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Unread 11-08-2012, 10:52 AM   #1
CBFintheODD
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Exhaust manifold removal tips?

Hey everyone,

I have an rusted out fingernail size exhaust leak right near the driver side collector downpipe and my exhaust guy told me it is not usable to patch. So this is prime time for me to remove the stock manifolds and de-rust to get em looking new w some soaking in Evapo-Rust.

So all the 9/16s bolts turn except the one in the far rear near the firewall on both sides. They look like a b-tch to get to as well.

I looked around some but did not find much, can any share some war stories at removing these manifolds? Right now my game plan is to soak all of them in PB Blaster twice a day for a week. Like I said, all of them turn except for the two that are hardest to reach.

Any tips on what I need to do to get these (without pulling engine... kidding) would be greatly appreciated.

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Unread 11-08-2012, 10:56 AM   #2
walkerhoundvm
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PB blaster is a good idea, there are also some home-brew penetrating agents I remember seeing on the forum.

Most importantly you'll need the right tools and easy access. If there's anyway to improve access to those that are hard to reach - lifting the tranny and propping the engine forward from the firewall (without bashing the radiator) may be an option? You can make it easier with tools and access, but this job is never "easy."

Good luck!
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Unread 11-08-2012, 06:09 PM   #3
roadhog304
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You should be able to get at least a box end wrench on the bolts to brake them loose and then use a ratchet, couple of extensions, and a wobble joint to get them out.
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Unread 11-12-2012, 07:19 PM   #4
CBFintheODD
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Thanks for the info, I noticed in some stock diagrams that the collector areas have studs in the actual manifold itself. Mine are rusted way beyond the point I can save them. Has anyone replaced the studs in the stock manifolds? If so, is it retapping one size up or are there any whammies I need to look out for? It seems once I get them off, I can remove the old studs (assuming drill them out bc they are 34 years old and rusted), retap and then replace with new studs? I just want to make sure I am not doing something that would cause a potential leak.

Also does anyone have any links to where I can score new OEM manifold bolts for the block?

Thx
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Unread 11-13-2012, 07:37 AM   #5
CSP
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I'd do whatever I could to get them out without drilling/tapping. There are lots of methods for getting rusted bolts/studs out and the most important thing is to have patience.

Penetrating lubes (not WD40), heat/quench methods with an oxy/acetylene torch, etc.

If you have to drill there are ways to be careful and drill out the majority without damaging the threads too.
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Unread 11-14-2012, 11:48 AM   #6
CBFintheODD
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Thanks for the tips. I actually ended up punting and buying new direct fit manifolds. Once they arrive, I will remove the old ones and hopefully fit the new ones on.

My only concern is the two farthest to access bolts near the firewall on both sides. The bolt heads on these are subpar at best and I am hoping to work a 14mm boxed end wrench onto them and ease them off.

I have never tried the heat/quench method and I do not have an oxy torch. I do have a regular propane torch so would this achieve the same thing? My guess is this is not a good idea bc the oxy torch can heat it up much faster and acutely? I am assuming using a propane torch would cause indirect heating in other areas?

At the end of the day, all of them (except the bolts near the firewall) broke loose with little effort. I am just hoping a few days of PB blaster/light tapping will be enough to walk them off.

Thanks again for the tips guys, it makes tacking non-glamourous projects like these more palatable.
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Unread 11-14-2012, 11:50 AM   #7
CSP
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Your CJ is SAE, not metric. Use the correct socket/wrench, not 14mm.

Propane is not effective because you need fast, direct heat. Propane just doesn't get hot enough and you lose too much heat to a large surrounding area before the part you're trying to heat up expands enough to make a difference. The surrounding area then expands also.
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Unread 11-14-2012, 11:51 AM   #8
walkerhoundvm
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It's good you're being patient. It would suck big time to break one of those off in the head. A stitch in time and all that.
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Unread 11-14-2012, 01:12 PM   #9
Matt1981CJ7
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CB,

It sounds like you're already committed to replacing the stock manifolds, but......

I wouldn't scrap the old ones. Dummies like me, who strive to keep things original, will pay decent money for them.

I paid $80 for these off of CL. I was quite pleased with how they cleaned up. The old studs twisted right out with a little PB and a pair of vice grips.

Matt
exhaustmanifold1.jpg   exhaustmanifolds3.jpg   exhaustmanifolds6.jpg   comingalong5.jpg  
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Unread 11-14-2012, 07:35 PM   #10
CBFintheODD
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Yep I am good on that, all are 9/16. I was referring to the bolt(s) being so deteriorated that getting a 14mm boxed-end might be the play if the 9/16 rounds out.

Quote:
Originally Posted by CSP View Post
Your CJ is SAE, not metric. Use the correct socket/wrench, not 14mm.

Propane is not effective because you need fast, direct heat. Propane just doesn't get hot enough and you lose too much heat to a large surrounding area before the part you're trying to heat up expands enough to make a difference. The surrounding area then expands also.
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Unread 11-14-2012, 07:50 PM   #11
CBFintheODD
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Matt1981,

Oh my God that is beautiful. I hope to pull my motor one day and get it looking that nice. Those manifolds cleaned up real nice. I honestly wanted to do exactly what you did. To me, it is more of a time situation. I need to get the exhaust leak remedied and I don't have time to wait to clean them up that nice. I have a toddler that takes most of my time so getting new mani's were the play.

Your process is appealing to me somewhat to see how good I can make the OEMs look and sell them.

Can you share with me your process? Also the paint you used, does it really stay on given the heat? I'd like to coat the new ones to prevent as much rust as I can. If you don't mind, what kind of paint did you use?

Also do you have a good place to buy new bolts? Mine on there now are not savable and need new hardware. Thx
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Unread 11-15-2012, 12:22 AM   #12
Matt1981CJ7
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CB

Check out ARB for the bolts.

I soaked my manifolds in Prep and Etch ($16/gal at Home Depot) for two nights, then wire wheeled them, then painted.

The paint is VHT (high temp) in aluminum. I baked it in the oven to cure it, per their instructions. So far, I've only got about 200 miles of run time on them, but they still look exactly like the pics.

Matt
exhaustmanifolds5.jpg   exhaustmanifolds8.jpg   exhaustmanifolds9.jpg  
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Unread 11-15-2012, 07:06 AM   #13
CBFintheODD
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Ha that looks like a nice oven, how did the wife let you get away with baking exhaust manifolds in her oven?? Did it stink up the house?

Thanks and I will follow the same process.

I was thinking of getting ARP fasteners but did not know if you had a specific sku you bought. No biggie, I can figure it out for myself once I get them off the motor.
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Unread 11-15-2012, 07:12 AM   #14
Matt1981CJ7
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CB,

The fumes aren't bad at all. I patiently and cleverly waited until my wife left to run errands. By the time she was back, I was done, and the aroma was gone. She never even asked about it.

Good luck,

Matt
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Unread 11-15-2012, 07:16 AM   #15
walkerhoundvm
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I got a new exhaust manifold and did what Matt suggested - prepped with phosphetch (for only 15 minutes using a 1:4 dilution with water), let it dry, then painted with black exhaust paint which is basically the color of your propane grill. I also did my intake manifold at the same time using a red VHT paint after phosphoetch. I just cured them on the engine according to instructions - run it for 10min, shut off for 30min; run for 20min, shut off for 30min; run for 30min, and you're done. Both are holding up well, the exhaust better than the intake (I think I just couldn't get the intake clean enough before etching).

I had a pair of left over headers after putting the new manifold in, so I did the same to them and sold them to cover some costs.







Not nearly as pretty as Matt's engine bay, but neither is the rest of my Jeep
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