Printable View
I'm having issues with a 355 imca sportmod engine car. 4412 carb with 75 jets and 5.5 power valve, 2701 intake , timing set at 36. The right side header is the only one that glows per video and people in the stands. I'm open to ideas I'm pulling my hair out trying to figure this out.
Intake leak or broke header/gasket
I've checked everything I can think of as far as a vacuum leak. It does have copper header gaskets on it and I haven't had any luck with them before.
high temp RTV red silicone works best for header gaskets
Glowing headers is usually unburned fuel in the header that is igniting or ignition timing is so late that half the air/fuel is still burning when going out the header.
Only being one side is strange/unusual....
I'd check the temp of each header tube with a heat gun at some lighter rpm and see if one or more is way cooler then the others. This might show 1 or more cylinders isn't firing all the time and leaving raw air/fuel in the pipes which is igniting at the higher RPM's causing the header to glow.
I'd also check and make sure the carb isn't running fuel in thru the boosters or out the vents from too much pressure or too high floats, causing fuel to run in and with G-forces over enriching the right bank - that's a stretch but just throwing out ideas
It could also just be rich and the right header isn't sealed good letting it suck in air at the head and igniting the unburn fuel in right header. Does it pop/bang during deceleration bad? if so is it mostly out of right header?
After re watching last weekend's race. The car was blowing fire on deceleration early in the race, but as the header started to glow is stopped doing it as bad if at all some laps which leads me to believe that it is just rich and header gasket is leaking. Would I 've wrong with that thinking?
might try a an angled intake spacer.
I am assuming Gas for fuel with that jet size.
have you done a plug check , especially side to side.
what spark plug type, and number are you running?
Have not been able to do a plug check yet. The track techs top 3 in the heat and top 5 in the feature, so we've been going through tech. I've ran autolites ar134s and just switched back to the Ngk 5674-8.
if you rev up the engine and close throttle like deceleration, does the engine exhaust just sound like: bbrrrrrrrrrrrrrrrrrrrr or does it: Brrr, pop, brrrrrr, pop, brrrrrrrrrrr, pop, brr, pop?Quote:
Originally Posted by jamminjayman5
sounds are hard to type but if it's doing the pop or bang, instead of a constant sound then you likely have a header leak pulling air into header. That will/can light off unburned fuel.
If so, Check gaskets and welds for cracks.
It doesn't do any popping in the shop, but I did pull the header and check for leaks. It looked like #8 may have been leaking at the gasket. I swapped gasket for some remflex gaskets a buddy told me fixed his header leaks so we will see tomorrow.
valves too tight?
Fox_hunter42 has the right idea.
If your exhaust valve is to tight OR it has a bent valve then you'll be blowing your power stroke out past the exhaust valve. Check your lash on your exhaust when the intake valve on that cylinder just closes. Also pump some air into the cylinder with the header off with your rockers backed off and see if it blows air out the exhaust. If its specific to that cylinder then its doubtful that its fuel. (Unless your float level its way high and its slopping over. Check your fuel pressure as well to see if its pushing past the needle and seat.)
Usually you have more cylinders acting up if its fuel.
There, try all that!
Mike
Its hard to see if the drivers side header is also glowing because of the distance across the track to the stands.
A plug reading will confirm what is going on.