# Advance Curve Springs



## Bensjammin66 (May 12, 2009)

In the sticky thread "GTO Tuning and Setup Tips" it says to try out Mr. Gasket Kit # 928G and to run the gold springs. 

Question #1: The spring hoops that slide over the studs in the distributor favor the top or bottom side of the center coiled section. So how should these be installed? So should they be installed with the center section of the spring up or down? The ones that were in there the outer hoops came right out of the middle of the center section of spring so there was no up or down... 

Question 2: The gold springs say they are the heavy ones in the kit. Has anyone actually ever used these from that sticky tuning thread? 

I found this link showing the spring weights and advances. 

The Studeblogger: Spring has sprung.


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## Bensjammin66 (May 12, 2009)

Just got off the phone with Mr Gasket Tech line. 
Gold is stiffest, silver is medium and black is lightest. 
A Google search shows LOTS of success with the gold springs in GM HEIs using the GM weights it came with. Ill give it a go, time it and post my results. 

Mr Gasket said it doesnt matter which way the springs go in, but center section down made most sense to me looking at it.


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## Lemans guy (Oct 14, 2014)

Ben you can mix me for a good advance curve as well try one medium and one light....


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## Bensjammin66 (May 12, 2009)

Lemans guy said:


> Ben you can mix me for a good advance curve as well try one medium and one light....


Im told with the stock weights dont use the lightest springs cause they will fatigue really quick. I am going to try the two golds and time it, then a gold and a silver and finally two silvers and see what they bring me. Id like 36 degrees in by 2800-3000. 
I can get the timing all in pretty early cause my motor is an aluminum headed 10.75:1 setup, i always fill up on 93 or 94 octane plus add about a gallon and a half of 110 mixed in it just for the smell so no worries on detonation. Ill see what i can come up with and what it likes and hopefully shine some light on what works well with a stock GM HEI unit.


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## geeteeohguy (Feb 2, 2008)

OEM install is with the center section of the spring facing _up_, with the 'tabs' on the bottom, so it can't drag. (Stock points type distributor).


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## Bensjammin66 (May 12, 2009)

geeteeohguy said:


> OEM install is with the center section of the spring facing _up_, with the 'tabs' on the bottom, so it can't drag. (Stock points type distributor).


How about an HEI any ideas? It doesnt look like itll hit anything but who knows once the weights really start spinning around.. Should i try them up instead you think?


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## geeteeohguy (Feb 2, 2008)

Whatever works.....they were installed originally with the bulk of the spring facing up...if clearance isn't an issue, it really won't matter.


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## Lemans guy (Oct 14, 2014)

Ben to get that curve down low I doubt those two heavy springs will do it. I have a sun distributor machine and it usually takes the lighter & medium springs on stock dizzy to get em under 3000. But it depends on weights and such. 

For the most Lighter springs faster the curve comes in, weights matter of course....


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## Bensjammin66 (May 12, 2009)

okay so I put the gold springs in and got to try the new setup out yesterday. 36 degrees in by about 3300rpm but WOW what a difference. Not sure if its the new headers or timing curve but the car is kinda dangerous at 3/4 throttle now. Zero traction and it makes rpm almost 2x as quick as before. Holy hell did this motor just wake up! Not sure if I wana mess with it any further its running A1 now


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## Lemans guy (Oct 14, 2014)

That is great, with a setup that strong and a curve under 3300, you will get great throttle response and at the low end which these Pontiac engines love.

What are you doing with your Vacumn advance? You want that right as well..

Base Vacumn and certifiable all contribute to the car being responsive and cruising smooth, accelerating right etc....


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## Bensjammin66 (May 12, 2009)

Lemans guy said:


> That is great, with a setup that strong and a curve under 3300, you will get great throttle response and at the low end which these Pontiac engines love.
> 
> What are you doing with your Vacumn advance? You want that right as well..
> 
> Base Vacumn and certifiable all contribute to the car being responsive and cruising smooth, accelerating right etc....


Well so far its just capped off. I have about 14 base timing and 36 total. I plugged in the advance and it shoots to like 50 degrees at part throttlw! I know they sell adjustable ones and limiters but im totally new to all that. So far so good, the car doesnt hard start and it runs like a raped ape. Think I should still play with the vac advance?


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## Lemans guy (Oct 14, 2014)

Ben ....if you drive on the street you want vac advance....

Set up right it will give great throttle response and cruising, will also help gas mileage without effecting top end speed. Here is the simple version. Timing has 3 parts all equally important. When you eliminate one leg the stool is not so good.

A race car track car, that drives from stop to full pedal down, vac advance can be eliminated, but you get way more throttle response with a lot less pedal angle.

Base timing is where you set it when you turn the dizzy.
Vac advance comes from the demand of your accelerator, thru Vacumn.
Centrifugal that's the weights and springs is ONLY RPM dependent.

