73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: Got Smoke? on August 21, 2011, 09:40:13 pm
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Ok so I was performing a tune up of sorts on my 79 this weekend. I purchased new plugs (ac delco), 8mm Auto Zone house brand wires, a vaccum advance, and a Mr. Gasket recurve kit.
Truck was running fine before I started I was just hoping to improve efficency a little....it seemed to be liking the gas a little to much lately. :D
I replaced the vaccum advance with just a stock replacement. I found out that mine wouldn't hold vaccum on a pump the other day when trying to find total advanced timing.
Next I installed the kit from Mr. G and everything was still moving freely even though the new bushings for the weights were a little snug. I used the black springs in the kit as they had the lowest and widest curve according to the graph and my motor does not see high RPM's. I then replaced each plug and wire one at a time to ensure no crossed wires.
I took the truck out on a test run and if just giving enough throttle to ease down the road its fine, but if you give it a lot of throttle try and accelerate quickly it feels almost like your holding the brake and pressing the gas at the same time? It will power on through whatever is holding it back...but it takes A LOT of throttle to do so enough for me to know somethings wrong. After coming back and finding the vaccum advance unhooked ::) I took it out for another test run, same effect. I tried swapping the lowest curve springs for the the middle of the three sets of springs...still no change.
The basic timing is set at 6* since I have a small 268 Competition Cam, it idles fine and you can even free rev it fine but once you start trying to drive its evident. Can someone point me in the right direction? Hoping I don't have to replace this distributor, the stock parts I pulled out were junk and not reuseable even if it did run ok.
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firing order, did you make sure its still 6 deg of timing?
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parking brake ;D
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firing order, did you make sure its still 6 deg of timing?
Did plugs and wires one at a time so no crossed wires. Correct firing order still
Also still certain on timing double checked.
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parking brake ;D
Disc swap on the cheap, no parking brake.
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the only thing i can think of is the vac advance
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Its either vacuun advance or timing. If you didnt tighten the distributor enough it could have turned on you
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Its either vacuun advance or timing. If you didnt tighten the distributor enough it could have turned on you
Well I know its not the basic timing...I checked and double checked it. I will put my vaccum pump on the new advance and see if it holds vaccuum tomorrow. I was getting a little >:( the other night and things only get worse when I get >:( so I called it quits.
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I had similar issues with a Moroso recurve kit in my MSD distributor. I messed with it endlessly and then eventually took it to the local hotrod shop and had them pull the dist and put it on the machine. Some of the aftermarket center plates and weights are the wrong shape/rate, and at a certain rpm they stop advancing and actually retard your timing. They kept the Moroso weights but replaced the center plate with the one they use, which they kept a secret. Put the old stuff back in to confirm if that's the problem. I have heard that the stock weights and center plate are about as good as it gets, so maybe try just swapping the springs until you find something your motor likes. All in too late makes a slug, and all in too soon makes it puke at high rpm.
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Also I would run at least 10 if not 12 degrees of initial advance.