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Head bolts nightmare
by
overdrivegear
on 16 Nov, 2008 15:48
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Ok, so I have a CR code 1.6 NA from '81. I did some head work and am now at the stage of putting the head back on. Like a good mechanic, I replaced the head bolts (which were originally the 11mm type). Went to go torque the head down with the specs in the Haynes manual with the third stage of torquing being 66 ft.*lbs (if my memory serves me correctly) and broke a couple bolts in the middle of the shank. First I checked the torque wrench calibration and it was fine. The threads in the block were chased out and the bolts were oiled like they were supposed to be when you install them. These were supposed to be OEM quality bolts, not some cheap knock-off. Now I'm going to put the original bolts back in with the original torque spec from the Haynes manual. If that doesn't work and I break a bolt, I'm thinking about putting in studs. I'd actually prefer to put in studs because this head bolt voo-doo is for the birds.
I've heard many different variations on what the torque stages are, but I want to know what is the method/values that you all have used for your 11mm bolts?
Any ideas as to why this has been so un-necessarily complicated for me?
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#1
by
vanagonturbo
on 16 Nov, 2008 16:20
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did you use 12pt or 6pt bolts?
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#2
by
rallydiesel
on 16 Nov, 2008 16:26
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Where did you get the bolts?
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#3
by
overdrivegear
on 17 Nov, 2008 05:33
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They came from Parts Place, Inc. Outfit out in the Detroit, MI area that specializes in VW parts...especially diesel evidently.
They were 12 point I think. I measured the diameter of the threads and the new ones were less than 11mm; more like 10.7 or something whereas the originals were 11mm on the money.
To backtrack a bit, I first bought some *discount bolts* from ebay and broke those first. I attributed cheap quality parts with breaking those so I went up to good quality parts...broke those too. What gives???
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#4
by
arb
on 17 Nov, 2008 05:56
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I've bought stuff from Part Place Inc, in person. They are not what they used to be. May items in their "current" catalog will get you "Oh that, we have not carried that for years" if you try and buy it.
Sounds like they sold you inferior bolts too. Sorry to say. If they are not the full 11 mm like the original, they are not OEM.
I bought OEM bolts from S & G Imported parts, in SE Michigan. No problems. But, if I had planned better, I would have gotten studs.
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#5
by
Turbinepowered
on 17 Nov, 2008 08:11
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Save yourself more headache: Stud it.
ARP 204-4701 is the part number I know.
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#6
by
maxfax
on 17 Nov, 2008 08:18
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Save yourself more headache: Stud it.
ARP 204-4701 is the part number I know.
X2!!
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#7
by
vanagonturbo
on 17 Nov, 2008 19:56
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They came from Parts Place, Inc. Outfit out in the Detroit, MI area that specializes in VW parts...especially diesel evidently.
They were 12 point I think. I measured the diameter of the threads and the new ones were less than 11mm; more like 10.7 or something whereas the originals were 11mm on the money.
To backtrack a bit, I first bought some *discount bolts* from ebay and broke those first. I attributed cheap quality parts with breaking those so I went up to good quality parts...broke those too. What gives???
Well partplace is part of the problem. Well, the main problem. They are selling you gasser 11mm STRETCH headbolts and you are using the torque spec for non stretch bolts. Problem found. Now go get some non stretch bolts, or torque the stretch bolts to gasser spec.
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#8
by
VW_Commuter
on 17 Nov, 2008 21:15
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I wouldn't even mess with the stretch bolts if you can afford a set of either Raceware or ARP headstuds. You will never have the expense of buying another set of headbolts ever again no matter how many times you pull the head, which is hopefully not too many more times.
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#9
by
overdrivegear
on 18 Nov, 2008 05:43
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Ok, so I messed up and bought stretch bolts. Are the original bolts stretch bolts? Is there any reason that I can't use them again? If they aren't stretch type, then it should be fine. Maybe there's a little case hardening on the bolt from heat tempering but that shouldn't effect the yield of the bolt significantly. I measured all of the originals and they're all the same length whereas I measured the stretch bolts that I removed after breaking a couple...they were stretched all across the board!
And BTW, where do you buy non-stretch bolts???
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#10
by
Turbinepowered
on 18 Nov, 2008 07:00
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Ok, so I messed up and bought stretch bolts. Are the original bolts stretch bolts? Is there any reason that I can't use them again? If they aren't stretch type, then it should be fine. Maybe there's a little case hardening on the bolt from heat tempering but that shouldn't effect the yield of the bolt significantly. I measured all of the originals and they're all the same length whereas I measured the stretch bolts that I removed after breaking a couple...they were stretched all across the board!
And BTW, where do you buy non-stretch bolts???
So far as I know, you can't buy them OEM anymore. You either have to buy from a fastener store, use your originals, or go studs. Studs tend to be your best option from a variety of angles, from thread engagement depth in the block to long term ability to be reused and clamping force ceiling.
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#11
by
lord_verminaard
on 18 Nov, 2008 07:15
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All head bolts for every VW watercooled engine, diesel or otherwise, is a stretch bolt of some type and they should not be re-used. The only thing I can think of that is happening is that either there is some crap on the threads in the block that is preventing proper torque, or there is oil filled up in the holes and by screwing down the bolt you are trying to compress it.
Either way, they shouldn't break that easily.
Brendan
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#12
by
Turbinepowered
on 18 Nov, 2008 07:22
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All head bolts for every VW watercooled engine, diesel or otherwise, is a stretch bolt of some type and they should not be re-used. The only thing I can think of that is happening is that either there is some crap on the threads in the block that is preventing proper torque, or there is oil filled up in the holes and by screwing down the bolt you are trying to compress it. Either way, they shouldn't break that easily.
Brendan
Head bolts from 70's era engines are not stretch bolts, gas or diesel.
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#13
by
overdrivegear
on 18 Nov, 2008 07:48
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All head bolts for every VW watercooled engine, diesel or otherwise, is a stretch bolt of some type and they should not be re-used. The only thing I can think of that is happening is that either there is some crap on the threads in the block that is preventing proper torque, or there is oil filled up in the holes and by screwing down the bolt you are trying to compress it. Either way, they shouldn't break that easily.
Brendan
Head bolts from 70's era engines are not stretch bolts, gas or diesel.
Why can't you reuse the old bolts if they're still in spec? Nobody has been able to give me evidence why.
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#14
by
molgrips
on 18 Nov, 2008 08:30
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Metal fatigue, I'd guess.