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  #16 (permalink)  
Old 10-26-2010, 11:32 PM
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I have my idle adjusted at 800 in neutral which drops it to 600 in gear . I didn't notice if you had a standard or auto trans. If it is an auto adjust your idle in neutral so that it is 600 in gear and I think you'll be happier with that . As for the 3 turns . Cliff said that is about right with a Holley because they have a coarser adjustment . I had been playing around with 2-1/2 turns and it just wouldn't smooth out , so I just started turning them out together a 1/2 turn at a time until it smoothed out . Then I ran them back in (one at a time) and then backed them out the same turns to make sure I had them both at the same place . ( I had a vacuum gauge hooked up the whole time) I then very slowly turned them in until I could hear it get just a little rough and the vacuum drop ever so slightly and then backed out 1/2 turn from there . When I rechecked to see where I was that's when I found out I was at 5-1/2 turns and called Cliff . Now my 355 idles like it has fuel injection . No Kidding ! It is that smooth !

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  #17 (permalink)  
Old 10-27-2010, 09:21 AM
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Quote:
Originally Posted by BlenderHead
it's an auto, i've only checked it in park, i'll have to try N and D and get back to you.

as far as total ignition timing, I really don't even know how to do that. Could someone tell me how to set total ignition timing, or total advance, I only know how to set initial timing at idle. I have a standard GM HEI ignition., thanks.
Connect timing light.

Rev engine to about 3000 RPM.

Read the all in total advance.

Adjust total advance less than roughly 36* unless you really know your stuff.
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  #18 (permalink)  
Old 10-27-2010, 09:34 AM
How fast is fast enough?
 
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8 to 12 is not enough. I'd try about 15-16 degrees initial. 36 total as already noted. A vacuum canister was installed as oem equipment on a LOT of cars, and still is. Get one out of a junk yard and hook it up to your manifold. Total cost is like $5, and it'll never hurt, can only help.
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Old 10-27-2010, 09:54 AM
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Quote:
Originally Posted by ap72
8 to 12 is not enough. I'd try about 15-16 degrees initial. 36 total as already noted. A vacuum canister was installed as oem equipment on a LOT of cars, and still is. Get one out of a junk yard and hook it up to your manifold. Total cost is like $5, and it'll never hurt, can only help.
The 36 degrees total is good and I am there with 14 degrees of initial , but set yours at what it takes . BUT , the vacuum cannister is NOT for vacuum advance . It was installed for the vacuum controlled accessories such as the air doors on the HVAC . There is a check valve in the cannister and if you run your vacuum advance off of it , you would always have full vacuum at the distributor and that is NOT what you want .
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Old 10-27-2010, 10:14 AM
How fast is fast enough?
 
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If you remove the check valve and just connect it to the manifold you'll see it dampen a shaky vacuum gauge.
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  #21 (permalink)  
Old 10-27-2010, 10:18 AM
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Full dist adv vacuum is good on some engines.
Can affect idle quality,temp, timing, and starting.
I run full vac on cammed engine.
Full vac won't hurt.
Excess tot adv can hurt.
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  #22 (permalink)  
Old 10-27-2010, 11:28 AM
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Quote:
Originally Posted by 001mustang
Full dist adv vacuum is good on some engines.
Can affect idle quality,temp, timing, and starting.
I run full vac on cammed engine.
Full vac won't hurt.
Excess tot adv can hurt.
True enough , but you wouldn't want a check valve in there because you would sure get detonation under hard acceleration .
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Old 10-27-2010, 11:30 AM
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Quote:
Originally Posted by ap72
If you remove the check valve and just connect it to the manifold you'll see it dampen a shaky vacuum gauge.
True enough . I guess I missed where you said to remove the check valve . My bad .
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  #24 (permalink)  
Old 10-27-2010, 11:46 AM
How fast is fast enough?
 
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Quote:
Originally Posted by adantessr
True enough . I guess I missed where you said to remove the check valve . My bad .
Most of the time its not integral, you don't have to remove anything, just omit installing it. That is on the ones I use which mostly come from s10s and Blazers.
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Old 10-27-2010, 11:58 AM
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Quote:
Originally Posted by 001mustang
Connect timing light.

Rev engine to about 3000 RPM.

Read the all in total advance.

Adjust total advance less than roughly 36* unless you really know your stuff.
How do I read the all in total advance? Do you mean with one of those timing lights that has the dial on the back of it, cause I just have a regular one with no dial.

and then how do i actually adjust it? by turning the distributor the same as initial timing?

