Has anyone re-used factory 12mm stretch bolts? - IDI Engine - VWDiesel.net The IDI, TDI, and mTDI source.

• Has anyone re-used factory 12mm stretch bolts? by fspGTD on 18 Aug, 2004 10:50
• Anyone tried this?
  
  I'm going to be doing my 1.6lTD's head and I was thinking, gee these bolts I know I bought all new ($50) last time I had the head off, and so I know they have only been used once.  Would they be OK to be used just one more time, or would the material have yielded so far that the tensile strength would drop off?  Then I got thinking there must be someone else who has tried it!  The only reason would be pur and simple: to save the $50 cost of the replacement head bolt set.
  
  PS - yes I would using head studs, but am sticking with the stock bolts, as required per my racing classes rules.  Thanks.
• #1 by Greasemonkey on 18 Aug, 2004 11:10
• A friend of mine has reused his head bolts on a 1.8 8v gas with a 3 layer steel gasket (reused that too) and he's running 10 psi boost. So far so good, long term is unknown. I'd hate to lose a race because of the head bolts though. I don't know if you know about them, but http://www.altrom.com has a lot of vw parts, their price for the 12mm  td headbolts is $1.40 US each. Cheap enough I'd say.
• #2 by v8volvo on 18 Aug, 2004 12:41
• Every single source on these engines I've EVER seen has emphasized that it's vital those stretch bolts be changed. I read a story in Car and Driver once where they were comparing some hotted-up Corvettes. One of them would have won except that the guys who put it together had reused the head bolts a few times, and they had stretched enough by the fourth or fifth time to leak compression and coolant on one cylinder. The car lost as a result, I think.
  
  That's more reusage than you're talking about, but then again those weren't even stretch bolts and they stretched. Plus, you're a diesel so you have more compression to start with, and you are running boost to boot. Change 'em.
• #3 by fspGTD on 18 Aug, 2004 14:56
• Thanks, $1.40 from altrom is a good price, but I have not bought parts there before, so have some questions.  With little information, IE: no country of origin, no brand names or images to go off of, I am a little cautious of their quality... can you tell me if Altrom's parts are generally OEM quality, or are they sub-OEM quality?  Do they supply generally mostly parts from quality brands?
  
  OK, I dug up the invoice from the local import place I bought my head bolts from, and I had remembered their price wrong... the bolts were actually $2.25 each and after adding 1-notch head gasket ($22.50), the total price for bolts and head gasket was about $50 US after tax.
  
  I remember being impressed with the bolts as they looked to be high quality, had a very nice finish, and I think were even stamped with "12.9" grade right on them.  When I torqued them up, I used moly lube and they torqued up quite smoothly.  I remember thinking it was a pity I'm going to be throwing these out next time I have the head off...
  
  I am still curious to hear from anyone who has tried re-using, at least once, the OEM 12mm head bolts.  And if so, what torquing procedure you used and what the results were.
  
  I am aware that all official service manuals say to always buy new head bolts and they only provide torquing instructions for torquing those new bolts to yield.  This torqueing procedure can't really be used over again at least not many time, as with enough uses and yielding of the material, the metal will "neck", loose tensile strength, and then will not be able to hold the head adequately down to the block.  Edit: perhaps they can be re-used, reliably, with a different torquing procedure...
• #4 by janb on 18 Aug, 2004 17:10
• I haven't bought any for a few months, but have always been $.99 here (OEM)  (heat shields are cheap too, and light to ship)  
  
  Halsey Import (PDX) 1-800-792-0081
  
  I have reused "new install" stretch bolts (weekend disasters and no stock on hand)  ie, overland / supplier had installed head gasket upside down on my last 1.9.  I haven't reused after they have been thru numerous heat cycles.  I intend to use 'econo' race ware next time  (188,000 tensile tooling bolts / with threads polished) they are ~$2 each at tooling component suppliers  
  
  I could have dropped some bolts off, as I just got back from RT to Tacoma (a nice morning drive)
• #5 by chrissev on 18 Aug, 2004 17:22
• Quote from: "fspGTD"

  Anyone tried this?
  
  I'm going to be doing my 1.6lTD's head and I was thinking, gee these bolts I know I bought all new ($50) last time I had the head off, and so I know they have only been used once.  Would they be OK to be used just one more time, or would the material have yielded so far that the tensile strength would drop off?  Then I got thinking there must be someone else who has tried it!  The only reason would be pur and simple: to save the $50 cost of the replacement head bolt set.
  
  PS - yes I would using head studs, but am sticking with the stock bolts, as required per my racing classes rules.  Thanks.

