View Full Version : Headers

4runner luv
08-26-2010, 10:16 PM
Tomorrow after I get off work, the long awaited adventure begins! Putting headers on my 3.4 liter 4runner. Been lugging these things around for almost 2 years now. Read all the write ups, bought all the parts (I hope), sprayed all the liquid wrench, and now it's time. Supposedly this is gonna be a major beetch... getting the old ones off at least. Really hoping I can get it done within the weekend (with time to get beers on Saturday night). I'm skeered!

I'm gonna attempt my first write up for this as well, complete with pictures. Wished I had done that for my locker retrofit, manual hub install, and lift cuz I learned how to do all of it by reading other peoples write ups on sites like these.

Oh the bloody knuckles are afoot! er... a hand!

4runner luv
09-08-2010, 10:23 PM

Okay, so first let me say... get everything ready. I made so many frickin' trips to the parts store and hardware store. I prolly coulda got this done in the allotted 2 days had I not had to walk to get all my parts and tools as I needed them.

In addition to the standard tools; sockets, extensions, wrenches, liquid wrench, the following are a must:

1) Sawzall - allegedly you can maneuver the stock crossover pipe out, but I couldn't even come close. Was way easier to cut it.

2) Impact wrench.

3) Wobble sockets, universal joint adapters (all impact quality)

4) Double bendy socket wrench (yes, that's the technical name, ha, ha). It has two joints on the handle... I couldn't have made it without this.

5) 12 - 10mm, 1.25 thread pitch, 35mm long, class 10.9 flanged hex head bolts. These are to replace the studs... again, allegedly you can use the studs, but I sure couldn't get headers over them.

6) Copper RTV and anti-sieze.

7) Female torx set (for extracting the studs). Though it can be done fairly easily by tightening two nuts in opposite directions on the stud, then using them to ratchet out the stud.

and just in case...

wouldn't be a bad idea to have a tap and die set, a bolt extractor, and a heli-coil set on hand.

09-08-2010, 11:37 PM
Cool socket wrench!

09-10-2010, 05:30 PM
When I put a Tri-y on my 20r 4 cyl. I needed a right angle drill and 5 Heli-coils. May you have better luck/skill.

09-10-2010, 05:51 PM
Female Torx would also help to remove the studs, this will make it easier to remove the old exhaust manifolds. good luck

4runner luv
09-10-2010, 06:04 PM
Oh.... I spose I wasn't clear. It is DONE! Came out pretty good too. I am just doing the write up now.

I put a header on my old 22r back when I was in college, and had to do the heli-coil bit on two studs. Yeah, that sucked donkey balls. Luckily, I didn't run into that problem this time. Spose an extractor set, heli-coils, and tap set, would also be good to have on hand before starting though.

Yeah, the female torx would have been nice, but when I started, I thought I was keeping the studs. Too hard to get the headers over them in the tight quarters, so I went to hardened bolts instead. It really wasn't that bad extracting them by tightening 2 nuts to each other on each stud, then removing that way. But yeah, I should add female torx to my list of tools to have on hand before starting.

4runner luv
09-11-2010, 09:29 AM
Okay, next thing to do is remove everything that's in the way.

Oh first... of course liquid wrench the hell out of every single bolt the day before... maybe even every couple days, 2 or 3 times, before starting.

On the driver side ya gotta disconnect the vacuum hoses, throttle cable, kickdown cable, fuel supply line, and return line. Ya don't actually have to remove them, just disconnect one end and pull them out of the way.

It is a bit of a pain, but overall easier to remove the steering spline/shaft. I couldn't get the spline part off, but all the connections/brackets come off without too much work.

Bend back the swirly brake line (I know, my terminology is professional as it gets).

Take the alternator off... I just left the cable on, and set it down in the engine bay.

Remove oil dipstick tube.

Remove heat shields from exhaust manifold.

You might be tempted at this point to remove the manifold itself, but it is easier to unbolt the crossover pipe and downpipe with the manifolds still securely mounted, so they don't flop around.

Now the passenger side:

Remove air intake assembly.

Disconnect brake line bracket from frame.

Bend back swirly brake line.

Remove transmission fluid dipstick tube.


Remove exhaust manifold heat shield.


4runner luv
09-23-2010, 06:42 PM
Not that anyone is anxiously awaiting, but I will get back to this.