I've read tons of magazine articles that talk about setting or adjusting "total" advance, but not once have I ever seen anything that says how to actually do it. so this is why I'm still a bit confused.
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Old 10-27-2010, 12:05 PM
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Quote:
Originally Posted by ap72
8 to 12 is not enough. I'd try about 15-16 degrees initial. 36 total as already noted. A vacuum canister was installed as oem equipment on a LOT of cars, and still is. Get one out of a junk yard and hook it up to your manifold. Total cost is like $5, and it'll never hurt, can only help.
15 to 16 degrees? if that much is required, then why does the little timing tab on the side of the timing chain cover only go up to 12 (or maybe 14)? It's definitely not made to read 16 deg btdc. Do you mean with vacuum advance hooked up to full manifold vacuum? cause I thought you were supposed to set initial timing with vac adv disconnected.

and again, hopefully you guys can help fill me in on this, but I still have no idea how to set or adjust that 36 degrees you guys keep talking about.

and yes, I do have the original vacuum canister, i had apparently pulled it out of the car when i did the engine swap, but i can put it back in. i'm not sure where it hooks up though, do i just run a hose from the carb to the canister?

thanks again for help and info..
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  #27 (permalink)  
Old 10-27-2010, 12:11 PM
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Quote:
Originally Posted by adantessr
The 36 degrees total is good and I am there with 14 degrees of initial , but set yours at what it takes . BUT , the vacuum cannister is NOT for vacuum advance . It was installed for the vacuum controlled accessories such as the air doors on the HVAC . There is a check valve in the cannister and if you run your vacuum advance off of it , you would always have full vacuum at the distributor and that is NOT what you want .
ok, 14 sounds better,

so does the vacuum canister have any effect on the carb or ignition.. or is it only for those air doors on the hvac?

thanks
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  #28 (permalink)  
Old 10-27-2010, 12:16 PM
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Quote:
as far as total ignition timing, I really don't even know how to do that. Could someone tell me how to set total ignition timing, or total advance, I only know how to set initial timing at idle. I have a standard GM HEI ignition., thanks.
Your tab is designed for a stock cam, performance cams need more timing.
There are three things to focus on

1) base timing or initial timing
2) mechanical advance- added by increasing engine RPM
3) vacuum advance- added subtracted by engine load/vacuum

The mechanical and vacuum advance levels need to be limited, a stock HEI will add too much typically.

IMO Just to get started on a proper HEI setup will require some more info/work on your part if you can get to it.

You want to cover all the bases starting with these steps as it will ensure that your efforts pay off:

Determine TDC:
http://www.crankshaftcoalition.com/w...op_dead_center

Make a timing tape for your balancer:
http://www.crankshaftcoalition.com/w..._a_timing_tape

Get a good timing light, and a good vacuum gage.

I would say that setting the base timing to about 16 deg BTDC would be a good place to start for this cam, set it there. Then rev the motor to 3500 (parking brake on & vacuum adv disconnected) and see what the total (base + mech) advance is, also note the RPM that the advancing timing stopped or maxed out, it may take 4000 rpm it may take 3000, typically you want all the mech advance in by approx 3000, vehicle weight,rear gears, tranny/torx conv have allot to do with this all in number of RPM. You can now determine what the mechanical advance is adding.

Hook up the vacuum advance now at idle on manifold vacuum and note the timing with an idle below 800, then rev the motor again 3500+ and note the total timing, you can then determine what the vacuum advance is adding, chances are it will be adding 20+ deg

Then take the car/truck for a spin with a vacuum gage tee'd into manifold or ported vacuum with the vacuum advance can hooked up, record the vacuum levels at various speeds/load conditions

The previous steps will prepare you for the work ahead, write down your findings:

Start by pulling the dist, clean it up good and check for excessive wear, dirt, grime, check the cap, rotor etc,,,this is a good bit on the HEI:

http://www.rustynutscarclub.com/HEI.htm

If your HEI is worn out then just get a new one, these are good and value is excellent:

http://skipwhiteperformance.com/deta...x?Item=6500-GY

Let us know what you find and post the numbers, chances are that you will need at the very least a vacuum advance limiter plate to limit the vacuum advance, this will fit either the stock HEI or the new version:

http://www.summitracing.com/parts/CRN-99619-1/

To get the mechanical advance curve set right and provide a way to set the range or rate of vacuum advance + the limiter plate:

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

the crane 99600 does not provide a way to limit your mechanical advance, only a set of springs to set the curve, the limiting of mechanical advance on a stock HEI is accomplished in many ways, one being bushings or some form of homemade stopper. The kit does include the adjustable can, a vacuum adv limiter plate and a set of curve springs.

My advice would be to forgo the rebuild of a stock partially worn HEI and get the one I linked, it comes with an adjustable vacuum advance and the mechanical limit can be set with a simple machine screw & nut, just add the crane limiter plate for about the same cost as adding other parts to the stock unit

The procedure to set all this up 2 follow...its really not that difficult
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  #29 (permalink)  
Old 10-27-2010, 12:53 PM
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WOW , that is some very good detailed info. thank you very much, no one has ever explained it that well before. and yes, the distributor is kind of old, so i should get a new one.

thanks again for that awesome detailed explanation.
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  #30 (permalink)  
Old 10-27-2010, 12:57 PM
How fast is fast enough?
 
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You want your vacuum advance conected to ported, your canister connected to the manifold. Set your timing with the vacuum advance disconnected and the reconnect it when done.
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