stinking idle on 440

[mopower440]

I have a .030 over 440 with a MP 284/484 cam installed at 104 degrees, the engine is right at 9.5:1. I have a prepped thermoquad on the car and it does great, i am very happy with the performance, but the idle stinks bad. I does not smoke at all, just makes your clothes smell bad when standing around it when idling. I have adjusted the mixture screws to where it does best so..any ideas? The timing is set idling at 20 BTDC

 

[turbine68rt]

Lean out the primary jetting? I had a similar opposite symptom with a lean idle condition.

 

[Darter6]

Not sure in your area but around here they have "Winter Blend" pump gasoline that stinks to high heaven.
Not as bad in a newer car injected with cats,but my old 88 Dodge truck with a carb no cats really stinks in the wintertime.Even fully warmed up to operating temp.

 

[mopower440]

This does it all year, i think its too rich at idle, but not sure on the TQ how to lean out the idle

 

[Jcharger]

Lean the idle. You may need to advance the initial timing to get it to idle with the leaner idle mixture. If it idles better but pings, you may need to recurve the distributor.

 

[BeepBeepRR]

Thermoquad jet kit on ebay.
https://www.ebay.com/i/221386284044...59gm2tOkSpbCJx_DD-xHfyRJg_baeIlEaAi_IEALw_wcB

 

[mopower440]

But what else is used to lean just the idle besides turning the mixture screws?

 

[RJRENTON]

IMO..
MOST Carter carbs use components in the primary booster venturii (idle feed restrictions, idle air bleeds and part of the idle fuel transition slots, immediately adjacent to the primary butterfly valves). The main metering components...rods, jets and step up piston springs...DO NOT control the idle mixture. Only the mixture screws are the only user adjustable component....everything else is via fixed non-adjustable drillings. IF the idle mixture is rich it is likely that one of the non adjustable air bleed orifices in the idel fuel feed circuit may be partially restricted. Suggest that you obtain a copy of the Thermoquad book (on line or perhaps Amazon) for a definitive explanation of how the TQ works, circuit by circuit.....very enlightening. Just my opinion of course.
BOB RENTON

 

[F4R/T]

Interesting Bob!

 

[Don Frelier]

I have the same cam in my Plymouth with a 383.
It too runs really well but it is pretty smelly.
I start it and get it out of the garage without delay.
It's going to smell no matter what you do it's just a matter of severity.
I'm not saying that there may be room for improvement.

 

[mopower440]

I have the same cam in my Plymouth with a 383.
It too runs really well but it is pretty smelly.
I start it and get it out of the garage without delay.
It's going to smell no matter what you do it's just a matter of severity.
I'm not saying that there may be room for improvement.

Is it just the nature of that cam or something?

 

[Don Frelier]

Somewhat slow ramps and a fair amount of overlap.

 

[MoparLeo]

Is this a new build and it has done this from the beginning or have you made part changes/adjustments recently and the problem started ? You say at idle you have 20° initial advance, at what idle RPM ?

 

[mopower440]

na its been like that. its idles at 900 rpm