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-   -   How important is it to use exact OEM bolts? (https://www.s2ki.com/forums/s2000-under-hood-22/how-important-use-exact-oem-bolts-1191658/)

B serious 02-07-2019 07:15 AM


Originally Posted by zeroptzero (Post 24563339)
The torque spec of that part is very low, perhaps just under 9 ft lbs apprx if memory serves correct, so that bolt should be okay as that amount of torque isn't much more than a hand tight snug. If it was me I'd just use a normal metric hex bolt and be done with it, but if that bolt was the right length it will fine. All you are doing with that part is keeping it compressed against the manifold so the o-ring seals, no crazy amount of torque needed.

No...sorry. I hate to be like this...but...

9LB-FT doesn't sound like much between us friends. But its ~the maximum allowable torque for a M6 C10.9 fastener. For reference, 9LB-FT causes ~2800LB in clamping load, depending on thread friction.

Its PAST the max allowable for a lesser fastener grade.

Those silly O-Rings seal properly given a clamp load that some nerd figured out. That's why the screw size, type, and location is where it is.

If "use whatever" worked...then Honda could have saved some cash by using lesser grade fasteners. Almost every hex screw on the car is C10.9.

It certainly matters.


Why am I like this?


Originally Posted by czirrfb3 (Post 24563311)
I think it is a stainless steel bolt exactly like this one:

Why would those be bad? Sorry I am not a mechanic and don't know much about this stuff. I will only have it in there for about a week longer until the new OEM bolts arrive think any serious damage could occur in a week? I have only driven it one time.

Mechanics don't realize this a lot of times either.

Stainless steel should never be used against aluminum. The corrosion reaction sacrifices the aluminium. Basically turns it into a powder.

Stainless fasteners also have a different torque/tension relationship. So the torque you put in doesn't equate to the right amount of clamping load for the joint.

A "standard grade" stainless fastener is also substantially weaker than a C10.9 steel fastener. So you CANNOT torque to C10.9 spec without stretching it out.

Use a plated C10.9 flange JIS hex screw and torque to spec. Again...McMaster carries them.

A week with the stainless bolt won't hurt, as long as you're not spraying it with a catalyst (salt water, for example).


shrykhar 02-07-2019 10:05 AM

Just wanted to take this opportunity to share this stretched bolt from my modding past. This was from a tensioner bolt after a (non-s2k) supercharger install - the extra force from the supercharger was more than the bolt was designed for and thankfully it didn't snap before it was found.

https://cimg6.ibsrv.net/gimg/www.s2k...c5b4557c09.jpg

czirrfb3 02-07-2019 11:38 AM


Originally Posted by shrykhar (Post 24563509)
Just wanted to take this opportunity to share this stretched bolt from my modding past. This was from a tensioner bolt after a (non-s2k) supercharger install - the extra force from the supercharger was more than the bolt was designed for and thankfully it didn't snap before it was found.

https://cimg6.ibsrv.net/gimg/www.s2k...c5b4557c09.jpg

I dont believe the IACV unit produces nearly that king of force if any =p

shrykhar 02-07-2019 01:43 PM


Originally Posted by czirrfb3 (Post 24563564)
I dont believe the IACV unit produces nearly that king of force if any =p

Ha, I know but this bolt is too neat to not share.

Manga_Spawn 02-07-2019 04:33 PM

Like someone said for serious load bearing parts I wouldn't run a random hardware store bolt even as it could easily break and cause more damage. This is things like suspension components, brake calipers etc. That isn't to say you have to but a bolt from Honda but that is often easier than figure out what grade the OEM bolt is and then finding the same grade bolt in the size and thread pitch you need. For something like your case I think it is probably find but it is smart to replace it with the right thing sooner rather than later.

For OEM honda stuff I always look it up on hondapartsonline or a similar site and then toss the part number in Amazon, ebay and even just google to find the best overall deal after shipping.


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