dmcisaac

I have a problem with glowing headers under full load and at idle,so much so its starting to melt stuff, the car is a 1984 vette with a 383 stroker with vortec heads with tuned port. i recently had car on the dyno and it was making good power at the wheels just under 340rwhp. but we could not dyno out the glowing headers by changing timing or fuel and air fuel ratios were good 12.6 full load and 14.1 at idle. i have hooker supercomp ceramic coated headers on it now with 2 magnaflow high flow cats, xpipe, magnaflow mufflers .could it be just the headers are to thin? would putting an lt4 exhaust manifolds help?anyone have any ideas.
thanks in advance.

Black89Z51

Did you put an infrared thermometer on them? Something is way off, either fuel or timing.

USAsOnlyWay

Is the EST wire reconnected?

If your wideband is reading correctly, which is not always the case, you should be fine AFR wise.

I think you need to mess with timing. What type of timing were you actually seeing? (Datalogging?)

If you set the timing with the EST wire disconnected, what did you set it to? I believe base timing in the computer is 6 deg. So if you set the physical timing to 12 degrees and then played around with the timing so you were giving "30" degrees at idle, you could actually be be at 36*. Same goes if you set it at 0 degrees. the computer assumes it is at base unless you tell it otherwise.

dmcisaac

ya the base timing was set with est unplugged at 6 degrees,the dynos wideband was the same reading as my cars wide band, im running 36 degrees total timing, the infrared thermometer on the manifolds was around 600 degrees

JrRifleCoach

Glowing headers is due to fuel still burning during/after exhaust stroke.
AKA late timing.

USAsOnlyWay

Sounds like you set it correctly. Are you sure the EST wire is reconnected? Sometimes it doesn't "click" and can re-disconnect causing the symptoms you are referring to.

If it is still connected, 36* advance should be more than enough. So either something is wrong there (not correctly base timed or issues with electronic spark advance.)

Additionally, it could potentially be over tightened rockers resulted in hanging the valves open.

Are all the primaries getting to a point of glowing similarly?

bjankuski

This situation sounds like retarded timing. Your power numbers are good so I am not convinced your timing is late. Are you sure you timing on the balancer matches the timing in the engine, (have you degreed the balancer to the engine)? Usually vortec heads like 30 degrees of timing (fast burn combustion chambers), is it possible that at 36 degrees of timing the engine is pulling a lot of knock retard and backing off you timing to the point of it actually being late?