Exhaust Manifold Removal/Info

[NEKExplorer]

I'm working on refurbing (not really rebuilding) a relatively low mileage 3.4 5VZ to replace my broken one with 270k. One of the refurbs I was thinking of is taking off the exhaust manifolds, cleaning them up, painting them and replacing the gaskets. My fear is that I end up breaking a stud or flange during this process and make more problems for myself. Anybody else removed these? Success stories? Horror stories? -Thanks

 

[gamefreakgc]

They are relatively straight forward to remove. Some of the studs will come out instead of the nut. Don't freak out when this happens, just keep track of which stud went where and put them back in when you're putting it back on.

As far as paint goes, it's not going to stay around for long. The manifolds are cast iron and tend to be a little rusty so paint won't stick to them. They also see extreme temps that will melt the paint right off.

 

[NEKExplorer]

That's the part I'm worried about, I don't have any experience replacing studs, don't really know how that works or how to do it.

 

[Riceye]

Vermont exhaust manifold studs/nuts are going to be a completely different adversary than ones on a SoCal engine. Proceed with extreme caution.

If you don't have an oxy/acetylene torch and skills, don't even try.

My $0.02.

 

[NEKExplorer]

Yeah that's what I was thinking, although for what it is worth the engine came from NY about 60-80 miles north of NYC. Only marginally milder weather than VT so you are probably right.

 

[19963.4lsr5]

On my 96 the nuts either ripped the threads off half the studs on the back of the Manifolds or crossover pipe or broke them.

On my 97 all the nuts came off the studs easy.

The studs in the head don’t worry if you pull them out. That happened to me on all three engines. I just soaked them and used a torques socket and removed the nuts from the studs.

Cutting the nuts off the studs that are threaded into the back of the manifolds and crossover pipe is the only safe way to get those nuts off.


Sent from my iPhone using Tapatalk

 

[gamefreakgc]

What year engine are you removing and what year are you putting in? Toyota redesigned the exhaust manifolds to equip 4Runners with dual cats starting in 99 and completely will all models in 2001. You might be forced to take them off if you have different kinds.

 

[NEKExplorer]

Mine's a 98 Limited - 5VZ-FE

 

[gamefreakgc]

Mine's a 98 Limited - 5VZ-FE

What's the year of the donor engine? You could probably visually compare the two, they look quite different side by side since they are different lengths.

 

[NEKExplorer]

Both engines are are '98s

 

[jlaho]

I just had both of my exhaust manifolds off and successfully installed them with new gaskets. Like others mentioned, the studs tended to come out with the nuts. If you're able to, separate the nuts from the studs that came out as a pair. There were a couple that I could not separate and installed them together anyways. I was careful to make sure all studs threaded in an appropriate amount before final torque. Best practice is of course to thread the studs in separately until they bottom out and then install the nuts and torque to spec.

I did have issues with the exhaust shield nuts being seized. I ended up having to drill those out after the manifolds were off. I live in northern Alberta where rust is an issue. Hope some of this helps.

 

[Kanoe]

When I pulled my exhaust manifold off I got sneaky. I used my ratchet with the star socket on the engine block stud in the tighten direction to keep the stud in position then used a boxed end wrench on the nuts. This method kept all the studs in the engine where they belong while taking the nuts off.

This works on a 3rz, maybe not enough room to do on the V6.

 

[NEKExplorer]

Nice idea- the engine is already out of the vehicle so should be plenty of room I hope.

 

[rideexileex]

Just did this on mine with 200k miles, all a OR, WA, MT, CO rig while fixing a broken motor mount perch / engine rebuild. I had an issue with about 1/2 the studs. Either had to weld a new nut on the end of a broken stud to remove it, and 3 of them that had to be drilled, chiseled, punched, and thread chased. I ended up chasing all the threads, and went ahead and just bought all new studs and nuts for everything. Was not pleasant, but it's now perfect.

One extra note is that with the old hardware (before I went crazy and just replaced it all), I noticed it was torquing to the whatever 30ftlbs called for, but not closing the gap much between the exhaust manifolds and the x-over pipe. New hardware has it nice and snug.