[Vwdiesel] Seven year Experiment with TTY Headbolts

[Stephen Kraus]

I have reused my Audi headbolts before, just torque them the highest value
and then check them after warming up.
On Nov 30, 2013 12:17 PM, "Mark Shepherd" <mark at shepher.fsnet.co.uk> wrote:

>
> H all
> I just thought I'd update with the lengths of those TTY bolts I reused 6
> times over, as I decided to renew them when I took the head off to start
> the noise
> reduction experiment.
> Bolt Old New
> Pos‘n (mm) (mm)
> 1: 127.45; 126.85
> 2: 127.35; 127.12
> 3: 127.24; 127.06
> 4: 127.25; 126.75
> 5: 127.61; 126.86
> 6: 127.04; 126.90
> 7: 127.65; 126.85
> 8: 127.52; 127.08
> 9: 127.30; 127.10
> 10: 127.29; 127.04
>
> Avg: 127.37 126.99
>
> As you can see the stretch wasn't very much, and less so if you ignore the
> outlayers, which may have been due to extra wrenching to cure a leak that
> actually down to a corroded gasket. Giving 127.30mm. It could be of
> course, that the old bolts were shorter than the new ones to start with.
>
> ========================================
> Message Received: Jul 19 2013, 02:21 AM
> From: "Mark Shepherd"
> To: vwdiesel at vwfans.com
> Cc:
> Subject: [Vwdiesel] Seven year Experiment with TTY Headbolts
>
> TTY bolts. ~What are they? They are merely normal bolts. They have a 10.9
> rating. I see of no benefit of angular torquing beyond torque to yield
> which is
> what people are doing when following the basic instructions. Especially if
> a readable scale torque wrench is available. Rename the bolts TIP, or
> Torque Into
> Plastic. Consigning the bolt to single use, or possibly one reuse, is
> wasteful, and a money making exercise for industry, just as VW killed off
> all those slightly
> warped heads, before changing their mind after ceasing production!
> Security shear bolts are the only ones that should be treated this way.
> At least one book of old that I have talks about strengthening of the bolt
> by taking it to near it’s limit and then relaxing it, before reapplying
> torque... Sounds
> like work hardening to me, albeit minimal repetitions.
>
> Below is the story of my current engine which was probably manufactured in
> 1983/4, and its last 7 years with a single set of new head bolts... A
> recent, (last
> month) picture of one of my bolts and someone else’s single use...
>
> http://imageshack.us/photo/my-images/5/8taq.jpg/
>
> Oct 2005 bought the gold 1985 Quantum TD wagon
>
> March 2006 bought the 1.6 gasser silver Quantum wagon [current car]
> August 2006 Transferred the mech TD engine into silver car.
>
> August 2008 Gasket failed. Hand skimmed warped head.
>
> http://imageshack.us/photo/my-images/98/eighthabradesi1.jpg/
>
> New gasket, new bolts. Torqued TO Yield point, but no further. Slackened
> each bolt in turn on engine warm, and again torqued up to yield point. No
> leaks.
> First head bolt use #0
>
> Sept 2010 engine becoming harder to start for the last month. Head off,
> Pistons good, but marked from continuous valve clash due to that admittedly
> over-
> zealous head skim 2 years earlier.
>
> http://imageshack.us/photo/my-images/834/number1piston.jpg/
>
> All bearings as new, and so not replaced, nor the still good tensioner,
> nor the unfrayed belt. 7 rings stuck, 160 thou gap;
>
> http://imageshack.us/photo/my-images/809/imgp9942.jpg/
>
> So I replaced rings $22 per engine, from Autohause:
> Conceived and implemented my infamous ‘Plastic Bottle Hone‘.
> Reassembled. Same headgasket; seeing as it had not leaked, nor stuck to
> the engine/head, so it had to be a good fit IMO.
>
> Not able to stop valves kissing pistons as this current gasket is a 3 hole.
> Reused the same head bolts, as they didn’t seem to be stretched. Again
> torqued them only up to yield point [measured with expensive Snap on T
> wrench,
> which was a gift ;o) ] Headbolt reuse #1
>
> Car ran well other than a little noisy, minimal oil use, mostly losses
> through leaks.
>
> Over the years I conducted numerous experiments with injecton timing,
> nozzles, and break pressures; reusing each heatshield and injector body in
> it’s
> allocated cylinder from 2005. Managed to change economy from 36 to a
> respectable 48 around town and from 39 to it’s current 61.5 on the
> interstate
> @60ish mph
>
> In 2012 I changed the heatshields for new ones, after one cracked when
