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  #16 (permalink)  
Old 03-19-2012, 05:29 AM
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Quote:
Originally Posted by Caballerokid


Here's the video of the mechanical advance mechanism. It shows the bind just near the home position. I think the thing is just shot... anyone confirm that?
The advance plate bushing is dry.

You can simply disassemble/clean/reassemble this distributor and in all likelihood be fine- the only thing that would prevent this is a worn out shaft or advance plate bushing at the top (bottom bushings almost never wear out, always have oil).

HERE'S an exploded view of an HEI distributor.
THIS is a description of an HEI rebuild. HERE is another HEI info/rebuild page.

The only tricks to taking the distributor apart is to use care removing the clip that holds the advance plate onto the distributor body, and to mark the gear as to what way it was removed so it will be reinstalled the same way so there's no issue w/the roll pin alignment. And I'd recommend using the stock advance weights and cam and not the cheesy aftermarket weights/cam.

There have been numerous threads on this if you need more info.

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  #17 (permalink)  
Old 03-21-2012, 08:25 PM
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Thanks for all the info guys! Very much appreciated! I'm going to pull out that distributor and throw in the E-Curve I bought. I'll prlly pull the old one all apart and do some playing. See if I can make her like new again or if it's just scrap finally after all those years. Thanks again guys!
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Old 03-21-2012, 11:14 PM
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my two cents... i check distributors with the springs on, it should spring quick and tight. that looked way too rusty for me. and when i time my motors i always have vacum of and pluged. rev motor to 3k and time to bout 35. i never really run the vacumm advance after. i use med springs. my motors never run hot and perform great. and i use normal hei dist. never had a fancy name brand stuff.
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Old 03-26-2012, 11:58 AM
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I got all the MSD ignition installed, the e-curve dizzy and blaster ss coil. The car runs again and the e-curve is really interesting! I set the total at 34 degrees ran the switches as follows switch 1=0 and switch 2=5 which gives me a 20 degree curve all in by 3500 rpm. So my initial timing was at 14. Then I hooked up the vacuum advance to ported vacuum and then full vacuum. Either way I ended up with 24 degrees initial and 34 total. It starts and stops fine just idles higher when at 24 rather than 14. Also the throttle is more snappy. I am finishing up the brakes currently so I haven't been able to drive it and more better tune but out of the box I love it so far. It's steady as a rock! I still notice that the vacuum need vibrates at around the 1000-1200 rpm and when lower around 700 it bounces around 4" but I think that is the chop in the cam. I have a miss or stumble off idle i think causing this. I was researching spark plugs, heat ranges, burn colors... I found this very good information I thought I'd share with everyone! I'm wondering if the plugs are slightly too cold at idle/off idle because I have never gotten a chance to really heat the motor up. I am running Delco R43T gapped at .045" they look pretty good to me but I need to do more playing. Here's the link to the spark plug info.

Spark Plug Reading
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  #20 (permalink)  
Old 03-26-2012, 02:32 PM
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Quote:
Originally Posted by Caballerokid
I got all the MSD ignition installed, the e-curve dizzy and blaster ss coil. The car runs again and the e-curve is really interesting! I set the total at 34 degrees ran the switches as follows switch 1=0 and switch 2=5 which gives me a 20 degree curve all in by 3500 rpm. So my initial timing was at 14. Then I hooked up the vacuum advance to ported vacuum and then full vacuum. Either way I ended up with 24 degrees initial and 34 total. It starts and stops fine just idles higher when at 24 rather than 14. Also the throttle is more snappy. I am finishing up the brakes currently so I haven't been able to drive it and more better tune but out of the box I love it so far. It's steady as a rock! I still notice that the vacuum need vibrates at around the 1000-1200 rpm and when lower around 700 it bounces around 4" but I think that is the chop in the cam. I have a miss or stumble off idle i think causing this. I was researching spark plugs, heat ranges, burn colors... I found this very good information I thought I'd share with everyone! I'm wondering if the plugs are slightly too cold at idle/off idle because I have never gotten a chance to really heat the motor up. I am running Delco R43T gapped at .045" they look pretty good to me but I need to do more playing. Here's the link to the spark plug info.

