I recently went to an end of season test and tune. I had been running a total advance of 36 degrees and reduced it to 32 degrees and the car ran about 7 hundredths quicker? I then reduced it to 28 degrees and it picked up a couple more hundredths? It is a lot easier on the starter when it's warm and at 28 vs 36 also.
I would like to know what others are running for total advance on their 500" R/B engines?
Thanks! MJ

How much is initial?

Did you verify TDC on the dampener and timing tab?
The reason I ask that is when we tested timing at the track or on a engine or chassis dyno all the RB we tested like from 34 to 36 max, the race cars would slow down in the 1/4 with 38 or 32 degrees total
That was a long time ago with stock stroke iron headed bracket motors running in Super Street.
We ran street hemi cars in NHRA stock and had the same results on both of those cars
My last pump gas 518 C.I. BB with iron and aluminum heads seemed to like from 34 to 36 degree also

Depends on the heads and the piston shape and the fuel as well as other things but typically a BB Mopar with aftermarket heads and a flat top piston will like 34 degrees of timing. Maybe more, maybe less but any new build I work on we start with 34 and work from there. 28 seems a little low for max performance so you might have something else going on with that combination.

What it likes will depend on a lot of variables like CR, quench, combustion chamber and cam timing/events. (Edit: I see Andy beat me to this..)

Mine likes 36° total on 91 no ethanol. Starts INSTANTLY and shuts off easily. That goes away when I pull 6° out for the nitrous. It is harder to start and doesn't like to shut off without running on. Eventually I will put a timing adjust knob in it for the MSD but for now I am doing it manually.

Thanks for the replies!
Here is some added info:
Yes, The TDC of the piston and timing mark was verified.
The pistons are flat tops with Indy SR heads Max Wedge type intake ports.
Running 110 race fuel and compression is 12 to 1.
MJ

My Little 383/432 Stroker

Edelbrock E Street 75cc

10.5-1 True Compression

200 # Cranking Compression On All Eight

Comp Cams XE275HL

Loves 15 Initial - 18 Mechanical - 33 Degrees Total
91 Octane No Ethanol

Indy SR heads with flat top pistons and 12:1 CR should like 34 degrees. What do your plugs look like? You might have something else going on. Maybe the wrong air fuel ratio or weak spark.

This has come up before, and I kinda took a poll on racers running timing on B and RB engines.

I don't remember anybody running less than 34 degrees total, with most running 36-38. This is with verified time marks. I also informally did this at the track, talking to Mopar racers with the same results.

If yours is running great at 28 degrees, that just doesn't sound right, in a couple of different ways.

I've been running 38 degrees for years, on a street 440, and a race 500 ci.

Good luck.

John, I know the engine Bill's running with SR's didn't really make a difference between 32 and 36 either. Other than starting easier at 32. It did go slower at 38. We made back to back passes though no dyno like most of these guys.

Joe,
Thanks for the feedback on Bill's engine. I'm a bit disappointed it didn't pick up with the 32 degrees of advance. Like Bill I've been adjusting out there on the track and watching the results. I'm going to pull a couple of plugs and share the pictures here.
John

A lot of factors go into total timing. So much that you really can't go off of anyone else's setup. AF ratio, spark plug heat range, altitude you are running at, RPM range, piston type, cylinder head and combustion chamber efficiency, and on and on and on.

I have a 500 B on alky with 13.3 compression and domes that doesn't like any less than 38 degrees total. And the domes make it want more timing from my experiences and I have ran similar setups with flat tops that want lower total, maybe not like you are seeing but in the lower 30s anyway.. If she wants to run at 28, I would run her at 28!

Mine seems to like about 36 total. I dropped it to 32 and it slowed down. Ron

FWIW my 470" low deck picked up power on the dyno when we backed it down to 32* from 34*.
I haven't put it in the car .


Mark

My 500" wedge always liked 34*. I ran several different cams in the 245* to 255* range.

Here are the # 1 ( right ) and # 2 ( left ) plugs right after the last run at 28 degrees total advance. I had gone back up to 32 degrees and slowed a bit and then back to 28 degrees and picked back up.
Thanks for the replies!
MJ

Can’t see the timing marks on the ground electrodes with those fuzzy pictures

But it’s running rich

It's rich and the plug looks hot. That's why it likes less timing. He is pulling timing to keep the plug from overheating, rather than let the plug function like it was designed.


I've seen that my entire life.

Mine runs 15-1, flat top, 4.5 bore, -1 head. 114 renegade fuel. 32 degrees. Any more timing does nothing for ET or MPH. It's run as little as 28 degrees. Barely killed .10 in ET.
Doug

A most efficient highly developed all race N/A motor on good quality high octane race gas will like less timing than a conventional bracket or Stock super Stock like motor will, I'm talking about Pro Stock and Comp Eliminator motors that like a BSFC in or lower than .32 Lbs. per hour
On your deal with those spark plugs it looks like pitting and blistering on the porclyn and way to hot on the heat range as well as rich on the AFR