Titanium Head bolt kits for GT/TR750 motors

[Kris Bernstein]

I am getting a quote together for a titanium head bolt kits for the GT/TR750
motor. The kit would include the 11 large 10.0X1.25 cylinder head bolts. I
am thinking the weight savings always helps but also the fact that the
bolts will be less likely to weld themselves to the studs on the upper case. It
is a real pain in the butt to replace the studs, if they are beyond repair.

The steel lock washer and rubber/steel flat washer will be replaced by a soft
copper washer. This will also save weight, as well as solve the problem of
sourcing the rubber/steel head washers.
I should have a price next week and have also asked the manufacture to
quote the job substituting aluminum as an alternate material at a
lower price.
Let me know if you are interested.

Kris

[Zook-e]

Good to hear from you Kris. I am interested.

[tz375]

Very interested in Anodized aluminum

[durgam]

If aluminum is used, hopefully its 7075. I would do some stress testing and a torsion test done on the bolts before use To insure that they can withstand the torque. Just a thought.....

[tz375]

TZ250 and 250 motors use Aluminum sleeve nuts which is why I mentioned it. One difference to the TZ though is stud spacing and on a TZ they are evenly spaced and that gives a fairly well distributed load.

On a GT, the studs are somewhat all over the place and of course the bore is wider so the stresses may be higher on individual bolts. That could be mitigated by adding a few more 8mm bolts or even a few 6mm bolts to hold the head down.

Who here can tell us the load/elongation of 6mm steel bolts, 8mm bolts and Aluminum sleeve nuts. If Aluminum sleeve nuts have more strength than 6mm steel, we need 8mm steel to be the yield point or weak link, not the sleeve nuts.

[Kris Bernstein]

Now it gets interesting as TZ Mike recommended 2024 as an aluminum alloy for the head bolts. I was thinking 6061T6....a lot of opinions here...
As the GT/TR motors tend to be real shakers, I'm thinking it's gonna' be Titanium.
Will keep everybody up to speed as I get closer to production time....

Kris

[tz375]

I'm no metallurgist but as I recall, the 2000 series are designed for easy machinability rather than strength. 6000 and 7000 in various heat treat levels are much stronger.

2024 is a high strength alloy and so are 6063 and 7075 and all have their uses.

According to the table I just checked, 7075 has an ultimate tensile strength of about 50% higher than 2024 and about half the elongation. And 6061 is not as good as either.

Does TZmike get his TZ heat nuts made of 2024 by any chance?

BTW, if you think a TR/GT vibrates I should let you ride one of my old TZs They are harsh.

[Kris Bernstein]

Yes, Mike does use 2024 on his re-manufactured head bolts...no failures to date but that doese'nt mean they'll hold up on the GT/TR's.

As I recall, my old TZ750 did shake a few of the fillings loose but my old 250's and 350's where...well...just as bad.
Now my modern 125's were like Swiss watches to 13,500 RPM!!!!

[tz375]

Kris,

How did the quote work out?

[kekems]

Hi Kris,
don't know if it is still time for that but depending on the price ,
i am interested
Marc