Spark Plug Reading
The idle being higher w/more initial advance is perfectly normal and expected. Obviously you can lower the idle to where you want it with the curb idle screw.

The slight stumble/hesitation off idle is likely an accelerator pump related problem, no big deal.

What are you using for a carb, and is it set up differently than stock? What intake are you using?

And good job on getting it so close.
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Old 03-27-2012, 07:41 AM
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Thanks Cobalt! I'm running a plain Edelbrock performer intake and an Edelbrock 600 electric choke carb. There isn't much to adjust on those but idle mixture and idle speed is there? The miss is at idle as well as off idle. The idle mixture screws are only out maybe 2 turns... I adjusted them in until I noticed the idle drop and then back out like a half turn so from what I remember about those carbs that seemed right. Idk... any better way I should be doing this or could a lean idle be causing the missfire?
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Old 03-27-2012, 12:41 PM
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On another note... does 22 or 24 degrees initial timing seem excessive if I were to leave it there? With this cam and 1.6:1 rocker arms instead of the 1.5:1. Also 10.2:1 compression... Just see'n what you guys think.

Hydraulic flat tappet
Basic Operating RPM Range 2,200-5,200
Intake Duration at 050 inch Lift 218
Exhaust Duration at 050 inch Lift 218
Duration at 050 inch Lift 218 int./218 exh.
Advertised Intake Duration 274
Advertised Exhaust Duration 274
Advertised Duration 274 int./274 exh.
Intake Valve Lift with Factory Rocker Arm Ratio 0.450 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio 0.450 in.
Valve Lift with Factory Rocker Arm Ratio 0.450 int./0.450 exh.
Lobe Separation (degrees) 106
Grind Number 274 H06
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  #23 (permalink)  
Old 03-27-2012, 02:33 PM
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Let the engine tell you what it likes as far as initial timing goes. If it's excessive, it'll be sluggish to restart when hot, like the starter was dragging or a low battery. If it's too low, the off idle performance will be sluggish and you may even get a pop out of the carb on hard acceleration right off idle.

That said, 22-24 degrees does seem a little high. But again, if the engine likes it there, then so be it. Be sure the total (initial plus mechanical) doesn't get too high, but I think you've got a good understanding of how the initial affects the total, etc. as well as how your new distributor works.

Don't be afraid to experiment! You have a safe baseline you can return to anytime things get too far out there. Likely as not, this is something you'll adjust off and on for the next good while until you hit on the sweet spot for this combination.

Be sure to do the adjustments (especially on the carb) w/the engine fully warmed up. This means like after a 10 minute drive, not just idling in the drive way for 10 minutes.

Readjust the idle mixture screws after the initial timing is changed. This is best done w/a vacuum gauge, but you can do it by ear, too. Adjust to get the highest idle where the engine isn't too rich. The way you're doing it is OK, but don't be afraid to turn them out a little more- just as long as the idle doesn't fall off on the too-rich side, obviously.

Use an extended tip plug (TS suffix) unless there's a reason you can't w/your heads. What heads are they? Fast burn chambers like the Vortec make more power w/less timing than traditional SBC production heads.
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Old 03-27-2012, 03:21 PM
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Take you vacuum gauge and hook it to engine vacuum, adjust your MB idle screws to max vac.

Also, in the future if you have vac fluctuations when the engine is running it us usually a sign of burnt intake valves or seats.

You can confirm this by performing a leak down test.
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Old 03-27-2012, 08:58 PM
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Quote:
Originally Posted by raceman14
... adjust your MB idle screws to max vac.
MB idle screws- wazzat?
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Old 03-28-2012, 12:55 AM
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Quote:
Originally Posted by Caballerokid
I got all the MSD ignition installed, the e-curve dizzy and blaster ss coil. The car runs again and the e-curve is really interesting! I set the total at 34 degrees ran the switches as follows switch 1=0 and switch 2=5 which gives me a 20 degree curve all in by 3500 rpm. So my initial timing was at 14. Then I hooked up the vacuum advance to ported vacuum and then full vacuum. Either way I ended up with 24 degrees initial and 34 total. It starts and stops fine just idles higher when at 24 rather than 14.
So the vacuum adv is adding 10 deg at idle on either ported or manifold vac?
I would say the so called ported port is not that in fact, it be manifold vac none the less.

