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 Post subject: Dist recurve for novices
PostPosted: Tue Jun 17, 2008 6:05 pm 
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Turbo Slant 6

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Location: Nelson, B.C.
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So this is fairly new territory for me but after reading some old threads it seems apparent that this is something I want to do. My '76 Dart parts car should have the donor that I will use since this sounds like the desirable core. My questions are plenty but to start with: what governor should I use; what spring choice (I have a couple old 383 and 440 distributors I can pillage) and what is the method for changing those. Finally, what is the best way to tune vac. advance? I know they have the little hex head screw inside the pod but is there a recommended method for adjustment? Any other crutial info on this treatment would be greatly appreciated. This is all for sake of torque and mileage in my lil' green wagon.

Thanks team, Pat.

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 Post subject:
PostPosted: Tue Jun 17, 2008 6:49 pm 
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I would try the green wagons stock springs in the EI dist.......

After a ton o thrashing I ended up using a stock 65 225 curve ....in a 75 dist using the 75 vac canister

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 Post subject:
PostPosted: Tue Jun 17, 2008 8:38 pm 
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Turbo Slant 6

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Location: Nelson, B.C.
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Quote:
I would try the green wagons stock springs in the EI dist.......

After a ton o thrashing I ended up using a stock 65 225 curve ....in a 75 dist using the 75 vac canister
Hmmm, I don't think I still have my original 170 distributor. Are the governor's stamped to tell what they are? Any other tips and advice to be had?

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 Post subject: Yes.
PostPosted: Tue Jun 17, 2008 9:59 pm 
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Location: Salem, OR
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Quote:
Are the governor's stamped to tell what they are? Any other tips and advice to be had?
sometimes the stamp is on the bottom of the governor (necessitating the pulling of the felt and the 'c' spring clip with a needle nose pliers to get it off)...

Most slant points distributors are an 11.5 stamp (so 23 degrees of advance as measured by timing light at the crank/balancer)...

Slant EI governors come in a variety of slots:

'15' - 1973-1975 EI distributor
'11' - 1976 EI standard distributor, and some export curves
'10' - Mopar Performance EI conversion distributor
'9' - some 1976+ distributors (like the Feather Duster, and most vehicles with the super six package, also became a standard for 1 barrel cars in the very late cars - about 1979+)

The best you can do, is try to get two similar distributors so you have one to change and one to run... (so if the curve isn't good, you can note the change and go back a step)...

The object is to get a curve that will advance fast enough to make best use of your engines potential without getting into the 'detonation zone'...

A good starting goal is to try and get the mech advance to be all the way in a bit above your cruise rpm (so if you cruise at highway speeds and turn about 2800 in top gear... try for 31-3500... so you get a smidge more when passing...)... try the points springs, a 'quick' linear formula is to swap the two 'light' springs from your 383 distributors (this usually ramps up at a moderate pace then levels out about 2300 rpm... if going for that rpm)... you can experiment with other spring kits like Mr.Gasket 925, or 928 and see if swapping just the light stock spring for a lighter spring gives you what you might want (the light spring will allow for a moderately quick advance in the low rpms, but the stock big 'stiff' spring will moderate things when the light spring runs out)...

The slant likes a bit of 'initial', so pick your governor and subtract 2 times the stamp from 30... (so 9R, would be 30-18 = 12)... so you could set your initial timing at 12BTC... I would start at 8 then work into the 12 and see what it likes...

For maximum mileage, vacc. advance is a must have.... depending on your build/compression/ gas you want to run... you will be looking to get a can that will give you the advance you need (the stamp on the arm is like the governor... so if it's an 8.5... it'll be good for 17 degrees at max vacc.)....

Best highway economy is seen in the 45-52 range (depends on build and driving style, and octane quality)... you want to pick a can that 'stays' in when you are cruising... doesn't over advance at low speeds (low rpm + high vac...), and 'leaves/quits advancing' when you stomp on it to 'pass'

Most cans are adjustable with the allen wrench in the snout... this can sometimes adjust how much it advances and/or when it comes in/for how long...depending on the make and model...

Your best buddy is a vacc. gauge hooked up to a port nearest the carb (this will see conditions similar to what your carb will 'tell' the vacc. advance from the timed vacc. adv. port).. go take a drive and note what your conditions are how is it at idle? While going light to light in traffic, while cruising the interstate (usually this is a 'range' like 14-17" Hg)....

Then you can go back and 'dial in' the vacc. advance to give you what you need when at cruise, but give less when the throttle is open more/ when passing... Check results with a drive and see if you have any ping, if so dial it back a bit and try again.

While doing this, you will also need to check your spark plugs and retue the carb a bit, since these are all inter-related once you change the timing you may have to dial the carb a bit to make sure it's still giving enough gas when it needs to...


good luck,

-D.Idiot


"Test, change, retest, change if necessary, test again...."


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 Post subject:
PostPosted: Wed Jun 18, 2008 9:17 pm 
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Turbo Slant 6

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Location: Nelson, B.C.
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Great info D.I. I look forward to putting it into practice. The idea of keeping a spare dist. on hand when doing this process is genius. I'll try and keep you posted once I make some head way.

