Down pipe nuts
 

Hey everyone, still new here so I figure to start off with a simple issue.

I have a 97 accord, f22b dohc nonvtec with a 2g dsm manifold, evo3 16g and 2gen dsm ported o2 housing with a custom down pipe.

I always have a small leak from the o2 housing to the downpipe. ill put in brand new gaskets and it still leaks. im guessing i need to have the sides of each part leveled to promote a perfect seal, but i randomly will have the bolts loosen on the downpipe. the down pipe does have a flex joint in it and the motor mounts are solid. any ideas on how to stop the nuts from loosening

get bolts with holes for cotter pins, and some castle nuts.

Take the nuts off and drill holes through them at one corner, from one flat spot to the a joining flat spot. Once you've done that and put them back on, just run a small piece of lashing/safety wire, from one nut to the next and the next.
This is a pic of a jig for doing what I just described, but I think you can do those few nuts without the use of a jig.
http://img218.imageshack.us/img218/4237/58880451.th.jpg

Or you could get some safety wire washers:
http://img218.imageshack.us/img218/9497/82018740.th.gif

You just put these under the nuts, fold up a couple of those edges, and then run the safety wire nut to nut to nut.

The name of the company that sells these items is...posse, google them.

good ideas. i will look at doing that, i didnt think to use safety wire on them

how long is your flex?

i had a problem on my dp where the flex was really stiff and didn't flex enough. I had bolts getting worked loose on my manifold and the dp flange. stepping up to a longer section of flexible tubing fixed it.

good luck

about 8-10 inchs of flex

yea, you're flex probably isn't the problem...mine was like 3 or 4" and i went up to around 10

is it studs and nuts or bolts? you can lock down studs w red loctite and get them in there solid and just worry about the nuts. not familiar w dsm stuff but it sounds like it should be a stud/nut type part. i've tried to ghetto stuff w bolts and gone back to a stud/nut setup for bolts loosening like this.

try copper nuts I use them all the time and they dont heat cycle as bad as reg nuts and try to work themselves off the stud. just be careful as they are kinda soft

another good idea