Also at 24 initial you would most likely be bucking the starter till the cows are home, so I guess its 14 + 10 manifold vacuum adv to get the 24 initial? cant see how ported would pull in 10 at idle even with the whizz bang ecurve. odd but I am unwise to its ways.

drive it like ya stole it, (all dubious intentions aside)
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Old 03-28-2012, 07:09 AM
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Quote:
Originally Posted by cobalt327
Use an extended tip plug (TS suffix) unless there's a reason you can't w/your heads. What heads are they? Fast burn chambers like the Vortec make more power w/less timing than traditional SBC production heads.
I need to check. They are the 882 heads that I worked over in college. (for what it's worth I am also running leaded 110) They have brand new 1.60" exhaust valves, good seats (no cracks), fresh 3 angle valve job, 1.94" intake valves, port matched intake runners and some polishing done in the exhaust ports, screw in studs and newer valve guides. I did all the work myself so they were cheap... But they are still 76cc chambers. The only reason I have to look into the "TS" plugs is because I am running an 1/8" dome piston .060" over. I never did deck the block, so the piston is .040" in the hole with a .015" shim head gasket so I could get the quench back close. I would just need to make sure there isn't any interference. I'm probably ok, but I'd want to be sure. Oh Cobalt, thats the neat thing with this dizzy, I set the total timing first and the dial switches remove timing to get your initial so I set my total at 34 degrees and then with the switches moved backwards from there.

And yes Custom 10, I haven't noticed any starter bucking. I have a gear reduction starter... maybe that suppresses the bucking??? But with the dial selection I made in the dizzy, when vacuum hose is connected I get 10 degrees of vacuum advance from the e-curve. It's not dependent upon how much vacuum but simply the presence of vacuum. If I do not want the vacuum advance curve added to the timing I just simply unhook it and plug the vacuum line. That would take me back to 14 degrees initial. The odd thing is it doesn't seem to matter which side of the edelbrock carb I connect it to, I still get the 10 degrees added in to the curve at idle. Now that begs me to ask, is there something whacked with this carb? It ran fine 7 years ago... lol. Ya, I know it's been a long time but no fuel sat in it over those years and it was stored well. I probably need to go through it but that is one thing I never ever mastered was carburetors Thanks for the help!
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Old 03-28-2012, 09:55 AM
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perhaps outside the scope of the thread, but 110 octane fuel is way more than you will likely benefit from at 10.2-1 compression.
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Old 03-28-2012, 10:00 AM
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Ya but where I'm at 100 unleaded is more expensive than 110 leaded. Plus I get the added benefit of the lubrication from the lead. Once I get the brakes finished I'm going to go fill the tank and it'll be a blend of 110 and 91. With a 5 gal blend of 110 and 17 gal of 91 will give me a final of 95 octane which will prlly perfect

Last edited by Caballerokid; 03-28-2012 at 10:09 AM.
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Old 03-28-2012, 01:01 PM
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Quote:
Originally Posted by Caballerokid
The odd thing is it doesn't seem to matter which side of the edelbrock carb I connect it to, I still get the 10 degrees added in to the curve at idle. Now that begs me to ask, is there something whacked with this carb? It ran fine 7 years ago...
The ported vacuum port should be just that- ported, unless the butterflies were open so far that the ported orifice in the throttle bore was "seeing" vacuum. But I wouldn't think that would be the case, given the fairly healthy amount of initial timing you have.

If the idle mixture screws are responsive, that about negates the possibility of the butterflies being open too far. That and if the idle is otherwise OK and there's no smelly exhaust, etc. that would indicate you were into the transition circuit at idle.

Sometimes (depending on exactly where the pick up point in the throttle bore the vacuum port is fed from) there can be a small amount of vacuum present at idle from a ported vacuum port. If the Ecurve is sensing just the presence of ANY vacuum, and not how much vacuum, I suppose that could do it.

I'd just use a vacuum gauge on both ports and see what the difference is. If they were the exact same, you'd pretty well know there was a bad gasket, or some other problem w/the carb.
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