One exhaust pipe exhausting cool air
 

I helped Mike, a friend of mine, install his new exhaust system on his '65 "R" clone today. He is running a moderate build 302, headers and 3" collectors. He went with 3" exhaust pipes and mufflers with turnouts in front of the rear wheels.
His engine was run in by the builder and Dynoed. Since installation he has run the engine for maybe 2-3 hrs using purple hornies header mufflers just to control the noise.

Today when he fired it up to check for exhaust leaks etc. I was standing close to the drivers side exhaust at first I paid little attention to the exhaust flow then while the car was warming up and coming up to temp. I noticed that the exhaust was cool, not getting hot. I went and checked the passenger side and it was blowing hot exhaust. After about ten minutes as the engine temp came up to about 180* the drivers side finally began blowing warmer exhaust though not as hot as the passenger side exhaust. Header temps felt the same. It was about 40-45* in his garage today

I guess I've never paid much attention to exhaust temps but I'm curious is this normal or does Mike have something wrong with his engine. Sounds great and there is no evidence of water in the oil or anything indicating coolant loss into the engine. I don't know all the details on his engine build but it has always sounded strong. Mike is not an engine guy either and was going to contact his builder tomorrow because he never much gave it much thought either.

3" too big
 

Gary,
The engine is ok,the exhaust isn't really going to get hot in the garage just at low rpm, but the exhaust is too big to scavenge the cylinders. He will lose 15% torque and HP. 2 1/2" is as large as it should be even for a strong 302.
Perry.:MECOOL:

I'd shoot the individual header pipes with a laser temp gauge. Lots of things can happen to the heat on its way to the rear of the car. Where it exits the head is where it counts.

BTW, I agree that he screwed the pooch with the 3" system. 2 1/2 MAX, with 2 1/4 being preferable for a 302.

Thanks for the info guys. Just puzzled mewhy one bank was blowing hot exhaust and the other cool. I have a 289 and 3" exhaust on my FIA but my mufflers are 2 1/2 in and out, 4" round tube. Within a few minutes of starting it is blowing hot from both pipes.
If what your saying is correct Mike just blew about $400 to have the exhaust welded up and then shipped to/from Portland for a ceramic coat.

tpinni,
Do you have a laser temp gauge we can borrow ;) A bit out of our price range for a limited use tool.

I think you can get them at Costco for about $60.00. Or an easier way is to just grab each header pipe. If it melts your skin, it's just right!:LOL: But seriously, just fill a squirt bottle with some water and shoot a dab on each pipe. The "sizzling" should be the same from each one. Just don't soak them. A little squirt will tell you what you need to know without risking a crack in the system.

Tom

Smokey used to tune carbs with a drop of oil on each primary tube, and watch it "skizzel." Get all the "skizzel speeds" the same and its jetted evenly.

Holy Skemoley! You mean I think like the great Smokey!?!