SkiRig

So, I talked myself out of buying a Dodge fullsize diesel, and am going to keep my paid off 4runner for awhile. It is a 1992 4x4 v6 with 175K on it. I ordered up some Thorley headers from Summit (ceramic coated, ~$620 shipped) yesterday to augment the power output a bit for pulling sleds and dirtbikes over the passes.

Does anyone have any tips or recommendations for the install? Other than patience and a few beers?

I will also be having the injectors serviced and setting the valves why I am at it.

Other mods to the engine: Jardine catback, 2.5" hi-flow cat and a old style Downey intake. I figure the headers will just about round out the eigne as far as the easy mods go, not much else to do to the 3slow.

RMA

I bought some used headers from a member here on yotatech for my 3.0 , I still have not installed them .
I am debating wether to change my trannsmission to a 5 speed and really cant make up my mind, as soon as i do I will install them. I hear they really make a difference.

The cross over routing would be easier on the 5speed and the power would better used.

Jay351

Hehe, my suggestion? Start limbering up....

Cut the crossover out, dont even bother trying to unbolt it, usually wont unbolt anyways...

SkiRig

Yea, a new nice blade for the sawzall is in order I think.

Jay351

Get a few, and a few cans of penetrent. Start spraying the exhaust studs now...

OutlawMike

The hardest part is getting the crossover out. Like was said above, sawsall the crossover if you know you will never put it back in. Get the PB Blaster on the bolts now, might save you some time.

When installing the headers, the driver's side is pretty easy, you just slip it in there, bolt it up. Downey recommended putting copper coat on the Downey gaskets. They had detailed instructions on that and made it out to be a very important detail.

For the passenger side, what does Thorley say to do with the EGR and the Reed valve? For Downey they provided a flex stainless pipe to hook up to the EGR. For the Reed Valve I had to hack the mounting bracket for the valve and mount it to the header, free floating as far as the bracket goes. In the end, not a big deal, but seemed a little severe.

The thing you need to worry about most is heat protection on the passenger side, as exhaust was not meant to go down that way. There are four areas to protect:

- Starter, buy a starter blanket from Summit and wrap the starter before putting the header in on the P-side.

- P-side floorboard/firewall. Buy some self adhesive thermal blanket and stick that to the bottom of the fire wall, the angled part at the bottom.

- Fuel lines, you will most likely need to carefully bend the hard lines to the side to get them away from the header tubes.

- Front E-brake cable. Make sure that the front half of the e-brake cable is re-routed away from the header and crossover. I melted mine, bought a new one, and put it in a heat shield "tube" from Summit. Summit made $100 off of my headers in heat shielding.

Good luck,

Mike

space-junk

iTrader: (1)

honestly, ive heard that you can negate most if not all the problesm with installing headers if you do a one inch body lift first... i know it seems extreme just to put headers in, but it makes servicing the engine easier in the future AND keeps you from having to spend the time having to coat the floor boards with heat shield...

just an idea...

SkiRig

Thanks guys, got some heat protection materials on the way from Summit. I will get some blades at Home Depot and hit the studs with PB blaster tonight.

SkiRig

Got the crossover loose tonight, I was able to unbolt the drivers side no problem, the sawzall with one Milwaukee Blue Torch blade (awesome blades by the way) made short work of the passenger side. Going to attack the manifolds tomorrow.

Justinlhc

I'd get the lines moved before you get the headers in. I wanted to see exactly how close it was going to be and what needed to be moved so I waited. It would have been much easier to do it before.

I hate body lifts, but I still am thinking about getting a 1" BL just to clear some room around the passenger side. It's just a bit too close to EVERYTHING.

For me, the drivers side was the PITA. I had to loosen the motor mount and jack the motor up a bit to get the header mounted up. I didn't use the new bolts they supplied so that might have been why I had to do that. Clearing the stock studs is the hard part, but I couldn't get the damn things out so I just left them.

Good luck with the O2 sensor. I had to hammer dents in to clear the nuts that hold the o2 in. I even used a thinner nut and it still wouldn't clear.

SkiRig

Clear what with the O2?

Did you just move all the lines away from were the headers will be?

Thanks,
Scott

Justinlhc

The flange for the o2 was way too close to the actual exhaust pipe on mine. There wasn't nearly enough room to fit a nut on the inside to bolt the o2 down onto the flange. Might have just been the set I got.

wii_tarded

take pics of the final product. i will be putting headers on mine when the new engine goes in.

SkiRig

I pulled the drivers side manifold last night, was actually pretty easy, the PB Blaster did the trick. I also pulled the studs in preparation for the bolts provided by DT. One of the threads is damaged though, a couple of threads came out with the stud on one of them. I am hoping that chasing them with a tap will fix it, if not, I will have to helicoil it.

The passenger side looks much tougher to remove the manifold, hopefully I can remove some stuff to get better access.

neilo

I installed a set of Thorley headers on a 91 4Runner with a 3.0 and the only problem that I have had was the clamped joilnts coming loose. I ended up welding all of the seams all the way around. It seemed to be sucking in air at the leaks and the O2 sensor was telling the engine to run richer causing it to load up a bit. When I did it I took the cat off and tossed it and replaced the muffler and everything back. So far so good it runs better and seems to be getting better mileage. I have not checked it but I am guessing close to 20 on the highway. One thing that I needed to get the bolts to the heads tight was some stubby wrenches. There is no way to get a torque wrench in there to tighten everything up to spec.

SkiRig

I spent an hour getting one nut off for the EGR on the passenger side manifold, what a pain. The nut started coming off then stripped and just started spinning on the stud and would not come off. I went postal on it with a die grinder and vicegrips and finally got it off. Hopefully I have better luck with the other fasteners on that side!

SkiRig

One last nut to get off on the passenger side manifold, it is the most forward nut on the bottom. It is really close to the AC manifold and is almost impossible to get to with anything other than a 1/4" ratchet. Anyone been there and done that?

SkiRig

Sawzall = 1
Manifold and crossover = 0

Got the passenger side manifold out after cutting it in half between the the first and second cylinders near the front. That allowed me to get a decent wrench on the nut.

Unfortunately, as I was installing the drivers side manifold, the back upper bolt pulled the threads out, I had trouble getting the stud out and the threads were damaged. I guess it is time for a helicoil!

SkiRig

The $70 helicoil kit saved the day on my bad thread in the head, drivers side is done, on to the passenger side.

Jay351

NIce progress! Those damn metric helicoil kits are expensive!! I remember buying one when I was repairing my crossthreaded spark plug.

Got any pictures of the progress??