Bent header bolts

[Mythos]

Apparently this is not uncommon. I have read about the issue in a couple other threads including this one.

https://www.hayabusa.org/forum/gen-ii-busa-information/166401-installing-full-brocks-exhaust-2.html

I'm installing my Tsukigi Cannon. All bolts came out pretty easy. I don't understand why it is so common to find them bent. I might reuse these if I was sure I would never thread into the block any farther than the OEM header was tightened but no way to be sure of that. Looks like I will be ordering new header bolts or going to Ace to hunt down the same thread/pitch bolts.

Just thought I'd mention this. Any thoughts much appreciated.


OEM header bolt. Bent.

[GIXERHP]

8mm by 1.25!

[Blanca BusaLess]

Hmmm? Seems to me a limpy oem piece. I bet a marine grade hardened steel bolt won't do that.
Maybe?

[Freechance]

I just looked and arp makes that bolt in stainless..i wonder if that would make a difference..i know arp bolts hold up really good..

[Mythos]

I was wondering WTF is "arp?" Google tells all as usual.
ARP-bolts.com | The Official Site of Automotive Racing Products, Inc.

Thanks, Freechance. I may just check that out.

[RYC1966]

I believe that it is good practice to use a anti sieze of correct grade when putting ss bolts in Al / or even lug nuts on a car...it helps prevent gauling.

[Freechance]

8mm by 1.25!

Do u happen to know the length?

[Mythos]

Do u happen to know the length?

The exact bolt is m8 x 1.25 x 25mm. Home Depot has them in zinc plated which I am not crazy about considering the beating the header bolts take from all the heat. Lowe's had the same bolt in a black finish for .60/each.

I picked up a couple bolts from Ace Hardware tonight. They look identical to the OEM. They were stainless steel for $1.60/piece so I did not get a full set of 8 bolts. I just threaded a 1.25 pitch nut (also found at Ace) over each OEM bolt and if it went on smooth, I considered it to be reusable. Just needed two new ones.

Thanks for ideas and help on this, bros.

I can't believe the OEM bolts bend that easy. 16.5 'lb is not that much torque. The bottom bolt on cylinder 1 and 2 are the ones I replaced.

[Mythos]

Just a link to another thread I started about a problem that is closely related to the bent header bolt problem. I also have thread damage to one of the header bolt holes in the engine block.

https://www.hayabusa.org/forum/busa-problems/168085-damaged-head-pipe-threads-please-help.html

[mr8ball]

I would check at a place like Valley Fasteners. They just sell bolts and screws. Go with the grade 9 and it will never happen again. I use to use them in my cars all the time and never had an issue with them. Best of luck

[TheGza]

The exact bolt is m8 x 1.25 x 25mm. Home Depot has them in zinc plated which I am not crazy about considering the beating the header bolts take from all the heat. Lowe's had the same bolt in a black finish for .60/each.

I picked up a couple bolts from Ace Hardware tonight. They look identical to the OEM. They were stainless steel for $1.60/piece so I did not get a full set of 8 bolts. I just threaded a 1.25 pitch nut (also found at Ace) over each OEM bolt and if it went on smooth, I considered it to be reusable. Just needed two new ones.

Thanks for ideas and help on this, bros.

I can't believe the OEM bolts bend that easy. 16.5 'lb is not that much torque. The bottom bolt on cylinder 1 and 2 are the ones I replaced.

Just installed a new exhaust, EVERY ONE of my header bolts are bent at the head

[mabupa]

Just installed a new exhaust, EVERY ONE of my header bolts are bent at the head

I found one way back when I installed my exhaust and just reused it. My ocd drove me crazy for a few weeks but I got passed that, until now that I saw this thread.

[TheGza]

I found one way back when I installed my exhaust and just reused it. My ocd drove me crazy for a few weeks but I got passed that, until now that I saw this thread.

Ya... I couldn't stand it, I went to 3 Ace hardwares to get a total of 8 new bolts because they all have to match and the first 2 stores only had 1 or 2 each Finally came across a Rural King and got all 8

[zucchero]

The exact bolt is m8 x 1.25 x 25mm. Home Depot has them in zinc plated which I am not crazy about considering the beating the header bolts take from all the heat. Lowe's had the same bolt in a black finish for .60/each.

I picked up a couple bolts from Ace Hardware tonight. They look identical to the OEM. They were stainless steel for $1.60/piece so I did not get a full set of 8 bolts. I just threaded a 1.25 pitch nut (also found at Ace) over each OEM bolt and if it went on smooth, I considered it to be reusable. Just needed two new ones.

Thanks for ideas and help on this, bros.

I can't believe the OEM bolts bend that easy. 16.5 'lb is not that much torque. The bottom bolt on cylinder 1 and 2 are the ones I replaced.

Can we use titanium bolts.Asking as I am not sure.

[ROADTOAD1340]

Can we use titanium bolts.Asking as I am not sure.

Best idea for future pipe removal would be to use steel bolts , or a steel exhaust spigot , with maybe a ti nut with anti seize . But , I have used full titanium bolts with anti seize and they have taken the massive heat well , actually just like the titanium header pipe they are clamping , and each removed okay .

[zucchero]

Best idea for future pipe removal would be to use steel bolts , or a steel exhaust spigot , with maybe a ti nut with anti seize . But , I have used full titanium bolts with anti seize and they have taken the massive heat well , actually just like the titanium header pipe they are clamping , and each removed okay .

Thank you for the guidance.I truly appreciate it.

[michael parris heuberger]

Thank you for the guidance.I truly appreciate it.

Hi. I will be using Ti nuts and studs.

[michael parris heuberger]

Hi. I will be using Ti nuts and studs.

Hi. Also an Inconal header.

[sixpack577]

Hi. I will be using Ti nuts and studs.

Along with 2 Huge nuts on the seat...attempting 300mph

[Blkoutbusa]

Hi. I will be a stud

Nice!