Headers not hot on 2 and 8

[curse]

What could be a cause of numbers 2 and 8 header pipes not getting hot. All other cylinders are getting over 300 degrees. 2 and 8 are only making it to around 114 degrees. Compression in all cylinders is 135-145 psi. When I put the timing light clip on the spark plug wires it flashes so I assume it's getting spark. Plugs are new. Would a bent valve cause this? It does not run smooth.

 

[PrairieDrifter]

What's the condition of your motor? Oil burner? Fresh rebuild? Freshened up?

 

[Snoots]

Gotta make certain those cylinders are firing.

 

[bucket]

Are #2 and #8 wires swapped?

 

[Joshua Keith]

Pull 2 and 8 plug and see if they already fouled. Could be running rich

 

[WFO]

Did you check the distributor cap, plug wires and boots?

 

[curse]

What's the condition of your motor? Oil burner? Fresh rebuild? Freshened up?

Low miles crate motor. I was told about 25000 miles. All I did was replace all gaskets.

 

[curse]

Are #2 and #8 wires swapped?

I don't think so but will double check today.

 

[curse]

Did you check the distributor cap, plug wires and boots?

All new. Maybe I will swap wires and see if the condition follows the wires.

 

[HotRodPC]

You should be able to hear an obvious miss in the engine if 2 cylinders aren't firing for whatever reason. If the firing order is correct, then I'd start at the plugs and check to see if they're bad or fouled. Then maybe bad or burnt plug wires on the headers, then next to the cap and rotor but you've said they're new so that shouldn't be the problem. I'd lean toward 2 and 8 are in wrong position as bucket mentioned, or the plug wires are burnt on the headers if it's a healthy engine.

 

[curse]

So I switched #2 and #8 wires with each other and all header tubes were over 350 degrees and it ran really smooth until I took it for a ride. I think the ride possibly jostled a bad wire?? I think I'll replace plug wires

 

[Raider L]

@curse,

And look at better routing as well. Get some wire looms with those stand off's to get the wires up off the header tubes.