> reforming using my ‘metered reforming’ vice grips and nut and ball bearing
> technique. This was after 64 reforms between them, or effectively on the
> 16th reuse of the 4 heatshields. Only 4 times had a shield leaked.
> Previously,
> somewhere on the GTD forum is a little competition that I set for the
> experts to spot single use shields from 7 or was it 9 reuses... Here it is:
>
> http://imageshack.us/photo/my-images/687/eightoldshims.jpg/
>
> I demonstrated that reuse of a heatshield, can be better than a new one...
> Here’s further proof: Only one year after changing to new shields, and due
> to
> the problem I created and am about to mention below; I had to change heads
> and wanted to carry injectors across because they are set accurately to
> 130bar, with timing set to a bewildering 22.5 thou, and interstate driving
> returning 61.5mpg. The #2 injector has stuck on the first use of the new
> shield:
>
> http://imageshack.us/photo/my-images/687/imgp2147ro.jpg/
>
>
>
> April 2013 head gasket leak. Corrosion bridging across metal of gasket and
> into water jacket. Replaced gasket. Same bolts torqued per spec, except once
> more stopping immediately plastic point reached each time, and released
> each bolt before final retorquing. This is bolt reuse #2
>
> About a month ago, (June 2013) I decided to please my daughter by quieting
> the engine down. Only solution I felt was a ‘new’ unskimmed head, or a
> homemade gasket. I added a 0.5mm aluminium roofing sheet. Reuse of head
> bolts! #3
>
> http://imageshack.us/photo/my-images/818/jmes.jpg/
>
> Car ran, but injection timing had altered Slightly harder to start. Before
> I could do more tests, cam belt snapped after two journeys totaling 7
> miles. It was an
> old belt.
> Ironically, it happened on the route to pick up a ’new’ head. A German
> made one off a 1.6N/A van.
>
> It turns out the belt jumped and the cam was snapped off at #3 and # 4
> lobes. Why did it jump? Well, I discovered after the final cam timing
> tweak, I’d
> forgotten to tighten the nut on the tensioner, and the nut was loose. I
> managed to get the new head. Marks on the pistons slightly worse than
> normal, but
> otherwise seemed fine. I did order new head bolts, but as I couldn’t wait,
> I reused the old ones yet again! So headbolt use #5
> Note had the old belt been replaced, the new belt is actually nearly 2mm
> thicker, and is a tight fit on even a slack tensioner, and wouldn’t have
> jumped. :o(
>
> http://imageshack.us/photo/my-images/836/nydo.jpg/
>
> Can a belt be too strong and damage the engine more than a weaker, but
> sufficient belt?
>
> I was given the second hand bolts with the ‘new’ head. I had intended to
> use these bolts, but as you can see in the picture; typically, most were
> longer than
> my ones, and, clearly sent well into the plastic region..
>
> http://imageshack.us/photo/my-images/5/8taq.jpg/.
>
> The vendor stated that the engine had been stripped because of a head
> gasket leak.
> Using the new head, has so far, been successful this last month, so he was
> telling the truth. I don’t know if he tried to torque up the head to stop
> the leaks,
> or not, so the stretch may, or may not be standard, but clearly more
> damaging to the bolt than my technique despite their 5th use...
>
> My retorqueing reaches about 95 to 105 lb-ft, I believe these bolts are
> 10.9 strength. It would appear that the torque is sufficient to hold the
> head onto the
> gasket
> As the new head bolts have arrived, I will be able to compare his single
> use bolts with new. Perhaps I will take one of my ‘reuseable’ bolts out of
> the head
> and compare; but maybe that will tempt fate, so I’ll wait until I need to
> remove head.
> Last Saturday,the car passed it’s annual test. 0.9% smoke on the ‘fast’
> test from cold...
>
> EDIT:
> It would appear that these bolts predate my ownership, as I can only find
> the saved bolts from my first diesel Quantum. The head on the Gold Quantum
> was
> an AML /[C]? Copy and conveniently had belt change date and mileage
> written on the fender. It was about 40,000 miles before my issue with
> warped head.
> So short bolt in picture had been used 5 times and is now on it's 6th...
>
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