Your car will not only be more powerful but lots smoother too.

What should your timing be at light throttle cruise, say 60 mph?

52 degrees BTDC......with your setup 36 is the total...way less powerful and inefficient at light throttle .......uses more gas too.

Top end pedal down has no Vacumn, so 36 is what you want, need and get...

You need more advance at idle and light throttle cruise because the mixture is not as rich, throttle plate is mostly closed, that 52 BTDC fires that leaner mixture with a very light pedal....

A 10 degree base timing
A 16 degree vac advance that comes in early
A 26 degree centrifugal advance

Hooked to full manifold vac at idle will give you 26 BTDC at idle and 36 total advance (vac advance is not considered a part of Total advance) 

Your car will run cool at idle, respond quickly, lose no top end, and give better mileage. You can move those numbers a little just keep the total at 36...

So like 12 base and 24 centrifugal and 16 vac.....still is 36 total and 52BTDC at light throttle cruise....


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## Bensjammin66 (May 12, 2009)

Right now for 36 total i am about 12-14 initial, to back that down to 10 initial i need more mechanical advance to hit my 36 total. Changin weights etc. Is there a specific weight kit you know of that puts numbers to the weights or is it trial and error?


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## Lemans guy (Oct 14, 2014)

Ben, you can keep that 36 total wit 12 or 14 whatever it is. Now you just need to put in a Vac advance can that will give you 14 or 16 more from the vac can.

Crane sells an adjustable vac can and limiter plate so you can adjust it. The limiter plate will limit the amount of advance the vac can can give and you turn the Allen fitting inside the vac can to adjust when the can comes in. 

So you want 8 degrees on the dizzy vac can adjustment which is 16 at the Crank.

16 will give you the 52 and about 28 at idle. Any knocking at idle retard it a couple degrees on the limiter. Keep 36 total base & weights....

You can change the weights but you have to block the travel of the dizzy springs to drop back the total there...

Some aftermarket dizzy' shave an easy adjustment for that stuff.....

My 326 runs with 26 BTDC at idle smooth as silk, 10 base, 16 vac.....

52 degrees at light throttle cruise gives me 14.7 AFR on both exhaust pipes barely touching the gas......:Scottwax1:


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## Bensjammin66 (May 12, 2009)

Which of these two would suit me best to limit the vac advance the easiest? The cam plate is recommended by many but the accel one says it has adjustability for both rate and amount of advance. I plugged mine in last night, no good. It adds AT LEAST 25 degrees. I have 12" vac at idle and about 22" at light throttle. 

http://www.summitracing.com/parts/acc-31035/overview/

http://www.summitracing.com/parts/crn-99600-1

Here are the instructions for the Accel Kit. 
http://prestoliteperformance.com/me...structions_vacuum_advance_points_v8_31034.pdf

Seems like 3 clockwise turns from fully out would give me 10 degrees advance between 10-20" of vacuum.


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## Lemans guy (Oct 14, 2014)

I have used the crane and not the accel, but I am sure you could use either. The Accel seems to limit the advance by controlling amount of vacumn and thereby how far it pulls the lever....

I guess it works rate of vacumn at the same time....

The Crane uses the limiter plate to mechanically block the lever on the vac can and the allen adjustment is rate of vacumn applied...

factory vac cans come in different set rates, say they start to open at 8 hg and are fully opened at 10hg etc.

the accel if it works as described would seem easier to adjust with everything hooked up....

but the crane is good as well.

main thing is to get that amount right, like the 16 degrees at crank that you need.....


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## Bensjammin66 (May 12, 2009)

So I picked up the Accel kit and a new MSD cap and rotor from summit last night. (Benefit of living 20 mins away from there Ohio headquarters) 
The Accel kit is very easy to use and limits the total advance degrees with an allen key through the port hole. Its only about 50 degrees here near Cleveland but i couldnt get the car over 140 degrees idling in the garage this morning where normally my electric fan bounces it between 170 and 185 regardless of outside temps. 
75mph in 5th gear on the way to work it wouldn't go over 120 degrees!! What a difference it made on cruising temps. Highly recommend the Accel kit. Though their instructions are a little off... The graph makes it look like 4 clockwise turns is 12 degrees. At least with my car making 11-12" at idle it was more like two turns added 12 degrees.


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## Lemans guy (Oct 14, 2014)

Ben you should see great idle temps as well, if you added 12 vac and have it all pulled in at full manifold vac, with your base at 14 that is 26btdc at idle it will run cool...

If it pings retard it 2 degrees at a time till it quits....

It should take it and once you adjust your idle mixture for that advance you will get a smooth idle and nice smooth acceleration.

Radical cams with low Vacumn can be dealt with by making vac can come in at low Vacumn....

You should notice a difference all through your idle and driving, and no top end power loss...

I might have to try one of those Accelerate cans!:Scottwax1::exclamation:


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