Author Topic: Dinged up piston replace?(ahu)  (Read 6947 times)

November 29, 2010, 06:41:01 am

BigVWman

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Dinged up piston replace?(ahu)
« on: November 29, 2010, 06:41:01 am »
Hello I recently acquired a 98 jetta that had unknown engine damage and was told it mad a burp sound and quit. It looks to me after pulling the head and seeing that minty fresh timing belt that there is more to the indigestion it suffered. The bouncing head of the #2 valve say it had a major calamity. I know i need to get head redone or replaced but the #2 piston is quite dinged up. Have you guys reused them when beat up or just replace with used? Its med hi mileage at 260k and i don't want to blow my budget. When replaced with used do you reuse the rings that have seated in that cylinder or replace with new? Also what is the chance the rod was damaged?The piston nor the head have any holes just lots of beat up nicks and gouges and at least one bent valve one broken valve both on no 2 other valves 'look" ok cam looks like it may have a hairline crack at no 2 but does turn as a unit, cylinder wall looks good. I don't have a ton of internal tdi experience usually when something like this has happened in the past i pull and replace but with the cost of replacement being so hi i want to try to save it. Also can i take piston out the top or do i have to drop the crank and come out below? Thanks in advance for help/advice! Have you seen these parts for sale lately anywhere? Any thoughts on those AMC spain heads on ebay?They are tempting but after my chinese driveshaft experience i'm hesitant to stray from VAG.
Tim
83 rabbit shell 92 cabby tdi conversion, 91 cabby aba conversion, 87 cabby,  87 gti,  01nb tdi new project,00 1.8t nb, 98 ranger,92 f150 flareside(its pink) 97 cabrio and a 00 cabrio!

Reply #1November 29, 2010, 08:04:51 am

CRSMP5

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Re: Dinged up piston replace?(ahu)
« Reply #1 on: November 29, 2010, 08:04:51 am »
piston required..

id suggest rod as it only takes less then 10cc of fluid to bend.. dents = good possibility

new rings..

comes out the top

Reply #2November 30, 2010, 01:40:03 pm

lord_verminaard

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Re: Dinged up piston replace?(ahu)
« Reply #2 on: November 30, 2010, 01:40:03 pm »
On my wife's IDI, I re-used the pistons that clearly had met some valves in a past experience.  That explained the aftermarket head that was on the engine when I got it.  :P


Cleaned them up, had my machine guy check them out and called them good.  I later had them Swaintech thermal coated with new rings. 


Measured the protrusion after installing new bearings, all good so no bent rods. 

Still running strong.

Brendan
81 Scirocco 'S -->Soon to be m-TDI
93 Corrado SLC VR6
'86 Golf N/A Diesel  -->Wife's car
1990 Audi CQ
05 New Beetle PD TDI


"I am a man, I can change... if I have to.... I guess....."

-Red Green

Reply #3November 30, 2010, 02:18:57 pm

BigVWman

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Re: Dinged up piston replace?(ahu)
« Reply #3 on: November 30, 2010, 02:18:57 pm »
Well mine may be a "little" worse?
Tim
83 rabbit shell 92 cabby tdi conversion, 91 cabby aba conversion, 87 cabby,  87 gti,  01nb tdi new project,00 1.8t nb, 98 ranger,92 f150 flareside(its pink) 97 cabrio and a 00 cabrio!

Reply #4November 30, 2010, 03:51:42 pm

theman53

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Re: Dinged up piston replace?(ahu)
« Reply #4 on: November 30, 2010, 03:51:42 pm »
That ^ may buff out...never hurts to have a backup plan though.

Reply #5December 03, 2010, 08:41:37 am

zukgod1

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Re: Dinged up piston replace?(ahu)
« Reply #5 on: December 03, 2010, 08:41:37 am »
Ya that looks like replacement is in order..

i had a similar situation.

Bought my car from a guy that didn't change the belt and it broke, caused problems and he had a local "Diesel" shop repair it. i bought it and drove about 15000 miles and it had more problems.
Pulled the head to find 2 yes 2 broken pistons. Lots of shoddy work along the way as well, missing bolts, wrong bolts etc etc.

