[Vwdiesel] Seven year Experiment with TTY Headbolts

[Mark Shepherd]

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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