replacing exhaust manifold

Okay I think I am going to try and replace the exhaust manifold this next weekend. Is there anything I really should know about before I start tearing it apart? It is on a 92 xj 4.0.

Don't bother unless your installing a performance header. Replacing a stock manifold for a stock manifold is a complete waste.

Also, you should spray lots of pentrating lube on the bolts the night before so it has a chance to work.

Don't forget a telescoping magnet stick so you can easily pick up dropped parts.

A fuel line hose remover comes in handy too.

Performance headers deliver relatively little performance over the stock tubular exhaust manifold. What they can deliver is resistance to cracking and corrosion. I can understand buying the header rather than paying the dealership price for a new manifold.

Don't forget a couple of new bolts/studs and a gasket for the downpipe.

I'll assume that you're replacing the manifold because it's cracked.

Get a 9/16" "Flex" socket - the one with the inbuilt universal joint. You don't need to alter the torque value when using this socket. It damn sure does help - especially on the lower rear screws.

Replace the studs - they're probably half shot anyhow. Standard allthread should work to cut new studs to length - 3/8"-16, as I recall.

Make sure you re-use the "dish" washers - they spread the clamp load of the screws.

Replace the screws - they're shot from heat-cycling anyhow. They should be 3/8"-16 x 1-1/4". Brass or bronze would be preferred; if you have to get steel, use SAE Grade 5. SAE Grade 8 screws are more sensitive to heat cycles, and will lose strength rapidly (brass and bronze will not only not gall against iron, but they'll get incrementally stronger as they're heat cycled.)

Use LocTite #272, or nothing at all. Never-seez is a good way to pull out the threads in the holes, and no other LocTite will hold to up exhaust heat.

I've had good luck using a thin, even layer of RTV Copper on both sides of the new gasket. If you don't have copper, don't use anything.

While you're about it, get two renewal kits for the fuel line quick-connects to the fuel rail and a set of fuel injector o-rings - you're going to have it torn half to bits anyhow, and you'll only end up adding a half-hour or so to the job.

That's all I can think of at the moment...

Wow Wally, I'll bet you're the only guy on this forum from Tooele. I went to high school there about 40 years ago. I think I'm getting old.

PaulJ said:

Wow Wally, I'll bet you're the only guy on this forum from Tooele. I went to high school there about 40 years ago. I think I'm getting old.

Click to expand...

I also bet your one of the only ones on here that knows how to say it. I am not from there I just live there.

Well I have the job done. Saved a little over $300.00 since I did it myself. It only took about 6 hours so I guess that is not that bad since all the shops around said the job says 4 hours to complete. Sounds much better.

Instead of paying the high $$$ price for the dealer quick connect fittings (aka hose repair kit), I found a cheaper source. I'll be replacing my cracked header in a couple months.

Dealer:

3/8" pn: 83504 447 --- $22.42
5/16" pn: 83502 745 --- $19.29

VS

Rigid Steel:

http://www.rigidsteel.com/y95pC3tIGk0.html

3/8" pn: 83504 447 --- $9.95
5/16" pn: 83502 745 --- $9.95

hi - newb here going to try to replace - how do I know which one I need - (Have a 93 4.0 Country) - thanks big time