Ended up with new pistons.. Was going to post a pic but seem to cant find them..
dan

99 Golf TDI (now CNG powered) , 82 TD Caddy

Reply #6December 03, 2010, 12:35:05 pm

BigVWman

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Re: Dinged up piston replace?(ahu)
« Reply #6 on: December 03, 2010, 12:35:05 pm »
Yep i figured the same thing. I have found a good used one and its on the way so that will help with the lower end now to figure out the where to get a reasonably priced head?!
Tim
83 rabbit shell 92 cabby tdi conversion, 91 cabby aba conversion, 87 cabby,  87 gti,  01nb tdi new project,00 1.8t nb, 98 ranger,92 f150 flareside(its pink) 97 cabrio and a 00 cabrio!

Reply #7December 09, 2010, 08:30:01 pm

boxer246

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Re: Dinged up piston replace?(ahu)
« Reply #7 on: December 09, 2010, 08:30:01 pm »
Well I dont know how bad your head is, but Frank06 over on the TDIclub forum up in Missouri (pretty sure thats where he is) is known to work magic with damaged TDI heads.  He can weld up badly damaged heads, fix damaged lifter bores (which no machine shop that I have talked to will even touch)....etc etc.  He likes to give you a complete package though, i.e. he wants to give you back your head ready to bolt on, with all gaskets and parts needed as a package deal....with good prices.  As a sidenote, Frank is a super nice guy with a darn good reputation.  He will set you straight.  I've got two heads I need to send him when I get the cash.

So either you find a good used head which will almost definitely need some work anyway, or buy a cheap new chinese head from a certain vendor, or spend some real dough on a good German head (anywhere from about $700 to $1000), or send yours to Frank.  AMC heads have mixed reviews.  Some say the valves are crappy, etc.

New German camshafts are available for around $130 from several vendors I've bought from in the past.
Aside from the cam, you (and this is just my guestimate, please dont take it as fact) you are probably looking at between $600 and $700 to get the head redone, with all necessary gaskets, seals and parts from Frank.

No you dont have to take crank out, just drop oil pan, unbolt rod, and piston and rod come out top.  New rings are prolly a good idea. 
I dont know what parts you are replacing in the bottom end (maybe just the damaged piston?) but if thats the case you might want to check that used piston weight against the others to make sure your in the ballpark.







Ash
'81 VW Caddy 1.6 now a TD
'88 Vanagon (building a AHU M-TDI)

Reply #8December 15, 2010, 06:00:20 am

BigVWman

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Re: Dinged up piston replace?(ahu)
« Reply #8 on: December 15, 2010, 06:00:20 am »
You are absolutely correct on frank06, he can work magic on heads i have seen pictures but with that magic comes a price tag that isn't in my budget.Its in Franks's best interest to sell a whole job. Then there is no chance of a failure because the buyer  reused head bolts or a poor quality gasket that could somehow be blamed on his work, use quality pieces including gaskets and peripherals and its a successful job, makes franks reputation stay as good as it is. By the way you are about right on price also. I did manage to find some generous folks here and on tdi. The head i have found is a GREAT deal and keeps me from trying Chinese products. I also scored a same weight group piston in decent shape here along with a turbo since mine had some minor indigestion with the stem and seat in it. I am going to do a light hone and new rings, new bearings while in there. If all goes well this weekend she should be up and running, i hope. i will update once i know if i was successful! One of the toughest pieces to find has been the darn rod bolts. A small piece like that such a large headache. Nobody seems to stock them even the local dealers, world pac, my two usual suppliers or even 1st vw(auburn vw). I find it hard to believe with how hard they are to find that everyone actually replaces them like they are supposed to!
Tim
83 rabbit shell 92 cabby tdi conversion, 91 cabby aba conversion, 87 cabby,  87 gti,  01nb tdi new project,00 1.8t nb, 98 ranger,92 f150 flareside(its pink) 97 cabrio and a 00 cabrio!

Reply #9December 15, 2010, 06:09:17 am

theman53

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Re: Dinged up piston replace?(ahu)
« Reply #9 on: December 15, 2010, 06:09:17 am »
so the old piston couldn't be buffed out? LOL

Reply #10December 15, 2010, 08:04:54 am

boxer246

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Re: Dinged up piston replace?(ahu)
« Reply #10 on: December 15, 2010, 08:04:54 am »
Dennis over at Marquette Automotive has rod bolts for like $50 per set.  I recommend him as wholeheartedly as I did Frank.....he ships fast, has all OEM, or OEM quality parts, and his prices are appropriate.  PM me if you cant find his site....I dont wanna paste his address here 'cause I dont know what the forum rules are on that kind of thing. Dont wanna piss some poor soul off!
Ash
'81 VW Caddy 1.6 now a TD
'88 Vanagon (building a AHU M-TDI)