12SecondTA

Alright, after a test drive with my engine guy, we designated the rattling noise i have at high rpm as ping.

The car runs pig rich, no joke, you better not light a match by the exhaust.

But either my stock hei dizzy is advancing too far, or my plug is way too hot.

I have a MSD pro billet dizzy on my shelf about to be installed.

MY plugs are fouled but the car still runs thanks to my Severely upgraded ignition.

My question si with a mallory 6a, and a MSD HVC coil, what plug should i run, i am currently being stupid running a R45TS, i was told i should run a R42TS, what is the forum recoomendation?

Sonix

iTrader: (1)

motor specs?
fuel being used?
timing at idle, and "total" timing?


use your timing light on each plug wire, to make sure they're all firing.

if you've increased compression, a stock plug like the R45TS is too hot. I'm running a R42T in mine. (the S means extended tip, which i'm not using.)
Look for a post by IHI, with a link to a website, which shows how to read your plug for heat range. It's about where the line on the ground strap is.

I don't think too hot of a plug would cause it to run rich, running rich causes it to run rich . Are you running rich to cover up excessive detonation?

flrtin1

The Champion site has a lot of good info on this plus if you follow the question links there are a lot sub links farther in with even more info

ChampionSparkplugs.com - Spark Plug 411

F-BIRD'88

If you're using a stock chevy head that would normally use a R45ts then switch to a R42t or Champion RV8C. if you have a big cam in your motor (lots of duration and overlap) You need to recurve your stock distributor to allow much more static timing at idle but the same 34-36deg mechanical at high rpm.
You need to limit the mechanical advance travel. from typical stock 20-24deg to about 12deg. (This will allow 22-24deg timing at idle) You want to limit the vacuum advance from typical stock 20 deg to about 15 at hi vacuum cruise (hiway)
You'll then be able to realign your carbs throttle plates with the idle transfer slot. (about .030" slot exposure) Remove the carb and adust the amount of idle fuel transfer slot exposure.
Unless the throttle plates are in this sweet spot the idle will be rich.
Increasing the idle timing allows you to close the throttles back down to the sweet spot and corrects the idle fuel burn time. A big cam's increased exhaust delution at idle ( egr effect) slows down the fuel burn rate at idle causing unburned fuel to go out the exhaust unless the timing is increased. this is whats fouling your plugs and causing the fuel smell in the exhaust.
replace your spark plugs as they are carbon fouled.

What cam are you using? What carb, jetting. what is the compression ratio?

12SecondTA

the cam is
.510/.544 duration @.050 234/244

Fuel is 93 octane

Carb is a Speed Demon, stock jet sizes.

Compression is 10.2:1, with a RHS Vortec head aftermarket casting, same combustion chamber.

13* initial, and i forgot the total, but the Stock HEI i think has 20-24* throw, tolerances varied, but i'm assuming its way too high, because of the pinging.

I have a MSD Pro Billet going in this weekend, gonna set initial at 18*, run it up to 36* max and go from there.

Gonna jet the carb as well, and use R42T's...

12SecondTA

thanks all, especially FBIRD'88, i am running a seemingly low initial timing to the specs i see, and feel i should have been running anyhow....

F-BIRD'88

As far as I know the RHS vortec heads should use a Vortec style spark plug same as GM L-31 vortec heads use. Use Champion RS12YC for Vortec heads.
A conventional R45TS plug does not have enough thread reach. Vortecs use a .708" reach plug. This is causing your fouling.
Further, "some" Demon carbs have a "idle eze" adjustment that allows you to add more idle airflow ( idle rpm) for big cams without haveing to open the throttle excessively. it is accessed thru the top of the carb. remove the carb stud.
If your Demon has a 3/8" vacuum port on the base, it is designed to be used with a functional PCV system. be sure to hook it up. The idle will be over rich other wise.

Your compression ratio is very high for pump gas. many vortec motors only need 30-32 deg total timing to give maximum power. only give yours as much as it really needs for total advance as you are real borderline for 93 octane gas.

12SecondTA

yikes.... i'll be replacing my bad plugs tomorow then, hopefully that will fix the rich condition for short term...

i travel 20 miles daily, and spend 20-25$ on gas each day!

Today, i had a freidn hold a lighter to the tailpipe at 3k rpm, and it shot flames, its running rich for some other reason then timing too...

F-BIRD'88

You aren't the first and won't be the last to try and use old style short reach plugs (R45ts) in vortec heads.
I think you see a marked improvement with the right reach Vortec plugs.

12SecondTA

i sure hope so, i have the correct set in my hand right now, and will be installing them after work...


Gonna get all i need, and install the dizzy sunday, with the limited advance and stuff...

it will be a nice car.

Even runing as rich as it does, its definately an LT1 killer, and i did own a '04 GTO a week ago... Running as poorly as it does, at 6500rpm it is still nice...