm mostly worried about the bore.

 
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john.jackson9213

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See my thread here: http://forums.tdiclub.com/showthread.php?t=441548

You will see I had an issue with a damaged 1Z piston and looked at replacing it with a later piston. Weights were way off.

Check the part number on top of the piston, contact Frank06. He has good used pistons that will match your part number and production date.
Buy one from him. Put new rings on the used piston AFTER you lightly hone the cylinder.

I happened to have a spare engine with a good piston that matched.

Good luck. You should be fine.
 

andy2

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You could probably remove the broken chunks and have no issues.I wouldn't worry about the weight lost/balance either.I've ran pistons in worse shape at higher power levels without issue.
 

Seatman

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I suppose the rods and pistons could be weighed while they're out so a little filing here and there could be done to help balance things out?
 

GT Beetle

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Looks like the piston has a crack down the center of the chip toward the top ring. I would not use it.
 

SkyRyder55

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i think the "crack" on the side by piston pin is probably a scratch from removing ring. but it looks like there is a crack in the dent in question.
 

[486]

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Nothing to add other than an ALH piston has the ring lands higher up.

File the stress risers (the little cracks from the metal being displaced into the valve relief) and run it.
 

twentyeight

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Ok, I filed it down (the bent part did mostly break off, which I expected) and it went ok. I was unable to find any cracks, although I did find another very small burr on the other side. Even still, I'm pretty nervous given that this is specifically a vehicle in which I plan to drive my family thousands of miles from any support network, except you guys of course :D.
Can anyone identify these so I can look for a replacement? Do I need a full set or can I get away with just a number 2? Should I ask Frans to ship over something while i have the chance? Or does my rather imprecise work look good enough?
It is #2 with on a 66 gram rod and says on the top:
808
M
1.197
79.44
028AA
 

GTiTDi

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Find a good, used set of pistons, plenty of ALHs getting parted out.

You DEFINITELY want to upgrade from early 1Z pistons, there are more than a few differences than "the top ring land" notably the biggest difference is having a bronze alloy wrist pin bushing and much bigger cooling channels around them...I found out after pushing my 1Z to the limit of acceptable EGTs due to lead foot and stock turbo!
 

GT Beetle

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Find a good, used set of pistons, plenty of ALHs getting parted out.

You DEFINITELY want to upgrade from early 1Z pistons, there are more than a few differences than "the top ring land" notably the biggest difference is having a bronze alloy wrist pin bushing and much bigger cooling channels around them...I found out after pushing my 1Z to the limit of acceptable EGTs due to lead foot and stock turbo!

Good advice , a used set of 4 pistons could be had for $50 to $100 ..from someones junk motor or parts etc.
 

D-cappz

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Answering the questions

Alright, looking for yet another set of pistons.
Is there a european car that has desirable pistons that I can have imported? Why do people run ASV pistons? I don't think I want to compression.
I see no one answered your question, so I might as well.
The euro PD150 (ARL) or the PD130 (ARZ I believe) have pistons that are the same bore as the ALH and they have cooling oil galleys, but the rods need to be changed to a Tapered end connecting rod. The oil jets also need to be changed to some BHW jets or something, so the crank needs to be removed.

ASV pistons are a good upgrade in place of the ALH pistons. ASV pistons come with oil cooling galleys and fit the same style none Tapered connecting rod that are found in the ALH's and the oil jets do NOT need to be changed. The ASV's are also the same bore, Making the upgrade to ASV much easier.
 
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twentyeight

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Thank you!

If I would have had this information my engine would have cooling galleys (and maybe tapered rods) now.

As it is, I just got new .5mm oversize AGR pistons (same as ALH) and followed Whitbread's advice on boring (0.0012 clearance) and it runs awesome.
 

