driving with cracked header

I took a hit in the exhaust, and it completely cracked the front header tube. The crack is all the way around the 1-2-3 tube where it joins the collector. There is about 1/4" gap now, I can't budge anything to close the gap. I know it is loud, but could this do any damage to the engine. I'm concerned with 2 areas...the O2 sensor is downstream and may not send a correct signal to the computer based on a bad exhaust stream, and secondly less back pressure, burning valves...old wives' tale?
I need to get this XJ ready for the next ECORS race in 2 weeks, I will probably race as is and find/install a new part later. Thinking about getting some header wrap or exhaust tape to try and contain some of the exhaust. Other than loud, think I'll be OK?

Here's a pic from below...
http://i51.photobucket.com/albums/f363/RenegadeT/2010-04-01001.jpg

Crown bumpstops disintegrated, bumpstop extension fell out (construction adhesive will not hold a hockey puck in), front driveshaft yoke hit the downpipe tearing a nice hole in it, and cracking the header. That's how I think it went down.

As far as burning valves unless its Super cold, like 0 degrees out where you live then you will have no problem. Other then that the computer will be affected by the loss of exhaust downstream. That crack is also pulling in fresh air as the exhaust passes which can cause grief for your computer finding the correct running conditions. By the looks of it the whole exhaust system is toast....should be replaced for maximum performance.

Well, o2 sensor reads false lean, computer increases the injector firing cycle trying to enrich the mixture to correct the false lean condition--wasted fuel, the excess unburned fuel from 4-5-6 will probably destroy the CAT, those are your downsides. Burning exhaust valves from a leaking exhaust manifold is not a an old wives' tale, but the leak would need to be closer into the exhaust port.

I would personally replace it before racing. Junkyard ones are cheap (to hold you off for a while) and heck you could probably booger weld it back together and throw a piece of scrapmetal over that hole just to keep it mostly together for the race.

I just had the same thing happen - I've noticed that the Jeep is a little off on power, idles and cruises a little rougher, and my mileage got progressively worse over a few cycles. I'm in the market for a new header at this point.

I would replace it before a "Race"

Will any 91-01 exhaust manifold will work, or was there a change with the new intake manifold (1996?). How about the pre HO XJ 4.0L? How about TJ or ZJ manifolds, will they work on my '95?

RenegadeT said:

Will any 91-01 exhaust manifold will work, or was there a change with the new intake manifold (1996?). How about the pre HO XJ 4.0L? How about TJ or ZJ manifolds, will they work on my '95?

Click to expand...

To my knowledge they all work from the early model to the late ones...even wrangler ones.

I put a 98 wrangler header on my 96 XJ and it was fine.

I just had welded mine it's been fine ever since, it's just a piece of metal tubing. I would at least give it a try first and see if it works for you, pulling the manifold is a real PITA and they are crazy expensive too.

In 2000 they add 2 mini-cats to the header to lower emissions so you may want to avoid anything after 2000.

See this is exactly why I keep saying the exhaust needs a flex section!! Why vehicles don't all have those, especially ones with poorly designed exposed exhaust piping, is a mystery.

You should be concerned with gassing yourself. The leak is a lot closer to the HVAC intake than the tailpipe

Ditto on being aware of gassing yourself.

My son's '97 that had a exhaust manifold crack that got larger / louder as the motor warmed up. He ended up in the emergency room for CO2 poisoning after a 1/2 hour drive to work left him all woozy.