  
  
  I think your main problem will be torquing them.  You are supposed to torque them to specs, then give them an additional turn to stretch them.  This crushes the gasket and stretches the bolt at the same time.  I don't know how you would torque them if they were already stretched.  You would need to know how much gasket crush is built into the additional turn and how much of it is bolt stretch.  Otherwise your gasket may leak, or you will crush it too much and ruin it.
• #6 by QuickTD on 18 Aug, 2004 17:55
• I was talking to one of the guys from Answer Engine Works in London Ont. He once had the opportunity to tour Volkswagen rebuilding in Toronto. He knew most VW engines used TTY bolts and was curious about the absence of boxes of new bolts at the final assembly stations. He questioned his guide and was informed that they didn't always use new bolts in the head, rods and mains. They had a go/not go guage they used to measure the bolts and reused the ones that weren't stretched too much. I'm not going to condone this behavior, but it's interesting that VW is OK with it. That said, new bolts are pretty cheap.
  
  I've always found altrom parts to be OEM quality and often made by OEM manufacturers (KS, Mahle). I have only ever purchased internal engine parts so I can't speak for their entire line.
• #7 by Greasemonkey on 18 Aug, 2004 18:54
• 95% of Altrom's stuff is very good, OEM quality like Bosch, Goetze, etc, etc, as good as any I've seen. the other 5% is stuff like the blower fans, window regulator, all things made in china, with notably poorer quality. That said, all other places beside the dealer will have the same crappy parts.
• #8 by fatmobile on 18 Aug, 2004 20:40
• Hey Jake, I've got a set of Febi/bilstein zylinderkopfschraubes  here.
   10 in the box, made in Germany.
   They only cost me $7.50 for the box. Part # 068 103 384 A
   I'd tell you where to get them but the place is in Chicago and doesn't ship worth a damn. I've got 2 boxes so these won't be missed and I'm probably going to Chicago or having a friend come this way soon so ...
   If you want them they are yours free ...well maybe a sponsor spot on your car with a picture of my smiling face on it. :lol:
    I forgot your address.
  vwfatmobileathotmail.com
• #9 by fspGTD on 19 Aug, 2004 14:28
• Quote from: "fatmobile"

  Hey Jake, I've got a set of Febi/bilstein zylinderkopfschraubes  here.
   10 in the box, made in Germany.
   They only cost me $7.50 for the box. Part # 068 103 384 A
   I'd tell you where to get them but the place is in Chicago and doesn't ship worth a damn. I've got 2 boxes so these won't be missed and I'm probably going to Chicago or having a friend come this way soon so ...
   If you want them they are yours free ...well maybe a sponsor spot on your car with a picture of my smiling face on it. :lol:
    I forgot your address.
  vwfatmobileathotmail.com

  
  
  Hey fatmobile - IM sent, how could I refuse that most generous offer?  THANKS!  
  
  I was doing some research (on vwdieselparts), and I found that some there had reported (you may have been involved in the thread I think SpikeTD!) that "OEM" VW Diesel head bolts that were only grade 10.8.  IIRC (I'm going to check when I pull the head), mine were grade 12.9.  Although I'm not sure, I also think they might have been "Febi" brand.  I will definitely double-check to see whether they were grade 12.9 or not when I get the head off.
  
  That is really curious, QuickTD, about the VW of canada factory tour.  So that is where they rebuild the VW motors?  I have a story, I don't know if it helps the case for fastener re-use, but a VW of Canada 1.6lTD motor with relatively low miles (although probably past their warranty period) had some sort of catastrophic bottom-end failure.  I know this because my dad bought the car with the failed motor.  I still don't know what happened exactly, except that a hole got put into the side of the block.  DieselsRCool might be able to fill us in as he bought the car and is rebuilding it!  Could it have been from VW of Canada re-using a bad fastener (like a rod bolt), that they shouldn't have?
• #10 by DieselsRcool on 19 Aug, 2004 17:34
• Hah! No wonder! :roll:
  
  Of all the used VW diesels I have purchased in the past, two had Canadian VW remans in the and both were blown up with crank problems. The only time I have ever seen crank problems in VW diesels. Looks like, as I suspected, they cut a lot of corners to improve the bottom line.
  
  Shame, shame! :cry:
• #11 by Centurion on 24 Aug, 2004 04:52
• Up here - we have one shop that will reuse headbolts -
  
  He is notorious for have engines which do a china syndrome after a year - and he keeps getting away with it.
  
  BTW - I have one of his engines in my car - leaking like a stuck pig - oil - anti - turbo leaks into the rad system!
  
  Not nice!
  
  Cheers - C
• #12 by quantumsyncro on 19 Sep, 2004 17:36
• Hey all..first post
  
  I'm also not condoning the reuse of head bolts but for Peugeot (if memory serves me correctly) diesel & TD 2.3 & 2.5 L engines you can reuse stretch bolts up to five times.
  
  BTW..I accidently forgot to replace the clutch plate bolts in my Golf 1.6D when I reinstalled it this past summer...and those are supposed to be replaced every time too...oops.
  
  later