Bronco_Bustin

My factory exhaust manifold is cracked bad.

Does anybody have any reviews of aftermarket replacement manifolds? (Crown, Dorman, etc...)

I've seen threads saying multiple factory replacements cracked over and over again so I don't want to go that route.

And I've seen tons of you trash talk shorty headers but I'd rather shorty headers with no performance gain that don't crack than exhaust manifolds from a company that pleads for a government bail out then sells itself to Fiat

I live in Commiefornia so it has to be CARB legal...

jimk403

We bought these from Rock Auto. They have several different brands, I think this is the cheapest. I could hear an exhaust leak but never found it until I removed the heat shield. We then tried the JBA headers, they don't crack but no gains gains either.
Now we have BBK long tube headers, a little noisy but they do allow the Jeep to pull hills easier.

JKduke86

I'm looking into this too. My driver side is cracked bad and I would rather put in shorty headers with no gain rather than deal with another OEM manifold cracking. However, reading all the problems with the heat from these and melting wires makes me want to shy away from those as well. What is the best option out there? If precautions are taken for the heat such as spark plug boots are people having good luck or are they still having problems? Any body had good luck from the crown replacement manifold?

mwtrent

If heat and melting things is your only concern just put header wrap on them and be done with it. Old school hot rods have been doing that forever.

Bronco_Bustin

I did this to get me by on the meantime... We'll see

Ajkaz

Definitely interested... Too bad the Ripp long tubes aren't carb cert!

SoK66

Couple months ago I discovered my driver side manifold was cracked in the usual spot between #2 & #4. Factory was on back order so I tried Rock Auto and Dorman's manifold. Between Rock Auto and Fed Ex the overnight delivery turned into a week, so I did an emergency patch with Quik Steel. Worked until I could install the Dorman. When I un-boxed the Dorman I discovered the port casting wasn't machined to match the head. One manifold port blocked the head port about 20%. Put it on until the factory manifold came in. FWIW, FCA has not improved the manifold design, same defect (thin casting between 2 & 4) exists in their replacement. If anyone can report on the Crown product it would be helpful to the discussion.

JoeRif

It's a shame this thread died a month ago - would've loved hearing about a quality replacement.

Bronco_Bustin

Well, at least the weld is still holding...

SoK66

Well, the stock replacement went on fine and after a few re-torquings seems to be holding up. One thing I did was clean the odd waxy stuff off the threads of the new manifold bolts. I used anti- seize on the threads and they torqued down smoothly and evenly. When I re- torqued them at 100 miles a few needed to be cinched up a tad. Later when I checked at around 500 miles they were all snug. The waxy stuff we think was some kind of thread locker the factory uses to eliminate the need to re- torque. However it's likely the stuff is the cause of the bolts seizing and snapping off in the heads that we've read about. Ideally, a stud washer and nut should be used, particularly on an aluminum head.