Timming Help

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321Scamp

321Scamp

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Hey guy

My 408 is having a bit of a miss. I had the initial timing set at about 12-14 but while driving at about 60 mph ( 2k RPM ) you can hear a miss. So I turned up the idle screw up to 2k and moved the timing till it smoothed out. Which made it at about 6-8. I running the vac advance on the normal side.

My question is what is a good timing for my car? It has a comp cams xe274h. I dont know if it is just a timing issue or if i have a different gremlin.

Thanks
 
I would start by plugging the vacume advance. Than I would set idle where you want it which Im sure isnt 2000. After idle is set run your car up to 3000-3500 rpm and check timing while doing this, turn dizzy till your between 32-35, tighten it down now check your initial it should probably like somewhere between 16-19, If you have all that drive it to se how she behaves dont hook up vacume till after you drive it, Your idle speed will jump up a little when you hook vacume advance back up. If your distributor doesnt fall into these guidlines you may have to get it recurved, Im not sure what dizzy your running, but this should help you.
 
That stroker is begging for an initial timing setting of 22-24 degrees possibly more at an Idle of around 1000RPM. You should have 32-34* total timing all in by at least 2200-2400 RPM. After you get the timing situated then move onto messing with the carb tuning.

Low initial timing will make your car VERY LAZY down low and mimick the systems that you are talking about.

In this order.

1) Ignition timing
2) Carb Tuning

Then after it is running its *** off.....

3) Suspension tuning
 
I forgot to add that after i smoothed it out at 2k... it was stumbling on the hit of throttle while cruising and was acting as if it was loading up. Which i guess it very well could have been.
 
Thats probably because your initial was way too low, do the timing first than the carb,
 
Going to have to limit mechanical advance in distributor to run right at a safe total number.

Mad dart and tek have you on the right path if you follow it.

Idle at ~ 900-100
Initial 18-22

Tune the carb at those settings and see where the total finishes. It will be a BUNCH snappier off at the hit of throttle. Won't likely smell like a raw fuel spill out the tailpipes either.
 
It is loading up cause there is not enough timing in it to burn all the fuel in the cylinders.

Your method of tuning by raising the RPM to 2K by the idle circuit on the carb and then messing with the timing is not correct at all.

You need to start over in the order that I posted above. Disconnect and PLUG the vac advance. Get the car to idle at around 1000rpm and set the inital timing to say 23*. You may need to back down the idle once you bring the initial up to get it back to 1000RPM. After you do that Rev the car with the timing light on it an see how much Mechanical advance you have in your dizzy. You will know when you rev the car and the timing on the light does not advance anymore. If you are getting more than 34* you will need to re curve your distributor so it has 34 or so degrees all in at 22-2400 RPM at a Maximum, keeping your initial timing at idle 23*. This is an example but it should work out pretty darn close an wake that 408 up big time.

Carb tuning comes after you have done the above.
 
Mad Dart said:
It is loading up cause there is not enough timing in it to burn all the fuel in the cylinders.

Your method of tuning by raising the RPM to 2K by the idle circuit on the carb and then messing with the timing is not correct at all.

You need to start over in the order that I posted above. Disconnect and PLUG the vac advance. Get the car to idle at around 1000rpm and set the inital timing to say 23*. You may need to back down the idle once you bring the initial up to get it back to 1000RPM. After you do that Rev the car with the timing light on it an see how much Mechanical advance you have in your dizzy. You will know when you rev the car and the timing on the light does not advance anymore. If you are getting more than 34* you will need to re curve your distributor so it has 34 or so degrees all in at 22-2400 RPM at a Maximum, keeping your initial timing at idle 23*. This is an example but it should work out pretty darn close an wake that 408 up big time.

Carb tuning comes after you have done the above.
Click to expand...

ok thanks i will mess with it tomorrow.
 
i am also running standard 360 champion plugs. think i should go a heat range colder?
 
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