i'm planning to do a header install in the next few days, this will be my first time working on the car, the measurment for the bolt (the one that fixes the heat sheield to the header), according to helms is
8 x 1.25 mm, now i assume that tells something about the diameter of the head times the length of the bolt, but when i tried to put a 8mm socket on that bolt, the socket was WAY too small, and the 12mm socket was the one that fit just right., so how does one read that 8 x 1.25mm to figure out which socket to use?
was i right all along and the helms just made a mistake?

 

I'm not too sure, but the 1.25 is the bolt pitch.

so it's prolly like Length 8mm X bolt pitch 1.25mm not sure tho.

 

8= the mm of the bolt not the head
1.25= the measurement of the thread.
thats the info just in case you loose it or strip it and needs to be replaced.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by N T R Z R &raquo;</TD></TR><TR><TD CLASS="quote">8= the mm of the bolt not the head
1.25= the measurement of the thread.
thats the info just in case you loose it or strip it and needs to be replaced.</TD></TR></TABLE>

. I've noticed that most of the the time the "head" is 2mm more than the bolt diameter. For example, with that 8mm, you'd probably need a 10mm socket.

EDIT: patrick has corrected me. Ignore the statement above.


Modified by 96dc2 at 7:41 PM 5/29/2003

 

so say i loose the bolt, i still don't know how "long" it should be then huh?
so it's still a bitch to replace, and since they don't tell me the diameter of the "head" i can't unscrew the damb thing without going through a bunch of sockets trying to guess what the size of it is, so the information in the helms
8 x 1.25mm isn't exactly the most useful in the world then huh?
or did i miss something (yet again)

 

the size of the head really dont matter
the thickness and tread is what is important
when you need to replace the bolt
and as for the lenght its measure in inches 1/4, 1/2, 3/4 and so on
just get used to it on the size of the head bolt
most of the time it will
be 8, 10, 12, 14, 15, 17, 19.

I guess they can spoon feed you on how to work on your car..

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 96dc2 &raquo;</TD></TR><TR><TD CLASS="quote">

. I've noticed that most of the the time the "head" is 2mm more than the bolt diameter. For example, with that 8mm, you'd probably need a 10mm socket.</TD></TR></TABLE>

10mm heads are usually 6mm diameter threads, and 12mm is usually 8mm dia. threads.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by subtleluck &raquo;</TD></TR><TR><TD CLASS="quote">so say i loose the bolt, i still don't know how "long" it should be then huh?
so it's still a bitch to replace, and since they don't tell me the diameter of the "head" i can't unscrew the damb thing without going through a bunch of sockets trying to guess what the size of it is, so the information in the helms
8 x 1.25mm isn't exactly the most useful in the world then huh?
or did i miss something (yet again)

</TD></TR></TABLE>

Trust me, work on your car enough and you will either memorize what bolts take which sockets, or you will be able to tell by looking at them what size socket they need. For a Honda all you need is 8, 10, 12, 14, 17, 19, and the occasional 32mm for the hub nut, and that's it. I don't know of any other socket sizes used on any Civics or Integras.

And 8x1.25 is the most important number, it's the only number that matters when you have to match a bolt to its nut or threaded hole. I was just replacing the manifold heat shield bolts last week with some stainless steel bolts, and I knew to get 8x1.25 because of what the Helms manual showed. The bolts I got are a bit longer, but that doesn't matter. The only bad thing is that the ones I got take a 13mm socket, and nothing else on the entire car is uses 13mm.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by PatrickGSR94 &raquo;</TD></TR><TR><TD CLASS="quote">

10mm heads are usually 6mm diameter threads, and 12mm is usually 8mm dia. threads.</TD></TR></TABLE>

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by subtleluck &raquo;</TD></TR><TR><TD CLASS="quote">so say i loose the bolt, i still don't know how "long" it should be then huh?
so it's still a bitch to replace, and since they don't tell me the diameter of the "head" i can't unscrew the damb thing without going through a bunch of sockets trying to guess what the size of it is, so the information in the helms
8 x 1.25mm isn't exactly the most useful in the world then huh?
or did i miss something (yet again)

</TD></TR></TABLE>
not a bitch to replace.
acuraautomotiveparts.org go there, look up the bolt you need. it tells you the width and lenth.



Modified by ragejed at 12:35 PM 5/30/2003

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by subtleluck &raquo;</TD></TR><TR><TD CLASS="quote">... so the information in the helms 8 x 1.25mm isn't exactly the most useful in the world then huh?
or did i miss something (yet again)</TD></TR></TABLE>
No, more like they missed something. If they wanted to be more complete, they would have said something like:
8x1.25 x 20mm

8x1.25 mm is the diameter and thread pitch
20mm is the length

Sometimes you have to worry about the strength, like grade 5 or grade 8.