So this weekend I adjusted the valve lashing for the first time on my 3tc. I quadrupled checkef everything so I know its set to what BRD racing(cam manufacturer) told me to set it at. Maybe its because I've never looked before but I'm really paranoid. Is it nornal for the header to glow at idle? Its dim enough you can only see it at night. All thats done to it is the stainless steel header, 3" straight pipe to a single chamber borla, and a mild cam. Since I adjusted the valves its running better than ever at idle though. Do you think its because its not getting any air to cool it down or do you think my timing might be a little off? It sputters(mis?) at idle when its warming up?

super lean conditions. and at idle its probably you have your valves too tight that they are slightly open maybe?

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I have a Metric S&!T ton of Datsun/Toyota parts pre 82 let me know if you need anything,

73 rb25 240z, body Bracing, cage, paint in progress.
78 Cressida Body, Paint, and 2jzgte in progress.

Ignition retard is more than likely the cause. Advance timing and check results.

Wouldn't advancing the timing make it worse?

Glowing normally means your not getting enough fuel I thought. Could you just adjust a carb a little to get more fuel at idle? I may be wrong here, just trying to give ideas since I ditched my carb awhile ago.

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Carb or efi, ignition timing principles are the same. Excessive ignition retard that burns late enough to push much of the combustion out the exhaust, causes an afterfire. But excessive advance (coupled with lean conditions) would go through the intake, and backfire. No doubt, there is more than one situation that can cause glowing exhaust at idle. But ignition retard is a very common one.

The cold-start misfire points to a lean condition. Obviously fuel needs to be adjusted first, but keep in mind engines (especially with modified valve events) tend to idle in their happy zone at all different afr's. One of my mill's is very happy at 19+:1 at idle. Granted, unless you can read inside the chamber, trying to obtain afr's at idle with an unrestricted exhaust and lots of overlap doesn't produce very accurate readings.

Given the information provided, I would start by verifying the cam install, and record the opening/closing and checking it against the specs. Then, the fuel mixture and on to ignition timing. Call the cam manufacture and obtain their recommendations for your combination. Mechanical, fuel, timing... always in this order. Then drive and watch afr's and knock.

If the header is still glowing, I would check the primaries with a IR thermometer, it could be that the wall thickness is thin enough to put off a glow in dark conditions.

CH2

just kidding... i'm done