Join Date: Aug 2008
Location: Miamisburg, Oh.
Exhaust temps per Cylinder
So my poor Impala has been on a slow death spiral for about 2 months now. Each time I drive it somewhere (granted - not very often) it seemed to get a little worse. Slightly rough idle, and a noticeable but small backfire (poof) out the exhaust. (both at idle and during acceleration) Not super consistent, but, you can't miss it and it wasn't cool to drive.
Long story short, I was suspecting the worst out of the Blueprint 383 because that's just my luck,...BUT as luck would have it, it appears to be just bad plugs. (NGK R5672A-9 with only 1500 miles. Blueprint suggested them in their documentation)
During and after the course of checking things, I've noticed that 2 of my cylinders have what I would call a significant exhaust temp difference.
Even granting a good amount of lenience, I think they are oddly cold.
This is a standard Blueprint 383 small block chevy, I think about 10-1 CR, and torquey roller cam with something like 224/232 duration, alum heads and 1 5/8" headers.
Six of the cylinders were between 650 and 750, measuring about 2"-2.5" off the head.
Number 5 was only around 400-450 and Number 8 was way down at 300ish.
These numbers are with the engine running around 2500rpm at best guess.
Since these plugs are brand new I hope to get a good read on them, but, I'm wondering if I should get a brand-name intake manifold or am I worried for nothing?