I just finished putting in the new 350 Oldsmobile motor. I was wondering if I can run straight headers to the exhaust shop? I am about 3 miles or so from the place that does my exhaust. I just don't want to suck a valve. Or should I Just get some cheap mufflers or glasspacks for the ride there. I want to hear what it sounds like with just the headers but don't want to damage the new engine. I haven't started it yet I was thinking of running the glasspacks for the first fire then just put a set of cheap mufflers on there for the ride.to the shop. And return the mufflers after.

 

I think youll be alright alot of people run open headers when drag racing, and they beat the snot out of their cars when they do it. Btw there are stupid laws about being to noisy though, i dont like being harrased lol

 

Ya I just don't want to suck a.valve with the stock heads.

 

Well some say its better to be safe than sorry. I have personally done it a couple times and never had a problem. I just drove it nice and easy MOST of the way there

 

You should be ok however I like exhaust quiet when I start an engine for the first time so I can listen for any noises that should not be there. Some cheapo mufflers just attached to collector would be better.

 

Ya I got some thrush mufflers I am going to put on until after the tuning is done then I will take them off and enjoy.

 

I think this whole "open headers hurt valves" myth comes from the same place as the offset engines myth. It certainly won't die.

Open headers will NOT hurt anything except your ears (or wallet if you get a ticket).

 

Now, if you had shorty headers, you might be taking a chance of warping a exhaust valve, if it got red hot and it was cold outside, but never would it "suck" a valve from headers!

 

Back in high school(when muscle cars outnumbered family cars among students) it was a tradition to uncap your headers on the first and last day of school. This was not a problem for us as we lived out in the country, and the long arm of the law was scarce. I loved the noise from my 455 with no back pressure encumberance. One thing I did note was that at a certain RPM, there was almost no noise at all. Usually I could achieve this with the transmission in 2nd(TH400) doing about 30 MPH. If you're only traveling 3 miles, you have to weigh the difference between time and expense of putting on mufflers, and the cost of a ticket. ( We loved to see the big 10' x 15' windows on the front of the school vibrate and shimmer as we pulled into the parking area!) Have fun Chumley

 

Well the long arm of the law isn't to much of an issue I know a lot of the officers in town. But it sounds like I will be okay running open. SWEET although I am going to get some strange.looks with it being in a Cadillac. Lol

 

Well this is a new one on me. Never heard of dropping a valve or warping one with open headers. Where does this stuff come from? While I was in the Marine Corps I raced my 70 Cutlass every weekend at the local track, uncorking the headers each time. I've never had a problem with valves, period. Of course the carb would have to be jetted up once you open the headers up but that's not always a given either. Maybe people have burned valves from too lean a condition? I don't know but I never heard of it.
As far as driving to the shop I'd recommend against it due to the noise. Just get some cheap header mufflers and run it that way.

 

Not sure if its related, but I burnt the heck out of some exhaust valves on my old '70 6cyl Maverick. A couple of the valves were burnt where they were only half there. I attributed it to a bitter winter and a completely rotted exhaust. Of course, this was a battered and abused daily driver used for months as a delivery/courier car....Lotsa stop/starting...

I can't imagine that a few minutes, or even hours, of open headers...paticularly if its not -10F outside..... would cause any problems.....

As for the noise.... It can't be any worse than some of the 'tards around here with their crappy boom cars...

 

If that were true, you wouldn't be able to run Top Fuel cars on a cool evening. You wouldn't be able to even start a car in Alaska when it's -40. And you certainly wouldn't be able to heat treat steel by quenching it after getting it red hot.

Now if somehow you could direct a pinpoint spray of liquid nitrogen at the valve stem while the engine was running, yes that would induce a thermal distortion. The distortion would also go away as soon as the valve equalized in temperature again.

I can only guess that the whole warped valve thing comes from welding sheet metal, which is a COMPLETELY different phenomena. In that case, you are solidifying the metal in a certain position when it is very hot, THEN it cools and shrinks, causing warped body panels.

 

The only thing I would do would be put a small turndown on the back of the header, not so much for nosie control, but the flames that could shoot out if you do decied to get on it.

As for dropping a valve. You're more likey to do that in a different way on a new rebuilt. But slim to none for just having open headers

 

burnt valve result from leaks at the head or removing the head pipes from a stock manifold. on the exhaust pulse when the exhaust gas moves back toward the cylinder a leak close to the head will allow fresh air to be pulled back to the valve which creates a ton of head at the valve. with headers the length is long enough that the fresh air at the end cannot travel far enough into the header. on a top fuel car with zoomies you dont drive around town much so the short length is not an issue.

 

LOL!

This is very interesting, I guess some of you guys have nothing better to do than to dream up these myths.

A top fuel dragster only runs for a very short period of time. Their valve material is very high dollar, normally not prone to warp. Plus they run so much fuel thru them that they are on the verge of hydraulicing. Ever notice how much fuel is coming out of the pipes when staging? That's to keep the engine cool, there is no cooling system on them.

Warped valves are the result of excessive heat and/or the inability to dissipate that heat, then they burn or warp. Could be caused by a lean mixture, improper timing etc. Theres almost no way enough cool air can travel back up the header tube to actually cool the valve in between pulses to cause warping, that's nuts.

Run the open headers, it'll be noisy and yes you can't hear the mechanical side of things but it shouldn't hurt anything, unless it's overly lean to begin with.

Jmo.

 

that is why I stated that the problem occurs when there is a leak at the head. that is the only time it will be close enough to draw in fresh air. I dont know the length of the pulse but I would think any opening more than several inches from the head is not going to cause an issue. in years past I have seen burnt valves on more than a few motors most caused by warped or cracked manifolds and many miles with that issue.

 

and yes I have heard the stories about not running open headers because of all the damage to the valves, of course I ran my 4 speed Trans Am around town for months with open headers. the great thing with a stick is when I saw the local law dogs I pushed in the clutch and killed the ignition till they went by then popped the clutch and hammered down. had a lot of fun with that car. sold it with open headers after a couple months as I shifted it at 6800 and didnt figure the factory crank was long for the world and I didnt want to explain the crankshaft laying in the street to the local law.