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 Post subject:
PostPosted: Fri Jun 20, 2008 10:55 am 
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Location: Black Diamond, WA
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Pat,

After recurving the distributor I can run at 16 degrees initial which is where I get the best mileage and power. Read Doctor Dodges article on doing a distributor recurve and setting up the vacuum advance. Once the EGR is gone and the distributor line is going directly to the carb you can run alot more advance and get allot of pep out of the engine.

Here is my set up.
I purchased a new 1974 electronic distributor and re-curved it with a red primary spring and extra long looped secondary spring from a 400 big block distributor. Using the stock 15R governor (long slots) with a 11R V8 vacuum advance screwed in 4 turns. (VC-208 can $10.26 at www.rockauto.com) Blue Streak cap, MO-3000 Echlin rotor, Chrome Blaster 2 coil, Blaster 2 resistor (.85 ohm) in place of the stock resistor and 8mm Blue Summit wires. Timing set at 16 degrees initial, 16 degrees mechanical for 32 degrees plus another 20 degrees with the vacuum advance for a 52 degree total. Using MOPAR's Orange ECU. With this setup I read 10 volts at the coil at idle.

Make an EGR block off plate or get one from the dealer. #3671447 lists for $5 Dealer item, p/n 3671 447, used with standard EGR valve gasket p/n 4173 167. Mine cost less than $8.00 with tax.

These are very cheap mods and really help the performance.

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Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG


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 Post subject:
PostPosted: Sun Jun 22, 2008 10:55 am 
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Turbo Slant 6

Joined: Tue Jul 10, 2007 8:08 pm
Posts: 616
Location: Nelson, B.C.
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Quote:
Pat,

After recurving the distributor I can run at 16 degrees initial which is where I get the best mileage and power. Read Doctor Dodges article on doing a distributor recurve and setting up the vacuum advance. Once the EGR is gone and the distributor line is going directly to the carb you can run alot more advance and get allot of pep out of the engine.

Here is my set up.
I purchased a new 1974 electronic distributor and re-curved it with a red primary spring and extra long looped secondary spring from a 400 big block distributor. Using the stock 15R governor (long slots) with a 11R V8 vacuum advance screwed in 4 turns. (VC-208 can $10.26 at www.rockauto.com) Blue Streak cap, MO-3000 Echlin rotor, Chrome Blaster 2 coil, Blaster 2 resistor (.85 ohm) in place of the stock resistor and 8mm Blue Summit wires. Timing set at 16 degrees initial, 16 degrees mechanical for 32 degrees plus another 20 degrees with the vacuum advance for a 52 degree total. Using MOPAR's Orange ECU. With this setup I read 10 volts at the coil at idle.

Make an EGR block off plate or get one from the dealer. #3671447 lists for $5 Dealer item, p/n 3671 447, used with standard EGR valve gasket p/n 4173 167. Mine cost less than $8.00 with tax.

These are very cheap mods and really help the performance.
Thanks Ted, my egr is already blocked off happily. When you say to use a "red" primary spring, is this an aftermarket spring? I hope that the 383/440 long springs are the same as the 400 for the secondary, since that's what I have.

With regards to vac advance, I haven't brought this up sooner since it was mentioned earlier in a carb thread I started but the current carb I'm using is the stock BBD from the '83 motor I used as my donor. It's been said that the port generally used for VA is not timed since there was no Vac pot on those distributors. Yesterday I finally found a BBD tag # 8145S that I hope will better suit my need for any VA.

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 Post subject:
PostPosted: Sun Jun 22, 2008 11:42 am 
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Supercharged
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Joined: Mon Jan 15, 2007 5:05 pm
Posts: 3767
Location: Black Diamond, WA
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Pat,

Actually I used the red spring from the 400 distributor. Yes, I have seen them in the 340, 383 and 440 distributors. The long spring is about 2 extra coils and the loop is a little longer for more throw. On the red spring I rotated the spring post cam out to keep the spring nice and tight, no slop for a smooth transition for the long looped spring.

On the timed port, hopefully you can find a port above the throttle plates. That should do it so the advance is not full on at idle. I have seen many cars tuned using a port under the throttle plate. It makes sense why they rattle and ping and get poor mileage :!:

Let us know how it goes. :D

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Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG


Last edited by Aggressive Ted on Sun Jun 22, 2008 6:46 pm, edited 1 time in total.

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 Post subject: What????
PostPosted: Sun Jun 22, 2008 3:09 pm 
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Joined: Tue Oct 29, 2002 8:27 pm
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Location: Salem, OR
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Quote:
The long spring is about 2 extra coils and the loop is a little longer for more throw.
2 extra coils on the stock large springs limits the upper end of the curve by providing much more resistance at higher revs (to the point that the mech may not be all in even by 6000 rpm)... A longer loop only gives you more advance after the vehicle starts when the car is at idle (from 'stop' to spin the loop goes from rest to tension as far as the loop allows it to go... if you have ping at very low rpms -idle to transition circuit, you can reduce this by rotating the spring cams and not allow the loop to quickly 'free fly', by reducing the amount of travel, or ou can use a shorter loop... if you look at points springs they have no loop to them to keep the timing from bouncing around, it just provides a long smooth curve....)


-D.Idiot


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