[486]

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ASV pistons are a good upgrade in place of the ALH pistons. ASV pistons come with oil cooling galleys and fit the same style none Tapered connecting rod that are found in the ALH's and the oil jets do NOT need to be changed. The ASV's are also the same bore, Making the upgrade to ASV much easier.
well, they do need to be bent just the same as if you were using any other piston with a channel in it
 

KERMA

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I say go for it.

if you are planning to rebuild the engine after getting just enough dyno pulls and 1/4 mile runs for some you tube videos anyway, I guess it doesn't matter too much. More smoke is all part of the show in that case and who cares about fuel economy.

I've seen TDI engines running with cracked pistons and bent rods and they do just fine. Maybe a bit more smoke, maybe use some oil, maybe you need to add coolant once in a while. the knocking sound can be fixed with a better set of speakers. But short of a hole in the block a tdi engine is really tough and it will pretty much run no matter what. Just make sure you don't mark and pray the timing belt and please be sure the wvo you use has a maximum of 35% water in it. No need to filter or preheat! They will run just fine, I saw some guy say that in a post. So be sure to tell everyone how it's running "fine and no problems" please!

Here's another money saving tip:

Before you do the build, drain the oil from the crankcase and store it in a 5-gallon bucket for re-use. Drape a shop towel over the top of the bucket to keep the dust out and you will be fine. You can also keep the oil filter in the same bucket. Why waste that money by throwing away perfectly good oil when it's good for 10k miles. Re-use it and get your full moneys worth!
 

[486]

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kerma, you've got some useful information about the EDC binaries from time to time but by and large you're a grade 'A-1' dick to anyone trying to piece and patch together anything to 'good enough'

to the OP, a year ago, dye penetrant test them if you are worried. I'd just look with magnification and probably run them. If they got oil channels in them then they are the good european 1z pistons which are rock solid pieces that are head and shoulders ahead of ALH pistons. File the top ring gap open a little if you're worried about sticking it.
 

QuickTD

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kerma, you've got some useful information about the EDC binaries from time to time but by and large you're a grade 'A-1' dick to anyone trying to piece and patch together anything to 'good enough'
Thanks man, for the longest time I thought it was just me...:)
 
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KERMA

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Wow. Just wow.

So the OP wasn't a troll post? You really can't be seriously considering assembling an engine with that piston?

I just showed my wife that picture and she said "it looks like it is broken"

I'm a dick for stating the obvious? Seriously, I thought this was a joke/troll thread.
 

rennsportmotorrad

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Hey maybe I'm an ass as well but anyone who would rebuild an engine and use a piston like that deserves what they get- ie another rebuild soon, I dont do major mechanical work on Cars but I am a BMW Motorcycle Master Tech, if a customer ask me to rebuild their engine and use that piston-I would show him the door and say---GET OUT
 

twentyeight

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Yeah, Kerma, sorry bud, but I don't do business with you specifically because of your attitude around here. Thanks for reenforcing that decision directly. If you thought that this was a joke thread and that your wife could provide an authoritative response maybe you should question your social skills and keep your mouth closed in the future?

I got this set of pistons (again, well over a year ago) from someone I consider very reputable around here. I was told by several more people that they'd be fine, and they almost certainly would be. [486] is on the money for how to handle it. That said new pistons are cheap enough (to me now) to make it a non-issue. Which is why the thread died for a year.

(I should throw them in the crooked deck that the incompetent machine shop made for me and see how long an obviously poorly-shaped TDI would run)
 

twentyeight

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Hey maybe I'm an ass as well but anyone who would rebuild an engine and use a piston like that deserves what they get- ie another rebuild soon, I dont do major mechanical work on Cars but I am a BMW Motorcycle Master Tech, if a customer ask me to rebuild their engine and use that piston-I would show him the door and say---GET OUT
I stand in awe of your master-tech-ness and customer-interaction skills. Well done.
 

turbovan+tdi

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Kerma, what an a s s , seriously dude. Get a grip, not everyone has money to buy the best of everything.

I know its a year old but no way I'd run that piston, even if I was broke.

Sorry about your machinist angle decking your block, :(

Hopefully you got money or another block out of him.
 
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