Ignition Timing

After reading Mike Canter's spark plug article I am wondering what is a good starting point for ignition timing on my combo? alcohol 440 Chrysler, around 11.5 compression, 871 tipped/stripped, 18 over 16lbs boost, street style alum wedge heads. We have started testing it with 30 degrees. I know 30 is safe so far. Has anybody started with a similar combo and more advance?

Gary Sylvester

 

Thats a pretty mild combination.

I was running standard canted BBC heads (iron), 505 CID, with a 10-71 and 22 Lbs of boost with 36 degrees of timing.

BUT, I was also running a Super Mag 3. I have found from research on the net, that the MSD Pro Mags have circuitry in them that prevent them from retarding at higher engine RPM, unlike the Super Mags, which retard with more RPM.

With alky, just keep leaning it down and upping the timing and watch the plugs closely.

 

It is mild. First blown combo I have built and I would like it to live a while. I am running a Super Mag 4. The cam is low lift and set for 7000rpm. The thing seems to have some decent power for what it is, even at 30 degrees. Of course I am coming from a 11.00 second car. I will sneak up on the tune up. Thanks for the input and any other info you folks have.
Gary Sylvester.

 

i ran that same combo about 30 years ago
stay around 34° and you will fine with the mallory
i ran it to 38° a few times
we found when you get up on the power and you will start cracking the block
clys thru main webs

 

Rule of thumb used to be a 440 wedge head liked about 4 degrees more timing than a comparable Hemi, alky liked about 4 degrees more than gas on normally aspirated. Agree with John, 34 should be plenty safe for your combo, you could sneak up a degree at a time until you reach the point of diminishing returns then back off 2 degrees, then start leaning in small steps. If you're running a steel block, it won't take much detonation to, at best, get into main cap walk, at worst, put some pieces in the pan.

 

alky 440

We run a very simallar setup.It would be alot quicker to call me.Have been running it for 3 years now.There is another guy that runs a set up very close your's also. I will look for his info.Home # 608 872 2117 cst eves.Hope I can help.

 

Cuda Customs, I will take you up on that and give you a call one evening. I have heard about the cracking block problems. I understand that can happen even with upgrades installed. I have installed a bed plate to help out. It is a cast iron block. Some guys have told me the higher the static compression the less timing you should run. The 34 mentioned sounds safe I will work my way up slowly. How do the stock steel cranks hold out? Ok, some of you are laughing now! That's ok, the plan is to step up to a Hemi as soon as dollars permit. Until then we will beat up on the stock stuff. It is interesting to hear that similar combos were run years ago. I figured it was rare to see a blown Chrysler wedge with the big Chevy working so well.
Gary Sylvester

 

Good stock steel cranks can take a far amount of abuse, especially if you're running a lighter rod and piston assembly and keep the rpms's reasonable, but you might want to keep the timing closer to 30, and check the crank and block for cracks on a regular basis, it's better to keep it together and running until you're ready to step up to the Hemi later on. What are you running, fast brackets????? quick 8???? What ET expectations are you looking for? Good looking car, btw......

 

Hi Guys,
We run a little old 383 wedge here in Australia in an altered. We have run as high as 36 on timing but that showed signs of detonation. We get 8 to 10 runs out of cranks before they are cracked and we test these every 4 to 6 runs. Our timing was run with 75cc combustion chambers and 9 to 1 compression. The main caps walk and more timing doesn’t help that. 14/71 on top with 2% od. Have run a best of 7.5 at 170mph. Try to keep it nice and mild.

 

Wicked, another Chrysler wedge and it's a 383. Now that is rare to see.
23T Hemmee, I see why you like the car, that is a cool ride you have there too. Our car is new so it has only seen testing so far. We have a little 1/8 mile track 2hrs away for fast bracket racing. 4hrs away there is two NHRA tracks in Div 6 (Mission and Ashcroft British Columbia) for the Top Comp or Top Dragster fast bracket. And until just recently we planned for trips to Spokane for their alcohol funny car deal that actually paid some dough to show and it was heads up (top 8 qualifiers). Our first time out with the car went well and I was pretty happy considering I have never driven a center steer blown car before. First time building one too. Anyway, we ran 5.21 @ 133mph 1/8 mile. That was 30 degrees, fat, 16lbs and at 7000 feet corrected. That run usually equates to a low 7 @ 190 ish at the local 1/4 mile tracks (much closer to sea level). Lot's of variables though so we won't know for sure until next season.
I have been helping a friend with a 427 in a digger that is very similar to mine an it has run 7.01 @ 204. That little Chevy does that with used up pistons, cast iron heads/block and a junkyard dumptruck crank.
Gary Sylvester