Need help recurving stock distro!!!!!

M

MandarinaRacing

Famous Member
Hi all. I think I'm going to have to re-curve my stock distributor. The advance is coming all the way like at 2500 rpm. I know that this is test and try procedure. I hope that all I have to do is swap springs, but I've never done this.I would appreciate any tips or pointers. I'm thinking of getting one of these kits...http://store.summitracing.com/partdetail.asp?part=CRN-99607-1&view=1

Thanks :wink:

Alex

PS: My set up consists of a DII with MSD 6A 280H cam
 
Unfortunately, that vacuum canister probably is for a V8.

The stock curve is typically very slow and comes in slowly until about 3500. Have you measured the advance to see what you are actually getting?
 
8)

Pull the breaker plate out of the bottom and see if it has two spots for spring attachment. On some of the distributors you can pull the breaker plate, carefully remove the rollpin, and swpa the side the spring is on. On my 2.3L distributor it can be changed from 23deg to 17deg. I thought someone said the 200 distributor can be shortened as well.

If Im wrong sorry. Havent disassembled mine yet.
 
that's usually correct. You should find two differnt slots. Beware, this number is distributor degrees. double the number for crank degrees.
 
Howdy Alex and All:

I just got the Sept. issue of Car Craft in the mail today and found a pretty good article entitled, "All about Advance Curves". It was with a GM HEI distributor and for a V8, but the concepts and terms are the same as with a DSII and a six cylinder. The big difference is the location of the advance weights and springs. HEI's are right on top and FoMoCos are under the stator plate- not one of Ford's "Better Ideas".

If you've got a friend to run the throttle, a tach and a dial-back-to-zero timing light, you can make a graph of what your advance cure is. It's good to know where you start. Be sure to disconnect the vacuum advance before you start.

Adios, David
 
Usually we recurve the the distributors for our hotrod sixes for 22 degrees all in at 2200 rpm. more rpm for higher comp ratios and taller gears. These motors like lots of inital timing so a well tuned distributor can yield quite a few hp. We have a sun distributor machine that we can change springs and weights right there and curve a distributor in about an hour. You have to know your motor mods, gears, trans, and vehicle weight and I can figure out a curve for you. If you want to send us your distributor we can curve it for you for $60 dollars. We also build full race 200 distributors that we machine the dist bodt and put a roller bearing up top and a bronze bushing where there is no support at the end of the shaft by the gear to stabilize it at high rpm.

Todd
 
That page gives some good info but take with a grain of salt the numbers stamped on the advance plate. They are usually within a few degrees but if they are on the plus side you will have to back off on your initial timing which will hurt your low end performance. We buy dozens of distributors from the salvage yards and I pulled two dII units and threw them on the test bench to see what they had. Both had 16 advance plates with bushings and the first actually had 33 degrees till 3000 and 30 from 3000 to 7000. The second had 35 degrees till 3000 and 32 from 300 to 7000. You have to keep in mind that an inherent trait of hall effect pickups lose 3-4 degrees after 2700 or so rpm. If you ran either one you would have to set your initial at 2-4 deg to keep under 36-37 degrees total which kills the bottom end. Lighter weights and custom advance plates let you tighten all this up and set a lot more inital and wake up the bottom end considerally.

Todd
 
How do I know how much total advance I need?
Also how many degrees of mech. adv. and how much vacuum advance I have???
I thought it was all a matter of swaping sprigns?????
Should I limit total advance???
All this is better done with the distro out of the car, but what if the set-up I choose doesn't work???
Powerbrakes, thanks for offering recurving my distro, but I can ship it to you :( . Isn't there a standard that I can work with??? I'm willing to trade off low end power for top end charge :twisted: .....

BTW my car weighs approx. 2500 to 2800 lbs. 280H cam ported flat top head, 500cfm carb, MSD 6A, MSD coil, 10.5:1 CR, 4.11 rear.

Thanks for the help :thumbup:

Alex
 
Alex,

Thats the same kit I bought to recurve mine. I had some info that the V8 vacuum advance would interchange with the I6 distributer, but they will not....They bolt on differently :cry: :cry:

I used the lightest springs on mine and full advance comes in around 2400 rpms. Base timing is set at 12 btdc and total advance is around 38 degrees. Your setup is the same as mine so it should be a good place to start :wink:

Later,

Doug
 
One quick question - when you guys are saying "38 total" you mean total mechanical, correct? Or are you counting vacuum advance in that number?
 
Initial + centrifugal + vacuum = total

How much advance an engine requires is dependent on many things, so no one setting will be correct for all engines. Normally, most engines will need between 30 and 40 degrees max under load, at full power. At cruise, under light throttle, the total may go to as high as 50 degrees.
 
Actually, total advance is only inital + mechanical. vacum is over and above the total setting. A ford dsII dist has 14 degrees total vacum advance but the amount of vacum required to get that would be 25 inches. In reality vacum advance will give you 6-8 degrees at 7 inches of vacum which is where you cruise at. Usually you have 24 or so degrees in a recurved performance distributor and 12 degrees inital to give 36 total, vacum advance gives you another 8 degrees to put you at 44.

Todd
 
The question I have is - do you really NEED to run vacuum advance? If I can dial in 36deg total (mech + initial) at 2500 RPM - what do I need vacuum advance for?
 
I personally do not run vacum advance at all. Vacum advance is just for gas mileage and is a pain to deal with. The weber combos do not have a good vacum venturi port and with a pretty wild motor you tend to get vacum from the port at idle. With no vacum advance you have a specific amount of timing that you can count on and it is the same every time.


Todd
 
Todd...

I am running a DSII on my built 200...

How long would it take you to re-curve one of these, and ship back to me...?
And what information about the buildup do you need?

I am in Atlanta GA and would consider sending you mine, instead of attempting this myself... I am running a DSII unit I bought new... but I would like to eliminate the vacume advance, and get a nice curve to fit the newly rebuilt engine.


Just thinking for now... but I am curious....
 
you guys are making me DIZZY with all this recurve talk. I am with Jimbo. If I keep my car, I would rather send it to get re-cruved. This above my skill level...a 4 out of 5 wrenches on the difficulty scale..
 
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