Gotta get back in a happy frame of mind to do a good write up... and as per my "trailer" post... I'm in a bad mood.

4runner luv
01-26-2011, 09:47 PM
Passenger side manifold off.


Driver side off.


Crossover off. I am told it is possible to get it out without cutting. I tried everything I could think of. Took transmission mounts off and lowered and raised tranny/engine to create space between the firewall, but never could quite get it.

If I had to do it over again, after experiencing getting the new crossover in, I think I would have just removed the plenum... probably could have got it out intact, and had a way easier time tightening the new crossover flange bolts.


Passenger side header in place. Very easy.


Piece #1 of driver side header in place. NOT easy. Getting it to wrap around behind the engine was a pain. Again, plenum off may have been the way to go. Notice, steering shaft detached. The extra inch of space was absolutely necessary.


4runner luv
01-26-2011, 10:12 PM
2nd driver side header piece in. Studs still in... was before I figured out that bolts are way easier.


2nd piece with bolts in. Notice the wrap around behind the engine. These pieces mate up together between the block and the firewall. See the stock photo (very 1st pic) to see what I mean. Sorry, couldn't get a good pic in such a tight space.


Okay, now skip a bunch of steps because I suck at taking pictures. Definitely need a 2nd person to keep records for this. Everything else is bloody knuckles, swearing, hitting headers really hard, and creating a maze of wobble sockets, extensions, and universal joints to tighten stuff up.

It won't fit together, and for that matter will seem so far out of wack, that you will think it's not made for a 4runner. Basically, just gotta put everything together loose and go back and forth from all the bolts, "sucking" it together.

In some cases, I had to get ridiculously long bolts to get it close enough to put the actual bolts in.

Another tip, don't use any of the supplied bolts... use hardened (class 10.9) bolts. I snapped a bunch of the supplied flange bolts.


Had a buddy weld 'er up for me. Used a piece of the original down pipe to get the slight bend needed to go into the cat. Someday I will do a new exhaust that doesn't flow so poorly as too probably negate the headers.


Made a small spacer from a piece of aluminum so the heat shield for the cable (transmission kick down?) would fit.


4runner luv
01-26-2011, 10:25 PM
What to do? Tranny dipstick won't fit?


Got a 2" long sleeve and 2 1/2" bolt at Ace to make an extension. Painted it purdy metallic silver (cuz that's all I had).


Also have to do some creative bending with the tranny dipstick tube to get it to fit.


Also, used rtv on the oil dipstick tube when I reinstalled it. The O-ring seemed pretty compressed and loose. Vuala! Appears to have solved my leak problem. Had a slow leak that I couldn't trace. Prolly, from where the oil dipstick tube goes into the block. Was leaking down the side of my oil pan.

4runner luv
01-26-2011, 10:32 PM
So, that was prolly the lamest write up ever. Half my pics were out of focus.

Definitely need a helper for a job like this. Had to build complex (to my simple brain) systems of extensions, wobble sockets, and universal joints, that would have been way more effective and easy had there been a second set of hands to provide fulcrum points and the like.

Went back and re-tightened all the header bolts... most were extremely loose. Torquing them would have been nice, but I couldn't get a socket on most of them, only a wrench. Don't think I have had a single leak yet though. That has been kinda surprising.

Next up: converting my 96-98 MAF sensor to a 99-02 for increased air flow. Just involves swapping the order of 4 of the 5 pins in the plug in (based on the writeup I found). Not 100% sure it will work, but got the parts cheap, and it's easy to switch back.

01-26-2011, 10:38 PM
Notice any better throttle response with the obx headers? Or even more power?

4runner luv
01-26-2011, 10:44 PM
Not so much on the throttle response. Power seems noticeable when going up a hill or something and then trying to accelerate. It was a little sluggish with the bigger tires and no regearing. Think the headers are more of a high rpm thing.

Also, there is kind of a weld bead or bulge (lip) on the inside of the downpipe, where the big flange is welded on (just before it bolts to the cat)... I'm thinking when I redo the exhaust, of taking that off and having it ground down, cuz it seems awfully restrictive. Maybe that will help.

Honestly, probably not worth the trouble unless you are going with a supercharger... I have heard that headers make more of a difference that way.

01-26-2011, 10:58 PM
Having high flow exhaust and intake are definitely critical with a forced induction setup. A way larger hp increase than an n/a motor. Now you just have a reason to Go supercharged :D