[klenzd]

I recently installed new headers on my vehicle. I took out all the old muffler and pipe as it was original to the car, 1968 XR7. So now I need to get the rest of the stuff done and my thinking was to drive it down the hill (I live in the mountains) to the muffler shop and have them finish it up. My dad mentioned that it's possible to damage my engine from the backflow on straight headers/pipes when it's cold. Temps up here have been around 30 at night and 50 during the day. Is this too cold? Do I need to wait until warmer days before driving it down the mountain?

 

[mopardon]

That is what I was told many years ago. Whether it holds muster, I do not know.

 

[1970fastcat]

Wont be an issue if you have full length headers. I used to run mine open header when I was in high school and never had an issue. I still don't know how much truth there is too it anyway. When I was about 10 or 12, I remember riding home with my dad on the back of his bike at night when it was cold and the rear pipe broke loose. The stud broke off in the head and the pipe was just hanging there. We rode all the way home, with blue flames shooting out at my leg, with no issue. It was over a 20 mile ride, though he did take it very easy.

 

[1969XR7Vert]

The only thing I have heard or understood is the increased chance of burning an exhaust valve/seat over time due to the lack of backpressure (and therefore flame propagation into the exhaust ports).

 

[xr7g428]

With shorty headers, it can be hard to keep the car running. There is a good chance it will back fire a bit too. I always just kluge the remains of the old exhaust on to get me to the muffler shop. It looks like crap under there, but it seems to get the job done.

 

[klenzd]

I installed Tri-Y's, so they are fairly long. I also thought about throwing the remainder of the old pipes back on and connecting the two together with some aluminum shingles, just to get me down the mountain. I'll let you know what I end up doing...don't really want to wait a couple months for warmer weather.

 

[cougar1]

You can drive to the muffler shop on headers. Done it many times. Just let it warm up a bit before you go if you're worried about running it cold. A short drive like that won't harm anything. If you were to drive it like that every day, then it might cause problems (most likely with your neighbors and the cops).

 

[dfwcatsclub]

Think of all the racers with open headers...not a problem.

 

[woodsnake]

I have a pair of cheapie header mufflers, for just such an occasion. Your neighbors and the police will appreciate your consideration....Something like this:
http://www.summitracing.com/parts/BIG-50230FLT/?rtype=10

 

[Bad69cat]

Shouldn't be an issue - it may run funny so be prepared to tweak it if neccesary. (may need to adjust choke a bit, richen it up, retard it, etc) IF you have P/S you will definitely want the drop bracket in place and welded before you go!!

 

[Local Hero]

Yeah, I think it's an old wives tale. Definitely OK with long tubes.... shorties, maybe an issue with prolonged use. I was all set to drive mine wide open to get my pipes bent until the mufflers didn't come in on time. I ended up rigging up some temporary mefflers so I could continue driving it working the bugs out of it. I drove it that way to the shop afterall.

 

[psychicmechanic]

I believe that the old wives tale actualy stems from the potential of a burnt valve from an exaust leak directly off a manifold to headgasket. That said, my Pathfinder exaust manifolds have been leaking for years with no problems. The drilling of broken exaust studs is not my favorite thing to do, so i procrastinate...

 

[WFOJOE]

The danger as I have always heard was that you could burn and/or wrp your valves. This would not apply, per the myth/rumor/legend if you had quality stainless steel or titanium valves.

The racer analagy is not applicable as they usually have the aforementioned quality stainless steel or titanium valves.

 

[Bad69cat]

LOL - Dude - I feel your pain! Clack, clack, clack, clack, clack, clack....(turns up radio and ignores on-lookers)

 

[dfwcatsclub]

The racer analagy is not applicable as they usually have the aforementioned quality stainless steel or titanium valves.

Nonsense. I have run plenty of stock valve motors with open headers with no damage. Another wives tale. Stick to facts.

 

[Art]

Nonsense. I have run plenty of stock valve motors with open headers with no damage. Another wives tale. Stick to facts.

+1
Another myth started by someone like my Dad

 

[big bad blue]

Let er eat! Guys on dirt tracks run weed burners and they get real hot, then cool done between heats.