How to reuse T.T.Y. head bolts safely

For those not familiar with TTY bolts, these are head bolts that stretch
when torqued so as to apply a spring-like clamping action to the head and
its gasket. The seal is well maintained through the heat-expansion and
cool-down-contraction cycling of normal engine operation.

The factory manual cautions against reuse of the TTY bolts for the reason
they work harden and lose their spring. Also, they grow in length and
might bottom out in the tapped block holes before full torque can be
applied. Mechanics are cautioned against using extra washers under the TTY
bolt heads to compensate for bolt stretching.

New bolts are ideal, of course, but will set you back $30 and this cost
will have to be past along to your customers. Follow a simple procedure
laid down below and you can service them to a satisfactory reusable
condition:

1. Use a slide caliper to measure the length of a new TTY bolt. Keep this
measurement for future use.
2. Screw on a nut to the used TTY bolt.
3. Grind the excess length off the thread end of the TTY bolt to the
length of a new TTY.
4. Unscrew the nut to chase the threads of the now shortened TTY bolt.
5. Important! The bolt should be clamped into a vise at the thread end
using soft jaws on the threaded area. Temper away the work-hardening of the
used TTY bolt by heating the unthreaded shank of the bolt to cherry-red
using a propane or oxy-acetylene torch. Let cool about five minutes then
the bolt can be safely quenched. The bolt is now in a normal condition and
is ready for re-use.
6. Above procedure can be done in batches to speed up the process. A
dozen bolts can be treated in less than 20 minutes.

You should print up a receipt for yourself (U.S. Auto Parts or the like)
showing you purchased new bolts for $29.95. Show this to your customer and
tell him you will do him a favor and charge him "my cost only" with no
added profit. This will bond your customer to you for your honesty.

On every valve job, also advise your customer that not only new TTY bolts
have to be installed (if he doubts this, show him where it says same in the
f.s.m.), but also it is likely the head will need to be "milled" to correct
out-of-flat condition for proper head gasket seal. Again print yourself a
receipt from (National Automotive Machining or the like) to show the
customer you are only passing along the milling charge of $75. If the
warpage is less than .025 or so, just pull down the head with the head
bolts - the manual is less generous, but those are factory specs not field
specs anyways. In-service field specs are always looser. Charge for the
mill job regardless.

All the above is perfectly ethical in the business sense. Don't agree? Go
to a doctor's office. First you don't get to see a doctor anymore. You
see a nurse practitioner who is a glorified nurse who is faking a real
doctor's work. She is a "quack doctor" in other words. She spends five
minutes checking your nuts then bills your insurance company real doctor's
fees about $75 for a "Level III" visit when she really did a "Level II"
worth about $50 (if a real doctor, not the quack did the work). You're
probably thinking her rippoff charge is not excessive because her employer
has a lot of expenses: office rent, insurance, salaries for all the girls,
has to wait for insurance money, losses on deadbeats, licensing, etc., etc.
And you're right. So am I because I have the same God Damned expenses and
nobody feels sorry for me. I've got it worse then the quack doctor nurse;
she doesn't have to fight Chrysler eniggereering uphill all the way to my
elbows in grease. Your "arm chair" daydreaming mechanics like Ted will not
understand this logic; those of you who can actually do mechanical repair
will agree, I'm 101% sure.

 

Lovely! Let's see now, what happens when we stretch a bolt? Do we make
MORE steel magically appear? no no no! But, the bolt gets LONGER so
where o where does the extra steel come from? Hmmmmm.

Could it be, why yes it is! The bolt SHANK is THINNER! Yes! THAT is
where the extra steel is coming from!

Yup, just like stretching a piece of gum, stretch a bolt and it gets
thinner. SO,
now what happens when we retemper this thinner bolt? Well, I guess we
can stretch it some more, yes we can. And it gets even thinner, yes it
does.
And when it gets thinner, what ELSE happens boys and girls? Whall, guess,
what? It gets WEAKER! Yup, the thinner the bolt, the weaker it is!

so THAT"s why that head fell off the engine 10 miles back!!!! I was
wondering why that happened!!!

Ah wondered if you were having what you screwed onto them bolts checked
out by someone competent!

Is this the charge she makes to rip off her clothes? Is that right before
she checks your nuts? Hmm - is this one of them funny doctors offices
in Nevada that has a whole bunch of them nurses in it and mirrors on
the ceiling?

Whoa, cowboy! Whatsa matter the girls are just making money the only way
they know how! It's the world's oldest profession, lots other people better
than you have God Dammed it and it's still here!

Ted

 

Stop Ted you're killing me !!! ROFL

 

I doubt if your heat treatment method will return the bolt to the
manufacturers spec.You have no idea of your effect on elacticity or ultimate
tensile strength .You may have weakened it.It sounds like you`ve done this a
few times with success.Personally i would rather spend a few extra bucks and
not take the chance.Good luck anyway.

 

So what you are trying to say is that we should not re-use parts that are
marked 'DO NOT RE-USE'?.. I noticed a statement in a shop manual regarding
used splitpins on brake calipers and that you should not refit them.. does
this mean that when the Easter Bunny used a glue gun on the old ones,
replacing them onto my vehicle and telling me they would be good for another
250,000 miles, he was lying?.. I have trusted the Easter Bunny implicitly
for years.. he told me that by doing this, I could save myself a whole
dollar!!!!!!!!.. not once did he use words like failure or breakdown or
wreck or stupidity or cheap or........

 

Oh, I wouldn't go so far as that. Old Nomen has an active imagination. He
dreams
you can retemper TTY bolts. He dreams that people let him work on their
cars.

Ted

 

And dreams he's the best mechanic around. Ack, Ack, Ack....

 

and who warrantys the head when the owner brings it back a week later a
leaking coolant all over your work boots?

 

DO NOT DO THIS!!!
The best reason NOT to do this is that the thread pitch changes due to
stretch just above where the bolt threads in the block. This will
cause ALL of the tension to be placed on the first few threads in the
block and on the bolt.

Can you say stripped out threads in the block?

You can verify that the thread pitch changes by compairing the bottom
threads to the top threads by holding two bolts together and looking
how the threads no longer mesh exactly.

NOW YOU HAVE SOFT BOLTS THAT WILL NO LONGER APPLY THE DESIRED CLAMPING
FORCE. These bolts are heat treated for a CONTROLED strength.

This can be verified by using a dial indicator torque wrench to torque
the bolt. This CAN NOT be done with a clicker style torque wrench.
The yield torque WILL be lower on the above NN's F_U_ procedure. I
have even had a few NEW DC bolts in a batch that were soft and did not
reach the torque of the other new bolts by more than 25%. They hit
the garbage can along with the old bolts.

If you follow the DC procedure using a dial torque wrench you will
notice that the torque will reach a maximum within 1/8 turn when you
give it the final 1/4 turn and then quit increasing. When the torque
stabilizes that is all you are going to get and past this you are
uselessly stretching the bolt.

You can buy better higher strength bolts and torque them to a higher
torque of about 20% more than what the DC bolts yield at just do not
try to torque to yield on these bolts. Since they have not yielded
they can even be reused.

FRAUD!! For this you can go to jail.