I'm going to be replacing my stock cracked header soon with an APN header and was wondering if anyone has any advice prior to me starting the whole project. I'm pretty mechanical but I have never done a header before so any advice from those who have done them before would be great.

Also, this will be installed on a 146,xxx mile 4.0L I6 in a 99 XJ.


Thanks

 

get a 14mm ratcheting wrench, and that apn header will need a dimple put in the back pipe where it otherwise hits the 99 intake.

 

Is that for the 0331 head or the 0630 head as well?

 

for the 0630, I had to do it on my 97 with a 99 intake and apn header.

 

Would you recommend going with a different header or is it pretty easy to make the notch?

 

I just used a socket and a hammer, I have no regrets. doesn't need to be dimpled much.

 

Cool, thank you. Did you have any issues getting the bolts out of the head?

 

i used a wood hammer handle to dimple mine, pretty simple

 

Personally I'd pull the whole head along with it and do the head gaskets while you're at it.

The lower bolts on the manifold are an absolute pain in the *** to get to, but you can pull the head and both manifolds as one piece pretty easily. Makes putting the header on a lot easier and takes about as long if you're handy with a wrench.

I wouldn't bother with a low mileage motor, but at 100k+ it cant really hurt. It's easier to do and doesn't really cost much at all. Then again I've got big hands so it's nowhere near as hard to pull all three as just manifolds for me.

 

pull the head too? are you off your rocker? You just turned a 2-3 hour job into a 10-15 hour job for the average joe.

No, I didn't have any problem getting the bolts out of the head... the problem is getting to the bottom ones, hence the mention of a ratcheting wrench. Don't expect to be able to get a torque wrench on them. You'll be torqueing them by feel with a wrench. it's a little bit of a reach into tight spaces, but it's really not that bad.

 

It's really simple to do, just a little time consuming your first time. You don't have any fluids to deal with (with the exception of a little gas from the fuel rail that will spill). Just a bunch of plugs and bolts. Since you're able to do all the suspension work you've done (I've followed your build - awesome work BTW), you'll have zero problem doing the headers.

When you have everything apart, you'll have very easy access to that motor mount, CPS, and freeze plugs. Things that would be a PITA otherwise. So if you may need those done, now would be a good time

Oh and get some copper gasket spray for the manifold gasket. And spray the crap out of it on both sides before putting it on. It'll really help with possible exhaust leaks

 

I've done two and I'm not exactly quick with that sort of thing. First one took me 7 hours, the second took me 3. I could probably do it in about 2 now. It's really not that hard at all.

 

I've done dozens, I spin wrenches for a living, lol. You're not draining the coolant, taking off the valve cover, pulling all the rockers and push rods while keeping them in order, disconnecting all lines and cables, disconnecting the exhaust, pulling the head bolts, and pulling the head, cleaning everything up, putting everything back together properly in 2 hours...

 

Ive done it in 3 not rushing, im pretty confident I could do it in 2. None of it is hard and I have a piece of 2x6 I drilled holes in that has markings for the rods and all the bolts so I can just set them in place in order as quick as I can pull them.

Exhaust all you have to do is pull the 2 bolts at the down pipe and the o2 sensor. The injectors, lines and plug wires are straight forward and quickly marked with tape.

If you pull the head and manifolds as one piece its a lot easier and faster. The only thing thats time consuming is torquing down the head bolts to spec.

 

This I'd have to see. O2 senser is after the header btw... no need to disconnect it.