I heard this before and wasn't sure if it was true, does it hurt the engine any to run with just the exhaust manifolds on? (I don't have the rest done yet).

 

Just the stock manifolds would be a little risky, IMO. Long tube headers are ok, but the stock manifolds are a little short. Just to see if it fires up, might be ok, but any extended time would not. Again, MHO.

 

I agree with shoebox. I would be afraid of valve float running with open manifolds. Open y-pipe should be ok (or at least better) but I wouldn't run open manifolds.

 

do you mean along the lines of needing back preasure or it running to lean or soemthing? like on old cars is you open the ehaust you need to re jet the carb also? fuel injected cars can compensate for that as long as you have the O2 sensors installed. i'm not sure if they are actually in the manifold or the y pipe as i've never tore mine apart.

as for what I think the others are telling you is that with the short manifolds you will be shooting fire out and could burn some wires or soemthing.

 

what they are trying to say I think is that w/ the stock manifolds the collectors are too close to the engine and might burn some of the exterior parts of the motor up from the exhaust. If you've ever touched an exhaust pipe you know what I'm talking about (i have) they can melt wires together, or even completely destroy o2 sensors if they are near or whatever. Ive run straight shorties for a week or so, but I also wouldnt recommend that unless you have some major ear protection

 

Flames not what matters without having enough pipe like a long tube you run the risk on messing things up severly bent valves etc.

 

How does it cause valve float? (just wondering..) By not having backpressure on the valves?

 

how would you bend a valve if you don't have enough pipe?

 

Ok, I have a question on this same issue. I will be installing my AS&M Headers here this weekend, can I drive it about 4 blocks away to the muffler shop to get the exhaust attached to it. Will it suck a valve in that distance? Please let me know, I'm really curious.

Thanks
Tuff.

 

Nothing to do with valve float, IMO. That is a different matter. What I was concerned about was a lean condition because of the lack of pipe length that would cause a burned valve.

 

Ditto........

 

Shoebox is right ,
one question though say it was overly cold outside and you were running strait manifolds when you shut off the engine it would suck the cold air in the motor would it not?

 

Is the lean condition/burned valve caused by cooler air?

 

It is caused by the extra oxygen that is available to burn. That causes excessive heat. There is still some burning of the mixture going on when the exhaust exits the head.

 

long time ago i cranked mine up and ran i for a second if that.. out the manifolds
but i wouldnt recommend doing it