Header pipe bolts and install

[dnk1999]

Well where my flex is on the header pipe, it finally came loose. My car sounds like a truck with straight pipes.....anyhow my questions arise with the bolts used to connect the manifold to the header pipe and also the bolts/nuts to connect it to the catalytic converter. Does anyone know what size nuts are to be used. None of the part shops here have a listing for them. Another question i have is: What do you recomend spraying on the rusted bolts/nuts to get them off with out killing myself. The last question i believe is Are there any tricks to allign everything or is it fairly simple to do so ?

[nswst8]

I just used some standard bolts, any auto parts store. The actual cat bolts are like $9.50 a piece.

I like PB Blast penetrating oil, get the engine to operating temp the shoot the bolts with the oil. Let stand for 20-30 minutes.

[dnk1999]

Thanks for the info i appreciate it a lot!!!!

[shepherd79]

when you put everything back together you can use neverseize coper (high temp) on the bolts. this way you won't nave any problems in the future.
Also, i recomend useing galvanize nuts and bolts. they never rust and they always come off easy.

[smufguy]

the bolts that hold the header to the head are 12mm nuts

the bolts that hold the Long runners to the downpipe (the part where the 4-2 and the 2-1 meets by the front of the motor) is held in by 14mm bolts

Using a liquid penetrant such as Liquid Wrench, PB Blaster or even the regular WD40 would work. Make sure u have a breaker bar and a 1/2" drive socket to remove the nuts from the studs.

when u reinstall everything, make sure you use antiseize on the bolts and apply the antiseize on the top of the bolt and exposed stud if you want to prevent rust. There is nothing you can do to prevent these bolts and nuts from rusting unless u use a different type of metal as Alex Mentioned. Most of the aftermarket headers come with steel or specially coated hardware to prevent corrosion.

[dnk1999]

Smufguy.......those descriptions of the bolts, are they for a 88 lx manual???? I was looking at the manual online and it shows something about the "self locking nuts" are 8x1.2 mm for the cat and header pipe connection as well the support bracket.....As for the connection form the top of the header pipe to the manifold is says 10x1.25 mm "self locking nuts" are these the wrong dimesnions or what? I dont want to end up buying the wrong bolts and have to take them back tommorrow while trying to connect the pipe. Any info/ answers would make me very grateful.
Thanx
Damian

[smufguy]

usually the bolt description on the spec sheets are the stud size (diameter) not the nut size, which is what i said in the above post. The nut size, is the same for all 3geez as far as i know, atleast it was the same for my 89lx, 88 dx and the 89 lxi i worked on.

[dnk1999]

Smufguy.... or anyone else that can help or answer these ?'s i have. Basically i started to work on the car to get the old heaedr piep off. Well..... i have an issue. one of the bolts seems to be to small to be an14 mm. the 13 mm has a little play and the 12 mm is way to small......any ideas
it doesnt look like the nut is stirpped. Is it possible that one of the nuts is a 13 or ?????????. Also noticed when i was trying to disconnect my cat that the resonator and the pipe coonected to it are rusted and cracked... hanging on by a thread. Is it safe to run the car with the headre pipe and cat only or what?
thanx for any answers!!!!

[smufguy]

Honda does not use Odd number socket size nuts. IF the bolt is not rounded off and seems to be fine, then possibility is that someone had work done to that area and replaced it with a different nut. Usually its a 14mm socket nut, not a 12mm. 12mm is the size on ur header flange bolted onto ur cylinder head.


It is not safe to run the car with just the header and the cat and everything else removed. Not only will be loud as fuck, the fumes will get into your car and its not healthy for you obviously. If any, u can do what i did. I broke off the stud on my header to downpipe so i just used metal wire to hold my header and downpipe in place and drove it off to the exhaust shop and got my DC header and full exhaust put it. If you are looking into just replacing ur Catback, do what i did, rig it so that the exhaust does not get dumped right under neath your car and take it to a shop and have it fixed. If the shop cannot fix it the same day and this is the only car you have for daily driving........... then you are screwed.

PS: If you really want to remove the nut out of the header, use a standard size socket and see which one helps u loosen it. If nothing helps, use a small pipe wrench, and break the nut loose. Normally, with the right socket and a breaker bar, any rusted bolt comes off with no problem................... that is unless u break it off the stud.

[Tailfin]

I had the same thing break, and I noticed the header to pipe bolts were indeed 14mm...but the pipe to the cat...looks like a rusted mound...like a brown stud with silly putty lumped in a few spots and rust covering it...I can't even make out what they are lol. Could be rivets or welds under there...I wouldn't know by looking...so I'm just going to take the new header pipe to the shop and let them deal with it.