Header install prep

Install is going to be in a few days and I wanna do this without as much trouble as I possibly can avoid. I know that I'll have to PB the bolts...but what bolts exactly am I gonna hafta PB? Also, as far as depressurizing the fuel system...anyone have a step-by-step procedure for this? Thank all and wish me luck?
-Charlz

You should be able to identify all the bolts just looking - but you're going to have to pull the two for the collector, and the eleven for the combination manifold (yes, you have to pull them both - they also have a common gasket.)

While you've got this apart, it would be a good time to install injector orings, and if you have the silly QD fittings at the rail, don't forget to get renew kits for them as well.

I HIGHLY suggest that you cut new studs for the two ends and the centre out of 3/8"-16 brass allthread rod (you should be able to get some at your local hardware store) and get some brass or bronze bolts instead of the steel ones. Apply the "floatation test" to the bolts you take out - toss them in the water. If they float, keep them.

Get a couple 3/8"-16 nuts for the collector as well - you'll thank me the next time you have to take this to bits.

Make sure to clean the mating surfaces of the intake and the cylinder head (Scotch-Brite works well for this) and a THIN layer of RTV copper on both sides of the manifold gasket works wonders.

Get LocTite 272 to keep the bolts in.

Don't lose the washers - and replace any that are missing. You should end up with a washer on each bolt - they help to spread clamping force, and they're slightly springy - which helps to take bending stresses off the bolts (while it's not a lot, the fact that aluminum expands twice as much as iron/steel is significant from the bolt's point of view...)

I've said this a lot - get a 9/16" universal socket - the one with the universal joint built into the shallow socket. The extra inch of clearance you get is well worth it!

Since you don't say what year your XJ is - consider this optional... Applies to 1987-1990 w/4.0 only...

Remove the EGR tube and valve BEFORE you pull the manifolds - this will allow you to handle the two manifolds separately.

When reinstalling, set the manifolds in place FIRST, install the bolts LOOSELY (no Loc-Tite yet) and install and torque the EGR crossover tube. Install the EGR valve, then remove and retorque the manifold bolts - in order - and apply the LocTite 272. If you torque the bolts first, you'll spend about two hours trying to get that damn EGR tube to line up (don't ask how I know...)

5-90

dubbinxj said:

Also, as far as depressurizing the fuel system...anyone have a step-by-step procedure for this? Thank all and wish me luck?
-Charlz

Click to expand...

There's a Schrader valve on the fuel rail. Put a rag under the valve and depress it with your fingernail. A little gas will come out. That's it.

def make sure you get new o-rings.

new gaskets.

mark which injectors are which.

mark which is the gas supply and which is the return.

what brand header?

i have a borla and its great.

No wonder I kept losing my brass bolts....

I never did the 'flotation test'. D'oh!

Thanks again all. I forgot to mention that I scored a gibson header for my '99.
Hope all goes well wth this...

I know you said to use the studs but a few guys are just saying it works just as good with bolts and washers. Does anyone know the size of bolts for the header?? I'm doing this project and it needs to go pretty flawless since I only have a wkend to do it in and then head back to school??? Thanks in advance.

VTEK1 said:

I know you said to use the studs but a few guys are just saying it works just as good with bolts and washers. Does anyone know the size of bolts for the header?? I'm doing this project and it needs to go pretty flawless since I only have a wkend to do it in and then head back to school??? Thanks in advance.

Click to expand...

The threads in the head should be 3/8"-16, and the screws are something like 1-1/4" long.

The studs aren't strictly necessary, but they do help to keep the amount of wrestling down when you're getting everything in place. They're at the ends, you hang the exhaust on them, and then put nuts on to keep it in place. Set the intake in place, start screws. Get all of the screws started, then get your torque wrench out. Torque to 19-21 pound-feet. Use a "flex" socket to get the lower back ones.

LOCKING COMPOUND - use LocTits #272 (or equivalent) or nothing. Anything else will break down with the exhaust heat.

Reuse the little dish-shaped washers, they're there for a reason (I've gone into that in detail before, no need to repeat myself.)

I often find it helpful to use a light, even coat of RTV copper on both sides of the manifold gasket.

Check torque on the screws and stud nuts annually - you'll usually find one or two loosening on you.

thank you gentlemen

oh yeah, has anybody told you that installing headers sucks??? thats one mod I would rethink if I had it to do over again. the main reason for that is heat, I should have had that ceramic coating put on the header but I was in a hurry....so now I have hood vents, aux fan bypass, and I actually wrapped the headers while they were on the jeep to try to lessen the amount of radiant heat in the engine compartment due to the headers. after doing all that I am finally happy but what a pain in the butt!!

anyone know of a good ceramic paint, or DIY ceramic coating that helps with heat?

MONSTERxbla said:

oh yeah, has anybody told you that installing headers sucks??? thats one mod I would rethink if I had it to do over again. the main reason for that is heat, I should have had that ceramic coating put on the header but I was in a hurry....so now I have hood vents, aux fan bypass, and I actually wrapped the headers while they were on the jeep to try to lessen the amount of radiant heat in the engine compartment due to the headers. after doing all that I am finally happy but what a pain in the butt!!

Click to expand...

And since you wrapped the headers, you'll probably get the chance to replace them again.....