What is the base advance curve of the Mopar Performance distributer? I have a limiting plate and the Mopar light springs to work with, and need to curve it for a 408 with 10/1 compression, EQ heads, Mothr Thumpr cam, (235/249/107 @ .050 duration). Manifold is a Rpm airgap, 1 5/8 to 1 3/4 step TTI headers. I am guessing 16 at 1,000 rpm, 34 total in at 3,000? Minnesota 93 octane BP gas.
Mopar performance distributer, as delivered advance curve?
- Thread starter gregsdart
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If it was me I would first determine what base timing my motor wants and desires and then drop the limit plate in as such to limit it it to 34/35. The light springs would be desired in most situations.
Brian Hafliger
Well-Known Member
16-18 is fine for that build...
This is a new motor, going on a Dyno for break in and tuning. What I would like to know is how much total advance is built in, and how fast it will come in. I want to get some pulls starting down low, hopefully 2500 Rpm and doen't want it too aggressive for that rpm range. Total will end up at probably 34 degrees
Thanks Brian. Will put the limit plate in restricting mechanical advance to 16, set total at 34,initial 18.
The gear ratio will have an affect. Lower ratios would need a different rpm for the advance to come in than a higher ratio.
moper
Well-Known Member
It's a crap shoot how they come out of the box. Or has been historically for the few I bought. One was shipped without the screws tightened down on the plate. I stopped buying MP some time ago. I prefer to recurve the originals.
You do not need a limiter plate for them, just find/borrow a set of keys for them with the max you want.
basically the same.
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Daves69
Well-Known Member
I believe there are some curves listed in the MP engine book for the mechanical only and vacuum advance. Not sure if it covers all MP distributors.
4secondsflat had some info at one time but the page link doesn't show it now or it's been taken down.
http://www.4secondsflat.com/Mopar_Distributor_Tech.html
4secondsflat had some info at one time but the page link doesn't show it now or it's been taken down.
http://www.4secondsflat.com/Mopar_Distributor_Tech.html
Getting info is a PIA lately on some models, I have all of the oem stuff from 51-74 on Mopar, getting into curves I can do them with oem parts then run them on the machine but give me the specs you want to run. I do like the MP and Mallorys that you can adjust the mechanical out anywhere, Accel has three points on the older, the OEM just change out the cam plate, not a big fan of welding them, Have a 426 Hemi one here right now with a tach drive I am doing and someone welded up the advance weights to the cam plate, now that was a new one, thankfully I have the parts to put it back oem. If you ever find a good site I WOULD LOVE TO KNOW IT.
67Dart273
Well-Known Member
Here's the thing............Not all MP have this setup. Some of them were built like the factory dists some had this adjustable deal which is in effect Mallory
Use the shank on drill bits and save your money on those keys. The measurements for the keys are on the boards somewhere.
IIRC, even the mallory keys aren't as accurate as they should be.
Older MP dist that use the limiter plate have a cast colored rotor tower. Mallory style advance have a bronze colored tower.
IIRC, even the mallory keys aren't as accurate as they should be.
Older MP dist that use the limiter plate have a cast colored rotor tower. Mallory style advance have a bronze colored tower.
mderoy340
Well-Known Member
When I setup my MP newer style every .009 = 1*
Thanks for the response, but I already have a new MP distributor with vacuum advance, the Mopar springs, and the limiter plate all from Mancini. Sooooooo, the only info I need at this point is how fast the advance comes in as delivered, and how much of a quick timing curve my deal will tolerate on the available BP 93 octane e10. I have some old distributors to rob springs out of should it need a lot of initial and slow curve.
it will take experimentation to get it really dialed in. every engine is different. or so I think.
T56MaxTorq
Well-Known Member
Since you're on the dyno, get the total time for your combo that provides the max power with a fuel mixture you're comfortable with. After that, if your fuel mixture is sexy throughout the whole band, then you'll have to tune by feel til it performs the way you want.
Unfortunately it's a complicated balance between ignition timing, fuel mix, load, and then how the chassis and drivetrain performs and handles that power. Change one of those variables and you likely have to tweak the others. But if you can set yourself a baseline of timing and fuel at wot, this will help will all other unknowns in the rpm band. Plot wot ign time on a graph and make a linear line to your idle time. the final result won't be a linear line but this will get you started.
I don't remember if you have one installed, but an air fuel meter really helps with tuning ignition time as well.
Unfortunately it's a complicated balance between ignition timing, fuel mix, load, and then how the chassis and drivetrain performs and handles that power. Change one of those variables and you likely have to tweak the others. But if you can set yourself a baseline of timing and fuel at wot, this will help will all other unknowns in the rpm band. Plot wot ign time on a graph and make a linear line to your idle time. the final result won't be a linear line but this will get you started.
I don't remember if you have one installed, but an air fuel meter really helps with tuning ignition time as well.
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