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Old 08-18-2013, 08:23 PM
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Fixed cracked header/helpful hints

About 2 years ago I replaced the stock cracked cast iron exhaust manifold with a header I bought off ebay. The replacement worked fine until last week when a weld at the collector broke. I debated buying a new one or repairing the cracked one. Finally I decided I would have to remove the cracked header regardless of what I decided, so removed it to see if it could easily be repaired. After removing and inspecting it I found that the weld on the top, in the center of the collector where the 3 pipes from the front come together with the 3 from the back was cracked. Also there was a crack on the #4 cylinder pipe where it entered the collector. I took it to a friend who looked it over and said he could repair it. Got it back the next day and it looked really good. Put it on yesterday and it ran great, no more leaks. Best of all it only cost me a little of $20 in new gaskets, and some beer!!!

Hints: feel free to add your own.

1. Before begining, take pictures for reference later.

2. The bottom bolt under the #4 cylinder is a PITA, coming out and going back in. It helps to be a contortionist and have long skinny arms!!!

3. I was able to remove the intake without having to remove the fuel rail and injectors, Haynes manuel said to do this, I was able to pull the injector electrical plugs off, there is a thin wire clip holding them on.

4. When reinstalling I went ahead and got the bottom bolts started in the holes. It is a lot easier than trying to hold everything up and blind stab a bolt into a hole and get it started, especially the #4 cylinder, did I mention it was a PITA!!

5. Take your time and go slow, you are not a NASCAR mechanic, if you are I don't think your jeep will qualify!!!

6. When you get frustrated and you will, sit down, have a cold glass of water or tea and a smoke if you do that. Think about what you are doing and go slow.

7. I got all of the bolts back in hand tight, then torqued them in order. You can't get a torque wrench on all of the bolts, especially the bottom one under the #4 cylinder, did i mention it is a PITA!!!!!

8. Almost forgot, there is a long bolt at the top of the power steering pump that had to be removed, it screws into the intake manifold. While everything is still loose it is easier to get it started.

9. Reconnect the injector plugs and the litte wire clips that hold them in place. Be careful those little things can go flying away and are almost impossible to find.

10. After everything is tightened up, go ahead and tighten up the serpintine belt, it is a good time to replace it if need be. Do this before reconnecting the fuel lines, it's just easier with them out of the way.

11. Reconnect all of the vacuum hoses and don't forget the one going to the brake booster, I did and found out as soon as I started it up.

12. Reconnect the throttle linkage.

13. Inspect your work and double/triple check everything, especially the vacuum line to the brake booster!!!

14. This is not a hard project, I did it in my garage with hand tools. Only used my compressor the blow out the residue after I cleaned all of the old gasket material off. I did not time myself, because I wasn't in a hurry, but it probably took 2-3 hours to remove everything and 4-5 hours to get everyhing back together. Did I mention the bolt under the #4 cylinder is a PITA!!!!

15. Forgot to mention above. When you have everything off it is a good time to inspect and clean everything. I used B12 chemtool to aid in getting the old gasket material off the head. I also used it to clean up the intake manifold and throttle body while it was off the engine. With eveything off take a flashlight and look inside the ports. You can see the valves and any deposits that might be on them. All of my intake valves were surprisingly clean, and the exhaust were all white like you would expect to see on your spark plugs. This is just an indication of how well your engine has been running and if there might be internal issues on the way. Mine looked real good for a jeep with over 160,000 miles on it.

I have been helped by this forum in the past and I hope this helps someone out there to pass on the help.

Feel free to comment and happy, happy, happy trails!!!!

Did I mention the bottom bolt under the #4 cylinder is a PITA!!!
1991 YJ 4.0L, K&N air filter, SS headers, 31X10.5, Congo Cage, etc...

When all hope is lost, and you have run out of options, you can always break out the "HOLY HAND GRENADE"!!!! It may not fix it, but you will feel a lot better.
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Old 08-18-2013, 08:34 PM   #2
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I was going to replace mine but I remember reading somewhere that the bolt under the #4 cylinder can be a real PITA. Did you find that?

All kidding aside thanks for the write up. I'm going to bookmark it for future reference.

Driving a jeep with a top is like screwing wearing a prophylactic. Maybe a little safer but doesn't feel nearly as good.
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Old 08-18-2013, 11:20 PM   #3
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I put headers on my 4.0 and don't remember it being too bad, but that was awhile ago. I will say the Haynes and similar manuals always tell you to pull everything off even when it's not necessary, so check things out before you give yourself more work. The book said I had to dicharge my A/C to change my heater core, I did not have to. Use the manuals as a guide only.

BTW B12 is the bomb! nothing cleans like it. It got my throttle body looking new.
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Old 08-30-2013, 08:26 PM   #4
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Old school trick..use studs and a flat,lock,and nut..
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