Need help adjusting timing. Whiplash cam

[Fern]

So I'm finally getting things done to the challenger.
I have a low comp 440 with a Hughes whiplash cam, I have adjusted the carb as much as possible and although it runs good, the exhaust smell is terrible. I'm thinking unburned fuel with the large cam.
I think the initial timing is set to 18. Does raising or lowering the initial timing make a difference to exhaust smell and still run right?

[JS29]

 

[Chryco Psycho]

You can play with spark plug gap up to .45 & use a hotter coil so there is a better chance of firing each cyl .
I doubt you will see any difference with more or less initial , if it likes 18* that should work well .
The cam overlap can push raw fuel through the engine & you didn't give the specs , rising idle speed will help a little also .

[MoparLeo]

Factory specs for initial advance on a stock 440,varies from 0 ° to 5 ° btdc. Look it up. Of course timing affects the fuel burn. Your eyes burning are telling you that.

[Chryco Psycho]

Yes factory specs are around 5* but that is also using a factory cam , I bet it will barely run at 5*.
This is clearly not a factory set up , so more initial advance is needed 14=18 is where I tune them , If you have longer duration , centerline at 110 instead of 114 then both the intake & exhaust valves are open together longer which allows more fuel into the exhaust unburnt .

[Fern]

If I was to bring the timing closer to 14*, will that help or hurt trying to burn the fuel?
IN all reality, I'm just trying to have the car smell less and still run well.
Thanks

[Chryco Psycho]

Try it , I bet it will be worse , hotter spark increases the chance of getting burn , less raw fuel int he exhaust

[Fern]

Try it , I bet it will be worse , hotter spark increases the chance of getting burn , less raw fuel int he exhaust

So increased timing burns better?
I'm at 18* already (will check to make sure) and think it's probably maxed out.
Will running a hotter plug make any difference?
If so, any suggestions?
Thanks
I really appreciate the feedback.
Champion RN12YC

[Chryco Psycho]

AS I said above increase the spark gap & use a higher output coil , using a hotter plug may just cause detonation

[Scooter]

Speaking of detonation, how much total timing do you have all in? 

[Fern]

Speaking of detonation, how much total timing do you have all in?

I believe all in is around 36-38.
I haven't touched it for a few years, so can't be positive.

[Fern]

AS I said above increase the spark gap & use a higher output coil , using a hotter plug may just cause detonation

Ok. I will increase gap, and look for a better coil. I believe the coil I have is a proform  coil. Not the best.

[JonH]

what carb? jets? tuneabilty? Do you have an AF ratio gauge in the car? I would attack the carb if it bothered me that much. You will always have the smell you are describing unless you put cat convertors on, and even then you may have some smell.

[HP2]

Cam specs are 107* lobe separation with a suggested 102* install.  .518 lift with 232* intake duration and 245* exhaust duration.  Intake opens at 14 btc, closes at 38* abc. Exhaust opens at 54.5 bbc and closes at 10.5 atc.  So you have 24.5* of overlap.

Hughes does state this about their Whiplash cam:
The OEM Distributors have terrible advance curves. Many go as far as 50+° advance which will cause major damage and have very poor acceleration. When you order a Whiplash cam ask for the special whiplash advance curve specs or we can supply you with a new Pertronix distributor (P/N PRT 7141700) and we will custom curve it for no extra charge.

They also add this about the cam specs:
These SMC cams have bad-to-the-bone idle, very quick stop light to stoplight acceleration! Idles like a funny car but smooths out above 1600-1800 RPM.
These cams are designed to drive better than the sound would imply. These are killer cruising cams made for low compression engines and  are designed so the cylinder pressure will not be reduced (Torque Killer!) like other cams of this size or type.

I would think for rough idle you would increase the overlap, which  would make a gassy smell, but to build power in a low compression case, you would want to reduce overlap to build cylinder pressure. Not sure how a Whiplash compares in that regard as they seem to have higher lift with lower duration than some comparable cams.

[Fern]

AS I said above increase the spark gap & use a higher output coil , using a hotter plug may just cause detonation

Ok. I will increase gap, and look for a better coil. I believe the coil I have is a proform  coil. Not the best.

Just wanted to close this out, in case someone had the same problem.
After I gapped the plugs to .45 and set timing to 13* initial and all in 34* at 2500rpm . The car smells much less and runs great.
Thanks Chryco, and every one else, for the great advice!