Owen Posted May 18, 2000 Share Posted May 18, 2000 After I get my engine running and timed right, I was planning to drive it to a muffler shop to get piping made for the exhaust. However, on zcar.com, I read that driving without an exhaust, even with just headers, can cook the valves. Is this true? If so, I will have to tow it or make my own system. Owen ------------------ http://www.homestead.com/s30z/index.html Quote Link to comment Share on other sites More sharing options...
Mikelly Posted May 18, 2000 Share Posted May 18, 2000 Owen, I was told the same thing by several hotrodders long ago before I ever thought of building cars.... The air being sucked back into the combustion chamber is supposedly a bad thing, and can cause the car to lean out (I believe) which causes bad things to happen to your valves. Someone else here can probably expand on this in greater detail, but the short answer is don't run it long without full exhaust on it. Mike ------------------ "I will not be a spectator in the sport of life!" mjk Quote Link to comment Share on other sites More sharing options...
DennisK Posted May 18, 2000 Share Posted May 18, 2000 Back in the old days of leaded gas, quite a few guys ran around with open headers until police stopped them for noise. I never heard of valves being cooked then, but today's fuels may have a different effect. I'll be in the same situation soon(I Hope!), and really didn't think this would be a problem. The shop I will have do my exhaust is 1/2 mile away and maybe a short distance is OK. Anybody who knows for sure is will save us all alot of time and money! Quote Link to comment Share on other sites More sharing options...
MYRON Posted May 18, 2000 Share Posted May 18, 2000 I dont think that you will have any problems.. Look at all the cars at the track that run upen headers... I ran my car for a long time without any exhaust beyond the block hugger headers...My engine is strong, its just the trannys that i keep breaking! Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted May 18, 2000 Share Posted May 18, 2000 I was told that the valves would cool faster after turning the engine off due to the shorter length of the headers which would cause the valves to warp. So when I run open headers I always stuff rags in the collecters after shut off. Who knows if it's true or not? Quote Link to comment Share on other sites More sharing options...
Owen Posted May 19, 2000 Author Share Posted May 19, 2000 This is pretty confusing. One thing that worries me now is do I get an exhaust system put on before I try to break in the engine? I guess I could just lay some pipe on the floor to exit the gasses to the outside... Owen ------------------ http://www.homestead.com/s30z/index.html Quote Link to comment Share on other sites More sharing options...
pparaska Posted May 19, 2000 Share Posted May 19, 2000 Before I learned how to weld, I would use flexible tail pipe and cheap mufflers hung whatever way was easy to get the engine broken in and drive to the exhaust place. That is what I would do to be able to break in the cam, etc. ------------------ Pete Paraska - 73 540Z - Marathon Z Project - pparaska@tidalwave.net">pparaska@tidalwave.net - Quote Link to comment Share on other sites More sharing options...
Owen Posted May 20, 2000 Author Share Posted May 20, 2000 I'm gonna do what Pete suggests. Another question I have is, is anyone here using resonators or silencers? I know I can never get the car quiet as a stock one but I want to get it as quiet as possible. Also, what kind of timing light is good? Owen ------------------ http://www.homestead.com/s30z/index.html Quote Link to comment Share on other sites More sharing options...
John Scott Posted May 20, 2000 Share Posted May 20, 2000 Or, have the car towed to the muffler shop. They can't check for pin holes etc, but will get you ready to fire off. If you live in a neighborhood like mine, those 2500 rpm, 30 minute, open exhaust cam run-ins, are hell on neighborly relations. Most of the turbo style mufflers still get really loud at anything but idle, and I was still pushing my luck with a muffler! In my younger days, used to run around with open exhaust for weeks at a time, never had a problem...that is with the valves! I know we have better metallurgy today. JS Quote Link to comment Share on other sites More sharing options...
Mikelly Posted May 20, 2000 Share Posted May 20, 2000 Owen, Yesterday I just bought a $70 timing light from sears and it has a dial on it for setting the advance without screwing around with a degree tape... Nice unit. Mike ------------------ "I will not be a spectator in the sport of life!" mjk Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted May 20, 2000 Share Posted May 20, 2000 heya, My first choice was to tow mine to the muffler shop. When I mentioned it to my bulider he said not to sweat it. He's 70 and has been in the racing biz for 40 years. He still has a rep as building them strong and dependable. I had no problems with mine. Although, be prepared for the temp needle to ride high on the trip over to the muffler shop. Just my 2 cents I am NOT a mechanic. Quote Link to comment Share on other sites More sharing options...
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